Dravet syndrome

Last revised by Dr Rohit Sharma on 24 May 2022

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.

The typical presentation occurs during the first six months to one year of life as tonic-clonic seizures (including status epilepticus) in a febrile child or after vaccination 6. These progress to drug-resistant myoclonic seizures and other seizure types at age 4-5 years, with developmental delay and subsequent intellectual stagnation 4,6.

The etiology for Dravet syndrome is genetic 6. In cases of Dravet syndrome following vaccination, the vaccination is not directly implicated in the pathogenesis, but is simply the precipitant for the initial seizure that heralds the syndrome 7.

Dravet syndrome is caused by a mutation in the neuronal sodium channel gene, SCN1A. However the mutated SCN1A gene is absent in approximately 15% of the patients who fulfill all the diagnostic criteria of the syndrome 6. Therefore it is possible that genes other than SCN1A, such as the GABAA-receptor gamma 2 subunit gene, might be involved 1.

Only a small number of patients with Dravet syndrome demonstrate any abnormalities on MRI brain (i.e. MRI brain is usually normal), which may include 5

Dravet syndrome is one of the most pharmacoresistant epilepsy syndromes 6. Sodium valproate is used as a first-line agent, with other antiseizure medications utilized including clobazam, stiripentol, and fenfluramine 6. Ketogenic diet may be used as an adjunct to antiseizure medication treatment 6. Vaccinations should be encouraged 6.

It was named after French pediatric epileptologist Charlotte Dravet (1936 - fl. 2022) who described this condition for the first time in 1978 as severe myoclonic epilepsy 3.

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