IS SHORT-TERM ACYCLOVIR TREATMENT RELATED WITH MORE UNFAVOURABLE OUTCOMES IN PATIENTS WITH HSV-1 ENCEPHALITIS?

ABSTRACT Background Herpes simplex encephalitis (HSE) is the most common form of sporadic encephalitis which is caused by herpes simplex virus type 1 (HSV-1). Current guidelines recommend intravenous Acyclovir for 14–21 days in cases of HSE. Objectives Optimizing the Acyclovir treatment duration is important in regards to preventing Acyclovir-related neurotoxicity and nephrotoxicity. Study design We retrospectively evaluated 13 patients, who were diagnosed with HSE by molecular testing (HSV-1 PCR positivity in cerebrospinal fluid), in two university hospitals in Istanbul, between 2010 and 2021. The patients were treated either 10 days or less as a short-term treatment regimen of Acyclovir or for 14 days or more as long-term treatment regimen Results The median age was 58 years (range 24–82 years) and 54% of them were male. The median follow-up time was 79 days (range 20-670 days) after discharge. Long-term treatment was used in 6 and a short-term treatment regimen was used in 7 cases. One of the patients died on the 4th day of Acyclovir treatment. One patient never received Acyclovir treatment. Of the 5 patients who received long-term treatment, 3 (21-28 days) had amnesia and orientation-cooperation restriction, one (21 days) died on the 2nd day of treatment, while the other (14 days) had no sequelae. There were no sequelae in three out of 5 patients who received short-term treatment. Conclusions We believe that it is necessary to determine the optimal Acyclovir therapy duration should be evaluated in a prospective randomized clinical trial in large patient population.