A major role for viruses in acute childhood encephalopathy.

29 children and 3 adults with acute depression of conscious level or acute onset of focal neurological signs were studied prospectively. 3 were found to have a non-infectious cause for their illness. The presence of interferon or specific antibodies in the serum and/or cerebrospinal fluid provided evidence of active virus infection in 25 of the remaining 29 patients. There was laboratory evidence that a virus had invaded the central nervous system in 11 patients. Early investigation gave the highest diagnostic yield. Since several common viruses were identified, it appears that the nature of the illness is due more to the host response than to the nature of the infective agent.