Diagnosis and Causes of Dravet Syndrome | Neurology

What is dravet syndrome?

Dravet syndrome is rare drug-resistant epilepsy that begins in the first year of life in an otherwise healthy baby. It is for life. It usually offerings with a prolonged seizure with a fever that affects one side of the body.

  • Most cases are due to severe mutations in the SCN1A gene.
  • Most children progress varying degrees of developmental disability.
  • Treatment involves finding the best combination of medications to treat seizures and prevent seizure emergencies. Diet therapy and vagus nerve stimulation can also be helpful.
  • The FDA approved two new drugs specifically for dravet syndrome. These include Epidiolex (cannabadiol, CBD) oral explanation approved in June 2018 and Stiripentol approved in August 2018. Fenfluramine (Fintepla) was approved in June 2020.
  • A multidisciplinary team and a primary developmental calculation are needed to address the many ways that Dravet syndrome can affect a child and their family.

Alternate name

Dravet syndrome, before known as severe myoclonic epilepsy of infancy (SMEI)

Types of dravet syndrome

Dravet syndrome is an unadorned form of epilepsy characterized by prolonged seizures that usually appear in the first year of life. As the disease develops, different types of seizures start to occur.

Seizures are classified into three main types depending on the part of the brain they affect: focal onset or partial seizures, widespread seizures, and unknown onset seizures. Focal start seizures start on one side of the brain while widespread seizures affect both sides of the brain simultaneously. In unknown onset seizures, the location in the brain where the seizure starts are not known.

Seizures also may be secret based on their cause such as, for instance, febrile seizures, or seizures caused by high temperature, as well as symptoms they cause, myoclonic seizures, clonic seizures, tonic seizures, tonic-clonic seizures, absence seizures, atonic seizures, principal impaired-awareness seizures.

Febrile seizures

Febrile seizures usually are generalized seizures. They are a convulsion activated by a fever that often accompanies childhood illnesses. In children with dravet syndrome, they typically occur within the first year after birth and often are much more severe than those seen in children with other diseases.

Most febrile seizures are brief and do not typically cause long-term health problems. However, repetitive prolonged febrile seizures increase children’s risk of emerging epilepsy and are the first sign that a child may have dravet syndrome.

Myoclonic seizures

Myoclonic seizures are another type of generalized seizure. This type of seizure causes children’s muscles to rapidly agree and relax, resulting in jerky movements. In children with dravet syndrome and other epilepsy disorders, these jerking movements happen on both sides of the body. These seizures usually do not affect the child’s consciousness, leave-taking them aware and able to think during the episode. When these seizures are current in children with dravet syndrome they usually occur by the age of two.

Clonic seizures

Clonic seizures can be either focal onset or widespread onset in origin. This type of seizure causes jerky movements in which the person’s muscles stiffen and relax. It often is difficult to differentiate a myoclonic seizure from a clonic seizure, but clonic seizures usually involve a more rhythmic jerky movement. This type of seizure most commonly occurs in babies and may last from a few seconds to one minute. These seizures cannot be stationary by restraining the child.

Tonic seizures

Tonic seizures can be also focal onset or generalized onset in origin. This type of seizure causes a person’s body to develop unexpectedly stiff. They usually happen while the person is sleeping and last less than 60 seconds. A person experiencing a tonic seizure may be completely aware of the episode or their awareness may be slightly impaired. They may feel tired or disordered after the event and have a headache. Tonic seizures are very rare in dravet syndrome.

Tonic-clonic seizures

Tonic-clonic seizures usually are widespread onset, but also can be focal onset. This type of seizure involves a combination of symptoms from tonic and clonic seizures. The tonic stage of the convulsion begins first with the person’s body abruptly becoming stiff, followed by the clonic phase in which the person’s body jerks rhythmically. These seizures typically last one to three minutes. Toward the end of the seizure, the jerky actions slow to a stop and the person’s body relaxes. During this time, the person may lose the switch of the bladder or bowels. A tonic-clonic seizure permanent for more than five minutes requires immediate medical help.

