Prognostic factors in childhood acute encephalitis.

We have studied the prognostic factors in 462 children, from 1 month to 16 years old, with acute encephalitis. Death occurred in 2.8% patients, 6.7% were severely damaged and 90.5% were cured with no or only minor sequelae. The risk of death or severe damage in patients less than 1 year of age was 5.0-fold (95% confidence limits, 2.2 to 11.6; P less than 0.001) greater than that of older children. When compared with those children whose level of consciousness had been normal before admission, children who had been disoriented before admission had a 3.9-fold (1.1 to 14.3, P less than 0.05) risk and those who had been unconscious had a 25.4-fold (7.3 to 88.1, P less than 0.001) greater risk of death or severe damage. The risk of death or severe damage in patients with herpes simplex virus encephalitis was 11.7-fold (3.8 to 35.8, P less than 0.001) and in patients with Mycoplasma pneumoniae encephalitis it was 7.0-fold (2.6 to 18.7, P less than 0.001) that of other children. All patients with none of the above mentioned risk factors were cured without any major sequelae. We conclude that specific attention should be paid to the youngest patients, especially to those with an impaired level of consciousness, and all available measures should be focused on early detection of herpes simplex virus or M. pneumoniae infection.