Cerebral hemiatrophy and hemiparesis following hemiclonic status epilepticus in Dravet syndrome.

Abstract

Dravet syndrome is currently considered as an developmental and epileptic encephalopathy and, recently, mandatory, alert, and exclusionary criteria have been proposed. Here, we describe three patients with Dravet syndrome with the typical early presentation including febrile and afebrile alternating hemiclonic seizures due to loss-of-function SCN1A variants. Subsequently, they developed episodes of febrile focal status epilepticus (SE) associated with hemiparesis and cerebral hemiatrophy with posterior focal seizures, as a consequence of Dravet syndrome. This sequence of events has been previously published in patients with Dravet syndrome and does not contradict the recent classification by the International League Against Epilepsy (ILAE). The ILAE guidance identifies "Focal neurological findings" as alert criteria and "MRI showing a causal focal lesion" as exclusionary criteria for making an initial diagnosis of Dravet syndrome at presentation. Our three patients would correspond to a severe phenotype, similar to the well-known presentation of generalized atrophy following prolonged status epilepticus. Common genetic findings in cases of diffuse and unilateral brain involvement may help explain these clinical presentations. Further genotype-phenotype studies may provide additional insights into this electroclinical behavior.