The clinical outcome and neuroimaging of acute encephalopathy after status epilepticus in Dravet syndrome

Aim: To analyze the clinical outcome and neuroimaging over a long duration follow-up in the currently largest series of acute encephalopathy after status epilepticus in patients with Dravet syndrome.

Method: Clinical and neuroimaging data of patients with Dravet syndrome with a history of acute encephalopathy (coma >24h) after status epilepticus from February 2005 to December 2016 at Peking University First Hospital were reviewed retrospectively.

Results: Thirty-five patients (15 males, 20 females) with a history of acute encephalopathy were enrolled from a total of 624 patients with Dravet syndrome (5.6%). The median onset age of acute encephalopathy was 3 years 1 month. The duration of status epilepticus varied between 40 minutes to 12 hours. Thirty-four patients had a high fever when status epilepticus occurred, and only one had a normal temperature. Coma lasted from 2 to 20 days. Twelve patients died and 23 survived with massive neurological regression. The median follow-up time was 2 years 1 month. Neuroimaging of 20 out of 23 survivors during the recovery phase showed diverse degrees of cortical atrophy with or without subcortical lesions.

Interpretation: Acute encephalopathy after status epilepticus is more prone to occur in patients with Dravet syndrome who had a high fever. The mortality rate is high in severe cases. Survivors are left with severe neurological sequelae but often with either no seizure or low seizure frequency.

What this paper adds: Acute encephalopathy is more prone to occur in patients with Dravet syndrome with a high fever. The mortality rate is high for acute encephalopathy after status epilepticus in patients with Dravet syndrome. Survivors have neurological sequelae.