Case of the Week November 26

A young woman returns from a 4 week trip with a febrile illness.  Her family doctor orders a blood film as part of the initial workup, and the following was seen.

Blood Film

What disease does she have and what treatment does she require?

This blood film shows a ring form trophozoite of the unicellular protozoan infection – from a plasmodium species. In other words, this patient has malaria!

A wise infectious disease physician once told me “Fever in a returned traveller is malaria until proven otherwise”.

Differential Diagnosis for Fever in a Returned Traveller:
Infections related to travel (i.e. Tropical Diseases)

  • Malaria
  • Dengue (South america and caribbean)
  • Typhoid (South Asia)
  • Influenza
  • Hepatitis A
  • Zika
  • Chikungunya

Infections unrelated to Travel Location:

(whatever is in your differential diagnosis for local infectious processes e.g. pneumonia, UTI, cellulitis, viral infections)

Non-infectious Etiologies:

Malignancy and DVT always have to be considered in your differential.

Remember to ask returning travellers the following

  1. Pre-Travel History:
    1. Did they seek pre-travel advice
    2. Immunizations received
      • Routine
      • Recommended
      • Required – Yellow fever, meningococcus
    3. Malaria prophylaxis
  2. Travel itinerary
    • Exact dates
    • transfer points
    • long plane rides – DVT
    • Crowded busses
    • accommodations
    • Time of year
  3. Exposure History:
    • What did you do while travelling?
    • Animal contact (humans, non-human mammals (brucella, Q fever, Rabies), arthropods, birds, reptiles)
    • Food and water (schistosomiasis, leptospirosis)
    • Specific Activities (especially sexual)
      • Caves – histoplasmosis, ebola
      • Safari – Malaria, rikettsiosis
Initial Investigations:
  • CBC and Diferential, Lytes, LFTs, Cr, Albumin
  • Malaria thick and thin film – need three blood films separated in time to rule out, or 2 rapid malaria tests negative
  • Blood cultures
  • Urinalysis and urine cultures
  • Depending on syndrome:
    • NP swab for influenza/RT viruses
    • CXR
    • Dengue serology/chikungunya serology/rickettsial and leptospirosis serology
    • Stool cultures, C Dif +/- ova and parasite
    • “Serology” – Extra red top tube that lab will hold
Treatment:
  • Empirically treat for severe malaria if sick (CNS, respiratory involvement)
    • Artesunate 2.4 mg/kg – 5 doses
    • IV quinidine if artesunate not available, administered with doxy or clindamycin
  • Non-severe malaria:
    • Atovaquone + Proguanil (malarone – 4 tabs daily x3)
    • Admit everyone with falciparum malaria – ensure they defervesce, keep pills down etc
  • Malaria ruled out:
    • Azithromycin +/- Doxy – South and southeast asia
    • Cipro 500 po BID x 7 days +/- Doxy – All other areas

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