Symptoms of Dravet Syndrome
Dravet Syndrome is a lifelong condition. Symptoms appear very early in childhood and develop over time.
Although Dravet Syndrome is recognised as a rare form of epilepsy, epilepsy is just one part of living with Dravet Syndrome - the range and severity of symptoms vary from one individual to another. Seizures typically begin during the first year of life. Over time other seizure types can occur and other symptoms emerge.
Initial signs - first year of life
Dravet Syndrome is initially characterised by prolonged, recurrent epileptic seizures often triggered by a fever. Seizures usually start in the first year of life (studies suggest the average age of onset is around 5 months, but can occur between one and 15 months). Until the onset of first seizures brain development appears normal. Seizures in the first year are often tonic-clonic (stiffness and jerking) or clonic (jerking) and may affect one side of the body (hemiclonic).
Febrile seizures (or febrile convulsions) are very common in childhood and are not usually associated with a form of epilepsy. They are caused by a high or rapidly rising temperature, often due to illness or vaccination. 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 (described as status epilepticus). These very long seizures may cause the child to be admitted to intensive care and have emergency treatment in A&E.
During the second year of life the seizures become more frequent and persistent. They may happen with or without a fever, and at any time of day and night. Between the ages of one to four, seizure types may start to occur, including:
- Myoclonic multiple muscle jerks (‘myo’ meaning muscle, and ‘clonus’ meaning jerk), which may involve one part of the body or the whole body
- Atypical absences (where the child will stare) with brief loss of awareness (usually less than 20 seconds)
- Focal seizures ( previously known as partial seizures), which may involve loss of awareness. Automatic movements such as smacking of the lips, wandering, or fumbling movements of the hand may be present
- Non-convulsive status, where the child develops a prolonged groggy, poorly functional state
Click here for more detailed information about seizure types.
The early development of children with Dravet syndrome is usually normal. However, during the second to fourth year of life, varying degrees of developmental delay typically become apparent. You may notice that speech and language is particularly affected. Other symptoms may also develop, including
- Learning difficulties, often severe, frequently including communication/ speech problems and incontinence
- Features of autism and/or attention deficit hyperactivity disorder, alongside inappropriate or obsessive behaviours, lack of awareness of danger or sensory issues
- Orthopaedic or mobility issues such as difficulties in walking (gait disturbance) and unsteadiness (ataxia), poor coordination or motor skills and muscle tone issues
- Sleep disturbances, often severe and persistent; and often alongside disruptive nocturnal seizures
- Eating, growth or nutritional concerns, potentially requiring a gastrostomy
Click here for more detailed information about the secondary conditions.
As children grow older, the seizure pattern may change. Partial and myoclonic seizures may lessen, and in some cases disappear, but convulsive seizures typically persist. Prolonged seizures may continue to be a risk and may still be more likely to occur with fever or illness.
Issues that may increase in frequency as the child grows older include nocturnal seizures developmental delays, and gait disturbances.
Many children with Dravet Syndrome have a good life expectancy, however, children who develop severe disability may have problems which will affect their lifespan. Sadly, children with Dravet Syndrome are at a higher risk of Sudden Unexplained Death in Epilepsy (SUDEP) than children with other types of epilepsy. Despite this they have an 85% chance of surviving into adulthood.
Click here for more information about SUDEP and advice on starting a conversation with your medical team on managing its risks.
Adults are increasingly being recognised with this type of epilepsy as adult specialists become more aware of the condition. Making the transition into adulthood (which legally occurs at the age of 16) can bring a range of new challenges and it is important to start preparing for this process early, when your child with Dravet Syndrome reaches the age of 14.
Click here to read more about ‘Transitioning to Adulthood’.