Autoimmune Epilepsy: Complete Guide to Symptoms, Causes, Diagnosis, and Treatment

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick Answer: What Is Autoimmune Epilepsy?

Autoimmune epilepsy is a type of epilepsy in which seizures are caused by the immune system mistakenly attacking brain cells. Antibodies — proteins that normally protect the body from viruses and infections — target receptors in the brain, causing inflammation and seizures. Unlike most epilepsy, standard antiseizure medicines usually don't do enough; the key treatment is immunotherapy.

What the research says

• Seizures in autoimmune encephalitis often stop faster and more often with immunotherapy than with antiseizure drugs alone. In a nationwide cohort of 153 patients with anti-LGI1, anti-NMDAR, or anti-GABA-B encephalitis, 72% (110 patients) had epileptic seizures and 89% of them reached seizure freedom. At least 53% became seizure free shortly after immunotherapy versus 14% on antiseizure medicines alone, with a median of 28 days to seizure freedom from the start of immunotherapy versus 59 days from the start of antiseizure medicines, and only 1 of 86 surviving patients developed epilepsy after the encephalitis resolved. (de Bruijn et al., Neurology, 2019) [3]

• The type of antibody matters for the outlook. In a retrospective cohort of 39 patients with seizures and neural antibodies followed for at least 3 years, patients with antibodies against cell-surface targets (NMDAR, LGI1, CASPR2) reached first seizure freedom far more often than those with intracellular antibodies such as GAD65 (88% vs 7%, P < 0.001), and terminal seizure freedom as well (80% vs 7%, P < 0.001). The authors concluded that seizures with surface antibodies are mostly acute symptomatic and transient rather than indicative of epilepsy. (Rada et al., J Neurol, 2021) [4]

Autoimmune Epilepsy at a Glance

Topic	Quick Summary
What happens	Antibodies mistakenly attack brain receptors → brain inflammation → seizures
Other names	Autoimmune associated epilepsy; acute symptomatic seizures secondary to autoimmune encephalitis
Most common cause	Autoimmune encephalitis (linked to NMDA, LGI1, CASPR2, GAD65 antibodies)
Other causes	Rasmussen syndrome (mainly affects children); cancer (paraneoplastic syndrome)
Most common seizure type	Focal seizures, sometimes with staring and loss of awareness
Diagnosis	Blood or cerebrospinal fluid antibody tests, MRI, FDG PET scan, EEG
Treatment	Immunotherapy (steroids, immunoglobulin, longer-acting medicines), plasma exchange, antiseizure medicines, surgery for Rasmussen syndrome
Outlook	Many become seizure free after immunotherapy, though it can take months; seizures continue for some

What Is Autoimmune Epilepsy?

The immune system protects the body from viruses, bacteria, and other harmful substances. Its weapons are antibodies, proteins that hunt down invaders. In autoimmune epilepsy, this system makes a critical mistake: antibodies mistakenly target receptors in the brain.

This attack leads to swelling in the brain, also known as inflammation, and seizures. Research has concluded more recently that epilepsy can be an autoimmune disease. The condition is also known as autoimmune associated epilepsy and acute symptomatic seizures secondary to autoimmune encephalitis.

A key difference from other epilepsy types: antiseizure medicines usually don't do enough to manage seizures in people with autoimmune epilepsy. Instead, immunotherapy medicines help reduce the immune response on the brain.

Diagram: How antibodies that normally protect the body turn against brain receptors in autoimmune epilepsy — from a healthy, protected brain to immune-driven inflammation and seizures. Image courtesy of rinnit.com.

What are the symptoms of autoimmune epilepsy?

Symptoms of autoimmune epilepsy may begin after an illness with a fever. Seizures come on suddenly and are serious.

The Seizure Types

• Focal seizures are the most common type in autoimmune epilepsy. Sometimes they cause a change or loss of awareness — the person may stare and not respond to the environment. Other focal seizures don't change awareness but cause different symptoms depending on which part of the brain is affected: one part of the body shaking, a feeling that something has happened before (déjà vu), nausea, or vision symptoms such as flashing lights.

• Faciobrachial dystonic seizures cause muscle contractions on one side of the face and in an arm, both on the same side of the body.

Signs That Point to an Autoimmune Cause

Seizures related to autoimmune epilepsy tend to have distinctive patterns:

• Seizures that happen several times a day

• Seizures that don't go away with antiseizure medicines

• Seizures that last more than five minutes or occur close together without the person regaining consciousness — known as status epilepticus

Other symptoms that may accompany autoimmune epilepsy include:

• Memory loss and trouble with thinking

• Personality and behavior changes

• Involuntary movements or clumsy movements

• Irregular eye movements

• Changes in heart rate, blood pressure, and other automatic functions

When to see a doctor: Get emergency medical care for a seizure that lasts more than five minutes, seizures occurring one after another with a loss of consciousness, high fevers, or trouble breathing. See your healthcare professional right away if you have had a seizure for the first time or have other symptoms of autoimmune epilepsy.

What causes autoimmune epilepsy?

