Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Self-experimentation in medicine wikipedia , lookup
Focal infection theory wikipedia , lookup
Dental emergency wikipedia , lookup
Mosquito control wikipedia , lookup
Eradication of infectious diseases wikipedia , lookup
Diseases of poverty wikipedia , lookup
Infection control wikipedia , lookup
PBL SEMINAR FEVER IN A RETURNED TRAVELLER OUR PATIENT CASE Our patient is Jenny Randall, a 23 y.o. female student who presents to her local doctor with cough and fever having recently returned from a 3 week holiday IMPORTANT 1. 2. What’s common is common The diagnosis is MALARIA MALARIA MALARIA until proven otherwise. How to take a History from a Returned Traveller Fever WWQQAAB Travel History: Country of birth Housing Occupation Contacts Other drugs Leisure time Animals Travel Eating and Drinking Sexual history CHOCOLATES HOPC Travel History: CHOCOLATES Travel History: Country of birth Housing Occupation Contacts Other drugs Leisure time Animals Travel Eating and Drinking Sexual history CHOCOLATES Patient History Ms Jenny Randall, a previously well 23 year old medical student, presents to her local doctor with a cough and fever. Jenny recently returned from a 3 week trip to Thailand, Cambodia and Vietnam. In the 3 days leading up to her presentation at the clinic, Jenny experienced the following symptoms: •fevers •rigours (what makes them rigours?) •myalgia •mild non-productive cough •malaise •mild headache •No relevant past medical history •Family history of CVD- father died of AMI at 58 Medications •OCP •Paracetamol for fever •NKDA Social History •Smokes 10-20 cigarettes/day, •no ETOH, •one regular and one new sexual partner in past 6 months, uses condoms 100 % of the time TRAVEL SPECIFIC QUESTIONS Born in Australia Travelled to Vietnam via Thailand and Cambodia for 3 weeks during the hot/rainy season Returned for two weeks before becoming unwell Stayed in budget, sometimes crowded accomodation throughout recent travel Exposure to water, mosquitos, flies Recent contact has a 'cold' Took prophylactic Doxycycline for one week before discontinuing Had pre-travel Typhoid and HepA immunisation and previous HepB immunisation Often prepared own food, no GI symptoms !~RED FLAG~! What symptom stands out as a red flag? RIGORS! What are rigors? Episodes of uncontrollable shakes with or without teeth chattering lasting 15 minutes or more. What causes them? •Bacterial sepsis e.g. From biliary sepsis or pyelonephritis, visceral abscesses, pneumonia •Malaria •Influenza Why can we not ignore rigors? Causes can be immediately life threatening and are treatable!! Pyrexia of Unknown Origin (PUO) Definition: In adults: T>38.3 for>3 weeks with no known origin despite appropriate Ix. Approach: - identify cause ◦ ◦ ◦ Detailed history and regular examination Confirm temperature objectively, ?admission, ?physiological with circadian pattern Guide investigation based on initial test results ◦ ◦ FBE, ESR, U+E, CRP, LFT, ANA, Rh Fx, TFT Regular cultures (any fluid – blood, sputum, urine, stool, CSF) CXR, CTA, echo CT, IVP, MRI, PET Treatment – ideally symptomatic prior to Dx Infection •Pyogenic Abscess •TB •IE •Toxoplasmosis •EBV •CMV •HIV •Brucellosis •Lyme Disease Malignancy •Lymphoma •Leukaemia •RCC •HCC CTD •Adult Still’s disease •RA •SLE •Wegener’s granulomatosis •Giant cell arteritis Misc •Drug Fevers •Thyrotoxicosis •IBD •Sarcoidosis •Granulomatous hepatitis •Factitious fever •Familial Mediterranean fever Blind investigation may be necessary ◦ Causes Empirical A/B therapy may mask infectious Dx Empirical steroid therapy may mask inflammatory response w/o treating cause Undiagnosable PUO – Sx usually spontaneously resolve, good prognosis Excluded from case differential Infection Connective Tissue Disease Tumours Drug Fever Miscellaneous Idiopathic Idiopathic Examination of a Returned Traveller Special points for an ID Ex Gen Inspection ◦ Patient Sputum cup O2 IV – anything running Drain tube Catheter – check urine Temp chart Distress (RR, diaphoretic, conscious state) Rash – blanching/nonTrack marks IVDU Any lines – sepsis? Weight loss – chronic illness ◦ ◦ Janeway Splinters