Severe imported falciparum malaria among adults requiring intensive care: a retrospective study at the hospital for tropical diseases, London

BACKGROUND: Malaria is the commonest imported infection in the UK. Malaria requiring ICU admission has a reported mortality of up to 25%. The relationship between ethnicity, immunity, and risk of malaria is complex. The Malaria Score for Adults (MSA) and Coma Acidosis Malaria (CAM) score have recently been proposed to risk stratify patients with malaria. METHODS: Retrospective study of patients with WHO severe falciparum malaria admitted to ICU at the Hospital for Tropical Diseases, London, UK. The relationship between clinical variables and risk of death or a prolonged ICU stay were examined with logistic regression. The predictive value of the MSA and CAM score were calculated. RESULTS: 124 patients were included. Cerebral malaria and acute kidney injury occurred earlier (median day 1) than acute respiratory distress syndrome (median day 3). Six patients had community acquired bacterial co-infection. Eight patients were co-infected with HIV, five of whom were newly diagnosed. The positive predictive value of a CAM score ≥2 or an MSA ≥5 for death were 12% and 22% respectively. Five patients died. No variable was significantly associated with risk of death. There were no significant differences between individuals raised in endemic countries compared to non-endemic countries. CONCLUSIONS: Mortality in patients managed in a specialist centre was low. Patients who died succumbed to complications associated with a prolonged stay on ICU rather than malaria per se. The clinical usefulness of the MSA and CAM score was limited. Co-infection with HIV was relatively common but compared to studies in children, bacteraemia was uncommon. The relationship between ethnicity and immunity to severe disease is complex.