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Published online: 28 March 2018
© Springer International Publishing AG, part of Springer Nature 2018
Abstract Dravet syndrome (DS) is a medically refractory epilepsy that onsets in the first year of life with prolonged seizures, often triggered by fever. Over time, patients develop other seizure types (myoclonic, atypical absences, drops), intellectual disability, crouch gait and other comorbidities (sleep problems, autonomic dysfunction). Complete seizure control is generally not achievable with current therapies, and the goals of treatment are to balance reduction of seizure burden with adverse effects of therapies. Treatment of co-morbidities must also be addressed, as they have a significant impact on the quality of life of patients with DS. Seizures are typically worsened with sodium-channel agents. Accepted first-line agents include clobazam and valproic acid, although these rarely provide adequate seizure control. Benefit has also been noted with topiramate, levetiracetam, the ketogenic diet and vagal nerve stimulation. Several agents presently in development, specifically fenfluramine and cannabidiol, have shown efficacy in clinical trials. Status epilepticus is a recurring problem for patients with DS, particularly in their early childhood years. All patients should be prescribed a home rescue therapy (usually a benzodiazepine) but should also have a written seizure action plan that outlines when rescue should be given and further steps to take in the local hospital if the seizure persists despite home rescue therapy.
Introduction
Dravet syndrome (DS), previously known as severe myoclonic epilepsy of infancy, was first described in 1978 [1] and is characterized by medically refractory epilepsy with frequent episodes of prolonged seizures (status epilepticus) that are often provoked by changes in temperature or photosensitivity [2, 3]. This severe epilepsy syndrome can be recognized and accurately diagnosed in the first 2 years of life when it typically first presents with one or more prolonged seizures, often hemiclonic in nature, during a febrile illness or following a childhood vaccination. The incidence of DS is between 1/15,700 [4] and 1/22,000 [5]. Some common epilepsy treatments may exacerbate the syndrome, making accurate diagnosis and precision therapy a must.
DS is a genetic disease, with most affected children ([85%) found to have mutations and copy number variants in the SCN1A gene [6-10]. SCN1A codes for the a-1 subunit of the type 1 voltage-gated, sodium channel (Nav1.1). The...