Osler’s nodes Erythema Track marks Bruising, petechiae Phlebitis Arthropathy, raynauds - CTD Tenderness? – localised? Organomegaly rashes Genitourinary ◦ ◦ ◦ ◦ New murmur Abdomen ◦ ◦ ◦ Crepitations, consolidation Praecordium ◦ Eyes – Roth spots (fundoscopy), pallor, jaundice (BW fever) Mouth – hygeine, ginigivitis, abscess Neck – lymphadenopathy Chest ◦ Hands ◦ ◦ ◦ ◦ ◦ ◦ ◦ ◦ Face ◦ Room ◦ Stool sample Urinalysis Discharge orchitis Legs ◦ ◦ Rash ulcers Signs in a returned Traveller On examination: Chest clear. Full CVS, respiratory and abdominal examinations NAD • No rashes, joints appeared normal. Vitals • HR 72 • BP 120/60 • RR 16 • T 36.2 With these history and examination findings, Jenny was sent home with a suspected viral URTI. The next day, Jenny re-presents with continuing fevers, having taken her own temperature measuring 36.9 that morning. • The Pattern of Fever Timeline of Jenny’s ‘fever’ Day 1 – onset of disease – T? Day 4 – visit doctor – 36.2 Day 5 – 10am – 36.9 Day 5 – afternoon – 36.9 Day 5 – night – 38.5 *NO FEVER RECORDED until day 5* ◦ Doesn't always follow typical pattern in all patients Typically – may be afebrile for days Atypically (common) – may be febrile or afebrile the entire length of the disease ◦ Accurate recording procedure ◦ Hx of fever given by reliable witness should not be ignored even if it is recorded as afebrile. Typical malarial fever patterns - not necessarily useful diagnostically DDx?? DDx!! Malaria (parasite) Typhoid (bacteria) Dengue fever (virus) Hepatitis A We want to rule these out before progressing to investigate for other conditions common in returned travellers. Other Infections To Be Considered in Returned Travellers Developing Countries Bacterial sepsis other than typhoid (such as meningococcal sepsis, sepsis from abdominal organ perforation, pneumonia, urosepsis) TB Dysentry Schistosomiasis Amoebic liver abscess Tick typhus Viral haemorrhagic fevers other than Dengue World Wide Influenza Atypical pneumonia URTI/viral infection STI including acute HIV infection UTI Pyelonephritis DIFFERENTIALS Malaria Dengue Fever Typhoid Fever Hepatitis A Definition Protozoa injected by Anopheles mosquitoes multiply in RBCs causing haemolysis, sequestration and cytokine release. RNA flavivirus (4 types) causing sudden fever, extreme myalgias and arthralgias. Bacterial infection with salmonella typhi (Gbacillus), causing severe diarrhoea Hepatits A virus (HAV), that is not chronic or progressive and has no permanent effect on liver, acutely causes liver damage using body’s own immune response rather than viral cytotoxicity. Mode of Transmission Mosquito vector, transfusion, vertical, needlestick ‘Aedes’ mosquitoes Faecal-oral route, complicated by asymptomatic typhoid (unknowing carriers) Faecal-oral route, Symptoms and signs Malaria non-specific flu-like symptoms: headache malaise myalgia anorexia fevers (periodic) chills faints rigors initially jaundice hepatomegaly splenomegaly Dengue Typhoid Hepatitis A Symptoms and signs Malaria Dengue non-specific flu-like symptoms: headache malaise myalgia anorexia fevers (periodic) chills faints rigors initially fever headache myalgia abdominal pain nausea vomiting diarrhoea rash jaundice hepatomegaly splenomegaly Typhoid Hepatitis A Symptoms and signs Malaria Dengue Typhoid non-specific flu-like symptoms: headache malaise myalgia anorexia fevers (periodic) chills faints rigors initially fever headache myalgia abdominal pain nausea vomiting diarrhoea rash fever (progresses slowly) malaise headache abdominal pains dry cough constipation or diarrhoea rose spots on trunk jaundice hepatomegaly splenomegaly bradycardia lymphadenopathy splenomegaly Hepatitis A Symptoms and signs Malaria Dengue Typhoid Hepatitis A non-specific flu-like symptoms: headache malaise myalgia anorexia fevers (periodic) chills faints rigors initially fever headache myalgia abdominal pain nausea vomiting diarrhoea rash fever (progresses slowly) malaise headache abdominal pains dry cough constipation or diarrhoea rose spots on trunk fever malaise anorexia nausea arthralgia abdominal pain diarrhoea itching bradycardia lymphadenopathy splenomegaly jaundice hepatomegaly