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Block 4 – Haematology Learning Objectives Arunan Sriravindrarajah The following lecture objectives were ordered thematically TABLE OF CONTENTS Haemopoiesis and Haemoglobin ............................................................................................................................ 3 Haemopoiesis and Stem Cells ................................................................................................................. 3 Role of Haemoglobin in Oxygen Delivery to Tissues ...................................................................... 4 Anaemia .................................................................................................................................................................. 5 Introduction to Anaemia ........................................................................................................................... 5 Megaloblastic Anaemia............................................................................................................................... 7 Iron Deficiency .............................................................................................................................................. 9 Auto-Immunity in Haematology ........................................................................................................... 10 Caring .................................................................................................................................................................... 10 Caring 1 – What Does Care Mean and How Can We Evaluate What We Are Doing? ....... 10 Caring 2 – Compassionate Care – Can it be Taught? .................................................................. 11 Caring 3 – Communication Near the End of Life – The Virtues in Clinical Practice .......... 12 Caring 4 – Who Cares for Whom? Narratives of People Who Are Dying .............................. 13 Haematological Cancer ......................................................................................................................................... 14 Leukaemia – Pathogenesis and Pathophysiology .......................................................................... 14 Leukaemia – What you Need to Know ............................................................................................... 15 Leukaemia – Bench to Bedside ............................................................................................................. 17 Lymphoma – What Is It? ........................................................................................................................ 18 Introduction to Chemotherapy.............................................................................................................. 20 Stem Cell Transplantation ...................................................................................................................... 22 Bleeding Disorders ................................................................................................................................................ 24 Physiology of Coagulation – Platelet and Clotting Factors ......................................................... 24 Acquired Bleeding Disorders .................................................................................................................. 26 Benefits and Complications of Treating Haemophilia ................................................................... 27 Blood Products in the Treatment of Disease ................................................................................... 28 Thalassaemia + Malaria ........................................................................................................................................ 29 Thalassaemia ............................................................................................................................................... 29 Prenatal Diagnosis of Thalassaemia ................................................................................................... 31 Epidemiology, Pathogenesis, Management, Diagnosis and Vaccination of Malaria .......... 32 Common Parasitic Diseases ................................................................................................................... 33 Approach to Infective Fever ................................................................................................................... 35 Clotting Disorders ................................................................................................................................................. 37 Thrombosis ................................................................................................................................................... 37 Thrombophilia.............................................................................................................................................. 39 1 Anticoagulant Medications ...................................................................................................................... 41 Diagnosis and Management of Pulmonary Embolism .................................................................. 43 Seminars ............................................................................................................................................................... 44 EBM – Role of Radiation in Leukaemogenesis ................................................................................ 44 EBM – Critical Appraisal of Diagnosis of DVT and PE ................................................................... 44 Medications in Pregnancy........................................................................................................................ 44 Death and Dying ........................................................................................................................................ 45 Services to the Elderly ............................................................................................................................. 46 Doctor, Child and Family ......................................................................................................................... 47 Molecular Diagnostics in Haematology .............................................................................................. 48 Ethics of Prenatal Diagnosis ................................................................................................................... 48 Video Presentation – Transfusion Practice ....................................................................................... 48 Case Presentation – Haemophilia and Von Willebrand Disease ............................................... 48 Practicals ............................................................................................................................................................... 49 Laboratory Skills – Full Blood Count and Coagulation ................................................................. 49 Laboratory Skills – Group X-Match ..................................................................................................... 49 Interpreting Abnormal Blood Counts / Films ................................................................................... 50 Interpreting Laboratory Tests in Bleeding Disorders ................................................................... 51 Interpreting Laboratory Tests in Anaemia ....................................................................................... 51 Imaging in Haematology ......................................................................................................................... 52 2 HAEMOPOIESIS AND HAEMOGLOBIN HAEMOPOIESIS AND STEM CELLS Understand the principles of haemopoiesis including cell types and classifications - Haemopoiesis refers to the formation of the components of blood All cellular components of blood are derived from Haematopoietic Stem Cells; they give rise to the following Progenitor Cells: o Lymphoid Progenitor Stem Cells (from which B-Cells and T-Cells develop) o Myeloid Progenitor Stem Cells (from which Erythrocytes, Platelets / Megakaryocytes, Basophils, Eosinophils, Neutrophils and Monocytes / Macrophages develop) ‘Stem Cells’ will mature into ‘Progenitor Cells’, which then mature into ‘Mature Cells’ (also known as ‘Effector Cells’) o Mature Cells will each have a different purpose / function within the body There are two different models of Stem Cell differentiation: o Stochastic – differentiation involves the cell immediately splitting into a Committed Progenitor Cell (specific type of Committed Progenitor is random) o Instructive – differentiation will involve the cell splitting into an Uncommitted Progenitor that will only develop into a Committed Progenitor after receiving a specific instruction / signal - - Distinguishing the categories of stem cells, progenitors and mature cells - ‘Haematopoietic Stem Cells’ (HSCs) have the following key characteristics: o Multipotentiality – HSCs can mature into a range of different cell lineages o Self-Renewal – Ability to divide into two cells yet remain the same (via asymmetrical division) HSC will divide into the same HSC as well as the differentiated progenitor cell This enables the quantity / level of Stem Cells to be maintained whilst also ensuring the production of sufficient quantities of the subsequent cell lineages ‘Progenitor Cells’ develop from HSCs but have a restricted differentiation potential o These cells are not able to differentiate into all components of blood, but only a specific subgroup (depending on the type of Progenitor Cell) o These Progenitor cells may have the ability to engage in self-renewal (although this is not always the case ‘Mature Cells’ will develop from Progenitor Cells, and are the end components of blood (e.g. Erythrocytes, Platelets / Megakaryocytes, Basophils, Eosinophils, Neutrophils, Monocytes / Macrophages, B-Cells and T-Cells) o Mature Cells will each have a different purpose / function within the body (e.g. Platelet – Clotting, Erythrocyte – Oxygen Transport, Eosinophils – Protection vs. Parasites, etc.) - - Understanding the types of controls and feedback mechanisms that determine cell fate and function e.g. cytokines, the stem cell niche, microRNAs - Haemopoietic Regulators (e.g. IL-3, GM-CSF) can have a variety of different effects on haemopoietic cells (e.g. proliferation, lineage commitment, maturation, etc.) o For example, the cytokine EPO will stimulate proliferation of certain parts of the RBC maturation pathway) Both Direct and Indirect Feedback loops that affect haematopoietic cells are present within the body o Indirect feedback loops are present within the body that influence the particular Mature Cells developed (e.g. Sensor in the kidney will detect oxygen levels in the body and will correspondingly send a signal to the Liver to increase / decrease production of EPO this will impact on the level of Erythrocytes in the body) o Direct negative feedback loops are also present in the body (e.g. higher levels of Neutrophils will result in lower serum G-CSF, which will lower the level of Neutrophil production, higher levels of Platelets will inhibit TPO, which will lower the level of Platelet production, etc.) - 3 - - ‘Stem Cell Niche’ refers to a microenvironment where stem cells are found, which interacts with stem cells to regulate cell fate (e.g. maintain in quiescence vs. self-renewal / proliferation) o There are several different factors that regulate stem cell characteristics within the niche (cell-cell interactions between stem cells, as well as interactions between stem cells and neighbouring differentiated cells, interactions between stem cells and adhesion molecules, extracellular matrix components, etc.) For example, there is a Haemopoietic Stem Cell Niche within Bone Marrow that inhibits the Stem Cells from exiting the bone marrow and travelling through the body o These niches integrate signals that mediate the balanced response of stem cells to the needs of the organism) MicroRNA is important in differentiation of Haemopoietic Stem Cells into its different daughter types Understanding the concepts of pluripotency and cell reprogramming - ‘Pluripotency’ refers to a Stem Cell with the ability to differentiate into any tissue in the body (except Placenta) o ‘Cell Reprogramming’ refers to the ability to convert one specific cell type into another specific cell type o ‘Direct Cell Reprogramming refers to inducing a mature cell to ‘undevelop’ back into a Pluripotent Stem Cell (which can then be redifferentiated into the various types of mature cells) o Techniques have been developed in recent years to enable Cell Reprogramming The development of Induced Pluripotent Stem Cells may enable the development of any tissue in the body (which can be used for treatment of diseases / injury, etc.) - Outlining some principles of cellular therapies and clinical manufacture of cells - ‘Good Manufacturing Practice’ for Cellular Therapies is a strong commitment to quality assurance is critical to provide safe, quality, effective treatment to patients; this will apply to all steps of the manufacturing process, including: o Collection o Processing (including cell selection, cell expansion, cell product formulation) o Treatment / Storage Using a more elastic culture substrate (compared to glass / plastic) will increase the lifespan for Haemopoietic Stem Cells outside the body (as this is more realistic / akin to the situation within the body) - ROLE OF HAEMOGLOBIN IN OXYGEN DELIVERY T O TISSUES Discuss the oxygen delivery system to the tissues - Oxygen delivery / supply to individual tissues depends on blood flow to the tissue (i.e. Cardiac Output) and oxygen content of the blood (as well as the fraction of CO in the blood) o The blood flow / oxygen supply to specific tissues will be inversely related to the resistance of that tissue to blood flow o Anything which reduces Cardiac Output will also reduce oxygen supply to tissues Oxygen content of blood will depend on lung function (which depends on ventilation and gas exchange) as well as the oxygen carrying capacity of blood (i.e. Haemoglobin levels) Note: Oxygen uptake by the tissue depends on the partial pressure of the oxygen in the tissue, on diffusion distances to the cells and a variety of factors which alter the affinity of haemoglobin for oxygen in the tissues - Discuss the structure and function of haemoglobin 4 - - - The function of Haemoglobin is to bind oxygen at the lungs and deliver it to the tissues and also bring the carbon dioxide by-product of oxidation back to the lungs for excretion in the breath Each molecule of haemoglobin has four haem groups, each associated with a protein chain (i.e. globin), as well as a total molecular weight around ~64,000 o The four haem groups each consist of iron atoms surrounded by a porphyrin ring o The four iron atoms are in the ferrous (Fe 2+ ) oxidation state and bind the four oxygen molecules (O2) with different affinity according to the order of attachment of O2 to each iron atom (positive co-operatively) Three substances (protons, carbon dioxide and 2, 3-diphosphoglycerate) are physiologically important because they encourage oxyhaemoglobin to deliver its oxygen to the tissues o Higher pCO2, lower pH (i.e. increased acidity), higher temperatures and higher 2,3diphosphoglycerate will decrease the affinity of oxygen to haemoglobin (and hence promote delivery of oxygen to the tissues) NOTE: The ‘Content’ section of the Compass page for this lecture has a lot of relevant information (http://smp.sydney.edu.au/compass/teachingactivity/view/id/5824) ANAEMIA INTRODUCTION TO ANAE MIA Introduce the topic of anaemia to medical students - ‘Anaemia’ is a reduction in red cell number and haemoglobin concentration in blood o This will result in a reduction in the oxygen carrying capacity of blood o Note: Anaemia is NOT a diagnosis (i.e. specific disease) but rather a common clinical problems resulting in a variety of signs / symptoms Sometimes there are no symptoms in Anaemia, but this will vary depending on the circumstances / general health of the patient, speed of onset and severity of the Anaemia o The symptoms that do occur are non-specific Tiredness SOB Chest pain Palpitations Headaches Dizziness o In contrast, Pallor (either conjunctival or palmar creases) can be a useful sign of Anaemia o Cardiac decompensation (e.g. Tachycardia, CCF, Postural Hypotension) are also signs of Anaemia o The following are specific signs for iron-deficiency Anaemia Angular Stomatitis Glossitis Koilonychia (i.e. spoon-shaped nails) Jaundice The underlying cause of Anaemia will either be: o Decreased production of RBCs; o Increased loss of RBCs; and /or o Increased destruction of RBCs Major categories of Anaemia are: o Bleeding o Deficiency Anaemia (e.g. Iron, Folate, Vitamin B12) o Haemolytic Anaemia o Anaemia due to Chronic Disease o Anaemia due to Primary Bone Marrow Pathology (this will cause other cell-lineages to be affected too) - - - 5 - Treatment of Anaemia will involve treatment of the underlying cause (e.g. replace Iron, Vitamin B12, Folate in deficiency Anaemia, treat chronic condition in Anaemia of Chronic Disease, etc. Note: The most specific test for Iron deficiency is a reduced Serum Ferritin level o However, Ferritin is an Acute-Phase Reactant, so levels may be normal or high when there is an iron-deficiency (due to another inflammatory process inflating the Ferritin level) Illustrate basic morphological features of erythropoiesis - MCV (Mean Corpuscular Volume) has a normal range of 80-100fL; this can provide an indication of the cause of the Anaemia (which is important as Anaemia is NOT a diagnosis) o Underlying causes of Microcytic Anaemia (MCV <80) include: Iron Deficiency (usually due to chronic blood loss) Thalassaemia o Underlying causes of Normocytic Anaemia (MCV of 80-100) include: Acute Blood Loss Chronic Disease Primary Bone Marrow Pathology o Underlying causes of Macrocytic Anaemia (MCV >100) include: Vitamin B12 Deficiency Folate Deficiency Haemolysis Liver Disease Drugs (e.g. Hydroxyurea) Reticulocyte Count provides a measure of the bone marrow response to the condition (e.g. Anaemia) normal range is 20-100 x 10^9/L o Reticulocytes are bigger than RBCs and will reduce in size as they mature into RBCs o Reticulocytes will also have a bluish-hue due to the presence of residual RNA within them o The level of Reticulocytes can provide an indication of the cause of the Anaemia: Increased Reticulocytes are associated with Haemolysis or Acute Haemorrhage Normal or reduced Reticulocytes are associated with Deficiency, Chronic Disease or Primary Bone Marrow Pathology Anaemias ‘Hypochromic RBCs’ will have increased % of pallor (i.e. white area) within the RBC ‘Target Cells’ in Blood Film suggest liver disease; these RBCs have a dot in the middle of them (which make them appear like a target) ‘Spherocytes’ are smaller, completely circle-shaped RBCs (rather than being oval-shaped); this can be an indication of Haemolysis ‘Sickle Cells’ involve sickle / crescent-shaped RBCs (which die after only ~10-20 days rather than the normal ~120 days; this will result in Anaemia) ‘Rouleaux’ involved RBCs being stuck together (as viscosity of blood is high); this is commonly observed in Multiple Myeloma ‘Leukaemia’ will involve the presence of excessive number of large immature RBCs (i.e. Myeloblasts) Note: Presence of White Cell in Blood Film is useful to provide a scale to compare the size of surrounding RBCs o Size of White Cells typically do NOT change very much compared to RBCs which can vary significantly in size - - Explain essential features of normal red cell