the returned traveller
Feverish patient doesn't have malaria
Tropical medicine specialist Dr Tom Doherty explains how to make the diagnosis, the investigations and possible treatments
A 37-year-old woman spent three months on a budget tour of India researching a cookery book. She had hepatitis A, hepatitis B, tetanus, polio and typhoid vaccinations. She took antimalarial prophylaxis with chloroquine and proguanil and was fully compliant, but was taking no other regular medication and had no significant medical history. Apart from a few short-lived episodes of diarrhoea, she was well. Three days after returning she developed a fever, associated with some myalgia and arthralgia but no localising symptoms. She had a negative malaria film. Her symptoms persisted and her GP found she had an axillary temperature of 38.6°C but no other signs of infection.
What questions would you ask the patient?
· Did she have any urinary tract symptoms? UTIs are common in women of this age any suggestion of dysuria, frequency or lower abdominal or loin pain would be worth eliciting.
· What about cough? Cough is reportedly the commonest presenting symptom of patients with typhoid although the mechanism is unknown.
· Had she noticed any difference in the colour of her urine? That may suggest malaria, or early jaundice.
· Had she been in contact with sick people?
· Had she been walking or bathing in fresh water? This would raise the possibility of leptospirosis.
What is the likely diagnosis and what else could it be?
Obviously in any traveller from an endemic area with an unexplained fever, malaria must be excluded.
· South Asia is the commonest source of typhoid, but only a relatively small proportion of febrile patients from this area will have that infection (the risk can be as high as 1:3,000 for travellers to the Indian sub-continent, and vaccines are no more than 80 per cent effective1).
· A non-specific viral infection is probably the most likely diagnosis, but this is a diagnosis of exclusion.
· Mundane conditions such as urinary tract infection, community acquired pneumonia, sinusitis and even simple skin sepsis need to be considered.
· Dengue fever is more common further east than India, but should be considered.
· Amoebic liver abscesses are usually (but not always) obvious.
What investigations would you initiate and why?
· A film for malaria parasites is essential. If the result is negative and malaria is still suspected, the film should be repeated every six to 12 hours for up to two days to rule out a false-negative result.
· A full blood count, ESR and C-reactive
protein are always helpful. Classically, patients with typhoid have a normal white cell count, and a lymphopoenia is supportive of a diagnosis of a viral illness. A neutrophilia suggests an underlying bacterial cause.
· Cultures of blood, urine, stool and a throat swab should be sent, and blood cultures repeated if the fever persists.
· If a diagnosis of typhoid is seriously considered, then a bone marrow aspirate should be sent for culture this is probably the investigation of choice.
· Unless a diagnosis is obvious, a chest
X-ray should be performed.
· If there is any suggestion of meningitis, consider a lumbar puncture.
· In terms of serological testing, the only one that may be useful in the acute phase is that for amoebiasis. All the others provide a diagnosis only long after the patient has been discharged.
What treatment would you offer?
For typhoid, ciprofloxacin is still the antibiotic of choice. Resistance is well-described from south Asia so a higher
dose than normal (perhaps 750mg twice daily) should be prescribed. Most UK
units recommend a minimum of 10 days but much shorter doses have also been used successfully, particularly in south-east Asia.
Because typhoid is an intracellular organism, it takes time for the antibiotics to eliminate the infection and so a rapid clinical improvement should not be expected. Even with fully sensitive organisms, the relapse rate is around
10 per cent. You need to warn people accordingly.
1 Pollard AJ, Murdoch DR. Travel medicine. Oxford: Health Press 200l