Dravet Syndrome

Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a rare and serious type of epilepsy. The first seizure often happens with a high fever and can last more than five minutes. It can lead to developmental delays, trouble with speech and language, and problems with balance or walking.

Long seizures can be dangerous, so care plans often include steps to stay safe and prepare for emergencies.

Symptoms of Dravet syndrome

A seizure is the first symptom. It often happens before your child turns 1 year old. The first seizure may:

• Last more than five minutes
• Happen with a fever, illness or high temperatures
• Cause uncontrollable shaking or jerking (convulsions)
• Affect only one or both sides of their body

After age 1, your child may have more seizures. These might happen without temperature changes.

Other symptoms may include:

• Balance and coordination difficulties
• Behavioral problems (like anger or aggression)
• Developmental delays (like trouble talking or understanding)
• Neurodevelopmental disorders (like ADHD)
• Problems sleeping
• Shakiness or an unsteady walk
• Slow growth or feeding problems
• Trouble controlling body functions like body temperature, heart rate or blood pressure (dysautonomia)
• Weak or low muscle strength

Dravet syndrome causes

A genetic change (variant) in a gene called SCN1A causes most cases of Dravet syndrome. This gene gives your body instructions to make sodium channels. These are tiny openings in cells that help carry electrical signals in your brain. These signals help brain cells talk to each other.

When there’s a change in the SCN1A gene, the sodium channels won’t work the right way. This can make it harder for your brain to control signals properly. It can lead to seizures and other symptoms.

Is Dravet syndrome genetic?

Yes, Dravet syndrome is a genetic condition. This means it happens because of a change in a gene. Most of the time, the gene change happens by chance and isn’t passed down from a biological parent. But in rare cases, it can run in families.

Sometimes, a parent may carry the gene change in some of their cells but not all. This is called mosaicism. Other times, the condition can be passed down in an autosomal dominant pattern. This means only one biological parent needs to have the gene change for a child to inherit it.

Not everyone with the SCN1A gene change will have Dravet syndrome. Some people may have the gene change but won’t have any symptoms. Some may have other forms of epilepsy or different conditions, like genetic epilepsy with febrile seizures plus (GEFS+), focal epilepsy or familial hemiplegic migraines.

Complications of Dravet syndrome

This syndrome can lead to serious problems. Some may be life-threatening. These may include:

• Getting hurt during a seizure
• A long-lasting seizure that needs emergency treatment (status epilepticus)
• Sudden unexplained death in epilepsy (SUDEP)

Your child’s healthcare provider will explain which warning signs to watch for. They’ll help you make an emergency plan to keep your child safe.

How doctors diagnose Dravet syndrome

Your child’s healthcare provider will do a physical exam, ask about their health and any past medical issues. Their provider will also ask about your child’s seizure history and any medicines they take.

They may order a blood or saliva test to check for changes in the SCN1A gene. They may also use imaging tests, like an MRI, or a brain wave test called an EEG. These early test results might look normal, so it can sometimes take time to get a full diagnosis.

How is Dravet syndrome treated?

The main goal of treatment is to reduce how often your child has seizures. As seizures can be different for everyone, care plans aren’t one-size-fits-all. Your child’s healthcare providers will create a plan unique to their needs. Treatment may include:

• Medications (antiseizure or rescue medications)
• Ketogenic diet (a special high-fat, low-carb meal plan)
• Therapies (like physical, occupational or speech therapy)

Which medications treat Dravet syndrome?

The U.S. Food and Drug Administration (FDA) approves these medicines to treat seizures from Dravet syndrome after age 2:

• Cannabidiol
• Fenfluramine
• Stiripentol

These medicines come in different forms, like pills or liquid, to make them easier to take.

Your provider may tell you to avoid certain antiseizure medicines called sodium channel blockers. Examples include carbamazepine, oxcarbazepine, lamotrigine and phenytoin. These can sometimes make seizures worse.

Rescue medications

Rescue medications are emergency treatments for continuous seizures. Your child’s provider will also help you create an action plan for home or their school.

These medicines can help stop a seizure. Most rescue medications are benzodiazepines, like:

• Clonazepam
• Diazepam
• Lorazepam
• Midazolam

They come in different forms, like nasal sprays, rectal gels, tablets that dissolve in the mouth (wafers) or films placed inside the cheek (buccal films).

When should my child see their healthcare provider?

Let your child’s provider know if they have two or more seizures that last more than five minutes. Tell them if the first one happened before your child’s first birthday. It’s also important to mention if the seizure was triggered by a fever or heat. These could be signs of Dravet syndrome.

After a diagnosis, you’ll meet regularly with your child’s care team. Tell their provider if your child’s seizures get worse, like happening more often or lasting longer, even after starting treatment.

Their provider will explain what warning signs to watch for and what to do in an emergency. Call 911 or your local emergency services number if your child:

• Has a seizure that lasts more than five minutes and causes trouble breathing
• Has back-to-back seizures without waking up in between
• Gets hurt during a seizure

What’s the prognosis for Dravet syndrome?

Your child’s healthcare provider can talk with you about their outlook. This can be different for each child. Kids with this syndrome have frequent, long-lasting seizures. These may become shorter and happen less often as your child gets older. Medicine may reduce how often seizures happen, but it usually can’t stop them completely.

Your child may need a little extra time to reach developmental milestones for their age. They might also need some help at school.

Also, your child’s care team may suggest seeing different specialists to support their needs. For example, a podiatrist can help with walking and may recommend special shoe inserts (orthotics). An orthopaedic surgeon might do a procedure to help with walking problems or spine issues like scoliosis.

Is there a cure for Dravet syndrome?

There’s no cure right now. And there’s no way to prevent it, as it’s a genetic condition. But researchers are working on new treatments.

What’s the life expectancy for a child with Dravet syndrome?

Children with Dravet syndrome have a higher risk of early death. This can happen from sudden unexpected death in epilepsy (SUDEP), long-lasting seizures or injuries. But many people live into adulthood.

Your child’s provider will give you the best information about what to expect. Every child is different, and statistics may not reflect your child’s unique situation.