metabolic processes - Erythropoiesis commences with a Pro-Erythroblast before maturing (in the following sequence) into a Basophilic Erythroblast, Polychromatic Erythroblast, Pyknotic Erythroblast, Reticulocyte and finally Erythrocyte o Each stage of progression will involve the cell becoming smaller in size o All the Erythroblast stages will possess a large central blue / purple area (i.e. DNA-filled Nucleus) o Erythrocyte will have a clear central area (reflecting the ejection of the DNA-filled nucleus from the cell) 6 - Haemolysis of RBCs will result in increased Bilirubin and Lactose Dehydrogenase levels (as these are released from within the RBCs) o Haptoglobin levels will also reduce as the free haemoglobin from the RBCs will bind to (and remove from measurement) Haptoglobin o Other changes include increased reticulocyte count and polychromasia (due to more ‘baby’ RBCs being produced to compensate the destruction of RBCs) and the presence of Spherocytes and Haemosiderinuria MEGALOBLASTIC ANAEMI A Understand the nature and cause of ‘Megaloblastic Anaemia’ - ‘Megaloblastic Anaemia’ is a blood disorder marked by the appearance of very large blood cells with an arrest in nuclear maturation o There are a large number of immature and incompletely developed cells o These megaloblastic red blood cells do not function like healthy red blood cells and crowd out the healthy cells, causing anaemia ‘Megaloblastic Anaemia’ is caused by impaired DNA synthesis; this can be triggered by o Deficiency of Vitamin B12 (i.e. Cobalamin) and / or Folate o Abnormalities of vitamin B12 or folate metabolism (e.g. Transcobalamin deficiency) o Other defects of DNA synthesis (e.g. congenital enzyme deficiency) Characteristic blood film for ‘Megaloblastic Anaemia’ includes: o Oval macrocytes o Anisocytosis / Poikilocytosis o Hypersegmented neutrophils (>5 lobes) Very large macrocytic RBCs (i.e. MCV >115-120) are likely to be related to Megaloblastic Anaemia rather than Normoblastic Anaemia Management of Megaloblastic Anaemia will involve giving replacement therapy of Vitamin B12 and / or Folate o Initial replacement will always be BOTH Vitamin B12 and Folate (never provide Folate alone) o Subsequent replacement will be based on test results o Note: Vitamin B12 is best provided via Intramuscular Injections, whilst Folate can be provided orally o Note: Patients with Pernicious Anaemia and / or Ileal Resection will need these supplements for life - - - Understand the sources, absorption and causes of deficiency of Vitamin B12 - Vitamin B12 (i.e. Cobalamin) is an essential coenzyme for DNA Synthesis, Metabolism of Fatty Acids (and some Amino Acids) as well as Energy Production (i.e. Kreb’s Cycle) o This is found in animal products (e.g. meat, fish, dairy, etc.) and is not affected by cooking o The body has stores of ~3-4 years of Vitamin B12 (i.e. Cobalamin) Appropriate metabolism of Vitamin B12 requires: o Adequate Dietary Intake o Digestion and Absorption; this includes requiring: Gastric Acid (to release Cobalamin from food) Pancreatic Proteases (to release Cobalamin from R-proteins) Gastric secretion of Functional Intrinsic Factor [IF] Ileum with functioning Cobalamin-IF Receptors o Transport in Plasma In plasma, ~20% of Vitamin B12 is bound to the active form Transcobalamin II (which transports Cobalamin after being absorbed in the Intestine to the cells that utilise Cobalamin) The other ~80% is bound to Transcobalamin I and III, though these have no identified role in Vitamin B12 metabolism o Intracellular Enzymes Deficiencies in Vitamin B12 (i.e. Cobalamin) may be due to: - - 7 o o - Inadequate dietary intake (e.g. Vegan, Pregnant Vegetarian) Inadequate release of Vitamin B12 from food; this may be due to: Gastrectomy Chronic Atrophic Gastritis / Achlorhydria, H. pylori Medications (e.g. Proton Pump Inhibitors) o Inadequate production of Functional IF Pernicious Anaemia Gastrectomy Hereditary abnormality of IF o Terminal Ileal Disease inhibiting absorption (e.g. Coeliac Disease, Ileal Resection, Crohn’s Disease) o Competition for Intestinal Vitamin B12 (e.g. Fish Tapeworm) o Transport Abnormalities (e.g. insufficient Transcobalamin II) o Inadequate Utilisation (e.g. Drugs that inactivate Vitamin B12 such as NO) Pernicious Anaemia involves a severe lack of intrinsic factor (IF) due to autoimmune disease affecting gastric parietal cells o This is associated with other organ specific autoimmune disorders (e.g. Hypoparathyroidism, Addison’s disease, Thyroid Disease) o There is a familial association with Pernicious Anaemia o Classic signs include: Prematurely grey hair Northern-European Lemon-yellow skin (due to jaundice) Shiny / beefy red tongue Mentally slow and broad-based shuffling gait Atrophic Gastritis o Diagnosis can be via: Presence of Intrinsic Factor antibodies Presence of Gastric Parietal Cell antibodies Understand the sources, absorption and causes of deficiency of Folate - Folate is a coenzyme in transfer of carbon molecules between compounds (e.g. Purine and Pyrimidine synthesis, amino acid interconversion) o This is found in most foods (highest in liver and yeast, also in green vegetables and nuts), but is destroyed by cooking o The body only has stores of ~3-4 months of Folate Folate is absorbed in the proximal / upper small intestine (i.e. at the Jejunal microvilli) and absorbed via an Active Carrier Mediated Transport (reduced folate carrier) and concentration dependent diffusion o After transportation from the small intestine, Folate storage within cells requires its Polyglutamation o This process requires Vitamin B12 and hence Folate and B12 and closely linked Deficiencies in Folate may be due to: o Inadequate intake (e.g. lack of fresh food, alcoholism, etc.) o Malabsorption (e.g. Small Bowel Disease [e.g. Coeliac’s Disease], Alcohol abuse, etc.) o Increased requirements (e.g. Pregnancy / Lactation, Malignancy, Hyperthyroidism, etc.) o Defective utilisation (e.g. Anti-Folate Drugs [e.g. Methotrexate]) o Hereditary conditions - - Understand the pathophysiology of the clinical syndromes caused by deficiency of Vitamin B12 or folic acid - Deficiency of Vitamin B12 and / or Folate will inhibit DNA synthesis, and hence will inhibit all rapidly growing (i.e. DNA synthesising) tissues (e.g. bone marrow, epithelial surfaces, etc.) o Vitamin B12 deficiency (NOT Folate deficiency) will also result in neurological damage in adults (due to demyelination) 8 o - - - This is due to the role of Vitamin B12 in Fatty Acid Metabolism, which is needed for the synthesis of the Myelin sheath surrounding neurons Megaloblastic Anaemia will involve the bone marrow attempting to increasing RBC production to counter the anaemia o However, the quality of the produced RBCs is low resulting in increased RBC turnover (which leads to higher bilirubin and LDH) Vitamin B12 and Folate are closely linked (as Vitamin B12 is needed for the storage of Folate after absorption) o Vitamin B12 and Folate deficiency are difficult to differentiate and may coexist, so always evaluate for both o Serum Folate levels rise in B12 deficiency as the cell is unable to convert THF Monoglutamate into THF Polyglutamate (as this requires B12) and hence the Folate will exit the cell back into the Serum Serum Homocysteine levels will be elevated in true Vitamin B12 and / or Folate deficiency this can be a useful measure when the serum Vitamin B12 and / or Folate levels are equivocal o Similarly, Methylmalonic Acid (MMA) serum and urine levels will be elevated in Vitamin B12 deficiency (but NOT Folate deficiency) IRON DEFICIENCY Understand the pathophysiology of the clinical syndromes caused by deficiency of iron - Iron in the ferrous form is an essential component of haemoglobin, and is responsible for binding oxygen in a pocket between the globin chain and the porphyrin plate o Daily red cell production requires 20 to 25 mg Fe2+ but only 1 to 1.5 mg of iron is absorbed each day from the diet o Iron balance therefore requires the quantitative re-utilization of iron from red cells being broken down at the end of their life (i.e. after ~120 days, the RBCs are consumed by Splenic Macrophages which recycle the iron from the RBCs for use in the rest of the body) Iron is absorbed by a selective process in the duodenum and jejunum and is transported in the plasma, bound to Transferrin, and transported to the bone marrow o Iron needs to be converted to its reduced form (i.e. Fe2+ and NOT Fe3+) prior to absorption in the duodenum o Red cell precursors have plentiful Transferrin receptors that allow the selective uptake of iron for incorporation into haemoglobin Most (65%) of the iron in the body is contained in haemoglobin, followed by 30% stored as Ferritin in the liver o 2mL of blood contains approximately 1mg of iron (i.e. equivalent to the average daily intake) o As a consequence, maintaining iron balance is a critical process that is easily upset by increased blood loss Iron deficiency is the commonest cause of anaemia world-wide, and the commonest cause of iron deficiency is excessive blood loss, although poor dietary intake or malabsorption can contribute o Iron deficiency leads to deficient haemoglobin synthesis, manifest as the production of Microcytic, Hypochromic red blood cells o Iron deficiency will also involve low Serum Iron, raised Transferrin, low Transferrin Saturation, low Serum Ferritin, and absent marrow iron stores Low Ferritin levels will be specific for iron-deficiency (though normal or high Ferritin levels cannot be assumed to indicate normal iron levels, as Ferritin levels can be raised due to inflammation) Note: Low Serum Iron with normal or raised Ferritin is NOT iron deficiency Iron deficiency is common in pre-menopausal females due to the cumulative effects of menstruation, pregnancy and lactation o In post-menopausal females and in males, the commonest cause of iron deficiency is gastrointestinal blood loss High dietary sources of iron include Liver, red meat, fish, poultry, peas and beans - - - - - 9 - Treating iron deficiency simply requires the administration of adequate doses of oral iron, usually in the form of slow release ferrous sulphate tables (Ferro-gradumet) (note: Parenteral iron is rarely required) - NOTE: The ‘Content’ section of the Compass page for this lecture has a lot of relevant information (http://smp.sydney.edu.au/compass/teachingactivity/view/id/4692) AUTO-IMMUNITY IN HAEMATOL OGY Understand the pathogenesis and principles of management of organ specific autoimmune diseases, using autoimmune gastritis as example - Auto-immune diseases occur when there is a breakdown in self tolerance and collectively are the third commonest cause of morbidity and mortality o They are precipitated by interaction of the environment with the genetically susceptible o Transient auto-immune responses can occur following inflammation, but only persist if there is a genetically susceptibility Common features of auto-immune diseases include: o Genetic predisposition o Female preponderance o Chronic fluctuating course o Presence of autoantibodies o Response to immunosuppression Auto-antibodies can develop against normal tissue (e.g. auto-antibodies against Gastric Parietal Cells in Pernicious Anaemia) o These auto-antibodies will damage / destroy the normal tissue resulting in pathology o Damage / destruction can be via complement cascade, antibody-dependent cell cytotoxicity, receptor blockage, receptor stimulation, immune complex deposition The main treatment for these autoimmune diseases is immunosuppression (e.g. corticosteroids, alkylating agents, monoclonal antibodies / biological agents, etc.) and / or IVIG o Furthermore, enzymes / vitamins can be provided as a supplement if these are affected (e.g. Intra-muscular Vitamin B12 supplementation in Pernicious Anaemia) - - - CARING CARING 1 – WHAT DOES CARE MEAN AND HOW CAN WE EVALU ATE WHAT WE ARE DOING? Articulate the nature of care - ‘Care’ is the provision of what is necessary for the health, welfare, maintenance, and protection of someone or something The nature of ‘care’ encompasses both behaviour and motivation o Behaviour refers to the actions undertaken by the health professional o Motivation refers to the attitude / approach undertaken by the health professional Have an awareness and knowledge about one's need for care - Caring is the expression of our humanity and it is essential to our development and fulfilment as human beings o Patients need care as this will affirm the value and significance of themselves, protect and encourage human dignity and provide a way for patients to express their feelings Understand the difference between care for friends and family and clinical care 10 - Clinical care is unique due to the circumstances of the interaction (i.e. patient is sick / weak / helpless, large information / power imbalance, dependence of patient on doctor, etc.) o Patients are seeking their clinician to connect with them and make them feel like they can rely on / trust the clinician Know what patients want from their caregivers - There is a distinction between curing an illness vs. healing / caring for a patient o It is important that doctors provide healing / care instead of just cures for the specific disease, as this more holistic approach is what patients desire / need (especially in circumstances of chronic disease, end-of-life, incurable diseases) o Patients want health caregivers to display ‘good qualities of humankind’ such as kindness, compassion and gentle care o Patients want to be loved, valued, affirmed, nurtured as human beings Spiritual care permeates all aspects of care we need an awareness of our own spirituality, and be aware of our own distress, losses, vulnerability and mortality - CARING 2 – COMPASSIONATE CARE – CAN IT BE TAUGHT? Understand what people who are dying want from their caregivers - A caregiver who cares about them personally (i.e. ‘high touch’) A caregiver who has expertise, including subspecialty, high-tech expertise with access to high-tech palliative care It is important for medical professionals to exhibit the appropriate body language to build a sense of trust with the patient (rather than simply being seen as the bearer of bad news) - Understand the importance of maintaining morale in people we are caring for - Terminally ill patients and / or patients in significant pain can become very depressed and forlorn at their predicament o Helping the patient set small, achievable goals can give them a sense of purpose, which can provide them with the motivation to continue o Maintaining this morale is very important to the patient’s well-being (which includes not only physical but mental status too) Acknowledge different ways of learning about compassion in others and ourselves - Music, art and literature can assist in helping understand what patients are feeling Articulate the meaning of empathy and its use in clinical encounters - ‘Empathy’ involves feeling what the patient is experiencing (i.e. imagine yourself into the other) o This will help understand the patient better and provide them with better care o Conversation with patients assists medical professionals to develop empathy “for it is here that we learn of shared experiences and feelings” Patients appreciate most a sense of connection / feeling that the doctor really cares about them o The human element of medicine (i.e. compassion, empathy, etc.) is what is most important to patients - Know what an illness narrative is and understand its power - Cultural / social norms that exist around death (including discomfort with death) can contribute to a sense of isolation / loneliness amongst those who are dying Medical professionals need to bridge these barriers and overcome this ‘illness narrative’, as patients will have an improved experience if they feel connected (rather than isolated) - 11 CARING 3 – COMMUNICATION NEAR T HE END OF LIFE – THE VIRTUES IN CLINICAL PRACTICE Outline common challenges in end of life care communication - Common challenges in end-of-life communication include: o Breaking bad news o Denial (which can be experienced by not only the patient and their family, but also by other doctors / nurses who continue to seek curative treatment [despite the condition being impossible to cure / treat]) o Collusion (i.e. family and medical staff withhold truth from patient) o Difficult questions o Emotional responses (e.g. anger [at themselves, medical staff, etc.], distress, etc.) Understand skills to use to overcome these challenges - Skills needed to overcome these challenges include: o Introduction o Contracting o Listening o Reflection o Clarifying o Exploring o Summarising o Closing Explain what happens to people experiencing a major loss - There are a range of different models regarding the response to major loss, such as : o ‘Five stages of grief’ (i.e. Denial, Anger, Bargaining, Depression, Acceptance) o Alarm, Searching, Mitigation, Anger, Gaining a New Identity o Shock, Pain, Sadness Generally, the different stages in response to a major loss will be: o ‘Facing the threat’ this will trigger emotions such as fear, anxiety, shock, disbelief, anger, denial, guilt, humour, hope, despair, bargaining o ‘Being ill’ diminution of intensity of all emotions (depression/sadness is common) o ‘Acceptance’ Acceptance will result in the patient feeling secure in themselves and their circumstances ‘Acceptance’ is difficult to achieve / reach; instead, a lot of people experience ‘Resignation’ - Articulate the various tasks of the clinical encounter near the end of life - Tasks in the end-of-life clinical encounter include: o Transfer of information (especially ‘bad news’) o Anticipation of problems and rehearsing responses o Reassurance Vulnerability / helplessness is common amongst seriously ill patients, and so it is important for the doctor to treat the patient in a manner which helps them resolve their confusion / anxiety and enables them to feel more secure o Encouragement and hopefulness Outline the virtues that may be of value in clinical practice - Trust / Honesty 12 - o Offer the worst and best scenarios o Never extinguish hope o Take responsibility for mistakes and apologise Compassion (distinguish from pity, empathy and mercy) Practical wisdom (i.e. ‘Phronesis’) Justice (i.e. fairness and equity) Fortitude (which is co-extensive with courage) Temperance Integrity Note: Neither party should impose their values on the other overriding another person’s values is an assault on their humanity and their person Know about personal limitations of care - Limitations of care include: o Scientific limits o Technical limits o Personal limits It is important to understand there are limits to one’s capabilities and that failure to recognise / stop at these limits will have adverse consequences for the individual o Spiritual limits o Ethical limits CARING 4 – WHO CARES FOR WHOM? NARRATIVES OF PEOPLE WHO ARE DYING Outline the main points of empathy, theory of mind and attachment theory in relation to caring - ‘Empathy’ is the capacity to enter the subjective world of another (i.e. their lifeworld) o This involve feeling as the other person is thought to feel ‘Theory of Mind’ is an understanding of one’s own mind and those of others o The more social interaction, the deeper a person’s understanding of others’ thoughts and feelings ‘Attachment Theory’ involves the understanding the approach people have to interpersonal relationships; these include: o Secure these people feel secure in the presence of their caregiver o Insecure – Avoidant these people are compulsively self-reliant (i.e. others can’t be relied on) o Insecure – Anxious these people are clingy / anxious in nature (as they lack faith in their own ability to cope) - - Understand the nature and quality of care received by people near the