Overview

A seizure is a sudden, uncontrolled electrical disturbance in the brain. It can cause changes in your behavior, movements or feelings, and in levels of consciousness. Having two or more seizures at least 24 hours apart that aren't brought on by an identifiable cause is generally considered to be epilepsy.

There are many types of seizures, which range in symptoms and severity. Seizure types vary by where in the brain they begin and how far they spread. Most seizures last from 30 seconds to two minutes. A seizure that lasts longer than five minutes is a medical emergency.

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

Most seizure disorders can be controlled with medication, but management of seizures can still have a significant impact on your daily life. The good news is that you can work with your doctor to balance seizure control and medication side effects.

Symptoms

With a seizure, signs and symptoms can range from mild to severe and vary depending on the type of seizure. Seizure signs and symptoms may include:

  • Temporary confusion
  • A staring spell
  • Uncontrollable jerking movements of the arms and legs
  • Loss of consciousness or awareness
  • Cognitive or emotional symptoms, such as fear, anxiety or deja vu

Doctors generally classify seizures as either focal or generalized, based on how and where abnormal brain activity begins. Seizures may also be classified as unknown onset, if how the seizure began isn't known.

Focal seizures

Focal seizures result from abnormal electrical activity in one area of your brain. Focal seizures can occur with or without loss of consciousness:

  • Focal seizures with impaired awareness. These seizures involve a change or loss of consciousness or awareness that feels like being in a dream. You may seem awake, but you stare into space and do not respond normally to your environment or you perform repetitive movements. These may include hand rubbing, mouth movements, repeating certain words or walking in circles. You may not remember the seizure or even know that it occurred.
  • Focal seizures without loss of consciousness. These seizures may alter emotions or change the way things look, smell, feel, taste or sound, but you don't lose consciousness. You may suddenly feel angry, joyful or sad. Some people have nausea or unusual feelings that are difficult to describe. These seizures may also result in difficulty speaking, involuntary jerking of a body part, such as an arm or a leg, and spontaneous sensory symptoms such as tingling, dizziness and seeing flashing lights.

Symptoms of focal seizures may be confused with other neurological disorders, such as migraine, narcolepsy or mental illness.

Generalized seizures

Seizures that appear to involve all areas of the brain are called generalized seizures. Different types of generalized seizures include:

  • Absence seizures. Absence seizures, previously known as petit mal seizures, often occur in children and are characterized by staring into space or by subtle body movements, such as eye blinking or lip smacking. They usually last for five to 10 seconds but may happen up to hundreds of times per day. These seizures may occur in clusters and cause a brief loss of awareness.
  • Tonic seizures. Tonic seizures cause stiffening of your muscles. These seizures usually affect muscles in your back, arms and legs and may cause you to lose consciousness and fall to the ground.
  • Atonic seizures. Atonic seizures, also known as drop seizures, cause a loss of muscle control, which may cause you to suddenly collapse, fall down or drop your head.
  • Clonic seizures. Clonic seizures are associated with repeated or rhythmic, jerking muscle movements. These seizures usually affect the neck, face and arms on both sides of the body.
  • Myoclonic seizures. Myoclonic seizures usually appear as sudden brief jerks or twitches of your arms and legs. There is often no loss of consciousness.
  • Tonic-clonic seizures. Tonic-clonic seizures, previously known as grand mal seizures, are the most dramatic type of epileptic seizure and can cause an abrupt loss of consciousness, body stiffening and shaking, and sometimes loss of bladder control or biting your tongue. They may last for several minutes.

When to see a doctor

Seek immediate medical help if any of the following occurs:

  • The seizure lasts more than five minutes.
  • Breathing or consciousness doesn't return after the seizure stops.
  • A second seizure follows immediately.
  • You have a high fever.
  • You're experiencing heat exhaustion.
  • You're pregnant.
  • You have diabetes.
  • You've injured yourself during the seizure.

If you experience a seizure for the first time, seek medical advice.

Causes

Nerve cells (neurons) in the brain create, send and receive electrical impulses, which allow the brain's nerve cells to communicate. Anything that disrupts these communication pathways can lead to a seizure. Some types of seizure disorders may be caused by genetic mutations.

The most common cause of seizures is epilepsy. But not every person who has a seizure has epilepsy. Sometimes seizures may be caused or triggered by:

  • High fever, which can be associated with an infection such as meningitis
  • Lack of sleep
  • Flashing lights, moving patterns or other visual stimulants
  • Low blood sodium (hyponatremia), which can happen with diuretic therapy
  • Medications, such as certain pain relievers, antidepressants or smoking cessation therapies, that lower the seizure threshold
  • Head trauma that causes an area of bleeding in the brain
  • Abnormalities of the blood vessels in the brain
  • Autoimmune disorders, including systemic lupus erythematosus and multiple sclerosis
  • Stroke
  • Brain tumor
  • Use of illegal or recreational drugs, such as amphetamines or cocaine
  • Alcohol misuse, during times of withdrawal or extreme intoxication
  • COVID-19 virus infection

Complications

Having a seizure can sometimes lead to circumstances that are dangerous for you or others. You might be at risk of:

  • Falling. If you fall during a seizure, you can injure your head or break a bone.
  • Drowning. If you have a seizure while swimming or bathing, you're at risk of accidental drowning.
  • Car accidents. A seizure that causes loss of either awareness or control can be dangerous if you're driving a car or operating other equipment.
  • Pregnancy complications. Seizures during pregnancy pose dangers to both mother and baby, and certain anti-epileptic medications increase the risk of birth defects. If you have epilepsy and plan to become pregnant, work with your doctor so that he or she can adjust your medications and monitor your pregnancy, as needed.
  • Emotional health issues. People with seizures are more likely to have psychological problems, such as depression and anxiety. Problems may be a result of difficulties dealing with the condition itself as well as medication side effects.