Autoimmune epilepsy is a rare type of epilepsy that occurs as a result of an immune system imbalance. It develops due to immune antibodies targeting the brain.
One potential cause of epilepsy is the immune system’s activity damaging the brain. However, this is rare.
The immune system usually helps protect people against disease and promote healing from injury. However, some conditions cause the immune system to attack healthy tissue, which may lead to chronic health issues.
Autoimmune epilepsy refers to
A 2020 study defined that autoimmune epilepsy refers to different diseases, but they all cause chronic seizures and the ongoing presence of antibodies that target brain proteins.
A 2021 case study notes that it is rare, affecting 14 in every 100,000 people.
The condition develops when certain antibodies target specific receptors in the brain. It is not clear whether these antibodies have any beneficial function or exactly why they develop. The receptors include:
- N-methyl-d-aspartate receptor (NMDAR)
- leucine-rich glioma-inactivated protein 1 (LGI1)
- glutamic acid decarboxylase 65 (GAD65)
Sometimes, these antibodies relate to a tumor, in which case a doctor refers to them as paraneoplastic. If immune cells and antibodies attack a large region of the brain,
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The specific type of autoimmune epilepsy diagnosis considers the brain region the immune system is attacking, the symptoms that present, and the receptors involved.
Autoimmune limbic encephalitis
According to a
This type occurs when the autoimmune response
- a disrupted sleep cycle
- memory problems
- rapidly changing moods
- difficulty forming thought processes
- seizures
Psychological symptoms can also develop depending on the brain region affected. For example, if the immune system targets the amygdala, which regulates emotions, a person may feel increased aggression and heightened emotion.
Learn about the parts of the brain and their functions.
Anti-NMDAR encephalitis
This type of autoimmune epilepsy targets a particular receptor called NMDAR. It is the
A doctor makes a diagnosis when they find specific antibodies in the blood — immunoglobulin G (IgG) — that target NMDAR.
Rasmussen syndrome
This type of autoimmune epilepsy develops in children, leading to a decline in speech, memory, and cognition and weakness on one side of the body. Seizures often develop around 1 to 3 years before other symptoms, and the syndrome usually starts between 14 months and 14 years.
Often, there is no identifiable cause, but symptoms can sometimes begin after a viral infection, suggesting it may be a trigger for some people. A blood test for specific antibodies may confirm the diagnosis. It is not often fatal, but seizures are severe and persistent, and Rasmussen syndrome can lead to learning deficits.
Sometimes, surgical treatment is necessary. This may involve the removal of a portion of the brain.
GAD65 antibody-associated epilepsy
Anti-glutamic acid decarboxylase (GAD) antigens target proteins inside the cells, which causes this type of epilepsy. According to a
However, a doctor may find anti-GAD65 antibodies in the blood. It is rare, with fewer than 200 cases of GAD65 antibody-associated epilepsy appearing in research.
It is more common among females in their third decade and those with other autoimmune conditions.
Epilepsy induced by systemic autoimmune disorders
Systemic autoimmune disorders (SADs) affect the whole body rather than just the brain. However, people with these types of conditions — especially lupus and rheumatoid arthritis — might have a higher risk of epilepsy, according to a 2021 review.
SADs cause inflammation, which can lead to damage to the brain that disrupts electrical signals, leading to epilepsy.
Febrile illness-related refractory seizures (FIRES)
FIRES involves treatment-resistant epilepsy that starts
The cause of this type is unclear, but autoimmune involvement and a genetic risk of faulty immune responses may contribute. A doctor makes this diagnosis when seizures do not respond well to antiseizure medications, and ongoing effects may involve language issues and movement difficulties.
As several types of autoimmune epilepsy can develop, symptoms may vary depending on the type and which brain region is affected.
However, the Epilepsy Foundation has identified some common features in different types of autoimmune epilepsy:
- several seizures a day from the start of the condition developing
- focal seizures, or seizures that start in a specific brain region rather than the whole brain
- seizures affecting a single arm and side of the face on the same side of the body
- changing mood, such as:
- atypical behavior
- memory issues
- personality changes
Autoimmune epilepsy disorders may develop quickly in a pattern known as new-onset refractory status epilepticus (NORSE). This might be the most severe presentation of autoimmune epilepsy, according to a
NORSE is a pattern of symptoms rather than a unique diagnosis and involves ongoing seizure activity that does not respond to antiseizure medications.
Other types of epilepsy, such as epilepsy that develops due to head trauma, can cause NORSE, but the cause is often autoimmune epilepsy.
An estimated 5% to 35% of individuals who begin to develop seizures may have autoimmune epilepsy, although the exact figure is unclear. Sudden, intense seizures are a feature of autoimmune epilepsy. According to the Epilepsy Foundation, groups with a higher risk might include the following:
- those with another autoimmune condition, including:
- a medical history that includes cancer
- a parent, child, or sibling with an autoimmune disease
If a healthcare professional believes a person may have autoimmune epilepsy, they may recommend the following tests, but the diagnosis can be difficult:
- blood tests to rule out other conditions, such as liver disease or systemic infection
- an electroencephalogram (EEG), a video EEG may be more helpful in recording an individual’s typical seizures
- brain MRI scans — however, results are often normal, especially early on in disease progression
- PET scans
- spinal tap, which can allow a doctor to look for particular antibodies in the cerebrospinal fluid around the brain
Healthcare professionals may also order tests to identify paraneoplastic antibodies, which are a result of cancer.
Why is it important to diagnose it early?
Early diagnosis of autoimmune epilepsy can help increase a person’s chances of stopping seizures long term. Getting the proper treatment early in disease progression might also reduce, slow, or stop brain inflammation.
While autoimmune epilepsy typically does not respond well to antiseizure medications, effective treatments are available. In particular, immunotherapy may be highly effective in treating inflammation in the brain and managing autoimmune epilepsy.
Doctors may prescribe steroid medications, including prednisone and methylprednisolone, to people with this condition. Individuals can take these by mouth, or a clinical team may administer them via an IV drip. Another therapy, intravenous immunoglobulin (IVIG), can help reduce inflammation and overactivity of the immune system.
The effectiveness of treatment depends on the type of autoimmune epilepsy. For example, people with cancer-related autoimmune epilepsy may have a lower outlook than those with anti-NMDA receptor encephalitis. People with a related tumor should also receive treatment for this.
Starting immunotherapy early is the best way to stop brain injury and prevent seizures in people with autoimmune epilepsy that does not link to cancer.
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Autoimmune epilepsy is a rare type of epilepsy that occurs due to the immune system attacking specific proteins in the brain, leading to seizures. The types include autoimmune limbic encephalitis, FIRES, and epilepsy induced by systemic autoimmune disorders. They also vary by the type of protein the immune system is targeting.
Common symptoms include frequent seizures, mood changes, memory issues, and personality changes. To treat autoimmune epilepsy, doctors use steroid medications and immunotherapy to address the underlying autoimmune response. However, a person’s response to treatment may vary depending on the type and how early they begin treatment.