Hamad, a 13-month-old infant, presents to the emergency department of his local hospital in Abu Dhabi with his first prolonged tonic−clonic afebrile seizure. He has experienced three febrile seizures in the past. The first two occurred at eight months of age due to a chest infection. They were prolonged, lasting over 15 minutes, and he required emergency medication and a three-day admission. The third febrile seizure was at nine months and associated with an upper respiratory tract infection. It only affected the left side of Hamad’s body and lasted for over 30 minutes before it was stopped with intravenous lorazepam and intravenous phenytoin.
A magnetic resonance imaging (MRI) brain scan and cerebrospinal fluid analysis are normal. His early development has been normal but he only started crawling at 12 months of age and he has no recognizable words. There is no family history of epilepsy.
Hamad’s history is unusual for simple or complex febrile seizures and should raise the possibility of epilepsy. The features that suggest a diagnosis of Dravet syndrome (also known as severe myoclonic epilepsy of infancy) include age at onset, frequent and prolonged nature of the febrile seizures, and recent development of a prolonged afebrile seizure and a background of possible developmental delay.
Hamad parents contacted Kidsheart Medical Center and was referred to Dr. Imad Yassin, consultant pediatric neurologist who performed a video-EEG. Dr. Imad Yassin considered the possibility of Dravet syndrome and referred Hamad to the Pediatric Genetic Clinic at Kidsheart Medical Center, run by Dr. Ayman El-Hattab, who undertook a blood test for DNA analysis to look for a mutation in the alpha (α) subunit of the first neuronal sodium channel (SCNIA) gene. A mutation is found in at least 80% of children with Dravet syndrome. An early diagnosis of Dravet syndrome established the cause of the Hamad’s epilepsy and therefore avoids the need for him to undergo a number of investigations, some of which may be invasive.