splenomegaly jaundice hepatomegaly splenomegaly Symptoms and signs Malaria Dengue Typhoid Hepatitis A non-specific flu-like symptoms: headache malaise myalgia anorexia fevers chills faints rigors fever headache myalgia abdominal pain nausea vomiting diarrhoea rash fever malaise headache abdominal pains dry cough constipation or diarrhoea rose spots on trunk fevers malaise anorexia nausea arthralgia abdominal pain diarrhoea itching bradycardia lymphadenopathy splenomegaly jaundice hepatomegaly splenomegaly jaundice hepatomegaly splenomegaly Fever in the tropical traveller <14 days 14 days – 6 weeks > 6 weeks Malaria Typhoid Leptospirosis Dengue fever Rickettsiae Acute HIV infection fever with CNS signs Malaria Typhoid Leptospirosis Hepatitis A or E Acute schistosomiasis Acute HIV infection Malaria Hepatitis B or E Kala-azar Lymphatic filariasis Schistosomiasis Amoebic liver abscess Viral/bacterial meningitis + encephalitis East African Trypanosomiasis Poliomyelitis fever with chest signs East African Trypanosomiasis Rabies Rabies Influenza Legionellosis Q fever Acute histoplasmosis SARS Tuberculosis Q fever Tuberculosis undifferentiated fever Incubation Periods incubation period: time elapsed between exposure to a pathogenic organism and the onset of symptoms Jenny returned home 2 weeks prior to feeling unwell (14 day incubation) no actual fever recorded until 5 days later however atypical presentation is common Incubation Periods Malaria Dengue Typhoid Hepatitis A P. falciparum 6-21d (typically 7-10d) P. vivax 10-17d P. ovale 10-17d P. malariae 18-40d 3-14 days 3-21 days 2-6 weeks most patients with malaria present within 2 months If fevers start >2wks typically 8-14 days after leaving a dengue area or lasts >2wks dengue can be ‘ruled out’ typically 28 days DIFFERENTIALS Malaria Dengue Fever Typhoid Fever Hepatitis A Definition Protozoa parasite. RNA flavivirus Bacterial infection Hepatits A virus (HAV) Mode of Transmission Mosquito vector, transfusion, vertical, needlestick ‘Aedes’ mosquitoes Faecal-oral route, complicated by asymptomatic typhoid (unknowing carriers) Faecal-oral route, Incubation period (link to case) P. falciparum 6-21d (typically 7-10d) P. vivax 10-17d P. ovale 10-17d P. malariae 18-40d 3-14 days 3-21 days 2-6 weeks most patients with malaria present within 2 months If fevers start >2wks after leaving a dengue area or lasts >2wks dengue can be ‘ruled out’ typically 8-14 days typically 28 days STRAINS OF MALARIA 1) Falciparum – Causes almost all severe disease (~85%). Characterised by systemic complications such as cerebral malaria and anaemia. 2) Vivax – Uncommonly causes severe disease, but overall infection rates are as common as Falciparum. Can cause “chronic” relapsing malarial disease. 3) Ovale – Uncommon cause of disease, and even then clinical picture is not as severe. Can cause relapsing disease as well. 4) Malariae – Similar to Ovale. THE MALARIAL CYCLE 1) MOSQUITO VECTOR 2) EXTRAERYTHROCYTIC 3) ERYTHROCYTIC PHASE Malarial Immunology Immunological evasion by Malaria – ◦ Malaria avoids WBCs by invading the body’s own cells and using these “self” antigens as a mask for infection. The body only has a chance of reacting during a lysis cycle when the parasites are free in the blood, though time is limited. ◦ Splenic removal is the only effective method of removal. Protozoal aggregation in small capillaries counters this – causes complications ◦ Investigations of a Returned Traveller DIFFERENTIALS Malaria Dengue Fever Typhoid Fever Hepatitis A Definition Protozoa parasite. RNA flavivirus Bacterial infection Hepatits A virus (HAV) Mode of Transmission Mosquito vector, transfusion, vertical, ‘Aedes’ mosquitoes needlestick Faecal-oral route, complicated Faecal-oral route, by asymptomatic typhoid (unknowing carriers) Incubation period (link to case) Millsy Signs and symptoms Millsy Ix and Common Thick and Thin Blood Serology (e.g. Findings films arbovirus serology) and PCR Basic principles: studies Parasite = microscopy Bacteria = culture Virus = serology Cultures - bone Serology for marrow, blood, anti HepA IgM stool, urine bone marrow culture has highest yield FBE ◦ HB 110, WCC 