The epidemiology, clinical features, and long-term prognosis of Japanese encephalitis in Central Sarawak, Malaysia, 1997-2005

Background. Japanese encephalitis is a major public health problem in Asia. However, there is little data on the long-term outcome of Japanese encephalitis survivors. Methods. We prospectively evaluated children with serologically confirmed Japanese encephalitis over an 8.3-year period. The patients were assessed and their outcomes were graded with a functional outcome score at hospital discharge and at follow-up appointments. We examined how patient outcome at hospital discharge compared with that at long-term follow-up visits, when changes in outcome occurred, and the prognostic indicators of the eventual outcome. Results. One hundred and eighteen patients were recruited into the study, and 10 (8%) died during the acute phase of illness. At hospital discharge, 44 (41%) of the 108 patients who survived had apparent full recovery; 3 (3%) had mild, 28 (26%) had moderate, and 33 (31%) had severe neurological sequelae. Eighty six of the 108 patients were followed up for a median duration of 52.9 months (range, 0.9-114.9 months). During follow-up, 31 patients experienced improvement, but 15 patients experienced deterioration in their outcome grade. In most cases, assessment during the first 3-6 months after hospital discharge was predictive of the long-term outcome. More than one-half of the patients continued to experience neuropsychological sequelae and behavioral disorders. A combination of poor perfusion, Glasgow coma score <= 8, and >= 2 witnessed seizures predicted a poor long-term outcome with 65% sensitivity and 92% specificity. Conclusions. Neurological assessment of Japanese encephalitis survivors at hospital discharge does not predict long-term outcome. Seizures and shock are treatable risk factors for a poor outcome at hospital discharge and at long-term follow-up visits.