Absence seizures

Absence seizures are a type of generalized onset seizure. This kind of seizure causes children to have lapses of consciousness where they have no recollection of the incident afterward. These seizures are abrupt and previous only a few seconds. They are considered by non-motor symptoms, although brief twitches may be present. A common symptom of this type of seizure is blank staring that is often mistaken for daydreaming. Once diagnosed, absence seizures can be controlled with anti-seizure medications. It is possible for children to enlarge absence seizures and this commonly happens in their teenage years.

Children with dravet syndrome also can have an additional type of absence seizure known as atypical absenteeism seizure. These seizures also are a kind of generalized onset seizures and usually happen after age two. Unlike regular absence seizures, children experiencing atypical absence seizures may be able to respond to external stimuli.

Atonic seizures

Atonic seizures can be focal onset or generalized onset. These seizures are also known as falling attacks because there is a loss of muscle control that results in flabby muscles. They usually last less than 15 seconds. They do not cause direct damage but can cause indirect injuries from falls. Head protection is often recommended for children with these types of seizures.

Focal seizures of altered consciousness

Focal deficient consciousness seizures usually occur after the age of two years and generally lasts one to two minutes. They originate on one side of the brain. The patient loses consciousness, so the main symptoms are lack of response and confusion. In addition, children can have automaticities such as lip-smacking or clumsiness.

Status epilepticus

Status epilepticus can occur in children with dravet syndrome. This is when a seizure lasts more than five minutes or when several seizures occur together with no recovery time in between. There are two types of rank epilepticus: convulsive and non-convulsive. Convulsive status epilepticus usually results from a prolonged tonic-clonic seizure. This type needs emergency medical treatment because it is life-threatening. Non-convulsive status epilepticus is usually caused by the prolonged absence or by seizures of focal altered consciousness. These seizures are harder to recognize because the symptoms are subtler.

What causes dravet syndrome?

Dravet syndrome is a genetic condition. In 80 percent of Dravet patients, the disease is caused by changes in the SCN1A gene. The remaining 20% of cases are believed to be the result of mutations in other genes, some of which have yet to be identified.

Most disease-causing mutations occur de novo, which means they are new and are not passed down from parents. But up to 10% of the time, mutations that cause dravet syndrome are inborn from parents in an autosomal dominant manner, meaning that just one defective copy of the disease-causing gene is enough for the condition to develop.

Dravet syndrome risk factors

As children with dravet syndrome grow older, their decline in cognitive function stabilizes. The degree of intellectual disability varies widely from mild to profound, however, most adolescents and adults with dravet syndrome are dependent on caregivers. Gait abnormalities appear to worsen during adolescence. Seizures tend to decrease in amount and duration with age. People with dravet syndrome are at higher risk than the general population for a sudden and unexpected death, but that risk remains low.

Dravet syndrome symptoms

The following list includes the most mutual signs and symptoms in persons with dravet syndrome. These characteristics can vary from one person to another. Some persons may have more symptoms than others, and symptoms can range from slight to severe. This list does not include all the symptoms or characteristics that have been described in this condition.

Signs and symptoms include:

  • Many different types of seizures.
  • Sudden muscle jerks (myoclonus)
  • Loss of developmental skills.
  • Intellectual disability
  • Trouble walking
  • Speech disability
  • Autistic-like behavior

The first seizures appear before one year of age and are often associated with fevers. In childhood, other types of seizures develop, and the incidence of seizures increases. Loss of cognitive and developmental skills can occur along with speech problems and difficulty walking. In adulthood, the number of seizures may decrease and nocturnal seizures may occur. More serious complications include the risk of ongoing seizures (status epilepticus) and sudden unexplained death.

This table lists the symptoms that people with this disease may have. For most diseases, symptoms vary from person to person. People with the same disease may not have all of the listed symptoms. This information originates from a database called Human Phenotype Ontology (HPO). The HPO collects information around symptoms that have been labeled in medical resources. The HPO is periodically updated. Use the HPO ID to access more detailed information about a symptom.

Dravet syndrome diagnosis

Dravet syndrome is a clinical diagnosis that was recently determined to affect 1: 15,700 babies born in the US. Approximately 80% of those diagnosed with dravet syndrome have an SCN1A change (1: 20,900), but the attendance of a mutation alone is not sufficient for the diagnosis, nor does the absence of a mutation exclude the diagnosis. Dravet syndrome is at the more severe end of the spectrum of SCN1A-related disorders, but it can also be associated with other mutations.