7.0, Plt 110 ◦ HB 100, WCC 7.3, Plt 90 ◦ HB 90, WCC 7.2, Plt 96 ◦ HB 95, WCC 7.2, Plt 115 UECs ◦ Jenny’s Ix Findings Na 140, K 4.0, Ur 7.0, Cr 110 LFTs ◦ Mildly elevated ALT and bilirubin, otherwise normal Atypical pneumonia - Legionella, Chlamydia species, Mycoplasma pneumoniae, Pneumocystis jiroveci serology pending CXR - clear Malarial Thick and Thin Film ◦ Negative ◦ Positive for plasmodium falciparum, parasite count 0.2% ◦ parasite count 0.1% ◦ parasite count 0% Hep A serology - Total Ab positive, IgM negative Hep B serology - Surface Antibody positive, surface negative Arbovirus (dengue) serology - negative HIV serology - negative Pregnancy Test - negative Malarial Thick and Thin Blood Films 3 thick and thin smears 12-24hrs apart should be obtained Highest yield of peripheral parasites occurs during or soon after a fever spike; however smears should not be delayed to await a fever spike. Thin Films - qualitative (speciation) Thick Films - quantitative (parasite count) Determining types of malaria Histological Differences Findings P falciparum P vivax P ovale P malariae Only early Yes forms present in peripheral blood No No No Multiply-infected Often RBCs Occasionally Rare Rare Age of infected RBCs RBCs of all ages Young RBCs Young RBCs Old RBCs Schüffner dots No Yes Yes No Other features Cells have thin cytoplasm, 1 or 2 chromatin dots, and applique forms. Late trophozoites develop pleomorphic cytoplasm. Infected RBCs become oval with tufted edges. Bandlike trophozoites are distinctive. Slides Plasmodium falciparum P vivax P ovale P malariae Normal Epidemiology and Risk Factors of Malaria Incidence 3 billion people (1/2 world’s population) living in areas at risk 1-2 million deaths per year 5th most common cause of death from infection worldwide 2nd most common cause of death from infection in Africa Where malaria occurs Most countries in the tropics 107 countries Transmission patterns Unstable transmission Lower levels of infection Temperature a bit cooler Climate varies with season Immunity Epidemic Stable transmission Year round infection Warmer conditions Less seasonal variation Closer to the equator Children affected the most Mostly asymptomatic in adults High Unlikely Efficiency of mosquito Efficient vector Inefficient vector Main parasite P. falciparum P. vivax Fluctuation Climate Clinical manifestation Social and Economic Toll •Cost to individuals •Cost to government Symptomatic disease occurs at all ages Low Likely Risk factors for travellers Destination Season Accommodation Activities Failure to carry out protective measures Taking counterfeit or substandard anti-malarials Who is the most vulnerable? Young children Pregnant women Immunocompromised individuals Immigrants from endemic areas living in non-endemic areas Treatment of Malaria Treatment There are many different types of antimalarial drugs The decision of which to use is dependent on the setting of treatment: ?Remote region - no infusion or injections available The resistances of the parasite Life-cycle of the parasite Antimalarials Acute Treatment Prophylaxis Chloroquine Chloroquine Quinine Proguanil Artemesinin and derivatives (Artemether/Artesunate) Atovaquone Doxycycline/Clindamycin + Quinine salt Doxycycline Mefloquine Mefloquine (overseas) Sulphadoxine + Pyrimethamine (Fansidar®) Traditional thinking Traditionally it has been taught that if the parasite is sensitive to chloroquine, then this will be used And if the parasite is resistant to chloroquine, a quinine salt is administered However these therapies are largely outdated, and nearly all P. falciparum are resistant to chloroquine. It is useful to know this however, as treatment of malaria is very dependant on the medical resources available, and as the newer, more effective drugs are also more expensive, in some areas of the world old therapies must still be relied upon. Current therapy in Australia - Uncomplicated Malaria For uncomplicated Malarial infection, an artemesinin derivative, typically artemether, combined with lumefantrine (sold as Riamet®) Administer 4 tablets/12 hours for 6 doses. Uncomplicated malarial infection can progress to a more severe form, defined