Seizure: Causes, Warning Signs, and When to Get Help
A seizure is a sudden burst of abnormal electrical activity in the brain that briefly changes how a person moves, feels, or behaves. Some seizures cause dramatic shaking and loss of awareness; others are subtle, like a blank stare or a strange smell that no one else notices. This page explains what seizures feel like, what can cause them, the warning signs that need emergency care, simple first aid and self-care, and how to find the right specialist near you.
At a Glance
What a seizure is and how it feels
Your brain cells talk to each other using small electrical signals. A seizure happens when many cells fire at once in a sudden, uncontrolled way. Depending on which part of the brain is involved, this can change your movement, awareness, senses, or emotions for a short time, usually seconds to a couple of minutes.
Seizures do not all look the same. That surprises many people. Knowing the main types helps you describe what happened to a doctor.
- Generalized tonic-clonic (grand mal): The body stiffens, then the arms and legs jerk rhythmically. The person loses consciousness and may bite their tongue or lose bladder control.
- Absence seizures: A brief blank stare or eye flutter, often in children, lasting only seconds. They are easily mistaken for daydreaming.
- Focal seizures: Begin in one area of the brain. The person may stay aware but feel a strange taste, smell, tingling, fear, or a rising feeling in the stomach. Others lose awareness and make repeated movements like lip-smacking or fumbling.
Many people feel an aura beforehand. This is a brief warning sign such as a funny smell, a sense of deja vu, or a sudden wave of dizziness. After a bigger seizure, a person is often confused, sleepy, and sore, or has a headache that lasts minutes to hours. That period is called the postictal phase, and it is normal.
What causes seizures
A single seizure is not the same as epilepsy. Many seizures are triggered by a temporary problem, and they may never happen again once that problem is fixed. Common triggers include very low blood sugar, low sodium, high fever in young children (febrile seizures), lack of sleep, alcohol or drug withdrawal, and certain medications.
When seizures keep coming back, a brain condition is usually the reason. The most likely causes link to these pages:
- Epilepsy is the leading cause of repeated, unprovoked seizures. It means the brain is prone to seizures over time, and it is highly treatable.
- Stroke can damage brain tissue and leave a scar that sparks seizures, especially in older adults.
- Concussion and other head injuries can cause seizures right away or months later.
- Encephalitis, an infection or inflammation of the brain, irritates brain tissue and can trigger seizures.
- Brain aneurysm and brain malformations can disrupt normal electrical activity.
- A migraine with aura is sometimes confused with a focal seizure, and the two can occur in the same person.
- Conditions that change the brain over time, such as dementia, Alzheimer's disease, and multiple sclerosis, raise the risk of seizures as well.
Brain tumors, low oxygen, and genetic conditions are other possible causes. Finding the cause is the main reason a first seizure needs a full medical workup.
When to seek emergency care (red flags)
Most short seizures stop on their own and are not life-threatening. Some situations, though, are true emergencies. Call 911 right away if any of these happen:
- A seizure lasts longer than 5 minutes, or one seizure runs into the next without the person waking up. This is a dangerous state called status epilepticus.
- The person has trouble breathing, turns blue, or does not wake up after the shaking stops.
- It is the person's first-ever seizure.
- The seizure happens in water, or the person is injured, pregnant, or has diabetes.
- A seizure follows a head injury, a high fever with a stiff neck, or a severe headache, which can point to stroke or brain infection.
For a known seizure that stops within a few minutes, you may not need the emergency room, but call the person's doctor to report it. Any change in the usual pattern, more frequent seizures, or a new type of seizure deserves prompt medical attention. This page is educational and cannot diagnose you. When in doubt, get checked.
First aid and self-care
If you see someone having a seizure with shaking and loss of awareness, you can keep them safe with a few simple steps.
What to do during a seizure
- Stay calm and time it. Note when it starts so you know if it passes 5 minutes.
- Ease them to the floor and move away hard or sharp objects.
- Turn them gently onto their side so saliva drains and the airway stays clear.
- Cushion the head with something soft and loosen anything tight around the neck.