end of life - what was good and what was not so good - Patients generally felt cared for by: o Doctor’s communication style (e.g. politeness, touch, rapport, bedside manner) The ‘look of caring’ in the eyes of a doctor was an important way for a doctor to communicate caring to the patient o Feeling valued, heard, respected (i.e. not patronised or made to feel inadequate) Patients will feel cared for by their doctor if the doctor takes the time and effort to get to know them as individuals (rather than being a ‘number in the system’ or a disease) o Doctor’s perceived manner & intentions (i.e. clarity, honesty, tact) o Feeling part of the doctor’s team (i.e. included in decision making and their opinions sought) Competence was communicated to a patient by considering not only the physical illness of the patient but other aspects of the patient too (e.g. psychological, social, etc.) - 13 - o Consistency and continuity of care was also important for establishing competence However, there were poorer experiences in the quality of care such as o Poor continuity of care o Time waiting and / or rushed appointments with doctor Therefore, avoid looking like you don’t have time (e.g. check watch repeatedly) as it will make the patient uncomfortable Aim to direction the conversation in a manner that doesn’t make the patient feel rushed Most patients will end up talking themselves out and stop speaking after a certain time o Arrogant, dismissive approach of doctor (rather than humble and collaborative) o Lack of empathy for patient (especially regarding the embarrassment / pain of particular treatment options) Understand what patients who are dying think about their doctors - Patients empathised with and cared for their doctor; this included concerns about doctors: o Being overworked o Facing unrealistic demands from patients o Lacking support for their own needs / vulnerabilities o Note: Family members of patients did NOT share these concerns consistently Explore the importance of reciprocity - ‘Reciprocity’ involves responding to a positive action from someone else with a positive action towards them this has important implications for the patient-doctor relationship o Patients will develop more trust and comfort with doctors who act positively towards the patient (and will feel more ‘cared’) o Conversely, patients will withdraw and become hostile in response to doctors who show disregard for the patient (and will feel less ‘cared’) Medical professionals who are providing care to patients should use reciprocity to help build and strengthen relationship with patients - HAEMATOLOGICAL CANCER LEUKAEMIA – PATHOGENESIS AND PAT HOPHYSIOLOGY Introduce the topic of leukaemia to students - ‘Leukaemia’ is a malignant proliferation of cells that arises following mutation within a single haematopoietic cell o This will infiltrate bone marrow and interfere with marrow function o This usually (but not always) circulates in the blood o Note: As Leukaemia arises from the malignant transformation of a single cell, all the resultant cells will be a clone of the original malignant cell Hence, there will be less diversity in Immunoglobulins expressed in patients with Leukaemia due to clonal proliferation of a single Immunoglobulin only) Leukaemias are paradigms for research and treatment of cancer given the easy accessibility to malignant cells (i.e. blood and marrow samples) o There has been a focus of pioneering laboratory research into pathogenesis (e.g. CML), with findings from research into leukaemia being applied to many other cancers o It has served as a model for cancer therapeutics (e.g. Childhood ALL, CML, APL, etc.) Leukaemia can be considered across the following two dimensions: o Speed of onset (i.e. Acute vs. Chronic) o Type of cells affects (i.e. Lymphoid vs. Myeloid) - - 14 - Bone Marrow Trephine and / or Aspirate will allow observation of the cells within the bone marrow; this can be used to identify the presence of a leukaemia; for example: o Bone Marrow Trephine of Leukaemia patients will have lost most of the fat within the bone marrow cavity between the Trabecular bone compared to normal patients o Bone Marrow Aspirate of Leukaemia patients typically has less differentiation / diversity of cell types compared to normal patients Outline the principle feature of leukaemia pathogenesis - A range of different factors may trigger / cause leukaemia including hereditary causes, chemicals (e.g. benzene), cytotoxic agents (e.g. alkylating agents), radiation, viruses and antecedent stem cell disorders (e.g. myeloproliferative neoplasms) Consequences of Leukaemia include: o Bone Marrow failure (i.e. failure of production of all cell lineages) This will result in anaemia, neutropenia, thrombocytopenia, etc. o Infiltration by Leukaemic cells o Systemic effects (i.e. constitutional symptoms) Other clinical and haematological features include: o Leucostasis o Bone pain o CNS involvement o Hepatosplenomegaly o Lymphadenopathy o Gum hypertrophy There are several common leukaemia-associated chromosomal translocations (e.g. ‘Philadelphia Chromosome’ involves translocation of Chromosomes 9 and 22, which affects the gene ABL; this will result in CML and / or ALL) o Leukaemia resulting from particular chromosomal translocations have a better prognosis than other leukaemia; hence, chromosomal analysis is critical when predicting prognosis of Leukaemia patients o Certain chromosomal abnormalities giving rise to the Leukaemia may suggest a possible treatment (e.g. APL Leukaemia results from translocation of RARA [Retinoic Acid Receptor Alpha] Gene; as a result, provision of Retinoic Acid is an effective treatment for this specific Leukaemia) - - - LEUKAEMIA – WHAT YOU NEED TO KNO W Discuss the principal features of leukaemia pathogenesis and pathophysiology - Leukaemia is mainly a cancer of the bone marrow rather than cancer of the blood (as bone marrow is where most of the WBCs reside) o Instead of having a spectrum of cell types in the bone marrow, Leukaemia patients will have monoclonal replication of one particular cell type, which then dominates the bone marrow Presenting features of Leukaemia include: o Bone marrow failure / lack of normal haematopoiesis this will result in anaemia, neutropenia and thrombocytopenia o Excess malignant blood cells this will result in hyperviscosity of blood, hepatosplenomegaly and / or bone pain in children Acute Leukaemias have a rapid onset and provide the body no opportunity to compensate; in contrast, Chronic Leukaemias have a slow onset and may trigger some physiological compensation for some symptoms - - Discuss the clinical features, patterns of presentation and natural history of the common forms of human leukaemia 15 - - - Acute Myeloid Leukaemia (AML) involves proliferation of minimally differentiated cells (i.e. excess Blasts in Bone Marrow and potentially Blasts in the Peripheral Blood) o This will result in the rapid development / onset of bone marrow failure o FBC will indicate Pancytopenia and potentially the presence of Blasts o AML may be suspected on blood film but definitive diagnosis requires bone marrow biopsy WHO diagnosis based on: Morphology (i.e. excess of myeloblasts) Flow Cytometry (based on proteins on cell surface) Genetics (review Chromosome number and structure( Clinical Syndrome o Treatment will vary depending on the circumstances / age of the patient Young (<70 years) and fit patients can be treated with high dose chemotherapy to achieve remission (with further chemotherapy or bone marrow transplantation for cure) In contrast, older patients are not able to tolerate the strong chemotherapy treatment needed, and so palliation (e.g. low-dose chemotherapy, blood transfusion, antibiotics, etc.) is provided instead of chemotherapy o The overall 5-year survival of all AML patients is 25%, though this low level is skewed by the significantly higher prevalence of the disease in older age groups (60+) (many of whom cannot tolerate chemotherapy treatment and / or have co-morbidities) Chronic Myeloid Leukaemia (CML) involves proliferation of myeloid cells in blood and bone marrow with relatively normal differentiation o Haematopoiesis is effective in these patients, who may exhibit Leucocytosis and Thrombocytosis CML patients will have high quantities of normal cells in the Peripheral Blood in addition to the presence of immature / primitive WBCs that should not be there (e.g. Myeloblasts, Promyelocytes, etc.) o There are three phases in the natural history of this disease: Chronic (usually lasting 2-4 years) Accelerated phase (6-12 months) Acute phase or blast crisis (2-4 months) similar to acute leukaemia o ~85% of diagnosis occurs during the Chronic Phase, with ~30% of patients diagnoses during routine blood tests (when the patient may be asymptomatic) o Median age at presentation is ~45-55 years and it affects 1.5 in every 100,000 people annually o Symptoms include fatigue, weight loss, abdominal fullness (due to Splenomegaly) and hyperviscosity o Treatment for CML resulting from the Philadelphia Chromosome will involve the use of Imatinib Imatinib will prevent the signalling cascade from BCR-ABL (on the Philadelphia Chromosome) by competitively binding to the ATP binding site on the BCR-ABL protein Survival rate for CML patients increased from ~20-30% to ~90% following use of Imatinib Acute Lymphoblastic Leukaemia (ALL) involves proliferation of minimally differentiated cells (i.e. excess Lymphoblasts in Bone Marrow and potentially Lymphoblasts in the Peripheral Blood) o This will result in the rapid development / onset of bone marrow failure o FBC will indicate Pancytopenia and potentially the presence of Blasts o This is the most common childhood cancer and is treated with combination chemotherapy given intravenously / intrathecally and radiation These are complex chemotherapy programs that last 2-3 years Childhood cure rate is ~85-90% Note: Intravenous provision of chemotherapy will typically not be effective in the CNS or Testicles for childhood ALL patients; hence intrathecal chemotherapy and radiation are also used o Adult ALL is rare; this is treated with chemotherapy (with consideration of bone marrow transplantation in younger and fitter individuals) 16 - Survival rates in adults will ALL are lower than children with ALL Chronic Lymphocytic Leukaemia (CLL) involves proliferation of lymphocytes in blood and bone marrow with relatively normal differentiation o There will be a slow accumulation of mature lymphocytes in blood / bone marrow (eventually causing lymphocytosis), with no features of bone marrow failure Other WBCs, RBCs and Platelet levels are normal and so it will take a long time before CLL worsens such that symptoms emerge o This is an indolent disease of the elderly, with ~25% of patients asymptomatic when they are diagnosed (based on a routine blood test) o Symptoms can include lymphadenopathy, splenomegaly, lymphocytosis, etc. (and eventually anaemia, hepatomegaly and thrombocytopenia too) o CLL patients have an increased risk of infection, including re-emergence of latent infections (e.g. Shingles) Immunodeficiency can occur in CLL despite the large increase in lymphocyte levels due to these extra lymphocytes being monoclonal (i.e. targeting only one antigen / lacking epitope diversity) o FBC will indicate lymphocytosis, whilst Blood Film will contain ‘Smudge Cells’ (which represent abnormal lymphocytes that rupture when prepared for blood film) These smudge cells that are abnormal and rupture exist due to the vast increase in the number of lymphocytes (which interferes with the normal maturation of Lymphocytes) o Bone Marrow Biopsy typically not needed for CLL patients; instead, use Flow Cytometry to confirm diagnosis Review Flow Cytometry for disproportionate split between Kappa vs. Lambda light chains [i.e. clonal population] and / or presence of T-Cell markers [e.g. CD5] on BCells) o Different staging criteria exist, with advanced stages occurring upon bone marrow failure (i.e. anaemia / thrombocytopenia) o Treatment of early stage disease is not considered beneficial; instead, treatment is indicated only for: Bone marrow failure (i.e. anaemia / thrombocytopenia) Disease related symptoms (e.g. fatigue, night sweats, weight loss) Symptomatic lymphadenopathy o Treatment of CLL will involve chemotherapy (e.g. Alkylating Agents, Cyclophosphamide, etc.), radiotherapy and supportive care (e.g. IVIG, Corticosteroids, etc.) Allogeneic bone marrow transplants are an option in the rare young patients with progressive disease LEUKAEMIA – BENCH TO BEDSIDE Illustrate how understanding the pathophysiology of leukaemia and lymphoma can lead to clinically relevant treatments - Improvement in life expectancy of Childhood ALL in the past 20 years due to systematic effort to develop optimal therapy (based on understanding of pathophysiology of Leukaemia) and progressively improving this therapy based on trial and error, research and experience Understanding that Leukaemia involves clonal proliferation of a single cell provides a mechanism to develop treatments (i.e. a therapy that can target the specific malignant clonal cell) o Chimeric Antigen Receptor (CAR) expressing T-cells combine the accumulated knowledge and techniques from Adoptive Cell Therapy, Gene Therapy and antibody structure to create a tumour specific receptor (that will target the specific malignant clonal cell) This involves combining a specific antibody targeting the tumour cell onto a T-Cell (which enables a functioning T-Cell without requiring the other typical stimulation factors [e.g. specific antigen, co-stimulation, proliferative cytokines]) o These CARs are inserted into the genome of effector T-cells using retroviral vectors and confer antitumor specificity to the genetically modified T-cell - 17 o o Initial studies have shown CAR treatment to be particularly effective in ALL, but also a possible cure in CLL and Non-Hodgkins Lymphoma Whilst the current cost of CAR treatments are high, there are current attempts to develop new procedures that can introduce relevant genes / DNA into cells for delivery at a much cheaper cost (which will increase accessibility and availability of CAR treatment) compared to a retroviral vector LYMPHOMA – WHAT IS IT? Introduce students to the disease process known as lymphoma - ‘Lymphoma’ is a malignant disease in which lymphocytes proliferate in an uncontrolled manner; this will lead to: o Lymphocyte accumulation most often in lymph nodes (one or more of neck, axilla, thorax, abdomen, inguinal); and / or o Lymphocyte accumulation in bone marrow There are two types of Lymphoma: o Hodgkins lymphoma o Non-Hodgkins lymphoma(NHL) Lymphoma is the 5th and 6th most common cancers among males and females in Australia and the US o This is one of few cancers with rising incidence (e.g. NHL has doubled in last 20 years) o Incidence of NHL in particular increases with age There are ~70 different types of Lymphoma B-Cells are the most common cause of Lymphoma o Malignant transformation of very immature, early-stage B-Cells will become Leukaemias, whilst malignant transformation of more mature B-Cells will become Lymphomas o Malignant transformation of the mature Plasma Cells though are termed Multiple Myeloma As Lymphomas are monoclonal, all lymphoma cells will have the same antigen receptor (i.e. all B-cell Lymphomas will produce the same antibody) o Gene Expression Profiling can be used to identify the number of different types of B-Cells in a proliferation of B-Cells (if these are monoclonal, this suggests a Lymphoma) Lymphocyte population can be identified via: o Histology (i.e. under the microscope) these will be small cells with minimal cytoplasm o Flow Cytometry o Cytogenetics / Molecular Genetics (e.g. there are multiple different chromosomal translocations that result in Lymphoma) Diagnosis of Lymphoma will involve: o Full history including ‘B’ symptoms (i.e. constitutional symptoms) o Full physical examination (including examination of lymphadenopathy and splenomegaly) o Lymph node biopsy (surgical excision biopsy is needed for accurate diagnosis and classification) Alternatively, core biopsy using Ultrasound or CT Scan can be used if excision is difficult (e.g. elderly, co-morbidities), but this is not preferred Note: Fine needle biopsy is inadequate for initial diagnosis but can be used as a screen to exclude other cancers or can be used at relapse of a known lymphoma o Other tests (e.g. flow cytometry, cytogenetics, molecular genetics, immunohistochemistry, etc.) Immunophenotyping (i.e. detection of antigen expression [e.g. CD19, CD20, CD5, CD23] and monoclonality using kappa and lambda) is important for lymphoma diagnosis and classification Staging is undertaken to determine prognosis and the appropriate treatment o This takes into account: Number of disease sites Presence of disease above or below diaphragm Presence of extranodal disease ‘B’ Symptoms (i.e. constitutional symptoms) - - - - - - - 18 o - There are four stages (with Stage1 involving single node, Stage II involving multiple nodes (but on same side of diaphragm), Stage III involving spread to either side of diaphragm, whilst Stage IV involves multiple organs [e.g. bone marrow]) CT Scan is the most commonly used imaging technique for assessing size and distribution of lymph nodes (although MRI, Chest X-Ray, PET and Ultrasound can be used) Highlight the basic pathological, physiological and clinical features of the disease - Clinical features (i.e. signs and symptoms) of Lymphoma include: o Lymph node enlargement o Systemic symptoms (tired, weight loss, fever) o Lymphadenopathy o Hepatosplenomegaly o Signs of marrow failure (i.e. anaemia, leucopenia, thrombocytopenia) Lymphoma is most often classified according to o Lymph node histology on excision (not fine needle) biopsy o Immunophenotyping o Genotyping (e.g. cytogenetics, molecular genetics) Lymphoma is most often staged according to: o Signs and symptoms o Disease spread NHLs are categorised according to rate of progression and prognosis as either: o Indolent (i.e. slow growing); these are: Slow growing (low grade) but often widespread at time of diagnosis Typically asymptomatic at diagnosis (which is made via node biopsy) Respond to treatment but relapse (these are considered non-curable) Indolent NHL only treated once it grows and starts to cause problems This growth and treatment may only be several years after diagnosis (rather than immediately)! Focus of treatment is to prolong the disease-free period and to alleviate symptoms Examples include nodular or follicular lymphomas Follicular Lymphomas involve the replacement of the entire lymph node with Follicles Follicular Lymphomas account for ~22% of all NHL cases and majority of indolent NHL Follicular Lymphomas are characterised usually by relapsing and remitting course Most Follicular Lymphoma patients are > 50 yrs of age and present with widespread disease (i.e. ~75% of have Bone Marrow involvement) o Aggressive (i.e. fast growing) This requires prompt treatment, with an aim for cure (complete remission achieved in ~85% of patients) The commonest therapy for Lymphoma today is R-CHOP (i.e. a combination of CHOP [Cyclophosphamide, Hydroxydaunorubicin, Oncovin, Prednisone] and Rituximab (i.e. anti-CD20 antibody)) Chlorambucil and other multi-agent chemotherapy regimens are also available Examples include Diffuse large B cell lymphoma, Burkitts lymphoma, Mantle Cell Lymphoma, Primary Mediastinal Large B-Cell Lymphoma (PMLBL) Diffuse large B cell lymphoma (DLBCL) is the most common aggressive lymphoma and will involve the replacement of the entire lymph node with a series of large B-cells (which are smaller than Follicles) 50% of DLBCL patients are curable with chemotherapy, but those that relapse