In the 2015 study, the clinical diagnostic criteria included at least 4 of the following:

  • Normal or near-normal cognitive and motor development before the onset of seizures
  • Two or more seizures with or without fever before one year of age
  • History of seizures consisting of generalized myoclonic, hemiclonic, or tonic-clonic seizures
  • Two or more seizures lasting more than 10 minutes
  • Lack of response to first-line antiepileptic drug therapy with continuous seizures after 2 years of age

Other hallmarks of the syndrome include seizures associated with vaccinations, hot baths, or warm temperatures; developmental slowdown, stagnation or regression after the first year of life; behavior problems; and speech delay.

Genetic test

Because many of these criteria are not apparent in the first year of life, and babies with dravet syndrome initially experience typical development, the study determined that genetic testing through an epilepsy panel should be considered in patients with either of the following:

  • 2 or more prolonged seizures per year of age
  • 1 prolonged seizure and any hemiclonic seizure (sustained rhythmic jerking of one side of the body) at 1 year of age
  • 2 seizures of any duration that appear to affect alternate sides of the body
  • History of seizures before 18 months of age and subsequent onset of myoclonic and/or absence seizures

If you suspect that your loved one might have dravet syndrome, ask your neurologist about the tests, which are available finished by your doctor or commercially. An epilepsy panel will test for SCN1A, as well as many other genes commonly related to epilepsy. After testing, it is optional to consult with a genetic counselor.

Dravet syndrome treatment options

Seizures in dravet syndrome can be difficult to control but can be reduced with anti-seizure medications such as clobazam, stiripentol, topiramate, and valproate. Because the course of the disorder varies from one individual to another, treatment protocols may vary. A high-fat, low carbohydrate diet can also be beneficial, known as a ketogenic diet. Although adjusting your diet can help, it does not eliminate symptoms. Until a better form of treatment or cure is discovered, people with this disease will have myoclonic epilepsy for the rest of their lives.

It is now known that certain anti-seizure medications that are classified as sodium channel blockers make seizures worse in most dravet patients. These medications include carbamazepine, gabapentin, lamotrigine, and phenytoin. Treatments include cognitive rehabilitation through psychomotor and speech therapy. In addition, valproate is often given to prevent the recurrence of febrile seizures, and benzodiazepine is used for long-lasting seizures, but these treatments are often insufficient.

Stiripentol was the only drug for which a randomized, double-blind, placebo-controlled trial was conducted, and this drug showed efficacy in trials. It acts as a GABAergic agent and as a positive allosteric modulator of the GABAA receptor. Stiripentol, which can improve refractory focal epilepsy as well as dravet syndrome, supplemented with clobazam and valproate, was approved in Europe in 2007 as a therapy for dravet syndrome and has been found to reduce the overall rate of seizures by 70%. For more drug-resistant seizures, topiramate and the ketogenic diet are used as alternative treatments.

Cannabidiol (CBD) was approved in the United States for the treatment of dravet syndrome in 2018. A 2017 study showed that the frequency of seizures per month decreased from 12 to 6 with the use of cannabidiol, compared to a decrease from 15 to 14 with placebo.

Dravet syndrome complications

  • Although the decline in cognitive function stabilizes with age in some people with dravet syndrome, most adolescents and adults with the disorder have mild to profound intellectual disability and require 24-hour supervision. This disability, along with seizures and other comorbidities, can also cause severe anxiety and social isolation, which inevitably affects the quality of life of caregivers as well.
  • Gait and balance problems associated with dravet syndrome can lead to falls. These falls, along with an increased risk of osteopenia (low bone mass), can cause bones to break. A survey study found that 70 percent of respondents use a wheelchair or adaptive stroller sometimes.
  • Seizures can cause drowning if they occur while a person is in or near water. Seizures can also increase the risk of lung complications, such as aspiration pneumonia, which occurs when you breathe in food, stomach acid, or saliva into your lungs, which can lead to sepsis.

Seizures (Generalized and Partial) Types and Causes | Neurology

What are the seizures?

Seizures are an unexpected, wild electrical aggravation in the cerebrum. It can cause changes in your behavior, movements, or feelings, and in your levels of consciousness. If you have two or more seizures or tend to have frequent seizures, you have epilepsy.

