Dravet Syndrome (DS)

Dravet syndrome (DS) is a rare type of severe childhood epileptic encephalopathy in which frequent, repeated seizures that are often refractory to treatment contribute directly to developmental delay or regression and cognitive impairment. Other features can be multisystemic, including signs and symptoms such as growth or nutritional problems, chronic infections, and orthopedic conditions. In approximately 80% of cases, DS is caused by a mutation in the SCN1A gene. ¹

Seizures

Usually, DS initially manifests within the first year of life, either with focal or localized seizures or with generalized convulsive seizures. During the seizures, which are frequent and prolonged (often lasting more than 5 minutes), jerking movements may first affect half of the body (hemiclonic) then switch to the other side of the body.^2,3 

The first seizure is often accompanied by fever; subsequent seizures may occur with or without fever. Infection and other illness, emotional stress, excitement, photosensitivity, and increased body temperature due to warm or hot baths, high ambient temperatures, or physical exertion can all trigger seizures in children with DS.³

Multiple types of seizures occur in children with DS, including hemiclonic, atypical absence (staring), myoclonic (involuntary muscle jerking), generalized tonic-clonic, photosensitive tonic-clonic, complex febrile, focal aware, focal impaired awareness, epilepsia partialis continua, and obtundation status seizures.^3,4 

In status epilepticus, a potentially fatal complication of DS,⁴ multiple seizures occur within 5 minutes or 1 seizure lasts longer than 5 minutes without a return to a normal level of consciousness between episodes.⁵

Read more about DS clinical features

Developmental Delays/ Cognitive Impairment/ Behavioral Problems

During the first and possibly second year of life, children with DS develop normally, but as the seizures increase in frequency, cognitive and emotional abnormalities become apparent, including developmental delay or regression, learning disabilities, behavioral problems, and difficulty regulating emotions.³

Hypotonia becomes apparent in most children with DS at approximately age 1. Soon after the first seizure, signs of neurodevelopmental delay manifest,⁴ including balance problems, crouched gait,² ataxia, and deficits in fine motor skills.⁴

The most frequently reported behavioral problems in children with DS include aggressiveness, irritability, autism, attention-deficit/hyperactivity disorder, opposition, and relational problems negatively affecting social life and adaptive behavior.⁴

Read more about DS comorbidities

Speech Delay

Speech delay, slurred or slowed speech, trouble speaking, and language deficits in constructing sentences are common symptoms of DS. Children with DS who demonstrate these forms of language delay may benefit from early intervention and treatment by a speech-language pathologist.^3,4

Growth/ Nutritional Problems

Approximately 60% of children with DS may exhibit problems with growth and nutrition to varying degrees. These include failure to thrive, nutrient malabsorption, poor appetite, feeding problems, osteopenia, scoliosis, and slow growth leading to a small stature or being underweight. Doctors may recommend a gastrostomy to place a feeding tube in severe cases.⁶ 

Read more about DS treatment

Chronic Infections

Infections of the ears, nose, throat, lungs, and digestive system occur frequently in individuals with DS, and the fevers and high body temperatures that accompany infection often trigger seizure activity.⁷

Orthopedic Conditions

Osteopenia, fractures, scoliosis, and foot and ankle deformities may develop as a consequence of motor deficits due to frequent seizures.^3,6,8 Children with DS may benefit from an assessment to determine if orthopedic surgery is necessary to correct lower extremity alignment problems.³  

Sleep Disturbance

Sleep disturbances occur in 75% to 97% of individuals with DS as a consequence of seizure activity at night. The resulting daytime sleepiness, behavioral problems, impaired learning, and fatigue negatively affect quality of life in children and adults with DS.⁹

Read more about DS complications

Dysautonomia

Impaired regulation of the autonomic nervous system results in temperature dysregulation, tachycardia, hypotension, syncope, dizziness, sweating problems, and issues with blood circulation and digestion/peristalsis.¹⁰ 

Sensory Integration Disorders

Progressive sensory dysfunction due to repeated, frequent seizures may be a sign of DS.¹¹ A small number of children with DS may have sensory processing disorders, requiring assessment and sensory integration treatment by trained pediatric occupational therapists.¹²

Read more about DS care team

References 

1. What is Dravet syndrome? Dravet Syndrome Foundation. Accessed March 14, 2023.
2. What is Dravet syndrome? National Institute of Neurological Disorders and Stroke. Accessed March 14, 2023.
3. Dravet syndrome. Cleveland Clinic. Accessed March 14, 2023.
4. Anwar A, Saleem S, Patel UK, Arumaithurai K, Malik P. Dravet syndrome: an overview. Cureus. 2019;11(6):e5006. doi:10.7759/cureus.5006
5. Status epilepticus. Johns Hopkins Medicine. Accessed March 14, 2023.
6. Growth and nutrition concerns. Dravet Syndrome UK. Accessed March 14, 2023.
7. Infections and immune problems. Dravet Syndrome UK. Accessed March 14, 2023.
8. Villas N, Meskis MA, Goodliffe S. Dravet syndrome: characteristics, comorbidities, and caregiver concerns. Epilepsy Behav. 2017;74:81-86. doi:10.1016/j.yebeh.2017.06.031
9. Sleep problems. Dravet Syndrome UK. Accessed March 14, 2023.
10. Dysautonomia. Dravet Syndrome UK. Accessed March 14, 2023.
11. Guzzetta F. Cognitive and behavioral characteristics of children with Dravet syndrome: an overview. Epilepsia. 2011;52(s2):35-38. doi:10.1111/j.1528-1167.2011.02999.x
12. Dravet syndrome: what is it and what can pediatric OT do? Theracare Pediatric Services. Accessed March 14, 2023.

Reviewed by Hasan Avcu, MD, on 3/16/2023.

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Maria Arini Lopez, PT, DPT, CSCS, CMTPT, CIMT

Maria Arini Lopez, PT, DPT, CSCS, CMTPT, CIMT is a freelance medical writer and Doctor of Physical Therapy from Maryland. She has expertise in the therapeutic areas of orthopedics, neurology, chronic pain, gastrointestinal dysfunctions, and rare diseases especially Ehlers Danlos Syndrome.