Autoimmune Encephalitis

Photo of a provider pointing at a computer display of a brain scan

Our team has the expertise to accurately diagnose and treat autoimmune encephalitis, a group of serious conditions in which the immune system attacks the brain.

You’ll find:

  • Highly trained experts who understand the many signs and symptoms of autoimmune encephalitis.
  • Advanced technology to test for the disease, and providers with deep experience analyzing the results.
  • A team of specialists who understand this complex disease so they can give you the best possible treatment.

Understanding autoimmune encephalitis

What is autoimmune encephalitis?

Autoimmune encephalitis is a collection of related conditions in which the body’s immune system attacks the brain, causing inflammation. The immune system produces substances called antibodies that mistakenly attack brain cells.

Like multiple sclerosis, the disease can be progressive (worsening over time) or relapsing-remitting (with alternating flare-ups and periods of recovery). Autoimmune encephalitis has many subtypes that depends on the antibodies present.

Left untreated, autoimmune encephalitis can quickly become serious. It may lead to coma or permanent brain injury. In rare cases, it can be fatal.

Who gets autoimmune encephalitis?

Autoimmune encephalitis was once considered rare, but doctors are finding more cases as their ability to diagnose it improves. A 2018 study found 13.7 cases per 100,000 people.

Factors that affect risk include:

  • Gender: This illness, like many autoimmune diseases, affects women more often than men.
  • Age: It can happen at any age but is diagnosed most often in young women.
  • Family history: It does not appear to run in families.
  • Race/ethnicity: It may be much more common among Black people, according to the 2018 study, but more research is needed.

What causes autoimmune encephalitis?

In many cases, the cause of autoimmune encephalitis is unknown. But experts say it can be caused by:

  • Exposure to certain bacteria and viruses, including streptococcus and herpes simplex virus.
  • A type of tumor called a teratoma, generally in the ovaries, that causes the immune system to produce specific antibodies.
  • Rarely, some cancers that can trigger an autoimmune response (when the immune system attacks the body’s own tissues).

Types of autoimmune encephalitis

Types include:

Symptoms of autoimmune encephalitis

Symptoms may come on over a period of days or weeks. They can also vary depending on the type of autoimmune encephalitis.

The early phase of the disease may include flu-like symptoms, such as headache, fever, nausea and muscle pain. Psychiatric symptoms may appear, disappear and reappear. Later symptoms may be more severe, such as a lower level of consciousness and possible coma.

Common symptoms include:

  • Impaired memory and understanding
  • Unusual and involuntary movements
  • Involuntary movements of the face (facial dyskinesia)
  • Difficulty with balance, speech or vision
  • Insomnia
  • Weakness or numbness
  • Seizures
  • Severe anxiety or panic attacks
  • Compulsive behaviors
  • Altered sexual behaviors
  • Behavior changes such as agitation, fear or euphoria
  • Loss of inhibition
  • Hallucinations
  • Paranoid thoughts
  • Loss of consciousness or coma

Diagnosing autoimmune encephalitis

Dr. Michael Lane, a neurologist, has particular expertise in treating patients with autoimmune encephalitis.
Dr. Michael Lane, a neurologist, has particular expertise in treating patients with autoimmune encephalitis.

Autoimmune encephalitis can be difficult to diagnose. Because it has been considered rare, doctors can mistake it for a mental health disorder or drug abuse. At the same time, early diagnosis is important to avoid serious complications.

At the OHSU Multiple Sclerosis Center, you can count on experts who recognize this complex illness and know the latest research.

If you show signs of autoimmune encephalitis, your doctor will do a neurologic exam to measure your reflexes, nerve functions, thinking and other processes. You also may have tests to rule out other conditions.

Tests may include:

  • A spinal tap (lumbar puncture) to withdraw a sample of cerebrospinal fluid, the liquid that surrounds your brain and spinal cord. The fluid can be examined for signs of autoimmune encephalitis or another disease.
  • Blood tests to look for antibodies that may indicate autoimmune encephalitis.
  • MRI (magnetic resonance imaging) scans of your brain to identify signs of the disease.

Generally, a diagnosis of autoimmune encephalitis requires three conditions:

  • Short-term memory loss, psychiatric symptoms or other symptoms of an altered mental state all within three months of one another
  • At least one of the following:
    • Numbness, weakness or paralysis that affects a specific limb or area of the body
    • Seizures that can’t be explained by other conditions
    • A high white blood cell count in the cerebrospinal fluid
    • An MRI that shows signs of brain inflammation
  • Ruling out other causes

Treatment for autoimmune encephalitis

Early treatment can greatly reduce symptoms and reduce the chances of long-term complications.

Treatments may include:

  • Surgery to remove a teratoma.
  • Steroids to reduce brain inflammation and the immune system’s response.
  • Plasma exchange (removal and replacement of the liquid part of the blood) to take out harmful antibodies.
  • Intravenous immunoglobulin (IVIG), given in an IV drip, to introduce antibodies from the plasma of healthy donors. IVIG removes harmful antibodies and reduces inflammation.
  • Immunosuppressant medications, if other treatments are not effective.

For patients

  • Referral: To become a patient, please ask your doctor for a referral.
  • Questions: For questions or follow-up appointments, call 503-494-7772.


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Image of a 3-D printed NMDA receptor from OHSU researchers studying a type of autoimmune encephalitis called Anti-NMDAR receptor encephalitis

Learn how OHSU researchers developed an animal model to help them study a type of autoimmune encephalitis called anti-NMDAR receptor encephalitis. It’s among many innovative studies aimed at improving understanding and patient care.