There are many types of seizures, which range in severity. The types of seizures vary according to where and how they start in the brain. Nearly seizures last from 30 seconds to two minutes. A seizure that lasts more than five minutes is considered a medical emergency.

Seizures are more common than you might think. Seizures can occur after a stroke, a closed head injury, or an infection such as meningitis or another illness. Often, the cause of a seizure is unknown.

Most seizure disorders can be controlled with medication, but seizure control can have a big impact on your daily life. The good news is that you can work with your health care professional to balance seizure control with the side effects of medications.

Types of seizures

Generalized seizures

Summed up seizures include the whole cerebrum from the beginning. Includes common subspecies:

  • Tonic-clonic (grand mal): This is the most common subtype. Your arms and legs will stiffen, and you may stop breathing for a bit. Then your limbs will vibrate. Your head will also move.
  • Absence seizures (petit mal): You lose consciousness briefly when you have one of these. Children get it more often than adults. It usually only lasts a few seconds.
  • Febrile seizures: These are the convulsions that a child may have from a high temperature caused by an infection. It can last a few minutes but is usually harmless.
  • Infantile spasms: These symptoms usually stop at the age of four. The child’s body suddenly stiffens, and his head turns forward. Many children with these diseases will develop these diseases later in their lives.

Partial (focal) seizures

There are two types:

  • Focal onset aware seizure: You remain conscious during a seizure, and it is very short (usually less than 2 minutes). You may or may not be able to respond to people while this is happening.
  • Focal onset impaired awareness seizures: It can cause loss of consciousness. You can also do things without knowing it, such as smacking your lips, chewing, moving your legs, or pushing your pelvis.

What are the symptoms of a seizure?

You can experience both focal and generalized seizures at the same time, or they can occur one before the other. Symptoms can last anywhere from a few seconds to 15 minutes per episode.

Sometimes, symptoms occur before a seizure occurs. May include:

  • A sudden feeling of fear or anxiety
  • The feeling of nausea in your stomach
  • Dizziness
  • Change in vision
  • A jerky movement in the arms and legs may cause things to fall
  • The feeling of leaving the body
  • A headache

Include symptoms that indicate a seizure:

  • Loss of consciousness followed by confusion
  • Having muscle spasms that cannot be controlled
  • Drooling or frothiness in the mouth
  • Drop
  • A strange taste in your mouth
  • Gnashing your teeth
  • Bite your tongue
  • The presence of sudden and rapid eye movements
  • Unusual noises, such as snoring
  • Loss of control of bladder or bowel function
  • Sudden mood changes

Causes of seizures

Seizures of all kinds are caused by abnormal electrical activity in the brain.

It can include causes of this disease:

  • Abnormal levels of sodium or glucose in the blood
  • Brain infection, including meningitis and encephalitis
  • A brain injury that occurs to a child during labor or birth
  • Brain problems that occur before birth (congenital brain defects)
  • Brain tumor (rare)
  • Drug abuse
  • Electric shock
  • Epilepsy
  • Fever (particularly in young children)
  • Head injury
  • Heart disease
  • Heat illness (heat intolerance)
  • High fever
  • Phenylketonuria (PKU), which can cause seizures in infants
  • Poisoning
  • Street drugs are angel dust (PCP), cocaine, amphetamines
  • Stroke
  • Toxemia of pregnancy
  • The accumulation of toxins in the body due to kidney or liver failure
  • Very high blood pressure (malignant hypertension)
  • Venomous bites and stings (such as snake bites)
  • Refrain from consuming alcohol or certain medications after using them for a long time

Sometimes, a cause cannot be found. These are called idiopathic seizures. It usually appears in children and young adults, but it can occur at any age. There might be a family background of epilepsy or seizures. If it persists repeatedly after treating the underlying problem, the condition is called epilepsy.

What is a diagnosis of seizure?

Your doctor will ask you for details about your epileptic seizure and conduct a neurological examination. This will include asking questions about your emotional state and testing your motor skills and mental function. Then they can order one or more of the following tests:

  • Blood or spinal tap tests to look for infection
  • Electroencephalography (EEG), during which a technician attaches electrodes to your brain to monitor the electrical activity inside it
  • An imaging test such as an MRI, computed tomography, or positron emission tomography (PET) scan to look for any problems in your brain

If it occurs frequently, your doctor may give you a more complex test in which electrodes are inserted into your brain through small holes in your skull. This can also be the first step in epilepsy surgery.