progress and die of lymphoma without transplant - - - 19 - DLBCL affects patients of all ages and may be localised or widespread Reed Sternberg Cells are pathopneumonic for Hodgkin Lymphoma (i.e. diagnostic for Hodgkin Lymphoma) o There will be two nuclei with prominent nucleoli within each nucleus of a Reed Sternberg Cells INTRODUCTION TO C HEMOTHERAPY Introduce students to the principles and practical aspects of cytotoxic chemotherapy for malignant disease - Oncology is fundamentally the science of cell proliferation focusing on both the physiology of mitosis and the study of apoptosis; this is because cells can become malignant if there is: o Increased activity of positive growth signals (e.g. proto-oncogenes) o Decreased activity of negatively acting growth signals (e.g. p53) o Reduction in the pathways leading to programmed cell death As a result, chemotherapy aims to reduce cell proliferation and / or increase apoptosis of malignant cells Cytotoxic chemotherapy will ideally exploit some unique property of tumour cells, thus providing ‘tumour-specific’ therapy o However, no such ‘pure’ cytotoxic drug exists; instead, there are collateral damage / sideeffects that limit the effectiveness of chemotherapy There is commonly a deteriorating quality of life for cancer patients following each successive relapse in the cancer Therapeutic Decision Making (i.e. choice of treatment) will depend on the type and progression of the cancer, the patient circumstances / condition and the medical team’s understanding of the cancer Treatment of cancer can involve: o Cytotoxic therapy o Local therapies (e.g. surgery, radiotherapy) o Endocrine therapy (e.g. Tamoxifen-oestrogen receptor blockade for breast cancer) o Immunotherapy (e.g. monoclonal antibodies) o Molecular therapy (targeting tumour-specific mutations) o Supportive Care (e.g. anti-emetics, transfusion, nutrition, psychosocial) This treats the side-effects of the different treatment provided (e.g. chemotherapy drugs can cause nausea, so provide supportive care to resolve nausea) - - Understand the biologic principles which underpin cytotoxic chemotherapy, as well as principles of supportive care (e.g. response assessment, toxicity grading, anti emetics, growth factor support) - There are five main classes of chemotherapy drugs, each having a different mechanism of action; these classes are: o Alkylating agents (e.g. Cyclophosphamide) These drugs crosslink DNA and therefore prevent DNA synthesis These are non-selective and hence toxic to all rapidly dividing cells; this has sideeffects such as: Anorexia, nausea / vomiting Alopecia Amenorrhea / Azoospermia Myelosuppression (i.e. marrow suppression) Immunosuppression o Anti-metabolites (e.g. Methotrexate, 5FU) – these are competitive inhibitors of S phase enzymes o Platinum compounds (e.g. Cisplatin, Carboplatin) – these drugs crosslink DNA and therefore prevent DNA synthesis 20 o - - - - Anti-tumour metabolites (e.g. Daunorubicin, Bleomycin) – these drugs have a range of different effects (e.g. cause DNA breaks, intercalate DNA base pairs) o Anti-microtubule drugs (e.g. Oncovin / Vincristine, Taxanes) – these drugs bind microtubular proteins disrupting microtubule assembly during mitosis (i.e. inhibition of the mitotic spindle leads to arrest in G2/M phases) Combination Chemotherapy is preferable to single chemotherapy as it reduces the risk of the cancer developing resistance to an individual type of chemotherapy o Combination Chemotherapy is based on four principles: Drugs active as single agents should be selected Drugs with different mechanisms of action Drugs with different dose limiting toxicities Drugs with different susceptibilities to resistance Note: Generally aim for maximum dose with minimum time intervals between doses. (generally 2-3 weeks for recovery) o Common Combination Chemotherapies include: MOPP (Mustine, Oncovin, Procarbazine, Prednisone) used to treat Hodgkins Lymphoma CMF (Cyclophosphamide, Methotrexate, 5-Fluorouracil) used to treat Breast Cancer CHOP (Cyclophosphamide, Hydroxydaunorubicin, Oncovin / Vincristine, Prednisone) used to treat Non-Hodgkins Lymphoma ABVD (Adriamycin [also known as Hydroxydaunorubicin], Bleomycin, Vinblastine, Dacarbazine [similar to Procarbazine]) < used to treat Hodgkins Lymphoma There are significant side-effects / toxicities from chemotherapy drugs o Assume all cytotoxic chemotherapy drugs cause: Anorexia, nausea and vomiting Alopecia (exceptions are 5FU [i.e. 5-Fluorouracil], Oncovin / Vincristine, Platinum Compounds [e.g. Carboplatin], Xeloda, Mitoxantrone) Myelosuppression(exceptions are 5FU [i.e. 5-Fluorouracil], Oncovin / Vincristine, Cisplatin, Bleomycin) Gonadal damage o The following cytotoxic chemotherapy drugs have the following unique toxicities: Daunorubicin / Idarubicin – cardiac toxicity Bleomycin – lung toxicity Cisplatin – kidney toxicity Vinca alkaloids – peripheral neuropathy (microtubule damage to nerve) Cyclophosphamide – haemorrhagic cystitis (in high doses) Supportive care for chemotherapy will apply pre-treatment, during treatment and post-treatment o Pre-treatment care includes counselling / education, optimising dental hygiene [as neutropenic state following chemotherapy can trigger re-emergence of any dental infections], fertility advice, nutritional support o During treatment care includes anti-emetics (i.e. anti-nausea medication) o Post-treatment care includes anti-emetics, laxatives, G-CSF, Autologous Stem Cell Transplant, etc. Research is currently focusing on monoclonal antibody therapy (e.g. Rituximab, Herceptin, etc.); this offers an possibility of cancer-specific treatments that have minimal side-effects / toxicity o There have been significant improvements in response / survival rates based on initial trials o Better understanding of the genetics and molecular pathways of cancer is improving outcomes Understand the importance of determining goals of therapy (e.g. cure versus palliation) - Goals of therapy can include: o Curative o ‘Debulking’ before surgery (as this will make it easier to remove a smaller tumour) 21 Adjuvant this targets micro-metastases that are too small to identify on imaging / scans (and hence prevent subsequent relapse of the cancer) o Radioenhancing this sensitises the cancer cells to be more affected / damaged by radiotherapy o Prolong survival o Palliative this provides short-term symptoms relief that will assist the patient in maximising their quality of life The choice of treatment will depend on the particular goals of therapy o This is due to their being different benefits and costs / harms for each type of treatment o The optimal balance between benefits / harms will depend on the goal of therapy (i.e. palliative care for older person with significant co-morbidities who wishes to survive until daughter’s weddings vs. curative treatment for childhood ALL) o - STEM CELL TRANSPLANT ATION Understand the rationale for autologous and allogeneic haematopoietic transplantation (HPT) in the management of malignant and non-malignant disease - ‘Stem Cell Transplant’ typically refers to a Bone Marrow Transplant, though this is not necessarily the case as there are many other potential types of Stem Cells that may be referred to Stem Cell Transplants have the ability to: o Enable patients to recover / survive high dose chemotherapy (which otherwise would kill them) The high-dose chemotherapy eliminates / eradicates the existing Stem Cells which then are replaced by the transplant (as otherwise the patient would lack the stem cells to continue to develop RBC, Platelets and WBCs) o Alternatively, stem cell transplants can be used to replace a defective immune system (e.g. SCID) or defective marrow cells (e.g. myelodysplasia, aplastic anaemia, etc.) Stem Cell Transplants can be divided into: o Autologous (i.e. from self) o Allogeneic (i.e. from another individual); this can be sub-divided into: Syngeneic = From an identical twin Matched Related donor (25-30%) Unrelated donor (VUD or MUD or UD) – Likelihood of match dependent upon haplotype / ethnicity) When matching patient vs. donor, there are 12 key alleles that are reviewed for matching (though there are thousands of different alleles / genes that exist) Haploidentical = Share a haplotype (closely linked ‘set’ of genes on Chromosome 6 that makes a donor partially matched >50%) Source of Autologous Stem Cells are Bone Marrow Harvest, Peripheral Blood Stem Cells and / or Cord Blood Patients receiving Stem Cell Transplants may undergo ‘Chimerism’ whereby they develop parts of their body based on the different genetics of the Stem Cell Transplant (i.e. change in blood type based on the transplant) - - - Understand the steps involved in HPT and the risks and benefits of transplantation in adults and in children - The following steps are required in an Autologous haematopoietic transplant: o Identify patient (i.e. less than 70-75, well, disease control, NHL, myeloma, other) o Induce Complete Remission or good Partial Remission (i.e. must be chemosensitive) Disease needs to be controlled prior to Stem Cell Transplant (i.e. Complete Remission or Partial Remission) or there is a high risk of relapse (and hence a waste of the Stem Cell Transplant) o Collect and freeze stem cells (BM or PB) after mobilisation or priming 22 - - - Stem Cells can be frozen indefinitely (longest known frozen stem cells that were then successfully used was ~30 years) o Conditioning (i.e. high-dose therapy that wipes out or "conditions" the immune system and bone marrow) o Stem cell reinfusion Stem Cells have receptors that will bind to and enter bone marrow after being infused intravenously After ~4 hours, the Stem Cells will commence producing bone marrow contents However, it takes ~12-18 days for the bone marrow to return to normal; this is the danger period where there is highest risk of infection / complications (as the patient is neutropenic) o Recovery (12-18 days) (note: Transplant-related Mortality is ~1%) o Disease restage o (Maybe) second transplant?? Maintenance o Gradual immune reconstitution / long-term effects The following steps are required in an Allogeneic haematopoietic transplant o Identify patient o Identify donor (Related, UD search, CB) o Decide on transplant type and conditioning (MAT, RIC) o Disease control (i.e. Complete Remission or Partial Remission) o (Optional) Back-up stem cell collection in some conditions (e.g. children with Thalassaemia) o Conditioning o Rest day (which allows all the chemotherapy to be excreted from the body and hence avoid destruction of the infused stem cells) o Stem cell infusion o Neutropenic period (during which there should be infection prophylaxis and GvHD prophylaxis) o Engraftment o Disease restaging o GvL effect o Immune reconstitution o Long-term effects and relapse The following types of ‘Conditioning’ are possible: o MAT (Myeloablative) aims to destroy all the stem cells (and disease) and let the new stem cells provide a replacement this will involve high doses of chemotherapy o RIC (Reduced Intensity Condition) aims to destroy just enough of the bone marrow / existing immune system (i.e. immunosuppression) to enable another immune system (from the stem cell transplant) to embed and develop this will involve low or no doses of chemotherapy This permits older patients to have transplants and is particularly applicable in diseases of older patients (e.g. myeloma, AML, NHL, CLL) However, this does not reduce the risk of GvHD or the risk of opportunistic infections Note: RIC does NOT aim to achieve total disease control from the chemotherapy but rather from the newly developing immune system Indications for an Stem Cell Transplant include: o Autologous ~90% of Autologous Stem Cell Transplants are for Myeloma, NHL and Hodgkin’s Lymphoma NHL and Hodgkin’s Lymphoma are indicated for these transplants only in relapses of when initial presentation is intermediate / high-grade There are a range of other conditions that might be indicated for Autologous Stem Cell Transplants though these are rarer (e.g. Autoimmune disorders, Amyloidosis, etc.) o Allogeneic Allogeneic Stem Cell Transplants are indicated for a range of different diseases 23 - - - - ~60% of Allogeneic Stem Cell Transplants are for AML and ALL (though Allogeneic Stem Cell Transplants can also be used in Myeloma and NHL) Allogeneic Stem Cell Transplants are also the treatment of choice for Immunodeficiency (e.g. SCID) and Severe Aplastic Anaemia (cure ~80% of patients) The following survival patterns occur following Stem Cell Transplants: o Large early mortality (i.e. Bone Marrow Transplants have a high mortality rate within 3 months due to the toxic effects of treatment) o Plateau in survival between 2-5 years o ‘Good’ disease better than ‘advanced’ disease o Note: Unrelated Donor (UD) Transplant Outcomes are increasingly approaching the level of outcomes for Related Donor (RD) Transplants (due to range of factors such as improved supportive care, more accurate matching, etc.) There are immunopathological consequences of an Allogeneic Stem Cell Transplant as the new stem cells (irrespective of the level of compatibility) will notice parts of the person as foreign bodies and drive an immune response o This is useful for killing the cancers in the body, but is damaging when its impact is on the non-cancerous parts of the body Consequences / complications of Stem Cell Transplants are typically predictable and follow a chronological series; these include: o Total Transplant-related Mortality within 100 days (~5-40%) Patients with resistant and / or advanced disease have higher TRM 100 (i.e. 100 day mortality) in addition to inferior long-term survival o Chemo-radiotherapy toxicity (100%) o Infection and neutropenic sepsis (85%) o Graft versus Host Disease (GvHD) (~30-80%) Graft versus Host Disease (GvHD) can produce severe burns, lesions / ulcers, destruction of the gut (resulting in diarrhoea) and a range of other immunopathological consequences This has a significant impact on mortality AND quality of life Note: Small amount of GvHD is associated with better outcomes (as this means the graft will also be attacking and destroying the host cancer too!) o Graft failure/rejection (5-10%) o Note: The complications/ side-effects of Transplants can be accurately calculated; this enables Haematologists to calculate the likelihood of benefit vs. likelihood of risk and know when it is too risky for the patient to receive a Transplant (and hence Transplants will be refused for particular patients) Long-term complications / consequences of Stem Cell Transplants are predictable and include: o Chronic GvHD (this will have a similar appearance of Scleroderma (skin lesions, mouth lesions, eye lesions, ulcers, joint deformity, etc.) o Infections (especially viral) o Cataracts o Sicca syndrome o Neuropsychiatric disorders o Renal disease o Endocrinopathies (E.g. Hypothyroidism, Osteoporosis, Growth Failure, etc.) o Sexual and reproductive dysfunction (e.g. infertility, erectile dysfunction, etc.) o Secondary cancers o Psychosocial complications (e.g. depression, anxiety, fatigue, etc.) BLEEDING DISORDERS PHYSIOLOGY OF COAGULATION – PLATELET AND CLOTTING FACTORS Understand the biochemical basis of coagulation including the role of blood vessels, endothelial and subendothelial cell surfaces, platelet plug formation, 24 and soluble coagulation factor pathways in development of the stabilised fibrin clot - - - Haemostasis is the normal physiological response to vascular injury that aims to stop bleeding and restore bloodflow; this will involve: o Platelets (to adhere at the site of the vascular injury) o Clotting factors (to generate fibrin) o Constriction of blood vessels (to redirect blood flow away from the site of injury and hence reduce bleeding) Normal endothelium inhibits platelet adhesion through the secretion of anti-aggregation cytokines (e.g. PGI2, t-PA, etc.) and agonist inactivation cytokines (e.g. ADPase, Thrombomodulin) o However, the subendothelial matrix has a range of different factors that bind platelets (e.g. von Willebrand Factor, Fibrinogen, Microfibrils, etc.) o For example, vWF is a long extracellular matrix that is able to grab and bind the passing circulating platelets Endothelial damage (due to vascular injury) will result in the release of vWF and Tissue Factor near the area of vascular damage o Platelets will adhere / bind with the matrix vWF (this adhesion is reversible) o Platelets will then undergo rapid activation and release a range of cytokines / granules that will provide a procoagulant surface for coagulation factors to assemble [i.e. anionic phospholipid surface] Tissue Factor ultimately attracts Fibrinogen, which will irreversibly glues different platelets together after which they cannot move away Fibrinogen can be rapidly converted into Fibrinogen Gel (i.e. Fibrin) within seconds and hence change a clot from liquid to solid (i.e. Fibrinogen is soluble, whilst Fibrin is insoluble) Platelets will secrete ADP and Thromboxane, which recruit new platelets to the thrombus, hence stabilising the growing Fibrin thrombus Microparticles released from activated platelets are critical to driving a range of outcomes (e.g. mediate coagulation, inflammation, etc.) o Note: The Haemostatic Plug will form that contains not only platelets, but also RBCs, WBCs and Fibrin o Note: vWF is also a carrier protein for Factor VIII Understand the processes involved in the finely balanced regulation and control of coagulation and fibrinolysis - Coagulation ‘cascade’ model involves two pathways: o Extrinsic Pathway (i.e. Tissue Factor and Factor VII leads to Factor X) this is measure by the Prothrombin Time (PT) [i.e. INR] o Intrinsic Pathway (i.e. Factor XII and XI leads to Factor IX Factor IX and VIII leads to Factor X) this is measured by the Activated Partial Thromboplastin Time (APTT) o Note: Both pathways combine to a Common Pathway whereby Factor X and Factor V convert Factor II to Thrombin, which converts Fibrinogen to Fibrin o Note: Ca2+ is needed for each of the conversion steps to occur within both pathways Coagulation ‘cascade’ model involves rapid amplification, as a single upstream factor can activate multiple downstream factors (leading to exponential activation) o Thrombin is the key molecule is the clotting process; small amount of Thrombin will trigger other upstream clotting factors resulting in amplified Thrombin production (i.e. Positive Feedback Loop) o Amplified Thrombin ‘burst’ will normally stabilise Fibrin clot (so failure to produce clotting factors due to Haemophilia deficiencies will result in an inability to form stable clots) There is built-in control of coagulation, by simultaneous triggering of antithrombin and fibrinolytic pathways o Thrombin acts as both a pro- and anti-coagulant, as higher Thrombin will trigger not only platelet aggregation, but also an anti-thrombotic pathway via Protein C (by inhibiting Factor VIII and V) (i.e. negative feedback loop) - - 25 o o The natural presence of Antithrombin-III (Serpin) affects multiple different Clotting Factors (i.e. Factor II, IX, XI, XII) and will reduce clotting There is a small amount of Antithrombin-III in circulation, which will deactivate any excess clotting factors (and hence prevent thrombosis) Enzymes / factors (e.g. tPA, Urokinase) secreted by healthy endothelium will promote Plasmin production, which causes fibrinolysis (i.e. clotting will be reduced once the endothelium return to healthy) ACQUIRED BLEEDING DISORDERS Understand the causes and mechanisms of impaired production of vitamin Kdependent clotting factors - The Vitamin K dependent clotting factors are Factor II (i.e. Prothrombin), VII, IX, X, Protein C, Protein S o Vitamin K is critical to converting these Clotting Factors into their