ANSWER 19
There is a raised bilirubin with normal liver enzymes, a mild anaemia with a high normal
mean corpuscular volume and a low platelet count. This makes a haemolytic anaemia
likely. The recent travel to Nigeria raises the possibility of an illness acquired there. The
commonest such illness causing a fever in the weeks after return is malaria. The incuba-
tion period is usually 10–14 days. The mild haemolytic anaemia with a low platelet count
would be typical findings. Slight enlargement of liver and spleen may occur in malaria.
The diagnosis should be confirmed by appropriate expert examination of a blood film.
The most important feature in this 24-year-old man is the fever with what sound like
rigors. He has no other specific symptoms. He looks unwell with a tachycardia and some
tenderness in the left upper quadrant which could be related to splenic enlargement.
Malaria prophylaxis is often not taken regularly. Even when it is, it does not provide com-
plete protection against malaria which should always be suspected in circumstances such
as those described here. The risk might be assessed further by finding which parts of
Nigeria he spent his time in and whether he remembered mosquito bites. Measures to
avoid mosquito bites such as nets, insect repellants and suitable clothing are an important
part of prevention.
He has no history of intravenous drug abuse or recent risky sexual contact to suggest HIV
infection, although this could not be ruled out. HIV seroconversion can produce a fever-
ish illness but not usually as severe as this. Later in HIV infection an AIDS-related illness
would often be associated with a low total lymphocyte count, but this is normal in his
case. Other acute viral or bacterial infections are possible but are less likely to explain the
abnormal results of some investigations.
The diagnostic test for malaria is staining of a peripheral blood film with a Wright or
Giemsa stain. In this case it showed that around 1 per cent of red cells contained parasites.
Treatment depends on the likely resistance pattern in the area visited and up-to-date
advice can be obtained by telephone from microbiology departments or tropical disease
hospitals. Falciparum malaria is usually treated with quinine sulphate because of wide-
spread resistance to chloroquine. A single dose of Fansidar (pyrimethamine and sulfadox-
ine) is given at the end of the quinine course for final eradication of parasites. However
there is increasing resistance to quinine, and artemesinin derivatives are increasingly
becoming the first-line treatment for falciparum malaria. In severe cases hyponatraemia
and hypoglycaemia may occur and the sodium here is marginally low. Most of the severe
complications are associated with Plasmodium falciparummalaria. They include cerebral
malaria, lung involvement, severe haemolysis and acute renal failure.
- No prophylactic regime is certain to prevent malaria.
- A traveller returning from a malaria endemic region who develops a fever has malaria
until proven otherwise. - Treatment should be guided by advice from tropical disease centres.
- If the malaria species is unknown or the infection mixed, treat as falciparum malaria.