- Stay until they are fully awake and reassure them, since confusion afterward is normal.
What never to do
- Do not put anything in their mouth. A person cannot swallow their tongue, and objects can break teeth or block breathing.
- Do not hold them down or try to stop the movements.
Living with seizures
If you have a seizure disorder, daily habits lower your risk. Take medicine exactly as prescribed and never skip doses. Aim for steady, full sleep, since being overtired is a common trigger. Limit alcohol, manage stress, and keep a seizure diary that notes the time, length, and anything that came before. Tell your doctor about all your medicines, because some can interact with seizure drugs.
How seizures are diagnosed
A doctor starts by hearing the story of what happened, so a witness account is gold. Bring details like how long it lasted, what the body did, and how the person felt before and after. A phone video of an event, if one exists, can be very helpful.
From there, testing looks for the cause and checks how the brain behaves:
- EEG (electroencephalogram): Records the brain's electrical activity through small sensors on the scalp. It can catch the abnormal patterns that point to epilepsy.
- Brain imaging: An MRI or CT scan looks for stroke, scars, bleeding, tumors, or malformations.
- Blood tests: Check blood sugar, sodium, kidney and liver function, and infection, since these can provoke seizures.
- Heart testing: Sometimes an ECG is done because fainting from a heart rhythm problem can look like a seizure.
Not every test is needed for every person. The goal is to decide whether this was a one-time provoked event or a sign of an ongoing condition that needs treatment.
When to see a doctor and which specialist
Anyone who has a first seizure should be evaluated, even if they feel fine afterward. See a doctor if seizures become more frequent, last longer, change in type, or if a current medicine stops working or causes side effects you cannot tolerate.
The specialist who treats seizures is a neurologist, a doctor who focuses on the brain and nervous system. For seizures that are hard to control, an epileptologist offers the next level of care. An epileptologist is a neurologist with extra training in epilepsy who can fine-tune medicines or refer you to a specialized epilepsy center for advanced options like surgery or a stimulation device. Children are often seen by a pediatric neurologist.
Good seizure care is a partnership. With the right diagnosis and treatment, most people gain strong control over their seizures and live full, active lives. You can find a neurologist near you using the directory below.
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Frequently Asked Questions
Common questions about seizure
What is the difference between a seizure and epilepsy?
A seizure is a single event of abnormal brain activity. Epilepsy is a condition where a person has a lasting tendency to have repeated, unprovoked seizures. You can have one seizure, from a fever or low blood sugar, without having epilepsy.
What should I do if someone has a seizure?
Stay calm, time the seizure, ease the person to the floor, and gently turn them onto their side. Move dangerous objects away and cushion the head. Never put anything in their mouth or hold them down, and call 911 if it lasts more than 5 minutes or it is their first one.
How long does a typical seizure last?
Most seizures last from a few seconds to about 2 minutes. A seizure that goes beyond 5 minutes, or repeated seizures without the person waking up in between, is a medical emergency called status epilepticus that needs 911 right away.
Can stress or lack of sleep cause a seizure?
Yes. Being very tired, missing sleep, and high stress are common seizure triggers, especially in people who already have a seizure disorder. Steady sleep, stress management, and taking medicine on schedule all help lower the risk.
What causes a seizure in someone with no history of them?
A first-time seizure can come from low blood sugar or sodium, high fever in children, head injury, stroke, brain infection, alcohol or drug withdrawal, or certain medicines. Because the cause can be serious, any first seizure should be evaluated by a doctor.
Do all seizures involve shaking and falling?
No. Many seizures are subtle, like a blank staring spell, lip-smacking, a strange smell, or a brief wave of fear or deja vu. These focal and absence seizures can be easy to miss, which is why describing the event to a doctor matters.
Are seizures dangerous?
Most short seizures stop on their own and are not life-threatening. The risks come from injury during a fall, seizures in water, very long seizures, and trouble breathing. Getting the cause diagnosed and treated greatly lowers the dangers over time.
Medical disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you have a medical emergency, call 911. Our editorial standards