Dravet-Syndrom

Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a rare form of epilepsy usually presenting in the first 1-2 years of life.

Clinical presentation

The typical presentation occurs during the first six months to one year of life as tonic-clonic seizures in a febrile child, almost indistinguishable from febrile seizures. These progress to myoclonic seizures at age 4-5 years and are drug resistant .

Pathology

Genetics

Dravet syndrome is caused by a mutation in the neuronal sodium channel gene, SCN1A. However the mutated SCN1A gene is absent in about 20% of the patients who fulfill all the diagnostic criteria of the syndrome. Therefore it is possible that genes other than SCN1A such as the GABAA-receptor gamma 2 subunit gene might be involved .

Radiographic features

MRI

Only a small number of patients with Dravet syndrome demonstrate any abnormalities on MRI, which may include :

• focal brain atrophy
• cortical dysplasia
• hippocampal sclerosis

Treatment and prognosis

Dravet syndrome is one of the most pharmacoresistant epilepsy syndromes. Valproate is used as a first-line agent to prevent the recurrence of febrile seizures and oral/nasal/rectal benzodiazepine is used for any long-lasting seizures. Stiripentol (Diacomit®) was approved as an orphan drug in 2007 in Europe for adjunctive therapy in Dravet syndrome . Ketogenic diet may be used as an adjunct to treatment.

History and etymology

It was named after French pediatric epileptologist Charlotte Dravet (1936- fl.2018) who described this condition for the first time in 1978 as severe myoclonic epilepsy .

Siehe auch:

• Lennox-Gastaut-Syndrom
• Ohtahara-Syndrom