HERPETIC ENCEPHALITIS IN THE ELDERLY - A REPORT OF 13 CASES

In a retrospective analysis of 13 cases of Herpes simplex encephalitis (mean age : 67,2 +/- 6,4 years; ten women, three men), the authors co nclude that this infection is more often due to Herpes simplex virus 1 in the elderly. Diagnosis is difficult at an early stage, and must be suspected in case of confusion (9/13), especially feverish (11/13), a ssociated with neurological signs (10/13), and particularly epilepsy ( 5/13). It requires a lumbar puncture which collect a clear and lymphoc ytic fluid. Prognosis of this encephalitis depends on early diagnosis and an presumptive therapy with acyclovir. EEG is helpfull showing per iodic activity (10/13). CT scan and MRI can show unspecific abnormalit ies, but often too late. Laboratory findings will secondarily confirm the diagnosis quite frequently, using new Elisa methods. Polymerase ch ain reaction allows earlier diagnosis. Geriatric cases seem more oten due to reinfection or to endogen virus reactivation rather than to pri mary infection.