Autoimmune epilepsy is caused by the immune system attacking healthy brain cells, most commonly through autoimmune encephalitis, Rasmussen syndrome or cancer-related paraneoplastic syndrome. Autoimmune epilepsy causes may include:

• Autoimmune encephalitis. A group of conditions that causes swelling in the brain because the immune system mistakenly attacks brain cells. It is the most common cause of autoimmune epilepsy. Certain types are commonly linked to it and are associated with antibodies that target NMDA-receptors, LGI1, CASPR2, and GAD65.

• Rasmussen syndrome. Immune cells known as T cells cause inflammation and brain damage that lead to seizures. People with autoimmune epilepsy due to Rasmussen syndrome may continue to have seizures after treatment.

• Cancer. Sometimes tumors trigger the immune system to attack healthy brain cells — known as paraneoplastic syndrome — which can lead to epilepsy.

What are the risk factors for autoimmune epilepsy?

The risk of autoimmune epilepsy is low, and it can occur in both adults and children. Risk factors include:

• Having another autoimmune disease, such as rheumatoid arthritis, Graves' disease, Hashimoto thyroiditis, Crohn's disease, ulcerative colitis, or lupus

• Having a history of cancer

• Having a parent, sibling, or child with an autoimmune disease

What are the complications of autoimmune epilepsy?

Complications of autoimmune epilepsy can include status epilepticus — serious seizures that last more than five minutes or occur one after another while the person is unconscious between them. These need emergency medical attention. Sometimes autoimmune epilepsy can also lead to seizures that don't stop with treatment.

Can autoimmune epilepsy be prevented?

You may not be able to prevent autoimmune epilepsy. But getting cancer screenings can help your healthcare professional find tumors and treat them early — this could prevent autoimmune encephalitis triggered by cancers, which can be a cause of epilepsy. Talk with your healthcare professional about your cancer risk and whether you should be screened for certain cancers.

How is autoimmune epilepsy diagnosed?

Diagnosis begins with a physical exam and a review of symptoms. Testing includes lab tests, brain imaging, and testing the electrical activity in the brain.

Test	How It Works
Lab tests	Check for the antibodies attacking brain cells, tested in blood or cerebrospinal fluid — the fluid surrounding the brain and spinal cord, removed during a lumbar puncture (a hollow needle into the numbed lower back). For some people, these tests don't find antibodies.
MRI	Looks for signs of autoimmune epilepsy in the brain and can rule out other possible causes of seizures
FDG PET scan	A fluorodeoxyglucose (FDG) brain scan that checks how well nutrients are being metabolized in the brain, offering clues about certain autoimmune encephalitis types causing seizures
EEG	An electroencephalogram measures electrical activity in the brain; it may show seizure activity, help diagnose autoimmune epilepsy, and rule out other conditions. A video EEG may record seizure activity.

How is autoimmune epilepsy treated by calming the immune system?

Treatment for autoimmune epilepsy differs from the treatment used for other types of epilepsy. Healthcare professionals use immunotherapy to reduce immune system activity and treat seizures. If cancer is the cause, treating the cancer is an important part of treatment.

Immunotherapy

Medicine	How It's Given
High-dose corticosteroids	Methylprednisolone (Solu-Medrol) through an IV for up to five days, then IV regularly for weeks with gradually lengthening time between doses; or oral prednisone — a high dose for up to five days, then a lower dose for several weeks, slowly lowered over time (tapering)
Immunoglobulin	Through an IV for up to five days, then lower doses regularly for several weeks
Longer-acting medicines	Depending on response to initial treatment: rituximab (Rituxan, Truxima), cyclophosphamide, mycophenolate (Cellcept, Myhibbin), azathioprine (Azasan, Imuran), or tocilizumab (Actemra, Tofidence, Tyenne)

Plasma Exchange

In plasma exchange, the liquid part of your blood is removed and separated from your blood cells. The blood cells are put back into your body, and your body makes more plasma. This therapy helps remove the antibodies causing the immune attack on brain cells.

Antiseizure Medicines

Antiseizure medicines don't work as well in people with autoimmune epilepsy, but they may still play a role. If immunotherapy makes you seizure free, your provider may suggest slowly reducing your antiseizure medicine dose over several months to see if seizures return.

Many people whose seizures are due to autoimmune encephalitis become seizure free after immunotherapy. It may take several months after treatment for the seizures to stop — but seizures continue for some people even after immunotherapy. People with GAD65 antibodies are less likely to become seizure free.

Rehabilitation and Surgery

If you have symptoms other than seizures, such as trouble with memory or speech, you may need rehabilitation — occupational and speech therapy can help. Rasmussen syndrome, which mainly affects children, usually doesn't respond to medicines; brain surgery often is needed to treat this type of autoimmune epilepsy.

How should you prepare for an autoimmune epilepsy appointment?

If symptoms are serious, you might need emergency medical care. For less serious symptoms, you may start with your healthcare professional or be referred to a neurologist — a doctor who specializes in nervous system conditions.

