HHV-6A, HHV-6B, and HHV-7 in Febrile Seizures and Status Epilepticus

Febrile seizure is defined as a seizure associated with a febrile illness without a history of afebrile seizure or evidence of an acute central nervous system infection or other insult. Febrile status epilepticus is defined as a febrile seizure with duration greater than 30 minutes. Febrile seizures are the most common seizure type under age 5 years. Febrile status epilepticus is associated with an increased risk of temporal lobe epilepsy with evidence of acute hippocampal injury. Primary HHV-6B infection is a common cause of fever with both febrile seizures and febrile status epilepticus. Reactivated HHV-6B infection following stem cell transplantation has been associated with hippocampal injury and seizures in the context of limbic encephalitis. If the suspected association between HHV-6B infection and temporal lobe epilepsy is proven, then future studies may focus on therapy for HHV-6B infection for the prevention of epilepsy in these children.