Abstracts

Rationale: Dravet syndrome (DS) was first described by Charlotte Dravet in 1982, originally under the name Severe Myoclonic Epilepsy of Infancy. The DS seems to have a relatively low prevalence of about 1/40,000, more prevalent in males but presumably undiagnosed in many cases. Most of the patients (pts) with DS have mutations in the SCN1A gene, some also in other genes. The mortality rate among DS is high. The aim of the study was to describe the clinical long-term course of patients with DS. Methods: Based on a monocentric retrospective chart review we investigated all DS patients treated in the inpatient or outpatient facility of the Saxon Epilepsy Center at Radeberg. We looked for clinical data (i. a. seizures, MRI, EEG, intelligence, ataxia, mutations), medication, and complications in the long-term course. Results: We identified 51 DS pts (26 male, 25 female), which we followed between 2 and 50 years (mean: 15 years). Most of the pts (n=38) were diagnosed at our center. The average age was 24 years (7 to 54 years). In 24 pts (47%) diagnosis was established in adult age and diagnosis was done in our center. Seizure types included generalized tonic-clonic seizures (GTCS) in 90% (n=46), myoclonic seizures in 61% (n=31), tonic seizures in 45% (n=23), and absence seizures in 20% (n=10). Febrile convulsions occurred in 82% (n=42). MRI was performed in 31 pts with general signs of atrophy in 5 pts and hippocampal sclerosis in 2 pts. All pts showed mental retardation, mild (35%, n=18), moderate (39%, n=20), or severe (25%,n=13). 76% (n=39) of the pts were genetically investigated, 30 of them were SCN1A positive, 2 were PCDH19 positive, 7 were negative. EEG recordings showed generalized epileptic discharges in 23 pts (45%) and focal discharges in 2 pts (4%). Clinically most of the pts (n=33, 65%) showed moderate (n=24) to severe (n=9) ataxia, ataxia was exclusively seen in adults. All pts were treated once in lifetime with sodium valproate, 22 pts (43%) with clobazam as long-term medication, 18 pts (35%) with bromide and 24 pts (47%) with stiripentol. Other anti-epileptic drugs were used in nearly all pts with lower frequencies. Three pts (6%) are seizure free for years, one of them with oxcarbazepine. In 20 pts (39%) seizure frequency was reduced with seizures mostly during sleep. In 25 pts (49%) temperature sensitivity of seizures was reported. Four pts (8%) died due to SUDEP in adult age. Conclusions: Our results are similar to those of other studies, especially Akiyama et al. (Epilepsia 2010 Jun;51(6):1043-52) with two differences: In our group are less seizure-free pts and more pts who died due to SUDEP. DS is not very well known by adult neurologists, in all our adult DS pts diagnosis was not supposed by them. The knowledge of clinical signs and long-term course of DS is therefore extremely important. The combination of mental retardation, ataxia, and refractory GTCS especially during sleep helps to find the diagnosis in adults even if history about the early childhood is not present anymore.  Funding: None