Download 23.Clinical pathophysiology of the blood sysytem

CLINICAL PATHOPHYSIOLOGY OF
BLOOD SYSYTEM
Objectives
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•
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Identify the components of blood.
Enumerates what does blood do.
Define the anaemia.
Discus the etiologic classification of anaemia.
Objectives Cont.
• Identify the clinical manifestations, Aetiology,
Diagnosis, Treatment, Nursing care for:
 Iron deficiency anaemia.
 Megaloblastic or Macrocytic Anaemia:
Cobalamin(vitamin B12)
Folic acid deficiency
 A plastic Anaemia
 Haemolytic Anaemia
 Haemolytic Anaemia
Hematology
Study of blood and blood forming tissues
Key components of hematologic system are:
Blood
Blood forming tissues
Bone marrow
Spleen
Lymph system
What Does Blood Do?
• Transportation
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–
–
–
Oxygen
Nutrients
Hormones
Waste Products
• Regulation
– Fluid, electrolyte
– Acid-Base balance
• Protection
– Coagulation
– Fight Infections
Components of Blood
• Plasma
– 55%
• Blood Cells
– 45%
– Three types
• Erythrocytes/RBCs
• Leukocytes/WBCs
• Thrombocytes/Platelets
Erythrocytes/Red Blood Cells
• Composed of hemoglobin
• Erythropoiesis
= RBC production
• Stimulated by hypoxia
• Controlled by erythropoietin
– Hormone synthesized in kidney
• Hemolysis
– = destruction of RBCs
– Releases bilirubin into blood stream
– Normal lifespan of RBC = 120 days
Leukocytes/White Blood Cells
• 5 types
– Basophils
– Eosinophils
– Neutrophils
– Monocytes
– Lymphocytes
Thrombocytes/Platelets
• Must be present for clotting to occur
• Involved in homeostasis
Anaemia
Definition
The term of anaemia refers to a deficiency in the
number of circulating red blood cells available for
oxygen transport
What is the etiologic classification of anaemia ?
1- Iron deficiency anaemia
When the stored iron is not replaced, haemoglobin
production is reduced leads to iron- deficiency
anaemia
Anaemia Cont.
Iron deficiency anaemia Cont.
Aetiology
Inadequate dietary intake, malabsorption.
Blood loss of haemolysis
Gastrointestinal blood loss e.g. Peptic ulcer,
gastritis, oesophagitis.
Menstrual bleeding....
45 ml.....loss of 22mg of iron
Pregnancy...diversion
of iron to the foetus
Iron deficiency anaemia Cont.
Clinical manifestation
In early course , the client may be free of symptoms
Mild.... Pallor , fatigue and exertion dyspnea.
Sever.....
 Nail become brittle and concave and longitudinal ridges.
 Glossitis (inflammation of tongue), bright- red .
 Cheilosis (inflammation of lips- The corners of mouth
may be cracked, reddened and painful.
 Headache, paresthesia.
 Burning sensation of the tongue result to lack of iron
in tissues.
Iron deficiency anaemia Cont.
Management
Diagnosis
 Peripheral blood smears (CBC)
 Low serum iron levels, and elevated serum iron- binding
capacity.
 Absent iron stores in the
bone marrow.
 endoscopy, or colonoscopy
to detect GI bleeding.
Iron deficiency anaemia Cont.
Role of nutrients for erythroporesesis
 Cobalamin (Vit B12) has role in RBC maturation found in red
meat especially liver.
 Folic acid has role in RBC maturation in leaves, fish.
 Vitamin B6 has role in haemoglobin synthesis found in eggs,
whole grain and bread, potatoes.
 Amino acids has role in synthesis of nucleoproteins
found in eggs, meat, milk, milk products
 Vitamin C has role in conversion of folic acid to its active
forms aids in absorption.
Iron deficiency anaemia Cont.
Medical therapy
Oral iron supplements (ferrous sulphate)
It should be taken after meals and with orange juice
Told the client that the stool will be black.
