Dravet syndrome: a study of 53 patients.

OBJECTIVE: We analyzed the electroclinical features, treatment and evolution of patients with Dravet syndrome (DS).
MATERIAL AND METHODS: We evaluated the clinical records of 53 patients that met the diagnostic criteria of DS according to the ILAE classification of 1989 seen at our center between February 1990 and December 2004.
RESULTS: Thirty-four male and 19 female patients met the diagnostic criteria of DS. Mean time of follow-up was 10 years. The mean age at onset was 6 months and in all patients the seizures were associated with febrile illness. Myoclonias were found in 39 children. These seizures appeared between the ages of 1 and 5.5 years, with an average of 1 year and 5 months. The seizures were difficult to control with AEDs. All patients presented some degree of mental delay. At the age of 6 years, one of the children in our series presented kinesigenic paroxysmal dyskinesias. Twenty patients were placed on the ketogenic diet (KD). Two did not tolerate the KD and the diet was ineffective in five cases. The other 13 showed different degrees of control of seizures.
CONCLUSION: The present study confirms the severity and intractability of the seizures and the difficulties to make an early diagnosis in DS. The onset of febrile seizures or seizures related to infectious disease or vaccination, focal or generalized, prolonged in time and during the first year of life, is especially suggestive of DS. The final diagnosis is usually made after 2 or 3 years when the electroclinical picture is complete, but earlier diagnosis is desirable. Myoclonias are the most representative type of non-febrile seizures in this syndrome but are not always present. Cognitive development is poor in all patients. Treatment with the KD should be considered early. A ion-channel disorder could explain the association between DS and paroxysmal diskinesias, as seen in one of our patients.