A myoclonic seizure is a type of seizure that causes uncontrollable muscle jerks and twitches. They are usually brief and minor and can happen in epilepsy.

When they occur in epilepsy, they tend to occur in a series, with multiple seizures happening in succession.

Myoclonic seizures typically occur on both sides of the body and only last for a second or two. The person cannot control them, but they remain awake during the seizure.

Keep reading to learn more about myoclonic seizures, including the causes, symptoms, and treatment options, as well as some ways to prevent them.

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Myoclonic seizures involve twitching, which can be in just one muscle or several muscles simultaneously. These twitches are usually quick, lasting for just a second or two, but there can be many within a short period of time.

A person may only have myoclonic seizures themselves, but myoclonic seizures can also occur as a symptom of several types of epilepsy.

Some of these include the following.

Juvenile myoclonic epilepsy

This type of epilepsy usually starts during puberty or early adulthood. It is one of the most common types of childhood epilepsy, accounting for 5–10% of all epilepsy cases. About 50% of cases are associated with a positive family history.

It affects the upper parts of the body, including the neck, shoulders, and upper arms. It can occur when a person is waking up.

A person with juvenile myoclonic epilepsy may also have generalized tonic-clonic seizures, or muscle stiffening followed by jerking in the whole body.

Myoclonic astatic epilepsy, or Doose syndrome

This type of epilepsy is rare, affecting around 1–2% of children with epilepsy. The usual age of onset is 18 months to 4 years.

Characteristics include generalized seizures, myoclonic seizures, atonic seizures (“drop attacks”), and absence seizures. Children with this type of epilepsy may develop some learning disabilities.

Lennox-Gastaut syndrome

This is an uncommon type of epilepsy, affecting about 1–5% of children with epilepsy. It is difficult to control, and it usually starts in very young children.

People with this type of epilepsy have multiple different types of seizures. Myoclonic seizures can affect the neck, shoulders, upper arms, or face. People may also have intellectual disabilities.

Progressive myoclonic epilepsies

These are a group of uncommon conditions, and they are present in up to 1% of epilepsy cases in children and adolescents. Seizures are a combination of myoclonic and tonic-clonic.

People with progressive myoclonic epilepsies may have trouble walking and talking. The symptoms tend to get worse over time.

A disturbance in the brain, spinal cord, or nerves causes myoclonic seizures.

This disturbance can result from:

  • electrolyte imbalances, such as sodium, potassium, or glucose
  • a head or spinal cord injury
  • an infection
  • a stroke
  • a brain tumor
  • kidney or liver failure
  • drug intoxication
  • a prolonged lack of oxygen to the brain
  • heredity

Myoclonic seizures feel like brief twitches or jerks in a muscle. These twitches may occur only once or in sequence. They may or may not have a pattern, and they may occur rarely or very frequently.

They sometimes occur when the person is waking up or moving.

A doctor will diagnose myoclonic seizures by asking questions about the person’s symptoms and the timing of their seizures. It is important for them to determine whether the symptoms are truly myoclonic seizures or whether they are due to clumsiness, tics, or nervousness.

Results from an electroencephalogram (EEG) test, which is a test that detects electrical activity in the brain using electrodes, or an MRI scan can also help with diagnosis.

The doctor may also order blood or urine tests.

Once the doctor confirms the diagnosis, they will develop a treatment plan. If possible, they will treat any underlying causes of the seizures as well, such as correcting electrolyte imbalances.

The doctor may prescribe medication to control or reduce the frequency of the seizures. They will carefully consider potential side effects of the medication and interactions between other drugs a person may be taking.

Below is a list of medications that doctors may prescribe in order to treat myoclonic seizures. They will start with an agent that has shown the best effectiveness for the specific seizure type.

It is not uncommon for an individual with seizures to require more than one type of medication.

Possible treatment choices include the following:

  • clonazepam
  • barbiturates
  • phenytoin
  • levetiracetam
  • valproate
  • primidone
  • hormonal therapy
  • 5-hydroxytryptophan
  • botulinum toxin injection

It is important for a person with myoclonic seizures to take their medication exactly as the doctor prescribes it. Routine laboratory monitoring of medication levels can help guide treatment. The doctor or pharmacist will discuss any precautions relating to driving, operating heavy machinery, or pregnancy.

In many cases, treatment will be long term. This is true even if a person remains seizure-free. Relapse of seizures can occur if a person stops their treatment plan.

Some people may be resistant to anti-seizure medications. Research is ongoing for alternative therapies. Several surgical procedures are available. Clinical trials evaluating the potential benefits of dietary factors, including the ketogenic diet and the use of herbal supplements, are currently taking place.

The vagus nerve stimulator has had approval for the treatment of some types of epilepsy. A healthcare professional will implant this device in the chest, and the device will send electrical currents to the vagus nerve in the neck. Larger studies must continue in order to reveal the full potential of this treatment method.

Avoiding some of the triggers of myoclonic seizures can help prevent additional or more frequent seizures.

Triggers may include:

  • sleep deprivation
  • alcohol intake
  • drug use
  • emotional stress
  • anxiety
  • fatigue
  • photosensitivity, due to flashing lights, sunlight, TV, or computer screens
  • hunger
  • temperature extremes
  • medication noncompliance

Myoclonic seizures are usually brief, and a person does not lose consciousness when they experience one.

If a myoclonic seizure occurs, the person should stop moving. If other people are around, they can help prevent the person from getting hurt by helping stop any involuntary movements.

That said, there are some instances when a person who has experienced a seizure needs medical help.

A person needs medical help if they:

  • are experiencing their first seizure
  • have a seizure that lasts for longer than 5 minutes
  • lose consciousness
  • have recurring seizures in a short period of time
  • experience continued confusion and agitation after a seizure
  • are pregnant
  • have a chronic medical condition, such as diabetes or heart disease
  • have difficulty breathing
  • injure themselves

The type, frequency, and severity of myoclonic seizures will vary from person to person.

There are many potential causes, including electrolyte imbalances, severe muscle fatigue, and epilepsy. It is important to know one’s triggers to avoid them effectively.

If a person requires medication to control their seizures, it is important that they take them exactly as directed. Many people with myoclonic seizures can lead active, productive lives.