Gamma-Carboxyl Glutamic Acid form, which is needed to enable the Clotting Factor to bind to the local site of injury o Warfarin will impair Vitamin K levels resulting in a fall on these clotting factors Shorter half life of Factor VII compared to Factor IX and X means that PT will become abnormal prior to the APPT becoming abnormal Causes / mechanisms of Vitamin K deficiency include: o Inadequate dietary intake (commonly found in green, leafy vegetables) o Insufficient Bile salts (which are needed to emulsify Vitamin K prior to its absorption in the intestine into the blood) o Pancreatic impairment (as pancreas secretes digestive enzymes needed to break down food) o Malabsorption in the intestine - Understand the causes of excessive consumption of clotting factors - Disseminated Intravascular Coagulation (DIC) involves the inappropriate and excessive activation of coagulation o Excessive consumption of platelets and coagulation factors results in thrombocytopenia, prolonged coagulation tests and bleeding o Furthermore, excessive consumption of anticoagulation and fibrinolysis factors result in thrombosis, fibrin deposition and end-organ damage Causes of DIC include: o Severe infections o Malignancy (e.g. APML, leukaemia, metastatic cancer) o Obstetric complications (e.g. placental abruption) o Shock o Liver disease / failure o Transplantation / organ rejection o Extra-corporeal circulation (e.g. cardiac bypass) o Extensive intra-vascular haemolysis (e.g. ABO incompatible transfusion) o Snake bite DIC is generally a clinical diagnosis and will be indicated by the presence of bleeding AND clotting Treatment of DIC will involve removing / treating the underlying cause and transfusion with FFP and Platelets (and Cryoprecipitate is low in Fibrinogen) - - Understand the effects of anticoagulant excess - Anticoagulant excess can result in insufficient / ineffective clotting factors; this will result in reduction in thrombosis and potentially bleeding (e.g. purpure, petechiae, haemorrhage, bruising / ecchymoses, etc.) Anticoagulant excess can be caused by: o Presence of inhibitors of coagulation factors (e.g. Lupus Anticoagulant) this can be identified through Mixing Studies (i.e. if APPT time continues to be abnormal when patient blood is mixed with normal blood) - 26 o o Excessive activation of Plasminogen (causing increased Fibrinolysis) Drugs (e.g. Warfarin, Heparin) Distinguish mechanisms of increased destruction and decreased production of platelets in causing thrombocytopenia - Decreased production of platelets may be due to generalised bone marrow failure (e.g. chemotherapy, other drugs, malignancy, aplastic anaemia, alcohol toxicity) Increased destruction of platelets may be due to immune-induced (e.g. ITP), drug-induced (e.g. HITTS), genetic (e.g. TTP), disseminated intravascular coagulation (DIC) and / or dilutional (i.e. due to massive transfusion) Alternatively, thrombocytopenia may result from sequestration of platelets in the spleen Note: Platelet deficiency will result in superficial bleeding (i.e. skin, mucous membrane, etc.), whilst Clotting factor deficiency will result in bleeding deep in soft tissues (e.g. joints, muscles) o There is a high risk of spontaneous bleeding when the platelet count is below 10 - - BENEFITS AND COMPLICATIONS OF TREATING HAEMOPHILIA Illustrate the benefits of correct and adequate treatment in Haemophilia including: o Replacement demand therapy to control bleeding episodes o Replacement demand therapy is more convenient and easier for compliance, as the patient will administer the dosage as needed However, the bleeding into the joint already occurs and so the joint will eventually degenerate There are also increased risk of inhibitors developing based on this ondemand therapy Intravenous access is less problematic as the frequency of transfusions / therapy is much lower Furthermore, the cost of transfusion products is lower given the lower frequency of treatment Prophylactic therapy to aid normal joint and physical development; and o Prophylaxis of Clotting Factor will provide ongoing protection against joint and muscle bleeds (i.e. haemarthosis), as severe bleeding with minimal trauma is only likely to occur when clotting factors are below very low levels (i.e. <5%) This will reduce the number of joint haemorrhages and the resultant joint damage compared to episodic therapy with Factor VIII (i.e. transfusion of Factor VIII in response to bleeding) Hence, this will avoid long-term joint deformation and impairment of joint function Furthermore, continuing treatment as prophylaxis reduces the risk of inhibitors to the clotting factor developing Treatment prior to any surgery, dentistry, or invasive procedures This will reduce the risk of bleeding / complications as a result of surgery, both during the surgery and post-surgery Remember to main adequate ‘trough’ levels of factor levels post-surgery too (e.g. in general, factor levels should be maintained in the normal range for 3 to 4 days after a vaginal delivery and up to 7 days after a caesarean section) To understand the three main classes of complications in haemophilia resulting from: o Adverse physiological responses to blood and factor VIII transfusion 27 o Blood and Factor VII transfusions may trigger the development of inhibitors to these clotting factors Confirmation of presence of inhibitors can be detected via Mixing Studies Risk of development of inhibitors is associated with larger genetic mutations in gene encoding Factor VIII, event-based treatment (rather than prophylaxis), intensive treatment and lack of vWF Transfusion-transmitted disease o Various viruses may be transmitted (e.g. historically Hepatitis C and HIV, currently CMV) Failure to maintain optimal treatment regimens Compliance is generally quite good in haemophilia patients (given the significant, painful consequences of bleeding) However, compliance does become a greater challenge during adolescence as patients seek to become more independent and rebel (furthermore, the success of treatment so far has made them unaware of the adverse consequences of failing to comply, which increases the risk of non-compliance) Other challenges to compliance include frequency of transfusion, cost, venous access, time spent with Haemophilia Treatment Centre and relationship with healthcare professionals BLOOD PRODUCTS IN THE TREATMENT OF DISEASE Understand the principles of blood transfusion - Every donation is tested and found negative for Hepatitis B, Hepatitis C, HIV, HTLV-1 and Syphilis o The residual risk of contracting these viruses is negligible (i.e. less than 1 in 1,000,000) o Other factors are also assessed (e.g. blood type, presence of RBC antibodies, CMV antibody, Malaria antibody [only on donor with travel history]) Whole blood is no longer transfused directly; instead, whole blood is split into its different components (e.g. RBCs, Platelets, Plasma, etc.) and each of these components are transfused as needed o RBCs and Platelets are leucodepleted (which reduces the risk of infectious diseases when these are within white cells) o FFP (Fresh Frozen Plasma) can be split into Cryoprecipitate (i.e. rich in Factor VIII, XIII and Fibrinogen) and Cryo-depleted Plasma [also known as Cryosupernatant] (remainder of FFP, which will include Factor IX) Pre-transfusion testing of patients is conducted to determine blood group, Rh blood type and presence of any RBC antibodies o Crossmatch then occurs to identify and obtain the appropriate blood for transfusion for the patient (i.e. preference for donor and recipient to be ABO-compatible, although noncompatibility is possible in certain situations as the donor plasma [i.e. alloantibodies] is not being transfused) Transfusions of blood products should only be given when the expected benefits to the patient are likely to outweigh the potential risks o The decision to transfuse red blood cells should be based on clinical judgement of patient factors, response to any previous transfusion, and haemoglobin levels Indications for transfusions of the following are to: o RBCs Improve oxygen carrying capacity Volume replacement o Platelets Treat or prevent bleeding due to Thrombocytopenia or Functionally Abnormal Platelets There are a variety of situations where platelet transfusion is appropriate (e.g. Platelet count <10, to maintain Platelet count >50 during surgical procedure, etc.) - - - - 28 - Note: Thrombocytopenia does not equal platelet transfusion (as rarely transfused in ITP / TTP when there is rapid platelet destruction) o Fresh Frozen Plasma Control of bleeding due to deficiency of coagulation factors (this may be due to liver disease, Warfarin overdose, massive transfusion, etc.) Note: This is NOT indicated for volume replacement or specific factor deficiencies (as factor concentrates are available) o Cryoprecipitate Fibrinogen Replacement (e.g. DIC) o Cryo-depleted Plasma Warfarin reversal TTP Shelf-life for the following blood products are: o RBC – 42 days refrigerated o Platelets – 5 days with agitation at room temperature (as will become damaged if refrigerated) o Plasma (i.e. FFP, Cryoprecipitate, Cryo-depleted Plasma) – 12 months frozen, but ASAP once thawed Note: There is a time delay (~20 minutes) for the Frozen Plasma to thaw to the right level before it can be infused into the patient Discuss the rationing of blood products and cost effectiveness of alternative treatment strategies - Patient Blood Management aims to avoid unnecessary use of blood, which will reduce the demand for blood and the exposure to the risks of blood transfusions o This involves timely application of a range of strategies to achieve haematological optimisation, reduce blood loss and optimise tolerance of anaemia in an effort to reduce or avoid transfusion o This model of care is shown to reduce morbidity/mortality and improve patient outcomes o There is currently a ‘single unit policy’ whereby blood should be prescribed only one unit at a time Supply of blood products is limited (e.g. Platelets have a shelf-life of ~5 days only) and so the decision to use blood products should be made carefully o Furthermore, there are significant costs associated with the screening / testing of blood products so alternative treatments (e.g. saline volume replacement) are significantly cheaper Avoiding blood transfusions also avoids the adverse transfusion risks / reactions such as: o Allergic reactions o Bacterial sepsis o Haemolytic reactions o TACO (Transfusion-associated Circulatory Overload) / cardiac failure o TRALI (Transfusion-related Acute Lung Injury) - - THALASSAEMIA + MALARIA THALASSAEMIA Consider Thalassaemia as an important public health problem worldwide and in Australia o This is a genetic disorder which affects certain at-risk populations, and provides a model for how molecular (DNA) technology can be applied to detect genetic diseases - Alpha Thalassaemia involve a deficiency of Alpha-globin chains, whilst Beta Thalassaemia will involve a deficiency of Beta-globin chains 29 - - The Alpha Globin gene is expressed on Chromosome 16, whilst the Beta Globin gene is expressed on Chromosome 11 Beta Thalassaemia has an autosomal recessive genetic inheritance and commonly results from a mutation (rather than deletion) of the Beta-globin gene o Heterozygous carriers are also known as possessing ‘Thalassaemia trait / minor’ o There are >200 known Beta Thalassaemia mutations There are a group of patients with Thalassaemia Intermedia (i.e. in-between Thalassaemia Major and Thalassaemia Trait) due to the involvement of the Beta+ mutation (i.e. reduced Beta-globin rather than absent Beta-globin) Genetic testing can be used to identify the precise nature of the genetic disorder (i.e. number of genes affected, specific mutations involved, etc.) o This information will enable a more accurate assessment of the impact of the Thalassaemia o Examples of genetic tests include PCR, Mutation Analysis by Restriction Enzyme Digestion, Oligonucleotide Probes (which will either bind vs. not bind depending on whether the mutation is present) and Amplification Refractory Mutation System (which will amplify different lengths of a gene depending on whether a mutation is present vs. absent) Understand the pathogenesis, haematological and molecular (DNA) approaches to diagnosis and the clinical phenotypes of Thalassaemia - Beta Thalassaemia will involve a deficiency of Beta-globin chains o This leads to an excess of Alpha-globin chains, which eventually precipitate in the bone marrow and inhibit the function of the bone marrow There will also be in an increase in HbF and HbA levels too (formed from Alpha + Gamma Globin and Alpha + Delta Globin respectively) o This will lead to the haemolysis of RBCs as well as a process called ‘Ineffective Erythropoiesis’, which result in the production of altered shorter-life RBCs This will result in anaemia, which triggers increased marrow expansion (and hence iron absorption) The side-effects of marrow expansion such as bone deformity, wasting, gout, etc. as not seen in the developed world following blood transfusions, as the erythropoietin upregulation and marrow expansion is suppressed Note: Iron loading in Beta Thalassaemia patients is a major cause of morbidity (e.g. cirrhosis, cardiac failure, endocrine deficiencies [leading to problems such as infertility]) However, these side-effects are observed in the developing world where the ability to suppress erythropoietin upregulation and marrow expansion is limited o Beta-globin is only expressed initially at ~6 months of age Hence, babies cannot be initially tested for Beta Thalassaemia (which involves deficiency of Beta globin) at birth, as the Beta globin has yet to be expressed fully The clinical phenotype of Beta-Thalassaemia will involve: o Transfusion dependent o Extramedullary haematopoiesis (leading to hepatosplenomegaly and bone deformities) o Iron accumulation (leading to cirrhosis, cardiac failure, endocrine deficiencies, etc.) o Susceptibility to infection o Hypermetabolism The blood film for Beta Thalassaemia will involve: o Hypochromic microcytic anaemia o Anisopoikilocytosis o ‘Target’ RBCs o ‘Tear Drop’ RBCs o Basophilic stippling o Nucleated red cells o Note: Iron deficiency Anaemia has a very similar appearance to Beta Thalassaemia trait on a blood film (e.g. hypochromic, pencil cells, etc.) - - 30 - - - - Management of Beta Thalassaemia will involve regular blood transfusions (every 4 weeks), iron chelation (e.g. Deferiprone, Desferroxamine, etc.), occasional splenectomy and management of complications / symptoms in other systems (e.g. cardiac, hepatic, etc.) Alpha Thalassaemia involve a deficiency of Alpha-globin chains o This is often caused by deletions (rather than mutations) of the Alpha-globin gene o There are different types of Alpha Thalassaemia depending on the number of Alpha-globin genes absent; for example: HbBarts hydrops fetalis [4 out of 4 gene deletion]) These patients will have pallor, oedema, massive hepatosplenomegaly and accumulation of HbBarts on blood film This is typical fatal for infants HbH disease [3 out of 4 gene deletion] These patients will have splenomegaly, variable anaemia and exacerbations of haemolysis Carriers (i.e. 1 or 2 gene deletion) will be asymptomatic or show mild symptoms (e.g. mild anaemia, hypochromic microcytosis, etc.) o Excess of Beta-globin chains can result in four Beta-globin chains combining to form a HbH body these are observed on the blood film and appear like ‘golf balls’ HbH bodies can be found in Alpha-Thalassaemia carriers in addition to those with HbH disease (though it is more common in HbH disease) Pathogenesis of Alpha-Thalassaemia involves: o Defective haemoglobin synthesis o Peripheral haemolysis (as HbH bodies are unstable and will precipitate in aged red cells) o High oxygen affinity of HbH disease and HbBarts results in these haemoglobin being physiologically ineffective in oxygen delivery DNA Studies are the only definitive test for Alpha-Thalassaemia if HbH bodies are not visible on the blood film (which is common in carriers of Alpha Thalassaemia) Management of Alpha Thalassaemia and HbH disease are effectively the same (i.e. transfusion during periods of increased haemolysis, occasional splenectomy) Understand the world-wide distribution of Thalassaemia and its relationship with malaria - Alpha and Beta Thalassaemia have a similar distribution geographically (i.e. Asia, Central Africa, Mediterranean) o The distribution of Thalassaemia is near the equator (i.e. mosquito / malaria regions), as Thalassaemia acts as a protector against Malaria o Similarly, areas at higher altitudes in the Mediterranean (where there is less risk of malaria) have a lower prevalence of Thalassaemia Whilst there are hundreds of mutations for Beta Thalassaemia, only a few of these mutations are common in individual countries - PRENATAL DIAGNOSIS O F THALASSAEMIA Consider Thalassaemia as a genetic disorder which can be detected by prenatal diagnosis - Thalassaemia is an inherited disorder of the ratio of Alpha and Beta-globin chains o It does NOT depend on the absolute level of Alpha and Beta globins; only the ratio! o For example, a patient with Alpha and Beta Thalassaemia will continue to have a ratio of Alpha and Beta globins of One, and hence will have no problems Diagnosis of Thalassaemia may be performed by either analysis of the blood film or genetic testing o DNA testing can specify whether Thalassaemia is present as well as the precise mutations that are causing the Thalassaemia Pre-natal genetic testing of the parents can identify the presence of any Thalassaemia genes / traits and enable a measurement of the risk to the offspring - - 31 Discuss the molecular techniques used to make a prenatal diagnosis: o Polymorphic linkage; o This involves examining the relationship between two genetic loci to determine the presence of a mutation in the gene of interest (even if the precise mutation cannot be identified) Deletion analysis; o RFLP analysis; and This reviews the DNA for a set of common deletions associated with Thalassaemia o Restriction Fragment Length Polymorphism (RFLP) involves comparing the length of DNA fragments that are separated by restriction enzymes Differences in the length of the fragment compared to the ‘normal’ example are suggestive of a genetic mutation DNA sequencing This involves determining the precise order of nucleotides in a DNA molecule This provides a highly precise method of identifying mutations EPIDEMIOLOGY, PATHOG ENESIS, MANAGEMENT, DIAGNOSIS AND VACCINATION OF MALARIA Understand the need for rapid and accurate diagnosis of individuals suspected to have malaria - Malaria is a obligate intracellular protozoa of the genus Plasmodium that is transmitted by Anopheles mosquitoes o This produces acute or chronic infection, most commonly characterised by paroxysms of fever, anaemia and splenomegaly o This a major worldwide illness (i.e. global incidence 300-500 million) and can cause significant mortality (i.e. annual mortality > 1 million) o Rapid and accurate diagnosis is needed to be able to provide the appropriate therapy This will also be important for assessing the effectiveness of treatment, and whether a change in treatment in needed Manifestations are a consequence of asexual forms and their interactions in the blood; this will involve: o Haemolysis of parasitised and normal cells o Haemoglobinuria (Blackwater fever) and Acute Renal Failure (tubular toxicity) o Hypoglycaemia secondary to parasite consumption of glucose and/or inadequate hepatic gluconeogenesis o Acidosis, SIADH and hyponatremia o Note: Density of parasitemia is dependent on the proportion of susceptible erythrocytes Most clinical symptoms relate to rupture of schizonts and destruction of erythrocytes; these