Dravet syndrome, also known as severe myoclonic epilepsy in infancy (SME), is a very rare childhood epilepsy syndrome. It affects as few as 1 in 500 children with epilepsy and most commonly starts with seizures that are very similar in character to that of febrile convulsions. Although this syndrome may develop from as young as 6 months, the most typical aspects of the syndrome may not become apparent until 2 years of age, which means diagnosis is sometimes delayed.
With Dravet syndrome, seizures will often begin as early as 6-10 months and much like febrile convulsions can be associated with a high temperature. Seizures will likely be tonic-clonic, which present with jerking movements and stiffness.
Febrile status epilepticus is common during the first year of Dravet syndrome, which means a seizure can last for an extended period of time, between 15 and 30 minutes. If this occurs, it’s crucial that you call 999 immediately.
During the second year of life, it’s likely that seizures will become more frequent. At this point they may occur with or without a fever. Myoclonic seizures and focal seizures often become more common during the second year of life, in addition to tonic-clonic seizures.
Children with Dravet syndrome are often photosensitive, this means that seizures can be triggered by flashing lights and also even certain patterns. Hot environments are also a common trigger with Dravet syndrome.
In order to make a diagnosis, a full history of the seizures will be required, along with descriptions. The more details a doctor has from the parents the clearer it will be to make a diagnosis.
An electroencephalogram (EEG) test will normally be used to help confirm a diagnosis. This will record the electrical activity within the brain and display evidence of epileptic activity. A seizure may be induced within a controlled environment during the test in order to confirm the diagnosis. Flashing lights may be used to test for Dravet syndrome, although not all children with the syndrome are photosensitive, the majority are.
Blood tests may be used to search for a specific mutation that’s found in 8 out of 10 children with Dravet syndrome. This mutation is known as the SCN1A mutation and can be helpful to confirm a diagnosis of Dravet syndrome.
Unfortunately, Dravet syndrome is known to be one of the syndromes that is particularly resistant to anti-epilepsy medications (AEDs). Sodium valproate and topiramate are commonly tried first, although clobazam and stiripentol may also be prescribed.
It’s likely that a combination of medications, such as sodium valproate, stiripentol and clobazam, will be the most effective treatment. The most effective combination can take some time to find, and involve an element of trial and error.
A ketogenic diet has been found to be helpful, although it should only ever be used alongside the prescribed AEDs and under the guidance of a qualified dietician.
Seizures will likely continue to be difficult to control throughout childhood, which means that learning difficulties are commonplace, which can range from mild to severe. Children with Dravet syndrome can also become unbalanced and increasingly unsteady, this is known as being ataxic. Children with Dravet syndrome will likely need care throughout their life, however, by the age of 16 the seizures may become less frequent.
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