A seizure at certain times can lead to conditions that are dangerous for you or others. You may be in danger:

  • If you fall during an epileptic seizure, you can injure your head or break a bone.
  • If you have a seizure while swimming or showering, you are at risk of accidental drowning.
  • Car accidents: A seizure that causes loss of consciousness or control can be dangerous if you drive a car or operate other equipment.
  • Pregnancy complications: Seizures during pregnancy pose a risk to both the mother and the baby, and some antiepileptic medicines increase the risk of birth defects. If you have epilepsy and are planning to become pregnant, work with your doctor so he can adjust your medications and monitor your pregnancy, as needed.
  • Emotional health problems: People who have this disease are more likely to have psychological problems, such as depression and anxiety. The problems may be a result of the difficulties dealing with the condition itself as well as the side effects of medications.

How are seizures treated?

Treatments for seizures depend on the cause. By addressing the cause of seizures, you may be able to prevent future seizures. Includes treatment of seizures caused by epilepsy:

  • Pharmaceutical
  • Surgery to correct brain abnormalities
  • Nerve stimulation
  • A special diet is known as the keto diet

With regular treatment, you can reduce or stop the symptoms of this disease.

How can you prevent seizures?

In many cases, a seizure cannot be prevented. However, maintaining a healthy lifestyle can give you the best chance to reduce your risks. You can do the following:

  • Get enough sleep
  • Eat a healthy diet and stay well hydrated
  • Exercising regularly
  • Engage in stress reduction techniques
  • Avoid taking illegal drugs

If you are taking medication for epilepsy or other medical conditions, take it as your doctor recommends.


Types and Symptoms of Epilepsy | Neurology

What is epilepsy?

Epilepsy is a brain disorder in which a person has recurring seizures over time. Seizures are episodes of uncontrolled and abnormal activation of brain cells that cause changes in attention or behavior.

In epilepsy, the electrical rhythms of the brain tend to become unbalanced, causing recurrent seizures. In patients with epilepsy, the normal electrical pattern is suddenly and synchronously damaged by electrical energy, briefly affecting their consciousness, movements, or sensations.

Alternate name

  • Seizure disorder

Types of epilepsy

Epilepsy is classified into two types, which include:

Generalized seizures affect both sides of the brain.

  • Absence seizures, sometimes called petit mal epilepsy, blinks rapidly or gazes into space for a few seconds.
  • Tonic-clonic seizures also named grand mal seizures, can make a person
      • Cry out
      • Lose consciousness
      • Fall to the ground
      • Have muscle jerks or spasms

Focal seizures: Seizures caused by electrical impulses arising from a relatively small or “localized” part of the brain (known as a focus). There are two types of focal seizures:

  • Focal seizures with retained consciousness, this type of focal seizure were previously known as a simple partial seizure.
  • Focal seizures with a loss of consciousness, this type of focal seizure may also be called a focal dyscognitive seizure (previously identified as complex partial seizures)

Causes of epilepsy

Causes of epilepsy include:

  • Genetics
  • Brain structure abnormalities
  • Metabolism changes
  • Immune system abnormalities
  • Trauma
  • Stroke
  • Tumors
  • Infectious disease
  • Unknown causes

Symptoms of epilepsy

Symptoms of epilepsy vary. They depend on how much the brain is affected and where the affected area is.

Generalized seizures: If you have this type of seizure, the seizures start on either side of the brain (or quickly affect the networks of brain cells on both sides).

  • Generalized motor seizures (Grand Mal): The patient loses consciousness and often collapses. Loss of consciousness is followed by violent shaking (known as the “tonic” phase of seizure) instead of normal physical activity (known as the “tonic” phase of seizure), followed by a deep sleep of the patient (called the “postical “or” after a seizure ” phase). During grand-mal epilepsy, injuries, and accidents such as tongue biting and urinary incontinence can occur.
  • Generalized non-motor (or absence) seizures: They are called “petit mal” seizures. The loss of consciousness is so brief that the person usually does not change position. For a few seconds, the person can:
    • Have a blank stare
    • Blink rapidly
    • Make chewing movements
    • Move an arm or leg rhythmically.

