Clinical Review Lesson of the week

Assessing the severity of malaria

BMJ 2003; 326 doi: (Published 12 April 2003) Cite this as: BMJ 2003;326:808
  1. David A J Moore, specialist registrar,
  2. Richard M Jennings, research fellow,
  3. Tom F Doherty, consultant physician,
  4. Diana N Lockwood, consultant physician,
  5. Peter L Chiodini, consultant clinical parasitologist,
  6. Stephen G Wright, consultant physician,
  7. Christopher J M Whitty, consultant physician (
  1. Hospital for Tropical Diseases, London WC1E 6AU
  1. Correspondence to: C J M Whitty
  • Accepted 7 November 2002

Life threatening malaria may develop even in patients who appear relatively well at presentation

Malaria caused by infection with Plasmodium falciparum kills over 1 million people a year.1 In 2000, 1592 confirmed cases were reported to the United Kingdom's Malaria Reference Laboratory; 16 of these people died (John Williams, personal communication, 2002). Guidelines have been published to identify patients with poor prognostic signs.24 A recent study suggested that patients infected with P falciparum who present with uncomplicated disease may be treated safely outside hospital5; however, patients not uncommonly present without adverse signs but deteriorate over the next 24–48 hours despite apparently adequate treatment. This deterioration occurs because P falciparum undergoes repeated cycles of maturation approximately every 48 hours4: only the schizonts (mature forms) of the parasite sequester and cause pathology, while the trophozoites (immature forms) are relatively insensitive to antimalarial treatment.6 We present two cases from the Hospital for Tropical Diseases that illustrate why the severity of falciparum malaria may be underestimated at presentation.

Case reports

Case 1

A 62 year old white man presented with a four day history of fever 19 days after returning from a two week holiday in Mozambique. He reported taking chloroquine 600 mg weekly and proguanil 200 mg daily as prophylaxis. On admission, he was febrile (38.4°C), with a pulse of 104 bpm, but examination was otherwise unremarkable. His blood film showed trophozoites and schizonts of P falciparum and parasitaemia of 2.9%. His haemoglobin was 12.2 g/dl (normal range 11.5-15.5 g/dl), white cell count 3.6×109/l (3.0×10 …

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