Recognising febrile seizures is important in the diagnosis of Dravet syndrome. Febrile seizures are caused by a high or rapidly rising temperature, often due to illness or vaccination. These are usually tonic clonic or hemiclonic seizures.
- Tonic clonic seizures involve a stiffening of the arms and legs (tonic phase), followed by jerking of the arms, legs, and head (clonic phase).
- Hemiclonic seizures are similar, though only one side of the body convulses.
- Febrile seizures are very common in childhood and usually are not associated with a form of epilepsy.
The first suggestion of Dravet syndrome may be when the first febrile seizure happens in early infancy and is prolonged, lasting more than ten minutes and sometimes over half an hour (status epilepticus). These very long seizures may cause the child to be admitted to intensive care and have emergency treatment in A&E.