POST-MALARIA NEUROLOGICAL SYNDROME

Background Neurological signs and symptoms are common in malaria, but observations in Vietnam and Thailand have pointed to a discrete transi ent neurological syndrome after recovery from severe infections. Metho ds A prospective study of the post-malaria neurological syndrome (PMNS ) was conducted at two centres in Vietnam over four years. Criteria fo r inclusion were recent symptomatic malaria infection with parasites c leared from blood (and in cases of cerebral malaria full recovery of c onsciousness), and development of neurological or psychiatric symptoms within two months after the acute illness. Half of the patients with severe falciparum malaria had been taking part in a randomised trial o f antimalarials. Findings Of 18 124 patients with falciparum malaria t reated (1176 of whom had severe infections) 19 adults and three childr en had subsequent PMNS; in one patient it followed uncomplicated malar ia and in 21 it followed severe malaria. The overall incidence (95% co nfidence interval) of PMNS after falciparum malaria at the main study centre was 1.2 per 1000 (0.7 to 18 per 1000) and relative risk (95% CI ) for developing PMNS after severe versus uncomplicated falciparum mal aria was 299 (40 to 2223). 13 patients had an acute confusional state or psychosis, six had one or more generalised convulsions, two had gen eralised convulsions followed by a long period of acute confusion, and one developed a fine tremor. At the time of PMNS diagnosis all patien ts were aparasitaemic. The syndrome was self-limiting, median duration 60 h (range 24-240). PMNS was associated with the use of oral mefloqu ine. In the randomised trial 44% (10/228) of patients with severe mala ria who received mefloquine after parenteral treatment developed PMNS compared with 0.5% (1/210) of those who received quinine; relative ris k 9.2 (95% CI 1.2 to 71.3, p=0.012). Interpretation Mefloquine is not the only risk factor for PMNS but it is a strong one. Where an effecti ve alternative drug is available, mefloquine should not be used after treatment of severe malaria.