Parenteral iron is administered by IM or IV
Megaloblastic or Macrocytic Anaemia
It characterized by morphological changes caused
by defective DNA synthesis and abnormal RBC
matured.
The common forms of mgaloblastic anaemia:
1- Cobalamin(vitamin B12)
o Result from dietary deficiency.
o Deficiency of gastric intrinsic factors.
o Intestinal malabsorption and increased
requirement.
Megaloblastic or Macrocytic Anaemia Cobalamin(vitamin B12)
Symptoms
a. General symptoms of anaemia .
b. GIT manifestation a a sore tongue, anorexia,
nausea, vomiting and abdominal pain.
c. Neurovascular manifestation as weakness,
parethesias of the feet and hands, muscle
weakness, impaired thought process ranging
from confusion to dementia
Megaloblastic or Macrocytic Anaemia Cobalamin(vitamin B12)
Diagnosis
Abnormal Schilling test result which demonstrates, the
inability to absorb vitamin B12.
Treatment
I. Parenteral administration of vitamin B12 once/month.
I. The nurse should ensure that injuries
are not sustained because of the
diminished sensation to heat and
pain due to neurologic impairment.
I. Protect client from burn and trauma.
II. Evaluate skin for redness.
Megaloblastic or Macrocytic Anaemia
Folic acid deficiency
Folic acid required for DNA synthesis leading to RBC
formation and maturation.
Daily requirement of folic acid 100 to 200 mg.
Causes
• Poor nutrition (Lack of vegetable, yeast, nuts, grains.
• Malabsorption syndrome.
• Drugs that impede the absorption and use of F acid
(oral contraceptives ,anti seizure agents).
• Alcohol abuse and anorexia.
• Haemodialysis client because of folic aid is dialyzable.
• Pregnancy, and increased requirement & malnutrition.
Megaloblastic or Macrocytic Anaemia Folic acid deficiency
Clinical manifestation
Similar to cobalamin deficiency except the absence of
neurologic problem, this lack of neurologic involvement
differentiate folic acid deficiency from vit. B12.
Diagnosis
Low serum folate level.
Treatment
 Anaemia caused by a dietary deficiency can be treated with
1 mg of folic acid for 3- month period.
 Diet ... Orange, meat, eggs, cabbage, citrus fruits .
A plastic Anaemia
Related to reduced or impaired erythrocyte
production (fatty bone marrow).
Aetiology
It can be divided into the major groups:
1- Congenital
Caused by chromosomal alterations.
2- Acquired as a result of exposure to:
 Ionizing radiation, chemical agents (DDT, alcohol)
 Viral and bacterial infection(hepatitis, miliary TB)
A plastic Anaemia
Aetiology Cont.
Prescribed medication(alkalating agents,
antimicrobial)
Pregnancy.
Idiopathic
Pathophysiology
It caused by depression of activity of all blood-producing
elements { There is decrease in white blood
cells(Leukopoenia), Platelets(Thrombocytopoenia), and
decrease in the formation of RBC, which lead to
anaemia.
A plastic Anaemia Cont.
Clinical Manifestation
Pallor of skin and mucous membranes.
Cardiovascular (fatigue, and dyspnea on
exertion, palpitation)
 Cerebral responses
Infection of skin and mucous membrane.
Haemorrhagic symptoms(bleeding tendencies
into the skin and mucous membranes, nose,
gums, vagina and rectum
Pallor of skin
A plastic Anaemia Cont.
Management.
1. The CBC characteristically reveals a pancytopoenia
(a marked decrease in the numbering of cell types)
2. The reticulocyte count is low .
3. Bone marrow examination and biopsy
Treatment
 Bone marrow transplantation from a donor
with identical human leukocyte antigen for
person younger than 40 years.
A plastic Anaemia Cont.
 The remainder of persons are treated with
immunosuppressive therapy.
Nursing care
Is based on careful assessment and management of
complications of pancytopoenia by:
o Private room.
o Protective isolation
o Provide and instruct the client on meticulous hygiene.
o Assessment and maintenance of oral care regimen.
o Monitor invasive lines for sign of infection.
