Objectives: As suggested from a high rate of preceding severe febrile convulsions, viral infections
may be one cause of temporal lobe epilepsy (TLE). The impact of herpesvirus infections
for TLE is uncertain.
Material and Methods: A detailed analysis of 23 pediatric patients (age 1–15 years) with epileptic seizures
related to non-tumorous temporal lobe lesions, including hippocampal atrophy/dysplasia
in 9 (group A) and hippocampal sclerosis in 14 cases (group B).
Results: Frequent febrile convulsions (n >3) preceding the diagnosis of TLE were noted in
only three patients (13%) (group A=2, group B=1). No further etiological factors were
detected in group A patients. Among group B patients, three had suffered serious perinatal
events and two had shown an epileptic status during an encephalitic episode of unknown
etiology. Surprisingly, in seven further group B patients distinct cerebral herpesvirus
infections were found (HSV=3, EBV=2, CMV=2; intrathecal synthesis of specific anti-viral
antibodies present). One additional girl developed severe hippocampal sclerosis when
a primary EBV infection caused an epileptic status. Whereas additional inflammatory
brain lesions were noted in patients with cerebral HSV infections, isolated hippocampal
sclerosis was found in the five cases with CMV or EBV infections.
Conclusions: In addition to febrile convulsions that may cause neuronal damage by means of seizure-induced
metabolic processes, distinct herpesvirus infections may be one further important
cause of hippocampal sclerosis and TLE. The extent of brain damage may depend on the
type of herpesvirus, ranging from isolated hippocampal sclerosis (CMV, EBV) to marked
temporal lobe damage with additional brain lesions (HSV). Intensified research on
the relationship between herpesvirus infections and temporal lobe damage may provide
new treatment options for patients with TLE.
