An unselected series of 22 children (13 males; age range 1 mo to 13yr, median 2yr 4mo) with acute encephalopathy were studied prospectively at the Royal Manchester Children's Hospital, UK. Symptoms of a viral prodrome consistent with viral encephalitis were present in 17 (77%), and laboratory evidence of viral infection in 7, including adenovirus, HSV/CMV, Coxsackie, and varicella. Symptoms were respiratory in 7, rash in 4, malaise and fever 3, and diarrhea in 3; and neck stiffness was present

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... n 3. All showed deterioration of consciousness over a few hours. One was diagnosed with herpes simplex encephalitis, and 1 had received rubella immunization 26 days before presentation. Neurologic symptoms and signs developed at a median of 8 days (range 3-28d) after presentation. Seizures occurred in 18 patients; they were focal in 10 and generalized in 8. CSF pleocytosis was found in 14/22, an elevated CSF:serum albumin ratio indicative of impaired blood-brain barrier in 18/21, a raised intrathecal immunoglobulin production and IgG index in 15, oligoclonal bands in 14/17, and elevated interferon-alpha (IFN-a) levels in CSF or serum or both in 16/18. An initial disruption of the blood-brain barrier was followed by intrathecal antibody production. A young age, a deteriorating electroencephalogram pattern with generalized slowing (grade 1) progressing to amplitude and burst suppression (grade 2) and finally, electrical silence (grade 3), and prolonged impairment of blood-brain barrier were associated with a poor prognosis. The persistence of intrathecal IFN-a was indicative of a good prognosis. A Glasgow Coma Score (GCS) of 7 or less in 15/22 at presentation did not predict outcome. Nine of 14 with a good outcome had low GCS vs 4/8 with a poor outcome. Of 20 survivors, 7 had moderate/severe impairment. Of 9 children aged 2 years or less, 6 were neurologically impaired. (Clarke M, Newton RW, Klapper PE, et al. Childhood encephalopathy: viruses, immune response, and outcome. Dev Med Child PEDIATRIC NEUROLOGY BRIEFS (ISSN 1043-3155)