Seizures and epilepsy in herpes simplex virus encephalitis: current concepts and future directions of pathogenesis and management.

Mortality related to herpes simplex virus encephalitis (HSE) dropped dramatically with the systematic initiation of antiviral treatment in encephalitic syndromes. Further efforts need to be taken to reduce long-term morbidity in the survivors. In this regard, the high rate of postencephalitic epilepsy, which is frequently refractory to medical treatment, contributes significantly to the unfavorable clinical outcome of the disease. Seizures during the acute phase of HSE are the main risk for the development of postencephalitic epilepsy. Yet, there are no randomized controlled trials for the management of acute seizures, preventive measures or the ideal duration of antiepileptic treatment. Hence, concepts for the medical treatment of seizures during the acute phase of HSE and postencephalitic epilepsy are eagerly awaited. Epilepsy surgery is a potential treatment option for the latter, but only promising in a subgroup of patients suffering from unilateral mesio-temporal lobe epilepsy and congruent neuropsychological impairment. Relapsing HSE and post-infectious autoimmune conditions can lead to seizures in the aftermath of acute HSE. These conditions need to be kept in mind in order to promptly assure the initiation of accurate diagnostic steps and respective treatment. The purpose of this review is to summarize the current pathogenetical understanding, clinical and diagnostic considerations, and treatment options of seizures in acute HSE and postencephalitic epilepsy.