by: •Altered conscious state •Jaundice •Oliguria •Parasite count>2% of RBCs •Acidotic Current Therapy (2) - Severe Malaria Treatment alters slightly in severe malaria, and the primary treatment is a different artemesinin derivative IV Artesunate, 2.4mg/kg on admission and given every 12 hours until oral therapy is possible Use artemether+lumefantrine when infection is less severe It is also essential to carefully monitor and correct if necessary the patient’s: fluid levels, blood glucose urine output •Daily parasite counts, platelets, U&E's and LFT's should also be taken Prophylaxis Prophylactic therapy is typically chosen based on the area the individual may be travelling to. •In general terms, due to the high levels of chloroquine resistance, Atovaquone+proguanil (Adult: 250+100mg PO) is used, 1-2 days before travel, and 7 days after. •Doxycycline (100mg daily) is also used; 2 days before travel, contuining until 4 weeks after. –SE: Oesophagitis, photosensitivity, vaginal thrush •Mefloquine (250mg weekly) is not used in Australia, yet is used widely around the world. Complications of Malaria Complications of Malaria CNS: cerebral malaria Renal: blackwater fever: haemoglobinuria + haemolysis + renal failure, uraemia (acute tubular necrosis) Blood: severe anaemia (haemolysis, dyserythropoiesis, splenomegaly with sequestration and folate depletion) Respiratory: acute respiratory distress syndrome (ARDS) Metabolic: hyperglycaemia, metabolic acidosis GI: diarrhoea, jaundice, splenic rupture haemorrhage Other: shock/hypotension (especially with secondary bacterial infection), hyperpyrexia Complications of Malaria CNS: cerebral malaria Renal: blackwater fever: haemoglobinuria + haemolysis + renal failure, uraemia (acute tubular necrosis) Blood: severe anaemia (haemolysis, dyserythropoiesis, splenomegaly with sequestration and folate depletion) Respiratory: non-cardiogenic pulmonary oedema/ acute respiratory distress syndrome (ARDS) Metabolic: hyperglycaemia, metabolic acidosis GI: diarrhoea, jaundice, splenic rupture haemorrhage Other: shock/hypotension (especially with secondary bacterial infection), hyperpyrexia Cerebral Malaria - recognised by a decreased conscious state not a headache - causes 80% of deaths from Malaria and will kill 15-20% of the people who have it even with treatment Non-cardiogenic Pulmonary Oedema - caused by overhydration, increased permeability of pulmonary vessels in response to the infection or by the clogging of pulmonary microcirculation by infected red cells - 50% mortality Renal Failure - caused by dehydration, increased blood viscosity and the products of haemolysis - adequate rehydration needed Prognosis Criteria for a poor prognosis: < 3 years old Pregnancy Fits Comas No corneal reflex Papilloedema Pulmonary oedema/ARDS HCO3- <15mmol/L Plasma or CSF lactate >5mmol/L Hyperparasitaemia (>5%RBCs or 250,000/mL) Hb <5g/L Creatinine >265mmol/L Malaria pigment >5% neutrophils Complicating infection DIC >20% of parasites are mature trophozoites or shizonts The main criteria for poor prognosis: The species of Malaria: P. Falciparum The number of parasites: >5% of RBCs Pre-Travel Advice Traveller’s Advice Risk assessment Administer vaccinations Malaria prevention Essential preventive behaviours • Risk assessment: – – – – – – – – – – – – – Itinerary (country / regions / dates of travel) Urban / rural Age Past vaccination Hx Comorbidities Current Medications Pregnancy status Allergies Purpose of trip Risk exposures (blood, body fluids, extreme sports, outdoors) Types of accomodation Travel insurance Level of aversion to risk • Administer Immunisations – Routine vaccinations – Travel vaccinations Malaria Prevention • Essential preventive behaviours – Food and water safety – Protection against STDs (always use condom) – Motor vehicle safety – Personal safety (appropriate dress, crime, recreational activities, local customs, etc.) – Altitude / motion sickness / jet-lag OBJECTIVES RED FLAGS ◦ Rigors = hospital admission HOW TO TAKE A HISTORY IN A RETURNED TRAVELLER ◦ How to take/interpret a fever MALARIA ◦ Diagnosis ◦ Pathophysiology ◦ Management COUNSELLING A PROSPECTIVE TRAVELLER