Fever in a Returning Traveler

Approach to fever in the returning traveler:

1) History:

• Detailed travel hx with dates (to calculate incubation period)
• Exposure history (mosquito bites, water, food)
• Visiting friends and relatives vs staying in tourist areas
• associated signs and symptoms
• Duration and pattern of fever
• immunizations tatus
• Use and adherence to antimalarial chemoprophylaxis

2) Differential Diagnosis (not an exhaustive list!)

• Must rule out MALARIA
• Incubation period: anywhere from 2 wks to a year.
• Plasmodium falciparum: must be immediately ruled out as can be rapidly fatal
• Non-falciparum (P. vivax, P. ovale, P. malariae, P. knowlesi) cause febrile illness but are rarely fatal
• Must keep malaria on the differential, even if on chemoprophylaxis due to resistance
• "hectic" fever +/- headache, cough, GI problems.
• Invx: thick and thin smears x 3, rapid antigen testing, CBC (thrombocytopenia without leukocytosis is characteristic, may have anemia from hemolysis), bili, liver enzymes
• Complications: altered LOC, seizures, acidosis, ARDS, liver failure, severe hemolysis, renal failure, cerebral malaria
• Must start antimalarials parenterally if severe infection or if levels exceed 4% of visible erthrocytes
• Dengue
•  Caused by a mosquito-borne flavivirus in tropical and subtropical areas
• Incubation period of 4-7 days
• Clinical Sx: lymphadenopathy, erythema/nonspecific maculpapular rash, leukopenia and thrombocytopenia
• Serious infection: dengue shock and dengue hemorrhagic fever
• Clinical diagnosis + confirmed with serum antibody titers
• Rickettsia
• Triad of fever + headache + myalgia
• Examples: African tick typhus, Mediterranean tick typhus, scrub typhus
• Transmitted by arthropods (painless eschar at inoculation site) in grassy areas
• Leptospirosis
• History of exposure to fresh water
• fever+ myalgia + headache + rash (Conjunctival suffusion is a diagnostic sign)
• Typhoid
•  Causal agent: Salmonella enterica. Fecal oral transmission
• Sx of fever+abdo distension + constipation+lymphadenopathy
• Invx: Leukopenia +thrombocytopneia. Dx by blood C+S.
• Treated with fluoroquinolone/3rd gen cephalosporin

See the following article for further details: Illness after international Travel