A plastic Anaemia Cont.
Nursing Care Cont.
o Avoid bladder catheterization.
o Instruct family and visitors on careful hand washing.
o Nursing intervention for preventing bleeding.........
Teaching the person with a plastic anaemia include:
 Prevent infection.
 Prevent haemorrhage.
 Prevent fatigue.
Haemolytic Anaemia
Definition
Premature destruction of erythrocyte occurring at such a rate
that the bone marrow is unable to compensate for the loss
of cells.
Haemolysis can occur either extra vascular or
intravascular.
 In extra vascular, the spleen removes erythrocytes from
circulation at much more rapid rate.
 In Intravascular it is secondary to the erythrocyte lysing
and spilling the cell contents into the spleen
Haemolytic Anaemia Cont.
Aetiology
The causes may be acquired form or hereditary forms
Acquired forms
 Immune system-mediated haemolysis is caused or
associated with transfusion reactions, haemolytic
disease of the newborn
 Traumatic haemolysis is caused by presence of
prosthetic heart valves; structural abnormalities of the
heart; haemodialysis.
 Infectious haemolysis are due to bacterial infection
(cholera, typhoid)
Haemolytic Anaemia Cont.
 Toxic (chemical) haemolysis occurs as the result of
exposure to toxic chemical agents; haemodialysis or
uraemia.
 Physical haemolysis are due to burns and radiation.
 Hypophosphatemic haemolysis are due to
hypophosphatemia (phosphate deficiency in plasma.
Hereditary Form
 Structural defect i.e., plasma membrane defect,
destruction due to fragility of the erythrocyte.
 Enzyme deficiency i.e., deficiency of glycol tic enzymes
Haemolytic Anaemia Cont.
Clinical Manifestation
 Ischemia occurs when red cells clump in the capillary
beds, causing cyanosis, pain and paresthesia.
 Haemoglobinuria.
Management
Diagnosis
The presence of the antibody or complement on the
RBCs (direct Coomb’s test) or in the serum(indirect
Coomb’s test)
Decreased Hct.
Increased reticulocyte and bilirubin
Anaemia caused by blood loss
Anaemia resulting from blood loss may be caused
by either acute or chronic.
Aetiology /Pathophysiology
I. Trauma
II. Complications of surgery
III.Diseases that disrupt vascular integrity.
There are two clinical concerns in such
situation
First
 There is sudden reduction in the total blood volume
that can lead to hypovolaemic shock.
Haemolytic Anaemia Cont.
Treatment
Mild cases require no treatment.
Supportive care includes:
 Administering corticosteroids and blood products.
 Removing the spleen.
Nursing Management
 Teach the client about drug therapy.
 Preparing the client for surgery.
Anaemia caused by blood loss Cont.
Second
 If the acute loss is more gradual, the body
maintains its blood volume by slowly increasing
the plasma volume.
 Consequently, the circulating fluid volume is
preserved. But the number of RBCs available to
carry oxygen is significantly diminished.
Anaemia caused by blood loss Cont.
Clinical Manifestation
Clinical manifestation of acute blood loss according to varying
degrees of blood volume loss as follows:
Volume
loss
Clinical manifestation
10%
None
20%
No detectable signs or symptoms at rest, tachycardia with exercise
and slight postural hypertension.
30%
Normal supine blood pressure and pulse at rest , postural
hypertension and tachycardia with exercise.
40%
Blood pressure, central venous pressure, and cardiac output below
normal at rest, rapid , threading pulse and cold and clammy skin.
50%
Shock and potential death
Anaemia caused by blood loss Cont.
Management
Replacing blood volume to prevent shock.
Identify the source of haemorrhage and stopping
blood loss.
IV fluid used in emergency includes dextran,
albumin, or crystalloid electrolyte solution such
as ringer lactate
Blood transfusion (packed RBCs)
Supplemental iron .
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