What is seizure
Last updated: April 1, 2026
Key Facts
- Seizures can be caused by epilepsy, fever, head injury, stroke, brain tumors, infections, or low blood sugar
- Symptoms vary from unaware staring spells to violent shaking, depending on which part of the brain is affected
- Not all seizures involve convulsions; some cause only loss of awareness or unusual sensations
- A single seizure doesn't necessarily mean someone has epilepsy; epilepsy is diagnosed after recurring seizures
- Emergency medical help should be called if a seizure lasts longer than 5 minutes or multiple seizures occur
Understanding Seizures
A seizure is an abnormal burst of electrical activity in the brain that disrupts normal brain function. During a seizure, neurons fire rapidly and uncontrollably, causing physical symptoms, behavioral changes, or loss of consciousness. Seizures are more common than many people realize, affecting approximately 1 in 26 people at some point in their lives.
Types of Seizures
Seizures are classified into two main categories: generalized seizures affect the entire brain and often cause loss of consciousness and convulsions, while focal seizures affect only one area of the brain and may preserve awareness. Common types include tonic-clonic seizures (with rigid muscles followed by jerking), absence seizures (brief staring spells), and myoclonic seizures (sudden muscle jerks).
Causes of Seizures
Seizures have many triggers. Epilepsy, a neurological disorder, causes recurring seizures without an external trigger. Fever-related seizures commonly affect young children. Other causes include head injuries, stroke, brain tumors, infections like meningitis, very low blood sugar, alcohol withdrawal, and sleep deprivation. Sometimes no cause is identified.
Symptoms and Duration
Symptoms depend on seizure type and location in the brain. Some people experience an aura (warning signs) before seizures begin. Physical symptoms may include uncontrolled shaking, stiffness, loss of consciousness, biting the tongue, loss of bladder control, or rapid eye movements. Most seizures last 30 seconds to 2 minutes. Prolonged seizures lasting over 5 minutes (status epilepticus) are a medical emergency.
First Aid and When to Seek Help
If someone has a seizure, stay calm and protect them from injury. Turn them onto their side to prevent choking, cushion their head, and never restrain them. Call emergency services if the seizure lasts over 5 minutes, multiple seizures occur in succession, the person is injured, or it's their first seizure. After recovery, many people feel confused or tired.
Diagnosis and Treatment
Seizures are diagnosed through medical history, neurological exams, and EEG testing that measures brain electrical activity. Treatment depends on the cause and seizure type. Anti-seizure medications are the primary treatment for epilepsy. Surgery, lifestyle modifications, and specialized diets may help some patients. Identifying and avoiding triggers also reduces seizure frequency.
Related Questions
What's the difference between a seizure and epilepsy?
A seizure is a single event of abnormal brain electrical activity. Epilepsy is a neurological condition characterized by recurring seizures. Not all seizures indicate epilepsy; someone may have one seizure due to fever or injury without having epilepsy.
Is it safe to help someone during a seizure?
Yes, you should help. Place them on their side to keep airways open, remove nearby hazards, cushion their head, and time the seizure. Don't put anything in their mouth or restrain them. Call emergency services if the seizure lasts over 5 minutes.
Can seizures cause brain damage?
Most individual seizures don't cause permanent brain damage. However, severe or prolonged seizures (status epilepticus) can potentially cause lasting damage. Proper treatment and seizure management help minimize this risk.
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Sources
- CDC - Epilepsy and SeizuresPublic
- Wikipedia - SeizureCC-BY-SA-4.0