A seizure happens when abnormal bursts of electrical activity occur in the brain, caused by epilepsy, fever, head injury, low blood sugar, or other conditions.
What happens
A seizure is a sudden burst of abnormal electrical activity in the brain.
Causes
- Epilepsy, the most common cause of repeat seizures.
- High fever (febrile seizures in children).
- Head injury, stroke or tumor.
- Low blood sugar or sodium.
- Alcohol or drug withdrawal.
- Infections such as meningitis.
Types
Focal seizures start in one area. Generalized seizures involve both sides of the brain.
Call 911 if
It lasts more than 5 minutes, repeats, the person is injured or has trouble breathing, or it’s their first seizure.
Brain mechanism
A seizure results from a sudden, abnormal burst of electrical activity in the brain. Neurons fire excessively and in synchrony, which disrupts normal brain function. Symptoms depend on the part of the brain involved.
Epilepsy
Epilepsy is a condition with two or more unprovoked seizures. About 3.4 million people in the US have active epilepsy, according to the CDC, and about 1 in 10 people have a seizure at some time.
Types
- Focal seizures start in one area and may or may not affect awareness.
- Generalized seizures involve both sides of the brain, including tonic clonic (grand mal), absence and myoclonic seizures.
Causes
- Genetic factors.
- Head injury.
- Stroke or brain tumor.
- Infections like meningitis or encephalitis.
- Low blood sugar or sodium.
- Fever in young children (febrile seizures).
- Alcohol or drug withdrawal.
- Lack of sleep.
- Flashing lights in photosensitive epilepsy.
Often no cause is found.
First aid
- Stay calm and note the time.
- Move hard objects away.
- Cushion the head and loosen tight clothing.
- Turn the person onto their side after the shaking stops.
- Do not hold the person down or put anything in the mouth.
Call 911 if
The seizure lasts more than 5 minutes, repeats, the person is hurt, pregnant, has diabetes, does not wake up, or this is their first seizure.
Diagnosis and treatment
Tests include EEG, MRI and blood tests. Anti seizure medications control seizures in about 70% of people with epilepsy. Surgery, vagus nerve stimulation and diets such as the ketogenic diet are other options.
How a seizure starts
A seizure is a burst of abnormal, excessive electrical activity among brain neurons, which can temporarily affect movement, awareness, sensation or behavior. About 1 in 10 people will have a seizure in their lifetime, and epilepsy, defined as two or more unprovoked seizures or one with high risk of recurrence, affects about 3.4 million people in the US, according to the CDC. Causes include genetics, head injury, stroke, brain tumor, infection such as meningitis, low blood sugar, alcohol withdrawal and high fever in young children (febrile seizures). In many cases, no cause is found.
First aid and treatment
During a convulsive seizure, stay calm, note the time, move hard objects away, cushion the head and turn the person on their side after the shaking stops. Do not hold the person down or put anything in the mouth. Call 911 if a seizure lasts over 5 minutes, repeats without recovery, happens in water, occurs in someone who is pregnant, injured or diabetic, or if breathing does not resume. Diagnosis uses EEG and MRI. About two thirds of people with epilepsy can become seizure free with anti seizure medicines, and surgery, nerve stimulation and diet therapy are options for others.
Based on data from the CDC and the Epilepsy Foundation
