Tropical Fever Management

Diagnostic Approach

The American College of Physicians recommends that malaria testing must be performed immediately in all patients with fever who have visited a tropical country within the past year, as this is the most important potentially fatal cause of tropical fever 1, 2
Perform both thick blood film and rapid diagnostic test (RDT) simultaneously for initial malaria workup 1, 3
If initial tests are negative but clinical suspicion remains, repeat testing: three thick films/RDTs over 72 hours are required to confidently exclude malaria 1, 3, 4
Most Plasmodium falciparum cases present within 1 month of return, but can occur up to 6 months later; P. vivax, ovale, and malariae can present up to a year or longer after travel 2

Document exact locations visited, dates of travel and symptom onset, risk activities undertaken, timing of rash relative to fever onset, and immunization history and malaria prophylaxis use on all laboratory request forms 1, 3, 5, 6

Perform malaria film and RDT, two sets of blood cultures, complete blood count with differential, renal function and liver function tests, and urinalysis in all febrile returned travelers 1, 2, 3
Consider serum save for serology, EDTA sample for PCR, chest X-ray, and liver ultrasound as clinically indicated 1, 2, 3

In Sub-Saharan Africa, the highest priority is malaria (especially P. falciparum), and also consider typhoid, rickettsial infections, and viral hemorrhagic fevers 1, 2, 6
In South/Southeast Asia, the highest incidence is typhoid/enteric fever, and also common are dengue, scrub typhus, and malaria 2

Start empirical antibiotics immediately without waiting for culture results when suspected meningococcemia, RMSF, or typhoid with negative malaria tests 4, 5, 6
Do not withhold empirical treatment while pursuing diagnosis in severely ill patients 4, 5, 6

Immunocompromised patients have a lower threshold for hospitalization and empiric antimicrobial therapy, and may present with atypical or more severe manifestations 4
Pediatric patients develop rash with RMSF more frequently and earlier in illness course, and mortality in febrile children is significantly higher than non-febrile children 4

Immediate consultation with infectious disease/tropical medicine specialists is indicated for suspected viral hemorrhagic fever, positive malaria films requiring confirmation and species-specific treatment, undiagnosed fever after initial workup, and critically ill patients with tropical exposure 1, 3, 5

The American College of Physicians mandates malaria testing in all patients with fever who have visited any tropical or subtropical country within the past year, as this is the most important potentially fatal cause of tropical fever, and obtain two sets of blood cultures immediately before starting antibiotics, as enteric fever is a serious consideration from the Middle East/North Africa region 7
Complete blood count with differential, renal function and liver function tests, urinalysis, and chest X-ray are mandatory initial investigations, with consideration of serum save for serology and EDTA sample for PCR 7
Neurological symptoms, such as dystonia and unsteady gait, warrant urgent attention and could represent cerebral complications of enteric fever, hypoglycemia, viral encephalitis, or brucellosis 7

For suspected enteric fever from the Middle East/North Africa region, ceftriaxone is the first-line empirical choice if the patient appears clinically unstable 8
If clinically stable and traveled from Middle East/North Africa, ciprofloxacin remains an alternative, with treatment duration of 2 weeks 7
Do not delay empirical treatment while pursuing diagnosis in severely ill patients, and hospitalization is warranted given evidence of neurological dysfunction, systemic symptoms, need for parenteral antibiotics, or anemia requiring investigation 7

Immediate consultation with infectious disease/tropical medicine specialists is indicated for critically ill patients with tropical exposure 9
Do not assume Lebanon is "low-risk" for tropical diseases, and do not wait for negative malaria tests to start antibiotics, as fever in returned travelers can be rapidly progressive and lethal 7, 10, 11, 8, 12, 13, 9