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PBL SEMINAR

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. What’s common is common The diagnosis is

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PBL SEMINAR

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  1. PBL SEMINAR FEVER IN A RETURNED TRAVELLER

  2. 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

  3. IMPORTANT • What’s common is common • The diagnosis is MALARIA MALARIAMALARIA until proven otherwise.

  4. How to take a History from a Returned Traveller

  5. FeverWWQQAAB

  6. Travel History: CHOCOLATES • Country of birth • Housing • Occupation • Contacts • Other drugs • Leisure time • Animals • Travel • Eating and Drinking • Sexual history

  7. Take Jenny’s History • HOPC • Travel History: CHOCOLATES

  8. Travel History: CHOCOLATES • Country of birth • Housing • Occupation • Contacts • Other drugs • Leisure time • Animals • Travel • Eating and Drinking • Sexual history

  9. Jenny’s 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 • 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

  10. 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 accommodation throughout recent travel • Exposure to water, mosquitoes, 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

  11. !~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!! • !~Admit patient with rigors to hospital~!

  12. 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 • Blind investigation may be necessary • FBE, ESR, U+E, CRP, LFT, ANA, RhFx, TFT • Regular cultures (any fluid – blood, sputum, urine, stool, CSF) • CXR, CTA, echo • CT, IVP, MRI, PET • Treatment – ideally symptomatic prior to Dx • Empirical A/B therapy may mask an 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

  13. Examination of a Returned Traveller

  14. Special points for an ID Ex • Gen Inspection • Room • Sputum cup • O2 • IV – anything running • Drain tube • Catheter – check urine • Temp chart • Patient • Distress (RR, diaphoretic, conscious state) • Rash – blanching/non- • Track marks IVDU • Any lines – sepsis? • Weight loss – chronic illness • Hands • Janeway • Splinters • Osler’s nodes • Erythema • Track marks • Bruising, petechiae • Phlebitis • Arthropathy, raynauds - CTD • Face • Eyes – Roth spots (fundoscopy), pallor, jaundice (BW fever) • Mouth – hygeine, ginigivitis, abscess • Neck – lymphadenopathy • Chest • Crepitations, consolidation • Praecordium • New murmur • Abdomen • Tenderness? – localised? • Organomegaly • rashes • Genitourinary • Stool sample • Urinalysis • Discharge • orchitis • Legs • Rash • ulcers

  15. Signs in a returned Traveller

  16. 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.

  17. The Pattern of Fever Typical malarial fever patterns - not necessarily useful diagnostically • 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.

  18. DDx??

  19. 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. THE BIG FOUR

  20. 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

  21. DIFFERENTIALS

  22. Symptoms and signs

  23. Symptoms and signs

  24. Symptoms and signs

  25. Symptoms and signs

  26. Jenny’s symptoms and signs

  27. Fever in the tropical traveller

  28. 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

  29. Incubation Periods

  30. DIFFERENTIALS

  31. BASIC PATHOPHYS. STRAINS OF MALARIA

  32. THE MALARIAL CYCLE 1) MOSQUITO VECTOR 2) EXTRA-ERYTHROCYTIC 3) ERYTHROCYTIC PHASE

  33. 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

  34. Investigations of a Returned Traveller

  35. DIFFERENTIALS

  36. Jenny’s Ix Findings • 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 • Na 140, K 4.0, Ur 7.0, Cr 110 • LFTs • Mildly elevated ALT and bilirubin,otherwise normal • Atypical pneumonia - Legionella, Chlamydia species, Mycoplasmapneumoniae, Pneumocystisjiroveci 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

  37. 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)

  38. Determining types of malaria Histological Differences

  39. Slides • Plasmodium falciparum • P vivax • P ovale • P malariae • Normal

  40. Epidemiology and Risk Factors of Malaria

  41. 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

  42. Where malaria occurs Most countries in the tropics 107 countries

  43. Transmission patterns • Social and Economic Toll • Cost to individuals • Cost to government

  44. 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

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