Human Herpesvirus 6-Associated Encephalopathy in a Child with Dravet Syndrome

Abstract

Dravet syndrome presents with generalized and unilateral clonic or clonic-tonic seizures that occur during the first year of life, followed by severe epilepsy. Prolonged seizures are often provoked by fever and usually followed by recovery of the previous condition. We describe the case of a 13-month-old girl with Dravet syndrome who experienced severe neurological sequelae as a result of human herpesvirus 6-associated encephalopathy. Biphasic clinical course was observed, with fever and prolonged seizures at onset and late seizures refractory against antiepileptic agents. Serum concentrations of proinflammatory cytokines and matrix metalloproteinase-9, which have been associated with development of acute encephalopathy, were not markedly increased in this patient, suggesting that these molecules were not the main causes of neuronal damage in this patient. Instead, seizure susceptibility due to SCN1A mutation may have contributed to acute encephalopathy in our patient.