What is Dravet Syndrome in Epilepsy?

What Is Dravet Syndrome? A Guide for Parents and Caregivers

It can really be stressful for parents when their children, who appear completely healthy and achieve all early growth milestones, unexpectedly start having long seizures after a fever. This could be Dravet syndrome, a rare but severe epilepsy that begins in infancy and is highly treatment-resistant.

The duration of these seizures elevates the risk of life-threatening complications, including status epilepticus. It is a genetic disorder which is often misunderstood and overlooked, but research is finally finding more profound genetic connections and new treatments.

Read on to learn more.

What is Dravet Syndrome?

Dravet syndrome is a severe, rare type of genetic epilepsy that usually starts during the infant's first year of life, even among otherwise healthy children.

Usually triggered by a fever, the seizures initially experienced are prolonged and resistant to treatment. Subsequently, children have several types of seizures, with most being resistant to conventional therapies.

Aside from epilepsy, Dravet syndrome also results in developmental delays, speech and motor impairments, and other neurological disorders. It is considered developmental and epileptic encephalopathy (DEE) and was previously referred to as severe myoclonic epilepsy of infancy.

What are the symptoms of Dravet syndrome?

Dravet syndrome is associated with a variety of symptoms, beginning in infancy with seizures and leading to other developmental, behavioural, and neurological concerns. The symptoms can vary in severity and in combination. These include:

• Seizures Starting Early: Seizures typically begin in the between 5 and 8 months of age and are often triggered by fever, also known as febrile seizures.
• Seizure Triggers: Fever and minor changes in temperature, hot baths, or hot environments can trigger seizures.
• Prolonged or Clustered Seizures: Some seizures are too long (more than 5 minutes), while others can occur too closely together and risk a person entering status epilepticus, a medical emergency.
• Developmental Delays: Movement and cognitive, language, and motor development can be slowed or regressed, generally becoming obvious after 12 months of age.
• Behavioural Problems: These may include hyperactivity, aggression, or signs of autism spectrum disorder.
• Motor and Balance Challenges: Ataxia (loss of coordination), tremors, unresolved/unsteady gait, and hypotonia (low muscle tone).
• Autonomic Dysfunction (Dysautonomia): The person has problems regulating body temperature, heart rate, or blood pressure.
• Feeding and Growth Problems: Poor appetite, difficulty swallowing, and/or failure to thrive.
   

Other symptoms may arise during childhood, including:

• Extended and recurrent seizures
• Autism spectrum disorders
• Developmental delays and cognitive impairments
• Challenges with movement and balance
• Behavioural issues
• Sleep disturbances
• Difficulties in processing sensory information (sight, hearing, touch, taste, and smell)
• Growth and nutritional concerns
• Issues with the autonomic nervous system, which regulates involuntary functions such as breathing, heart rate, and blood pressure
   

Is Dravet Syndrome Inherited?

Yes, Dravet syndrome is a genetic disorder, most commonly caused by a mutation in the SCN1A gene that affects how brain cells communicate with each other. Usually, the mutation occurs spontaneously and is not inherited; however, it may be passed down occasionally, either through mosaicism or autosomal dominant inheritance.

Having an SCN1A variant does not necessarily mean someone will have Dravet syndrome—some may have more benign epilepsy or no symptoms at all.

What Complications are Associated with Dravet Syndrome?

The most severe complications can be life-threatening and may involve:

• Sudden unexplained death in epilepsy (SUDEP)
• Injury resulting from seizures
• Status epilepticus (a condition of continuous seizures that necessitates urgent medical intervention)
   

Can Dravet Syndrome Be Cured?

As of now, there is no cure for Dravet syndrome since it is a lifelong genetic disorder and cannot be prevented. The condition itself cannot be prevented, many of its complications (e.g., injuries from falls, status epilepticus) can be prevented or mitigated through vigilant management, rescue medications, and safety precautions. However, ongoing research, including clinical trials in gene therapy, is also being conducted.

These studies pave the way for future precision medicine treatments. The care and management of Dravet syndrome aim to provide the best seizure management and quality of life, with each patient's management plan being individualised according to the patient's and family's needs.

How to Treat Dravet Syndrome?

The primary aim of treatment is to curb seizure severity and frequency, avoid complications such as status epilepticus, and enhance neurological and developmental function. Some of the key treatment methods include:

• Antiseizure Drugs: Initial treatments are valproate and clobazam. Second-line treatments like stiripentol, topiramate, fenfluramine, and cannabidiol (CBD) are also FDA-approved and can be used from age one.
• Avoidance of Some Medications: Sodium channel drugs like carbamazepine, lamotrigine, phenytoin, and oxcarbazepine should be strictly avoided since they exacerbate seizures.
• Ketogenic Diet: An extremely low-carbohydrate, high-fat diet can dramatically decrease seizure frequency in some people.
• Emergency Medicines: Benzodiazepines such as diazepam, lorazepam, midazolam, or clonazepam are administered during prolonged seizures or in emergencies. These can be in the form of nasal sprays, rectal gels, or dissolvable tablets.
• Therapies and Interventions: Physical, occupational, and speech therapies help manage motor delays, communication problems, and balance issues. Surveillance and control of gait difficulties, such as crouch gait, are also essential.
• Vagus Nerve Stimulation (VNS): Can be used in people who do not respond to medications.
• Support and Education: Family counselling, seizure action plans, and carer education are essential for home care and long-term management.
  
   

Dravet syndrome is a complicated, chronic neurological disorder based on genetic impairment. Early diagnosis and advanced treatment hold the key to optimal outcomes. As new therapies become available and genetic understanding broadens, promise indeed exists for individuals with this critical epilepsy.