Encephalitis or encephalopathy during an influenza-A epidemic.

Six female patients with encephalitis, mean age 36.5 (17-60) years, were admitted to the hospital during the 2000-2001 influenza A (H1N1) epidemic in the Osijek--Baranja County. In three (50.0%) patients, the manifestation of encephalitis occurred on day 4 or 5, and in two (33.3%) patients within 24-48 hours of the onset of influenza symptoms. The disease manifestations included headache, elevated body temperature, generalized fatigue, and consciousness disturbance through coma. Three (50.0%) patients had grand mal seizures. Pathologic electroencephalography findings were recorded in all six (100%) patients, whereas computed tomography showed cerebral edema in three (50.0%) patients. Elevated levels of hepatic enzymes and peripheral blood leukopenia were found in two (33.3%) patients in whom encephalitis developed early upon the onset of influenza. One (16.6%) of these patients died, whereas permanent sequels remained in the other two (33.3%) patients.