include: o Prodrome 2-3 days o Paroxysm with rigors (i.e. every 48 or 72 hours depending on the species of malaria) o Range of non-specific symptoms (e.g. headache, myalgia, back pain, fatigue, etc.) o Gastrointestinal symptoms (nausea, vomiting and diarrhoea) or respiratory symptoms (dry cough, dyspnoea) Physical examination will involve fever, pallor, jaundice and hepatosplenomegaly Laboratory abnormalities include anaemia, thrombocytopenia and sometimes leucopenia P. falciparum should be considered a medical emergency in non-immune individuals o Clinical findings are similar to other forms of malaria but more severe and acute Paroxysms often irregular and incubation shortest (i.e. 10-14 days) Symptoms include shock, parasitaemia, pulmonary oedema, renal failure, unrousable coma, etc. o More often more severe anaemia and multi-system involvement: “complicated malaria” - - - 32 - - - - o Mortality is up to 25% in non-immune individuals Gold standard for diagnosis is via microscopy the parasite can be identified within the RBCs o The key features to understand to identify the specific species of Malaria is: Size of parasitised RBC (is this enlarged?) How many forms of the parasite? (single vs. multiple) How many chromatin dots in the parasite? Is the parasite central vs. peripheral? What is the thickness of the ring form of the parasite? Is there stippling (i.e. appearance of coloured dots) in the cytoplasm? o Alternative diagnosis techniques include immunohistochemistry or molecular techniques Malaria has a highly effective immune avoidance strategy with the property of antigen switching. o ~2-18% of each malarial proliferation cycle is associated with a switching event o Natural exposure causes the development of strain specific (PfEMP-1) non-neutralising immunity, with recrudescences corresponding to antigen switching events o Note: Acquired immunity in natural populations is non-neutralising and protects against disease rather than infection. There are several drugs available for treatment of Malaria given the parasite is quite sophisticated and is able to develop resistance relatively easily o Artemisinine, Artemether and Artesunate are the latest drugs for Plasmodium falciparum, and they have superiority vis-a-vis the other drugs in terms of mortality (though resistance to these new drugs is developing) o Other drugs available include Mefloquine, Doxycycline, Chloroquine, etc. Haemoglobinopathies (e.g. heterozygous sickle cell trait, Thalassaemia) are protective for P. falciparum infections o They reduce the lifespan of RBCs, which makes it more difficult for a Malaria infection to proliferate within the person COMMON PARASITIC DIS EASES Describe the several protozoan and helminth parasites endemic in Australian communities and to discuss their role in disease in those communities - Giardia duodenalis o This is a Flagellate which reproduces by asexual reproduction o This has two forms motile (trophozoite) and cystic forms Cysts has passed in the faeces into the environment Whilst cysts tolerate cold water, they are very sensitive to UV and dryness o Characteristic morphology under the microscope (i.e. face-like due to two nuclei with prominent nucleoli) o Pathogenesis involves cysts from the environment excysting in the proximal small intestine where it will inhibit the villi and cause apoptosis in the enterocytes, hence disrupting absorption of nutrients in the body o This is the most commonly identified intestinal parasite in the world and spread by contaminated water or faecal-oral transmission o Clinical presentation commonly involves diarrhoea, epigastric pain, bloating, malaise, etc. o Diagnosis made via detection in faeces by microscopy or antigens as well as detection of trophozoites in duodenal aspirate Small one-off sample of faeces may not have the Giardia duodenalis, as the cysts / trophozoites are released only periodically May need to take multiple sample, or alternatively improve yield by concentration techniques or a larger sample of faeces o Treatment via Metronidazole, Tinidazole or Albendazole Metronidazole needs to be taken for 7 days, whilst Tinidazole only needs to be taken once a day Cryptosporidium hominis (parvum) o This is an obligate gastrointestinal tissue parasite (i.e. lives within Enterocytes in the GIT) - 33 - - This will disrupt the brush border and the absorptive surface of the small intestine As a result, there is altered small intestine permeability and secondary malabsorption o Cryptosporidium is a very small organism (~the size of a RBC) and will undergo asexual reproduction within humans Chlorine will not kill the Cryptosporidium Oocyst (i.e. infective form of Cryptosporidium); instead, filtration is needed to eliminate the Oocyst o US data suggests prevalence ~2-4% in immunocompetent hosts and 5-10% in immunocompromised hosts (e.g. AIDS) Infection is via direct contact with infected animals or ingestion of contaminated water Oocyst can persist in the environment if moist (>6 months) o Clinical presentation involves Acute cholera like illness with profuse watery diarrhoea, variable vomiting, low grade fever and abdominal pain This will occur for ~7-14 days in an immunocompetent host, but can persist for months in an immunocompromised host o Diagnosis made via identifying oocysts in stool using microscopy Similar to Giardia, there may be a need to take multiple sample, or alternatively improve yield by concentration techniques or a larger sample of faeces Alternatively, stool immunoassay detection is highly sensitive and specific o There is no clear treatment for Cryptosporidium; management comprises supporting the patient (e.g. hydration) and treatment of any underlying immunocompromising trigger Enterobius vermicularis o This is an intestinal roundworm (i.e. nematode) that require no external host They are found worldwide, and especially in developing countries Prevalence rates are highest in children ~6-12 years of age o They concentrate around perianal skin and are infective for ~3 weeks o Infection will result in pruritis; itching though can result in spread of the parasite (autoinfection) o Applying sticky tape to the perianal skin will collect the eggs and larva that congregate in that region; these organisms can then be examined microscopically for confirmation of the diagnosis o Treatment is via single dose of Mebendazole Echinococcus granulosus o This parasite is a Cestode (i.e. tapeworm) o Dogs are the definitive host and will excrete eggs in their faeces onto grass; this grass is then consumed by the intermediate hosts (e.g. sheep, cattle, etc.) leading to its spread to these intermediate hosts Humans are an accidental host from which it will no longer proliferate o There is a worldwide distribution, but it is mainly is a rural setting as the intermediate host is needed to sustain the cycle o Parasite will form a Hydatid cyst in various organs within the body Most infections with Hydatid Disease are non-symptomatic in humans and not a major issue Whilst normally there are no problems, there are circumstances (e.g. large physical sized cyst creating pressure in the liver / lung, ruptured cyst trigger anaphylaxis, etc.) that can cause problems o Hydatid cysts have a very characteristic appearance on imaging (e.g. CT Scan, Ultrasound) ‘Hydatid sand’ is a term for the larval forms of the parasite; these larval forms will exist within a Hydatid cyst o It is generally difficult to use medication to treat a cyst, as medication is spread to the point of disease via circulation However, the cyst is separate from the circulatory system (foreign, avascular structure) and so medications will generally not reach the cyst Instead, surgical removal is needed to treat / remove these cyst This will involve removal of the cyst contents, introducing a scolicidal agent within the cyst to minimise risk of dissemination of the parasite and 34 following up with treatment of Albendazole to eliminate any remaining parasite - Toxoplasma gondii o This is a tissue coccidian parasite (i.e. obligate intracellular parasite) causing Toxoplasmosis o This has two main forms: Tachyzoite form is the motile form that spreads from the GIT to other cells Bradyzoite form is the dominant form in the tissue o Key destination for Toxoplasma gondii are muscles, lungs, liver and lymphatics The infection can also spread to other parts of the body too, but will remain in a latent / dormant cyst phase (which is asymptomatic) Symptomatic infection will result in fever, night sweats, myalgia, headache, lethargy, etc. in addition to potentially lymphadenopathy These symptoms may appear similar to Glandular Fever o Patients with deficiencies in cell-mediated immunity have an increased risk of the Toxoplasma gondii disseminating and infecting the brain Alternatively, the latent cysts in the brain from an earlier Acute Toxoplasmosis will be reactivated due to the immunocompromise This will result in an abscess developing in the brain resulting in Toxoplasmic Encephalitis; this will be manifested via confusion, paralysis and other neurological symptoms o Ocular Toxoplasmosis typically occurs in younger patients; this can result in necrotic retinal lesion and can manifest as visual loss o Congenital Toxoplasmosis will cause neurodevelopmental problems in the child, including problems such as blindness, microcephaly, etc. This is more likely to occur when the mother has a primary infection of Toxoplasma gondii rather than a reactivation of pre-existing latest cysts o Diagnosis of Toxoplasmosis is via histology, isolation of the organism, PCR (using amniotic fluid) and / or serology Seroconversion is the main diagnostic method for acute infections of Toxoplasma gondii o Treatment of Toxoplasma gondii is via anti-metabolites Pyrimethamine is a folate antagonist that is used in conjunction with a secondary agent (e.g. Sulfadiazine, Clindamycin, Azithromycin) this combination treatment is quite successful APPROACH TO INFECTIVE FEVER Understand what constitutes an abnormal temperature, and the physiologic basis for the symptoms and signs of febrile illness - ‘Normal’ body temperature is not always 37 degrees Celsius; it will vary from: o Person-to-person o Different times of the day (due to circadian rhythms) (i.e. lowest at ~4am) o Different states of activity o Note: Different parts of the body are often at different temperatures (e.g. peripheries are cooler than central parts of the body, scrotum is 32 degrees rather than the normal 37 degrees, etc.) Relatively constant body temperature is important as temperature affects the speed of chemical reactions o The body enzymes will not work efficiently / effectively when the body temperature is beyond this tight range Thermoregulation is driven largely by the Anterior Hypothalamus in conjunction with neural temperature sensors and chemical / hormonal mediation; this will control body temperature though: o Central changes (e.g. behaviour modification) o Peripheral changes (e.g. vasoconstriction / vasodilation, sweating / shivering, etc.) - - 35 - - - - - ‘Pyrogens’ are fever inducing substances; exogenous pyrogens (e.g. microorganisms, toxins, etc.), which will trigger endogenous pyrogens (e.g. cytokines such as TNF, IL-6, IL-1) that impact the Anterior Hypothalamus resulting in changes in body temperature ‘Hyperthermia’ refers to various states causing unregulated temperature increase o Temperature may exceed 41 degrees Celsius this is very dangerous! Temperature > 41 degrees will cause permanent brain damage, whilst temperature > 43 degrees will result in Heat Stroke and commonly death o Pyrogenic cytokines not directly involved; instead, this is most often caused by heat stroke or adverse drug reactions (especially those affecting the CNS) Hyperthermia is more likely to be caused by the release of Prostaglandins into the Hypothalamus (rather than the release of Pyrogenic Cytokines) ‘Fever’ is defined as a sustained increase in temperature; this is a regulated phenomenon that is rarely significantly harmful o New onset of fever usually indicates acute inflammation, often infection o Fever may be detrimental in cardiovascular/respiratory disease Febrile illness (in addition to inflammation, tissue damage, tumours, etc.) will trigger a range of acute phase responses such as: o Neuroendocrine (e.g. fever, somnolence, loss of appetite) o Haemopoietic (e.g. anaemia, leucocytosis, thrombocytosis) o Metabolic (e.g. cachexia, negative nitrogen balance, etc.) o Other (e.g. increased levels of blood proteins such as CRP, Ferritin, Complement components, etc.) this raised level of blood proteins will increase the ESR Most febrile illnesses declare their origins within 1-2 weeks or resolve spontaneously o If they defy simple investigation they may be called Pyrexia of Unknown Origin (PUO), but no commonly-agreed definition Provide a framework for history taking from a febrile patient to show some typical signs associated with classic causes of fever - Classic causes of fever include infection, inflammation, cancer and miscellaneous / other (e.g. pulmonary embolism, cirrhosis, inherited diseases, etc.) The framework for the relevant history would be: o Observe temperature chart (e.g. any patterns, ‘true’ fever?, etc.) For example, fever peaking every 3 days, but with the temperature in the non-peak periods increasing over time towards the peak temperature is a sign of Malignant Tertian caused by Plasmodium falciparum (i.e. Malaria) o Age of patient o Geographic location (as type of fever will vary based on geography) o Duration of fever o Localising symptoms o Drugs / injections o Travel o Occupation / hobbies / domestic exposure o Sexual history - Provide a framework for: o The initial management of a patient with fever (including signs suggesting any severe illness); Systematic evaluation of the patient (i.e. taking an appropriate history, physical examination and investigations) is needed to identify the type / underlying cause of the fever New onset of fever usually indicates acute inflammation, often infection The context of the patient is critical to understanding the severity of illness (e.g. post-chemotherapy / immunosuppressed patient likely to have more severe illness, higher temperature likely to be more severe illness, etc.) 36 o Avenues for initial investigation of fever; o A description of heat stroke in malignant neuroleptic syndrome; and o Initial investigation should include exhaustive physical examination reviewing for rashes, lymphadenopathy, eye signs, etc. Baseline investigations conducted will depend on initial information from history and physical examination, but typically will include: Urinanalysis Full Blood Count Simple Biochemistry Various cultures (e.g. blood) Chest X-Ray Serology (depending on prior findings) Subsequent investigations that can performed if the fever persists and no cause is identified include: Further serology (e.g. blood-borne viruses) Ultrasound / CT / MRI Biopsy Neuroleptic malignant syndrome is a life-threatening neurological syndrome most often caused by adverse reaction to antipsychotic drugs This will result in hyperthermia (temperature > 38 degrees Celsius) as well as rigid muscles, excessive sweating, autonomic imbalance (e.g. tachycardia) and confusion / altered mental status The treatment of elevated temperatures Treatment choice will depend upon the type of fever / underlying cause; for example For classic fevers, resist temptation to give empiric treatment without careful consideration In contrast, in a severe nosocomial fever or neutropenic fever, treat immediately with broad spectrum antibiotics (with the antibiotics narrowed once the precise organism causing the infection is identified) o Initial empiric therapy of two broad-spectrum antibiotics typically involves providing a combination of Aminoglycoside and a Penicillin-based antibiotic (or 3rd generation Cephalosporin) Note: Benefits of treatment of fever itself (rather than underlying cause) are unclear Greatest benefits exists in children due to the risk of febrile convulsions Fever also places greater stress on the Cardiovascular system, and so may be a greater benefit in those patients with Cardiovascular disease CLOTTING DISORDERS THROMBOSIS Discuss the different management strategies associated with thrombosis - Thrombosis is the pathological occlusion of blood vessels in response to endothelial damage, stasis and hypercoagulability (i.e. Virchow’s Triad) o Management will include minimising / mitigating these three key elements of thrombosis Patients with a low pre-test probability of DVT should have a D-Dimer investigation o If this D-Dimer test is positive, then a Doppler Ultrasound should conducted o In contrast, if the patient has a high pre-test probability of DVT, then the D-Dimer investigation is generally unnecessary and instead a Doppler Ultrasound should be conducted initially - 37 o Note: Ascending Phlebography is the definitive diagnostic test in lower limb VTE; however, due to the cost, time and potential side-effects of this investigation, it is very uncommonly used (with Duplex Ultrasound preferred instead) Review the known predisposing factors to thrombosis - Arterial thrombosis will form a platelet-rich ‘white thrombus’; in contrast, venous thrombosis will form an erythrocyte-rich ‘red thrombus’ Predisposing / risk factors for Arterial Thrombosis include: o Major Elderly Male Sex Race Family History of Thrombosis Hyperlipidaemia Hypertension Smoking Diabetes mellitus o Minor Obesity Physical inactivity Stress/personality o Note: Atherosclerosis is a risk factor, as the rupture of Atherosclerotic plaque will trigger thrombosis Predisposing / risk factors for Venous Thrombosis include: o Prior history of VTE o Malignancy o Immobilisation (e.g. post-surgery, trauma, long-distance air travel, etc.) o Pregnancy (i.e. hypercoaguble state) o Oral Contraceptive Pill / Hormone Replacement Therapy (i.e. high oestrogen levels) o Dehydration o Infection o Elderly o Antiphosopholipid antibodies (e.g. Lupus Anticoagulant) - - Review the treatment of thrombosis - Treatment of thrombosis should be tailored to the individual and their condition o Treatment options for Arterial Thrombosis include: Medications Aspirin (and/or other antiplatelet agents [e.g. Clopidogrel]) Heparin Warfarin (only after initial heparin therapy this is used for long-term anti-coagulant) Thrombolysis (e.g. Streptokinase, tPA) Lifestyle (e.g. cessation of smoking, weight loss / reduction in obesity) Control of other risk factors (e.g. hypertension, hyperlipidaemia, diabetes, etc.) Surgical intervention (e.g. coronary angioplasty, carotid endarterectomy, stents and other endovascular procedures) Compression o Treatment options for Venous Thrombosis include: Medications Heparin Warfarin (only after initial heparin therapy this is used for long-term anti-coagulant) Newer anti-coagulants 38 Note: Conventional management of DVT will involve immediate administration of Heparin (as it will be effective immediately) before transitioning to longer-term Warfarin (as it takes time to be effective) Caval Filters These are generally not recommended, as it increases the risk of a Caval Thrombosis They are used when anti-coagulants are contra-indicated Control of risk factors (e.g. dehydration, immobilisation, etc.) Understand the need to manage the underlying predisposing factors - Thrombosis needs to be avoided due to the significant adverse consequences that may occur, such as: o Arterial Thrombosis may lead to Stroke / TIA, Myocardial Infarction, Unstable Angina, etc. o Proximal DVT will lead to Pulmonary Embolism in ~50% of patients Venous Thromboembolism (VTE) can have a sudden onset and can potentially be fatal o Therefore, prevention (via routine thromboprophylaxis such as Low Molecular