Why fever in a returning traveller matters
A fever after travel to the tropics is a medical emergency until a few dangerous causes are ruled out, because some of them can go from mild to life-threatening within a day. The travel history, taken carefully, narrows the list fast.
What to ask in the history
- Exactly where he went (cities, rural areas), and the dates of arrival and return
- Antimalarial prophylaxis: which drug, and whether he took it as prescribed, including after return
- Mosquito bite precautions: nets, repellent
- Vaccinations before travel (yellow fever, typhoid, hepatitis A)
- Food and water: street food, untreated water
- Fresh water swimming, animal contact, insect or tick bites
- Sexual contacts, and contact with anyone who was ill
- The fever itself: when it started, rigors, pattern; headache, cough, diarrhoea, rash, jaundice, bleeding
Red flags
- Confusion, drowsiness or seizures
- Jaundice
- Breathlessness or low oxygen saturation
- Bleeding: gums, nose, skin, urine
- Low blood pressure or low urine output
- Low blood glucose
- Severe anaemia
What to examine
- Temperature, pulse, blood pressure, respiratory rate, oxygen saturation
- Conscious level
- Jaundice, pallor, rash, bleeding
- Liver and spleen size
- Chest, and a look for neck stiffness
- Lymph nodes, throat, skin (eschar, bites)
First investigations
- Malaria test today: thick and thin blood films and/or a rapid diagnostic test
- If negative, repeat the films, typically up to three sets over 48 to 72 hours
- Full blood count, renal function, liver function, blood glucose
- Blood cultures, urine routine and culture
- Dengue NS1 or serology, depending on the timing
- Chest X-ray if there are chest symptoms; HIV test
Differential diagnosis of fever in a returning traveller
Grouped, not ranked. Which one fits this patient is for you to work out in the case.
Must not miss
- Malaria
- Typhoid (enteric fever)
- Bacterial sepsis
- Viral haemorrhagic fever (Lassa fever in West Africa, with a suggestive exposure)
Common tropical
- Dengue
- Viral hepatitis
- Leptospirosis
- Rickettsial infection
Ordinary infections
- Influenza or other viral illness
- Pneumonia
- Urinary tract infection
Other
- Acute HIV infection
- Schistosomiasis (Katayama fever)
Common mistakes
- A single negative malaria film does not rule malaria out.
- Forgetting that taking prophylaxis lowers the risk but does not remove it.
- Sending a feverish traveller home to 'see how it goes' before malaria is excluded.