A 24-year-old man presents to his general practitioner (GP) with a fever. This has been present on and off for 3 days. On the first day he felt a little shaky but by the third day he felt very unwell with the fever and had a feeling of intense cold with generalized shaking at the same time. He felt very sweaty. The whole episode lasted for 2.5h, and he felt drained and unwell afterwards. He felt off his food. There is a previous history of hepatitis 4 years earlier and he had glandular fever at the age of 18 years. He smokes 15–20 cigarettes each day and occasionally smokes marijuana. He denies any intravenous drug abuse. He drinks around 14 units of alcohol each week. He has taken no other medication except for malaria prophylaxis. He denies any homosexual contacts. He has had a number of heterosexual contacts each year but says that all had been with protected intercourse. He had returned from Nigeria 3 weeks earlier and was finishing off his prophylactic malaria regime. He had been in Nigeria for 6 weeks as part of his job working for an oil company and had no illnesses while he was there.
Examination He looks unwell. His pulse is 94/min, blood pressure 118/72mmHg. There are no heart murmurs. There are no abnormalities to find in the respiratory system. In the abdomen there is some tenderness in the left upper quadrant of the abdomen. There are no enlarged lymph nodes.
Normal Haemoglobin 11.1g/dL 13.7–17.7g/dL Mean corpuscular volume (MCV) 97fL 80–99fL White cell count 9.4 109/L 3.9–10.6 109/L Neutrophils 6.3 109/L 1.8–7.7 109/L Lymphocytes 2.9 109/L 1.0–4.8 109/L Platelets 112 109/L 150–440 109/L Sodium 134mmol/L 135–145mmol/L Potassium 4.8mmol/L 3.5–5.0mmol/L Urea 4.2mmol/L 2.5–6.7mmol/L Creatinine 74amol/L 70–120amol/L Alkaline phosphatase 76IU/L 30–300IU/L Alanine aminotransferase 33IU/L 5–35IU/L Gamma-glutamyl transpeptidase 42IU/L 11–51IU/L Bilirubin 28mmol/L 3–17mmol/L Glucose 4.5mmol/L 4.0–6.0mmol/L
Urine: no protein; no blood; no sugar
INVESTIGATIONS
Questions • What abnormalities are likely to be present in the blood film? • What is the most likely diagnosis? • What would be the appropriate management?
ANSWER
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 incubation 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 complete 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 feverish 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 widespread resistance to chloroquine. A single dose of Fansidar (pyrimethamine and sulfadoxine) 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 falciparum malaria. They include cerebral malaria, lung involvement, severe haemolysis and acute renal failure.