[Herpetic encephalitis: prognostic elements in adults and children (49 cases)]

In 49 cases (26 children, 23 adults) of proven Herpes simplex encephalitis, the authors studied the influence of age, disturbances of consciousness, time of diagnosis and therapy on patients' outcome, as well as the prognostic value of EEG data. Mortality was low in late childhood and young adulthood in spite of the constancy and depth of coma; it was very high in newborns and adults over 40 years of age and it was always correlated with the severeness of initial consciousness disturbances. The onset of periodic complexes (in 65% of the children and 78% of adults on the first EEG) does not systematically imply a poor outcome. Correlations between these EEG patterns and bioptic or surgical data tend to prove that these periodic complexes are already present in a prenecrotic state. Reversibility may be complete. On the other hand, the association between a contralateral focus or diffusion of initial abnormalities and an early coma imply a poor prognosis (12 deaths and 2 major sequellae in 14 cases). The importance of early presumptive diagnosis and therapeutical onset is stressed. The only cases of complete recovery are found among young adults treated early (surgery for older cases) thanks to an initial typical EEG. In young children, first clinical symptoms are often not evocative. Great importance should be attached to the onset of partial seizures and interictal loss of consciousness in a feverish child (24 out of 26 cases). Antiviral therapy should be started as soon as a Herpes simplex encephalitis is suspected, since the new antiviral drugs have a relatively low toxicity and do not interfere with the immunological diagnosis.