Partial (focal) seizures:

Simple partial seizures do not imply loss of consciousness. Symptoms include:

  • Changes to a sense of taste, smell, sight, hearing, or touch
  • Dizziness
  • Tingling and twitching of limbs

Complicated partial seizures include loss of awareness or consciousness. Other symptoms include:

  • Staring blankly
  • Unresponsiveness
  • Performing repetitive movements

Diagnosis of epilepsy

The diagnosis of epilepsy depends on your history of epilepsy. Your doctor will ask if you have any symptoms that you can remember, such as feeling weird or experiencing any warning signs before the seizure occurs. It can be helpful to talk to those who have seen your seizure and ask them for certain what they saw, especially if you do not remember the seizure.

Your doctor may also perform tests that include blood tests, an EEG (electroencephalogram), and brain scans, such as a CT scan or MRI.

A person can have epilepsy even with normal results on EEG and brain scans; however, abnormal results can help classify the type of epilepsy.

If your child or someone you know has epilepsy, it may help to videotape it on your mobile phone. This will support your doctor to make a more specific diagnosis.

Treatment for epilepsy

There is currently no remedy for most types of epilepsy.


The most common treatment used to reduce or prevent seizures is anti-seizure drugs. Your doctor may prescribe one or more medications to treat the specific type of seizure you have. Your doctor will need to adjust the dose and/or type of medicine to find the best treatment for you. 70% of epilepsy patients lose their medication without restrictions if they take it regularly. Some patients may need medications for life; Patients should not stop taking the medicine without first consulting their doctor.


Surgery is usually done if you know that your seizures start in a well-defined area of your brain that does not interfere with important functions like speech, language, or hearing. Medicine in other cases of drug-resistant epilepsy, your doctor may recommend a type of treatment called vagus nerve stimulation. To do this, you must place a small device under the skin of your chest. The device produces electrical pulses to the vagus nerve in the neck. 

It is difficult to control one type of treatment for children with certain types of seizures, which include a strict high-fat, low-carbohydrate diet. This diet is called the ketogenic diet. This diet must be prescribed and supervised by a doctor. Among all treatments, work with your doctor to decide the best treatment for you.


Researchers have found that a ketogenic diet can decrease or eliminate seizures in some children and adults. The diet is a high-fat, low-carbohydrate diet that helps to create ketones, which attack the brain and cause fewer or fewer seizures. Typical foods on this diet include eggs, bacon, avocados, cheese, nuts, fish, and a few fruits and vegetables.

The diet is strict and often begins in a hospital. It has been shown to be successful with some children who do not respond well to medication. However, it can be used in combination with a C-section in some people.


While seizures are connected to another medical condition, knowing and treating that medical condition is critical to prevention. If anti-seizure medications are prescribed, it is important to take the medication at the suggested times and avoid the medications.

  • Some people with epilepsy are very sensitive to alcohol. If this pattern develops, stay away from alcohol. Others may have seizures only after they have stopped consuming too much alcohol. The key to prevention is avoiding alcohol.
  • Insomnia and stress in some people with epilepsy definitely increase the frequency of epilepsy.


Having epilepsy puts you at risk for injury. During a seizure, you may fall, hurt yourself, or inhale food or saliva. You should avoid using heavy machinery, working at height, or underwater. You can even stop driving if your seizures are not controlled. Care must be taken around the water when swimming or bathing.

Children with epilepsy have trouble learning or concentrating.

Epilepsy affects your life and you need to pay more attention to your health. Some people experience a lot of anxiety or depression when they are first diagnosed.

When to contact the doctor

Call your doctor if:

  • You have a seizure that lasts more than 5 minutes
  • He was injured during the seizure
  • The process you usually feel during and after detention
  • It takes longer than usual to recover after a seizure
  • Your seizures become more severe or occur more often
  • The second confiscation takes place immediately after the first
  • You are pregnant
  • Do you have diabetes?
  • You may have sudden headaches, numbness, or weakness on one side of your body, or problems with vision or speech before you have a seizure. These could be signs of a stroke.

Departments to consult for this condition

  • Department of Neurology