Dravet Syndrome

Occurring in about one in every 30,000 births, Dravet syndrome is a catastrophic form of incurable epilepsy that begins in early infancy in an otherwise healthy infant. Also known as severe myoclonic epilepsy of infancy (SMEI), children with Dravet syndrome may experience dozens or even hundreds of seizures per day. These patients are also prone to prolonged life-threatening seizures called status epilepticus. These children often struggle with developmental delays, a variety of health problems and have an increased risk of sudden unexplained death in epilepsy.

Symptoms

Typically, Dravet syndrome will be suspected if a child experiences two or more seizures before 1 year of age, particularly if seizures are prolonged seizures, lasting longer than 10 minutes. These seizures tend to manifest for the first time as a febrile seizure, a seizure triggered by a high fever, but eventually progresses to severe spontaneous seizures. The syndrome can also present in a seizure that is triggered by vaccinations or warm temperatures. Other signs include speech delay, developmental delay or regression and behavioral issues.

Causes

More than 80% of Dravet syndrome cases are caused by a mutation in the SCN1A gene that codes for a voltage-gated sodium channel protein. The cause for Dravet syndrome patients without the SCN1A gene mutation is unknown.

Diagnosis

If your child has experienced two or more prolonged seizures before 1 year of age, speak to your neurologist as additional testing may be needed. An early diagnosis is critical to proper treatment and the best possible outcome. Testing may include genetic testing by an epilepsy panel including genetic and neurological specialists.

Treatment

Seizures in children with Dravet syndrome are often not responsive to currently available medications and are difficult to control. Because Dravet syndrome affects critical parts of cognitive and behavioral neurological portions of the brain, a multidisciplinary team is crucial to fully addressing the needs of a child with Dravet syndrome. Treatment options may include:

• Medication: Seizure treatment works to find the best combination of medicine. Getting the seizures under control is the goal, so the child can have the best possible quality of life, as well as improve developmental abilities and decreased mortality rates.
• Diet: The ketogenic diet has also proven helpful in children with Dravet syndrome. A ketogenic diet is a type of diet is very high in fat and very low in carbohydrates. Enough protein is included to help promote growth. The diet causes the body to make ketones – chemicals made from the breakdown of body fat. The brain and heart work normally with ketones as an energy source. This special diet must be strictly followed. Too many carbohydrates can stop ketosis. Researchers aren’t sure why the diet works, but some children become seizure free when put on the diet. The diet doesn’t work for every child.
• Vagus nerve stimulation: This treatment sends small pulses of energy to the brain from one of the vagus nerves, a pair of large nerves in the neck. If your child is age 12 or older and has partial seizures that are not controlled well with medicine, VNS may be an option. VNS is performed by surgically placing a small battery into the chest wall. Small wires are then attached to the battery and placed under the skin and around one of the vagus nerves. The battery is then programmed to send energy impulses every few minutes to the brain. When your child feels a seizure coming on, he or she may activate the impulses by holding a small magnet over the battery. In many cases, this will help to stop the seizure. VNS can have side effects such as hoarse voice, pain in the throat or change in voice.

Additional resources

• Dravet Syndrome Foundation
• NORD: National Organization for Rare Disorders