When making the appointment, ask if anything is needed in advance, such as fasting before a specific test. Then make a list of:

1. Your symptoms, including any that seem unrelated

2. Key personal information, including major stresses, recent life changes, and family medical history

3. All medicines, vitamins, or other supplements you take, including doses

4. Questions to ask your healthcare professional

Take a family member or friend along, if possible, to help remember the information you're given. Useful questions include:

• What's likely causing my symptoms?

• What other causes are possible?

• What tests do I need?

• Is my condition likely short term or lasting?

• What's the best course of action, and what are the alternatives?

• How can I manage this alongside my other conditions?

• What restrictions apply?

• Should I see a specialist?

• What brochures or websites do you recommend?

Your healthcare professional is likely to ask: When did symptoms begin? Do they occur all the time or off and on? How bad are they? What improves them? What worsens them?

Infographic: The complete autoimmune epilepsy patient guide — common signs, how the immune attack happens, risk factors, the four key tests, the treatment ladder, emergency rules, and the outlook. Image courtesy of rinnit.com.

Frequently Asked Questions

What is autoimmune epilepsy?

Autoimmune epilepsy is a type of epilepsy where seizures are caused by the immune system mistakenly attacking brain cells. Antibodies target receptors in the brain, leading to brain inflammation and seizures. It can occur with immune system conditions, especially autoimmune encephalitis.

What causes autoimmune epilepsy?

The most common cause is autoimmune encephalitis, a group of conditions where the immune system attacks brain cells — often linked to antibodies targeting NMDA-receptors, LGI1, CASPR2, or GAD65. Rasmussen syndrome and cancer (paraneoplastic syndrome) are other causes.

How is autoimmune epilepsy different from other epilepsy?

The seizures usually don't respond well to antiseizure medicines, and they often come on suddenly, happen several times a day, and may be accompanied by memory loss, personality changes, or unusual movements. The treatment targets the immune system — immunotherapy — rather than only the seizures.

Can autoimmune epilepsy be cured?

Treatment can stop seizures completely for some people, and many with seizures due to autoimmune encephalitis become seizure free after immunotherapy, though it may take several months. For others, seizures may continue after treatment — particularly people with GAD65 antibodies.

What tests diagnose autoimmune epilepsy?

Diagnosis uses lab tests (checking blood or cerebrospinal fluid for the antibodies attacking brain cells), an MRI, an FDG PET scan that checks how the brain metabolizes nutrients, and an EEG that measures electrical activity. For some people, antibody tests don't find antibodies.

Is autoimmune epilepsy an emergency?

Get emergency medical care for a seizure lasting more than five minutes, seizures occurring one after another with loss of consciousness (status epilepticus), high fevers, or trouble breathing. Otherwise, see your healthcare professional right away after a first seizure or if you have autoimmune epilepsy symptoms.

Can autoimmune epilepsy be prevented?

You may not be able to prevent it, but cancer screenings can help find and treat tumors early, which could prevent autoimmune encephalitis triggered by cancers — one cause of epilepsy.

Conclusion: What to Remember About Autoimmune Epilepsy

Autoimmune epilepsy is a rare but important condition, and three lessons stand out:

• When seizures are sudden, frequent, and resistant, the immune system may be the cause. Seizures that come on suddenly, happen several times a day, and don't respond to antiseizure medicines — especially with memory loss or personality changes — deserve a full autoimmune workup.

• The treatment targets the immune system, not just the brain. Immunotherapy — steroids, immunoglobulin, or longer-acting medicines — is the cornerstone, and when started early it can reduce inflammation, improve seizures, and for some people stop them completely.

• Speed matters, and vigilance matters. A seizure over five minutes or back-to-back seizures need emergency care immediately — and even after treatment, follow-up care and rehabilitation keep the recovery complete.

Explore more in-depth health guides in the library at rinnit.com. From the petit mal seizure (absence seizure) guide — about a different kind of seizure disorder and its treatments — to the full rinnit.com library, detailed health information is always one click away.

This article is for informational purposes only and is not a substitute for professional medical advice. Seek emergency care for seizures lasting more than five minutes, back-to-back seizures, high fevers, or trouble breathing.

References

1. Mayo Clinic Staff. Autoimmune epilepsy — Symptoms and causes. Mayo Clinic. December 21, 2024. https://www.mayoclinic.org/diseases-conditions/autoimmune-epilepsy/symptoms-causes/syc-20576892

2. Mayo Clinic Staff. Autoimmune epilepsy — Diagnosis and treatment. Mayo Clinic. December 21, 2024. https://www.mayoclinic.org/diseases-conditions/autoimmune-epilepsy/diagnosis-treatment/drc-20576912

3. de Bruijn MAAM, van Sonderen A, van Coevorden-Hameete MH, et al. Evaluation of seizure treatment in anti-LGI1, anti-NMDAR, and anti-GABAR encephalitis. Neurology. 2019;92(19):e2185-e2196. PMID 30979857. https://doi.org/10.1212/WNL.0000000000007475

4. Rada A, Birnbacher R, Gobbi C, et al. Seizures associated with antibodies against cell surface antigens are acute symptomatic and not indicative of epilepsy: insights from long-term data. J Neurol. 2021;268(3):1059-1069. PMID 33025119. https://doi.org/10.1007/s00415-020-10250-6