Weight Heparin / Warfarin) is a very valuable and useful therapy - Understand the importance of appropriate specific therapy in reducing the incidence of recurrence - Most patients with have some residual abnormality of the vein following a DVT (which predisposes them to subsequent DVTs) Strategies for prevention of thrombosis include: o Medications Low Molecular Weight Heparin (e.g. Clexane) (short-term) or Warfarin (long-term) Recommended duration of Warfarin therapy will be tailored to the individual depending on their VTE history (i.e. number and type of VTE) Duration may vary from minimum 3 months (VTE with a reversible cause) to indefinitely (i.e. multiple, unprovoked VTE) Aspirin (though effectiveness is mild) o Mobilisation o Hydration o Calf Compression (e.g. TEDS [i.e. Thromboembolism-deterrent Stockings]) - THROMBOPHILIA Understand the pathology, predisposing factors and the treatment of thrombosis - Thrombophilia means a predisposition to thrombosis; this may be due to: o Excess of procoagulant factors o Deficiency of anticoagulant factors o Abnormal Fibrinolysis o Toxic effects on the Endothelium Thrombosis maybe triggered by more than one cause, with a synergistic increase in risk between different risk factors o It is important to identify each of these risk factors to establish treatment o As such, treatment of each individual risk factor will reduce the overall risk of thrombosis Acquired risk factors for Thrombophilia include: o Elderly age o Obesity o Prior history of VTE o Malignancy o Surgery (especially orthopaedic) o Immobilisation - - 39 o - - - - - - Pregnancy Note: Risk of thrombosis is highest post-partum (in addition to risk during pregnancy) o High-Oestrogen levels (e.g. Oral Contraceptive Pill, Hormone Replacement Therapy) This is similar in effect to Activated Protein C resistance o Anti-phospholipid antibodies (e.g. Lupus Anticoagulant) This is one of the strongest thrombophilic factors, and can be a life-threatening condition with both Arterial and Venous Thrombosis o Dehydration o Infection Inheritable risk factors for Thrombophilia include: o Defect or deficiency of an anticoagulant protein (e.g. Antithrombin, Protein C, Protein S) this has a strong impact o Genetic mutation that result in increased tendency to thrombosis (e.g. Activated Protein C resistance, Factor V Leiden, etc.) this has a weak / moderate impact o Other conditions (e.g. Hyperhomocystenimia) this has a weak impact Antithrombin III deficiency is a strong thrombophilic condition with ~60% of heterozygote carriers developing VTE by the age of 60 o Antithrombin is a naturally occurring inhibitor of the coagulation cascade it binds irreversibly to and inactivates thrombin o 60% of patients will have a recurrence of thrombosis o There is a very high risk of VTE (50%) in pregnancy Activated Protein C (along with its co-factor Protein S) will inactivate Factor V and VIII o Protein C and S are vitamin K dependent proteins synthetised by the liver Warfarin targets Vitamin K dependent proteins and so will inhibit Protein S and C This inhibition of Protein S and C will occur prior to the inactivation of the clotting factors, and so initial commencement of Warfarin (without prior provision of Heparin) will trigger a pro-thrombotic state and potentially Warfarin-induced skin necrosis o Protein C is activated by Thrombin o Only ~60% of individuals with protein C or protein S deficiency will develop a thrombosis (i.e. moderate to strong thrombophilic condition) in the majority, the thrombosis will be unprovoked o There is a high probability of recurrence of thrombosis (60% of cases) Factor V Leiden involves a mutation that leads to increased resistance of Factor V to cleavage by Activated Protein C (aPC) o Patients with Factor V Leiden will have an Activated Protein C resistance (as Activated Protein C cannot effectively cleave the Factor V) o This is detected by a clotting assay (aPC resistance) or DNA analysis for Factor V Leiden o This is the commonest cause of inherited thrombophilia o Heterozygous Factor V Leiden is a weak thrombophilic factor and is unlikely to cause thrombosis without other pro-thrombotic factors being present (e.g. OCP, pregnancy and surgery) In contrast, Homozygotes for Factor V Leiden are at moderate risk of thrombosis Pro-thrombin G220210A Polymorphism results in levels of Prothrombin (i.e. Factor II) ~30% higher than normal this is a weak risk factor for thrombosis Thrombophilia testing should only be performed when the result will influence treatment decisions o The patient’s personal history and family history of thrombosis are always more important that the thrombophilia test result, and a negative test should not provide false reassurance o Testing selected patients (e.g. <50 years, family history, prior history of unprovoked VTE, etc.) may give an indication of risk of recurrence o Note: Screening for Thrombophilia does not affect clinical management, as initiation and intensity of anticoagulation should be the same in patients with and without inheritable thrombophilia Thrombosis is largely preventable through appropriate prophylaxis (e.g. medications, compression) o Risk of thrombosis and contraindications should be assessed for patients 40 o Patients are risk with no contraindications should be prescribed prophylaxis Understand the physiological balances that control the haemostatic mechanisms o The exercise of this balance, with excessive fluidity (i.e. haemorrhage) at one extreme and excessive "stickiness" (i.e. thrombosis) on the other is essential for normal blood flow and the maintenance of vascular integrity - The body has created a negative feedback loop to prevent excessive clotting o Undamaged Endothelium will express the Thrombomodulin protein, which will bind with passing Thrombin o This physically removes the amount of freely available Thrombin (which is a pro-coagulant), as well as triggering the activation of Protein C (which inhibits Factor V and VIII) o Hence, there are two mechanisms by which excessive Thrombin will result in the reduction of Thrombin ANTICOAGULANT MEDICATIONS Understand the coagulation pathway as a basis for understanding the sites of action of anticoagulants - Anticoagulants are agents that are antithrombotic through their effect on clotting factors (rather than an effect on Platelets) The coagulation pathway / cascade identified the different clotting factors involved in thrombosis / coagulation o Each of the different factors involved provides a different target for anticoagulation activity (i.e. inhibiting the factor will inhibit the overall coagulation pathway) - Understand the mechanism of anticoagulant action of currently available agents - Heparin o This increases the potency of Antithrombin III (naturally occurring antithrombotic agent) o Unfractionated Heparin (UFH) will be effective through inactivation of Thrombin (x1,0003,000) and to lesser extent Factor Xa and IXa o In contrast, Low Molecular Weight Heparin (LMWH) (e.g. Clexane) catalyse inhibition of Factor Xa only (as unable to catalyse inhibition of Thrombin) Warfarin o Several different clotting factors (Factor II, V, VII and X, Protein C, Protein S) are Vitamin-K dependent for activation o Vitamin K Antagonists (e.g. Coumarins such as Warfarin) will result in the production of dysfunctional clotting factors that are less effective o However, Warfarin affects both pro-coagulation factors (e.g. Factor VII, Factor IX, Thrombin) as well as anti-coagulation factors (e.g. Protein C, Protein S) The rate of clearance of the anti-coagulant factors is shorter than the rate of clearance for all the pro-coagulation factors As a result, Warfarin will initially be pro-thrombotic until the full rate of clearance for the pro-coagulant factors occurs Another anti-coagulant [e.g. Heparin] is typically required when Warfarin therapy is implemented to provide anti-coagulation until the full effect of Warfarin occurs (i.e. over this ‘bridging period’) o There is significant variability in the dosage of Warfarin depending on the patient, as the impact of Warfarin will significantly vary depending on the circumstances of the patient Novel Oral Anticoagulants (NOACs) o All the new anticoagulants that end in the suffix ‘-xaban’ (e.g. Rivaroxaban) are Factor Xa inhibitors - - 41 o o Alternatively, there are NOACs that are direct Thrombin inhibitors (e.g. Dabigatran, Lepirudin) Age, weight and renal function of the patient will affect pharmacokinetics (and hence dosage) Understand the side effects of anticoagulants - Heparin o Side-Effects Increased bleeding rate proportional to APTT Osteoporosis and fractures with prolonged use Elevated hepatic transaminases Hyperkalaemia Heparin induced thrombotic thrombocytopenia syndrome (HITTS) o Other considerations UFH Metabolism is via the liver (and hence can be used in renal impairment); in contrast, LMWH is primarily cleared renally (and cannot be used with renal impairment) APTT levels should be monitored with UFH usage, though is not needed with LMWH usage LMWH has a much more predictable anticoagulant effect compared to UFH As a result, daily monitoring is not required (except in selected patients with particular conditions) Does NOT cross the placenta Protamine Sulfate is a specific antagonist that will enable reversal of the effects of UFH (though only reverses ~60% of effect of LMWH) Warfarin o Side-Effects Exponential rise in bleeding risk with INR (excessive risk if INR > 5) Teratogenic (as it crosses the placenta) Skin-necrosis (due to thrombosis in small vessels following Protein C deficiency result from Warfarin intake) o Other considerations Unpredictable dose-response that will vary by patient Regular monitoring (~once a month once stable) is required for Warfarin given the variability in the impact of Warfarin on different patients Widespread drug and food interactions More regular monitoring is required if there are diet changes given the significant interaction effects of Warfarin with many different types of food Can be reversed via Vitamin K intake or PCC (Prothrombin Complex Concentrate) PCC is the first choice for immediate reversal, though Vitamin K augmentation is needed to sustain this reversal Novel Oral Anticoagulants (NOACs) o Side-Effects Increased bleeding risk o Other Considerations Rapid onset of action with no bridging required Wide therapeutic window with few drug and no food interactions Fixed dosing without monitoring (as there is predictable Pharmacokinetics) Renally eliminated, so may be contraindicated in renal disease Relatively short half-life means anticoagulation may be lost is dosage is missed Lack of reversal agent if there is significant bleeding Note: Indications for NOACs are NOT identical to Warfarin (e.g. NOACs indicated in non-valvular AF, but NOT indicated in prosthetic valve patients or Acute Coronary Syndrome) - - 42 DIAGNOSIS AND MANAGEMENT OF PULMON ARY EMBOLISM Understand the basic pathophysiology and management of pulmonary embolism (defined as the obstruction of a pulmonary artery, usually by a blood clot) - Pulmonary Embolism (PE) occurs due to a DVT that embolises and travels to the pulmonary circulation o This clot in the leg from the DVT can become dislodged and then travel to the lung resulting in a PE (which can cause death) DVT below the knee will not become a Pulmonary Embolism, but can risk becoming a DVT above the knee DVT above the knee has a risk of becoming a Pulmonary Embolism and hence requires treatment (e.g. anticoagulants, thrombolysis, Inferior Vena Cava filter, etc.) o Cramping / ‘torn muscle’ pain may be a sign of DVT Key symptoms of PE include: o Shortness of breath (~70-80% of patients with PE will present with Shortness of Breath) o Pleuritic Chest Pain (i.e. worse on inspiration) o Light-headedness (due to lack of oxygen transfer) Key signs of PE include: o Pleural rub o Tachycardia o Tachypnoea o Hypoxia o Swollen leg o Elevated JVP ECG of a patient with PE will have inversion of T waves on precordial leads Diagnosis of PE requires confirmatory testing: o CT Pulmonary Angiogram (CTPA) is the gold-standard test for PE o Ventilation Perfusion Scan (i.e. VQ Scan) or Doppler Ultrasound of lower limbs can also be performed to assess for the presence of a clot Treatment will include anticoagulation, oxygen therapy, IV fluids and analgesia these are highly effective at treating PE! o IV Heparin (unfractionated) was the standard immediate treatment for PE for many years and involved the continuous IV administration of Heparin Low molecular weight Heparin has been developed more recently and is preferable as it is easier to administer (sub-cutaneously once or twice daily) and requires less monitoring Warfarin (or the new anticoagulants such as Rivaroxaban) is the longer-term anticoagulation therapy used to treat patients presenting with PE o However, in special circumstances, treatment may involve thrombolysis, surgery (i.e. embelectomy) and / or IVC filters Thrombolysis involves the provision of an agent (e.g. Streptokinase and t-PA [Tissue Plasminogen Activator]) that will physically dissolve the clot Anticoagulants do NOT physically dissolve the clot, but rather stabilise the clot (which enables the body’s fibrolytic system to dissolve the clot) However, the difficulty with this treatment is that the risk of bleeding is high Embolectomy is only indicated in severe PE (e.g. patient with Systolic BP <90 and HR > 100 from >30 minutes) IVC Filter is particularly useful when a patient is contraindicated for the use of anticoagulant medications (e.g. post-neurological surgery) - - - - Understand the formation of venous and other types (e.g. fat, air, septic emboli, tumour) of embolisms - Risk of venous thrombosis / clotting increases with: o Stasis 43 - - o Endothelial damage o Hypercoagulability Air embolism can result from small amount of air accidentally entering the blood during surgical or other medical procedures (e.g. injection) o Alternatively, air will enter if a blood vessel is open and there is a pressure gradient favouring entry of the air o There is the existence of an air pressure gradient in the veins above the heart (though normally the pressure inside vessels is higher and hence air will not enter) Fat embolism can result from trauma to bone / soft tissue resulting in the release of fat into the circulation; alternatively, it may result from aggregation of plasma lipids due to disturbances in the emulsification of fat SEMINARS EBM – ROLE OF RADIATION IN LEUKAEMOGENESIS Develop the evidence-based appraisal skills to critically review articles in relation to electromagnetic fields and the genesis of cancer - Ecological Study is based on aggregated data for some population as it exists at some point or points in time o This will be used to investigate the relationship of an exposure to a known or presumed risk factor for a specified outcome o Ecological Study does NOT need to be across an entire country, but can be for a smaller geographic area (e.g. North Shore of Sydney); the key point is that this is a study based on a broad population rather than a study based on a sample of individuals Foreground studies will focus on a particular clinical question, whilst Background studies will provide context / commentary (rather than answering a particular clinical question) Observational studies that have a Relative Risk less than 2 are likely to have their result driven by residual bias rather than an underlying difference (given the lack of randomisation / adjustment for other exposures / factors) - EBM – CRITICAL APPRAISAL OF DIAGNOSIS OF DVT AND PE Understand the general framework of searchable questions in relation to diagnostic tests - Use PICO (Population, Intervention [i.e. Diagnostic Test], Comparator, Outcome) framework for developing searchable questions in relation to diagnostic tests Understand the study designs that are used in evaluating diagnostic tests - Clear, strong standards for studies on Diagnostic tests have only been developed in the past ~10-25 years o It is important there are clear standards to ensure the reliability and accuracy of the results A study design that can be used to evaluate diagnostic tests is the cross-sectional analytic study (e.g. where the results from the V/Q Scan are compared with the results from the angiogram) - Understand the concepts of pre-test probability, sensitivity and specificity - Pre-test probability = Probability of the presence of a condition prior to the diagnostic test Sensitivity = Proportion of actual positives correctly identified by the test Specificity = Proportion of actual negatives correctly identified by the test MEDICATIONS IN PREGNANCY 44 Understand the appropriate use of medications during pregnancy - New drugs will be classified as either B1, B2 or B3 (only older drugs are classified as A, C, D or X); each of these categories refer to different risk levels when used in pregnancy o The older categories are: A = Drugs taken by large number of pregnant women & women of child bearing age without proven problems C = Drugs, owing to their pharmacological effects have caused, or may cause harmful effects on foetus B1 = Animal data shows no problems B2 = Animal data inadequate B3 = Animal data shows problems, but significance to humans uncertain D = Have caused, or suspected to have caused foetal malformations (e.g. Warfarin) X = High risk – not to be used in pregnancy! o These categories don’t provide any information about how risk varies with the dosage or timing of use of the drug in pregnancy o The same drug taken later in pregnancy and / or in lower doses is less likely to cause problems compared to when taken earlier in pregnancy and /or in higher doses Category D drugs can cause significant malformations, so its use is a value judgment about whether the benefits of these drugs exceed the risk of the drug (e.g. anti-convulsants in Epileptic mother) There are a range of teratogenic drugs in humans; these include: o Anticancer agents o Alkylating agents (e.g. Cyclophosphamide) o Anti-metabolites (e.g. Methotrexate) o Androgenic hormones o Anticonvulsants (e.g. Carbamazepine) o Coumarin anticoagulants (e.g. Warfarin) o Retinoic Acids (these cause severe malformations!) Inter-species differences in teratogenicity may be due to different development and / or metabolism (as the teratogenic molecule may be the metabolite rather than the initial drug itself) between species o Certain drugs may not appear teratogenic in animal studies but actually be teratogenic in humans o Conversely, certain drugs may appear teratogenic in animal studies but are not teratogenic in humans Teratogens show threshold and dose-response effects Teratogens may not have immediate effects, but instead have delayed effects (e.g. delayed intellectual development due to alcohol exposure) Contraindicated Drugs in Lactation are those drugs that are dangerous are therapeutic doses (e.g. Chemotherapy drugs, street drugs, etc.) Low molecular weight Heparin (e.g. Clexane) is the treatment of choice in pregnant women when they require a blood thinner o In contrast, Warfarin is a Category D drug as it crosses the placenta and may cause intracranial haemorrhage or Fetal Warfarin Syndrome o Note: Epidural is contraindicated within 24 hours of the last Clexane infusion due to the risk of bleeding, so ensure patient stops Clexane infusions after entering labour (and notify the Anaesthetist regarding Clexane treatment) General principles of medication usage in pregnancy are: o Avoid polytherapy where possible o Use the lowest effective dosage o Older drugs generally have more pregnancy safety data o Minimise use of OTC and Herbal medications o Pointless using an ineffective drug purely for ‘fetal safety’ reasons - - - - DEATH AND DYING 45 Understand the variety of professional responses to death and dying among experienced staff - Dying patients key goals include symptom control, not being a burden on family and completing unfinished tasks Don’t be afraid to use the words ‘death’ or ‘dying’ as it is important to be honest o Leverage the experience / expertise of nurses who will have a lot of experience in death / dying and supporting patients and their families Providing spiritual care will be important; if the patient does not have their own spiritual provider, pastoral care / chaplain services can be provided via the hospital It is important to be clear when communicating bad news rather than using ambiguous euphemisms that may not be understood o There is a need to use the phrase ‘dead’ or ‘passed away’ when communicating about a patient death rather than euphemisms such as ‘moved on’ Studies have shown it will take ~3 minutes from the point of saying ‘dead’ or ‘passed away’ for a family member to understand / comprehend the patient has passed away o Family member will immediately undergo shock o The point of understanding / comprehension (which takes ~3 minutes) will be identified by the family member asking to do something (e.g. call a family member to pick up their children, see the body, etc.) or saying that they feel something It is important to speak / debrief will others regarding death to avoid becoming overburdened by death - - - - SERVICES TO THE ELDERLY Understand the complex needs of the frail and disabled elderly - Elderly people with cognitive impairment / memory loss are more likely to have falls, because they fail to realise they are older and lack the same mobility as when they were younger o This applies even if the patient can walk relatively well normally as they still may push themselves beyond their capabilities Elderly require support to complete activities of daily living (ADLs) and instrumental activities of daily living (IADLs) given the range of conditions affecting them such as: o Cognitive impairment / memory loss o Arthritis o Lack of mobility - Understand the range of services available to support the elderly and their carers in the community - Range of services available include: o Community Nurses – they can provide medication, dressings and assist with hygiene o Homecare – they assist with IADLs such as meal preparation, housework, laundry, shopping, transport to medical appointments, etc. o Meal Services (e.g. Meals on Wheels, Tender Loving Cuisine) o Community Transport – provide transport for both individuals and in groups (e.g. shopping, monthly outing, individual appointments, etc.) o Day Centre – provide respite for frail aged and dementia clients o Dementia Support Service – service for those caring for family/friends with dementia; they provide support and education to carers as well as in-house respite on a regular basis o Community Aged Care Package – provide ‘low-level’ care at home (i.e. similar to Homecare) o Extended Aged Care Package – provide ‘high-level’ care at home ComPacks are a case managed package of care for up to 6 weeks after discharge from hospital o This is available to those patients, of all ages needing two or more community services to return home safely with appropriate care in place o This consists of ‘low-level’ care at home (similar to Homecare) - 46 - Transitional Aged Care Program is a program to assist older people following a period of hospitalisation o The program is time limited, goal orientated and therapy focused (e.g. physiotherapy, OT, speech) as well as providing low-level care as needed (e.g. shopping, bill paying, personal care, housework, etc.) o The program runs for a period of 12 weeks o The program must be accessed directly from hospital Understand the accessibility and funding of the services available to support the elderly and their carers in the community - Many of these services are privately run (albeit by not-for-profit organisations) and need to paid for by the patient o Government support is available to subsidise the cost of many of these services o However, many of these services will still be expensive for an elderly patient on the aged pension DOCTOR, CHILD AND FAMILY Understand the issues and evidence in the area of child abuse - Five different types of child abuse include physical, sexual, psychological, neglect and / or domestic violence o Sexual abuse can include non-contact behaviours such as having children pose in sexually explicit manners, exposure of child to sexual material (e.g. pornography) o Physical abuse and / or neglect does not need to be intentional; instead, what is important is the outcome to the child Hitting children with implements is legal in NSW, although excessive discipline is illegal o Neglect is the failure to provide the basic necessities of life; this may or may not be intentional Neglected children may be underweight, overwhelmingly smelly, lack toilet training, sick, quiet / sedated, over-independent (as they are compensating for the lack of parental support, which means they lose the opportunity to be a child), stealing food (due to hunger), etc. o Serious psychological harm can occur where the behaviour of their parent or caregiver damages the confidence and self esteem of a child or young person resulting in serious emotional deprivation or trauma o Children and young people may experience harm from domestic violence on a number of levels Understand the responsibilities of the doctor vis-à-vis the child and family - Legislation specified that the ‘safety, welfare and wellbeing of the child or young person is paramount’ this means the child is always the priority (even if the client / patient is the parent) ‘Mandatory Reporting’ means there is a legal responsibility for health care workers to report child abuse and / or risk of significant harm to the authorities (i.e. Community Services or Child Wellbeing Unit) o Consequences of failing to report abuse is that children continue to be harmed, health care worker becomes an accessory to the abuse (and may lose their job / registration to work), etc. o Health care workers reporting in good faith cannot be have any action taken against them if the report proves to be unnecessary / incorrect o Risk of significant harm will include the parents not only intentionally failing to provide sufficient care but also being unable to provide sufficient care Personal lives of health care workers are reportable / relevant for their professional lives - - 47 o This will be when there is actions / problems in the personal lives of the health care workers that relate to children (i.e. under 18 years of age) MOLECULAR DIAGNOSTICS IN HAEMATOLOGY Understand the molecular biology techniques used in the diagnosis and treatment of patients with haematological disorders - Immunohistochemistry and flow cytometry have been used to identify the specific surface proteins on the different B-Cells and T-Cells present in haematological disorders o Identification of a monoclonal population is indicative of the presence of malignancy o Furthermore, presence of T-Cell proteins (e.g. CD5+) and B-Cell proteins (e.g. CD20) on a BCell is indicative of Chronic Lymphocytic Leukaemia (CLL) Identification of the specific DNA mutations causing a condition will provide an understanding of the severity of the condition (e.g. Thalassaemia, Thrombophilia, etc.) - ETHICS OF PRENATAL D IAGNOSIS Understand the ethical and legal aspects of prenatal diagnosis, particularly as they relate to haematologic disorders - Key legal and ethical aspects include: o Pre-diagnosis counselling (e.g. impact on test, types of possible decisions, etc.) o Optimum time for diagnosis o Limitations of diagnosis (i.e. informativeness and accuracy of pre-natal testing) o Perceived disabilities burden vs. procedural risk o Moral / spiritual considerations (e.g. value of life) o Technical and legal limits for termination o Post-termination support and counselling VIDEO PRESENTATION – TRANSFUSION PRACTICE Understand the rationale for clinical protocols and practices in the cross matching and transfusion of blood - N/A – did not receive this seminar Refer to ‘Lecture – Blood Products in the Treatment of Disease’ and ‘Practical – Laboratory Skills – Group X-Match’ for information on principles of cross-matching and blood transfusion CASE PRESENTATION – HAEMOPHILIA AND VON WILLEBRAND DISEASE Understand the clinical picture of patients with inherited bleeding disorders - There have been significant advances in haemophilia treatment since the 1980’s o Treatment (i.e. clotting factors) could now be performed within 15 minutes rather than the previous 4 hours This enabled treatment to be administered in home rather than in hospital As a result, patients with haemophilia from older generations would have significantly more damage to their joints (due to additional bleeding into the joint) compared to more recent haemophilia patients (who were able to receive treatment earlier) o The potency of the treatment has also improved in the past 20 years, which makes it easier to transport treatment for long periods (i.e. 4 weeks treatment can fit in a backpack rather than a whole suitcase) o There has been a ~tripling in the number of units per head in the past two decades (~2 units / head to ~7.2 units / head) due to the increased availability of recombinant blood products (rather than due to an increase in the incidence of Haemophilia) 48 - - - - - The severity of Haemophilia will be based on the level of clotting factors present as: o <1% Factor Levels are Severe Haemophilia (Spontaneous Bleeding) o ~1-5% Factor Levels are Moderate Haemophilia (Bleeding on Trauma) o ~6-20% Factor Levels are Mild Haemophilia (Bleeding on Surgery) o Note: The severity of the Haemophilia will be consistent in the family as the same mutation / deletion occurs throughout the family Haemophilia patients that are bleeding in their urine should drink more water as increased urine production will ideally wash away any clots Genetic Mutations cause ~50% of the cases of Haemophilia, with gene deletions (both small and large) another cause of Haemophilia Genetic therapies are being considered to resolve the absent or dysfunctional clotting factors in Haemophilia o Factor IX gene is smaller than the Factor VIII gene and is more amenable to gene therapy (as smaller genes are easier to insert into a vector) Genetic testing can be used to help women identify whether they are carriers of Haemophilia o Geneticists will definitely examine Intron 22 to determine whether this genetic abnormality that causes Haemophilia is present vWF (Von Willebrand Factor) disease is increasing in incidence (~1% of population now) o There are three types of vWF disease that are each different biochemically (which can be determined via gel electrophoresis) o Treatment of vWF disease requires normal human plasma (as recombinant blood products lack the Von Willebrand Factor and hence are ineffective) Distinguishing between Haemophilia A and B cannot be performed clinically; this necessitates laboratory testing o 1 Unit of Factor VIII will significantly increase the Factor VIII percentage whilst 1 Unit of Factor IX will only moderately increase the Factor IX percentage PRACTICALS LABORATORY SKILLS – FULL BLOOD COUNT AND COAGULATION Understand the laboratory investigations associated with anaemia and clotting (in particular blood counting, film preparation and examination, and basic coagulation testing) - Full Blood Count (FBC) refers to the Haemoglobin, White Blood Cells and Platelets Normal Range for the following blood components are: o Haemoglobin = 115 to 155g/L (women) OR 130 to 175g/L (men) o MCV = 80-100fL o White Cell Count = 4-11 x 10^9/L o Platelets = 150-400 x 10^9/L o Note: Remember that the reference ‘normal’ ranges are based on 95% of the population so there is a small minority These ‘normal’ ranges are also tailored towards Caucasian people so people of other ethnicities will have slightly different normal ranges LABORATORY SKILLS – GROUP X-MATCH Understand the major principles associated with blood bank procedures - There are very careful procedures / processes in place to screen for blood-borne viruses / bacteria, and ensure the blood transfusion is free from any bacteria / virus o Patient serum is tested against a panel of red cells to identify all clinically important antibodies (and hence antigens) Blood bank will assess the blood group (A, B, AB, O) and the Rh status of the patient and identify a compatible supply / donor of blood - 49 o o Cross-match will involve comparing the patients RBCs to different serum antibodies, as well as adding the patients serum to different group RBCs this provides a double-check to ensure the accurate identification of the patient’s blood group If antibodies were detected on the antibody screen of the patient’s serum, then blood is chosen that does not have the corresponding antigen INTERPRETING ABNORMA L BLOOD COUNTS / FILMS Understand the interpretation of abnormal blood counts and films - Normal Red Blood Cells will have a central area of pallor that is ~1/3 of the diameter of the entire red blood cells Neutrophil is ~2-3x the size of a RBC and will have a multi-lobular (i.e. segmented) nucleus o There will also be granularity in the cytoplasm Monocytes have a large sized nucleus and a relatively smaller % of cytoplasm compared to Neutrophils Iron deficiency o RBCs show slight hypochromasia and anisocytosis (i.e. variation in cell size) o Occasional pencil cells and target cells Leucoerythroblastic (i.e. carcinoma of the stomach) o Red cells show moderate anisocytosis and poikilocytosis (i.e. variation in cell shape) o There are occasional immature granulocyte forms and a few nucleated red cells o Platelet numbers are reduced Anaemia of Renal Failure o RBCs show anisocytosis and poikilocytosis, o Marked rouleaux formation Heterozygous Beta-Thalassaemia o RBCs show moderate anisocytosis and hypochromasia o There are target cells, and some basophilic stippling (i.e. RBCs display small dots on the periphery of the RBC) Chronic Lymphocytic Leukaemia o Marked lymphocytosis o Numerous ‘smudge cells’ Autoimmune Haemolytic Anaemia o Marked anisocytosis and polychromasia o Nucleated RBCs o Numerous Spherocytes Anaemia of Chronic Disease o Slight anisocytosis and polychromasia o Some Rouleaux formation Acute Myeloid Leukaemia o Red cells show moderate anisocytosis and poikilocytosis o Numerous blast cells (some with Auer rods) Auer Rods are elongated needles in cytoplasm of blasts Auer Rods are NOT present in Lymphoid Leukaemia Chronic Myeloid Leukaemia o Red cells show moderate anisocytosis and poikilocytosis o Leucocytosis with Neutrophilia and increase in the whole spectrum of blasts / intermediate precursors (e.g. pro-Myelocytes, Myelocytes, Meta Myelocyte, Band Neutrophil) o Eosinophilia and Basophilia Immune Thrombocytic Purpura o RBCs are normal o Platelet levels are markedly reduced - - - - - - - - - - 50 INTERPRETING LABORAT ORY TESTS IN BLEEDING DISORDERS Understand the principles of interpreting laboratory tests for bleeding disorders - The best indication of whether a patient is a bleeding risk is whether there is a history of bleeding o Anticoagulant tests provide a useful indication of the bleeding risk, but the actual bleeding risk will depend on the characteristics of the patient o Hence, the results from the anticoagulant tests do NOT necessarily provide a clear answer whether or not patient is a bleeding risk High haematocrit and high WCC patients may deliver spurious coagulation test results; this is due to these high levels taking extra space and reducing the space available for the Clotting Factors o Analysis of these samples will indicate lower Clotting Factor levels than there actually exists Factor VIII deficiency in a female patient is highly suggestive of the presence of Von Willebrand Disease When investigating for the existence of DIC (Disseminated Intravascular Coagulation), measure the levels of D-Dimer and Fibrinogen (in addition to INR and APTT) o High D-Dimer and Low Fibrinogen levels [and Thrombocytopenia] are indicative of significant clotting; when this is present with prolonged INR / APTT, this suggests DIC Remember to measure baseline coagulation levels prior to provision of anticoagulants (as this will enable an accurate calculation of the impact of the anticoagulant medication provided) When measuring the level of a drug in the body, measure the drug levels after 5 half-lives of the drugs (this is needed to reach the maintenance dosage level) o For Heparin, the time to measure the level of Heparin will be ~6 hours after infusion commences o Ensure NOT to take blood from the same location where the Heparin is being intravenously infused! - - - INTERPRETING LABORAT ORY TESTS IN ANAEMIA Understand the methods of diagnosis of anaemia on interpretation of laboratory investigations - Reticulocytosis will suggest that the supply of red blood cells is appropriate and hence the bone marrow is operating correctly o Any anaemia is these patients would indicate a problem with the demand for blood (e.g. haemolysis, haemorrhage) rather than supply of blood Low Ferritin is a highly specific marker of Iron-deficiency o The other iron metrics (e.g. Iron, Transferrin, Transferrin Saturation) are also important as Ferritin levels may not be sensitive enough and so the other metrics may be needed to detect iron deficiency For example, Ferritin levels is an acute phase reactant and may be increased due to other reasons (e.g. inflammation) which results in a normal Ferritin level despite being iron deficient o Transferrin Saturation is the next most useful measure of Iron deficiency after Ferritin levels Serum Folate reflects the recent intake of Folate, whilst Red Cell Folate is a better estimate of iron stores (as this is based on folate levels when the RBCs were formed [which would be up to 120 days prior]) Haemolytic screen will involve assessing several different factors for signs of bleeding o High Reticulocytes, High Bilirubin, High Lactose Dehydrogenase and Low Haptoglobin levels as well as positive Coombs tests (i.e. antibody present on surface of RBC’s) and Polychromasia and Spherocytes on a Blood Film will be indicative of haemolysis ‘Leukaemia’ will be indicated by high WCC counts in FBC o High WCC with high levels of lymphocytes is indicative of Chronic Lymphocytic Leukaemia (CLL) o Presence of T-Cell surface proteins (e.g. CD5) on B-Cells are also an indication of Chronic Lymphocytic Leukaemia - - - - 51 - The % of sickles and appearance of blood is not related to the clinical manifestation of Sickle Cell Anaemia o Sickle Cell Anaemia is a clinical diagnosis rather than a laboratory diagnosis IMAGING IN HAEMATOLO GY Understand the range of imaging modalities available for investigating haematological disorders - A wide range of imaging modalities are used for investigating haematological disorders; these include: o X-Ray o Ultrasound o CT Scan o MRI o Nuclear Medicine Scans (e.g. PET Scan) o Angiography Occult bleeding in the GIT historically was identified via Barium Enema (in addition to polyps and other abnormalities) o Now, alternative investigations such as Upper and Lower Endoscopy is used instead to search for occult bleeding Virtual Colonoscopy is a computer-generated image based on the CT scan; this can help identify polyps, lesions, etc. There are signs of Thalassaemia that may be visible from a PET scan, though the diagnosis of Thalassaemia will only be made based on the blood tests (and NOT the imaging) Sickle Cell Anaemia may be visible on an X-Ray from the occlusion of vessels, and its consequent impact on the bone Radiology / imaging can assist with determining the stage of the Leukaemia - 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