What is an Autoimmune Encephalitis?

Bandeau AE

Autoimmune encephalitis (AE) is a type of brain inflammation where the body’s immune system attacks healthy cells and tissues in the brain or spinal cord. It is a rare, complex disease that can cause rapid changes in both physical and mental health. Some patients have antibodies in their blood or cerebrospinal fluid (CSF) which are known to be associated with encephalitis, while others test negative for antibodies but have characteristic symptoms.  AE was recognized as a disease relatively recently. Because of this, some doctors may not be familiar with this condition, and it may be misdiagnosed as a psychiatric or neurological disorder. Early diagnosis and treatment are critical to minimizing both short- and long-term complications of this disease.


Inflammation in the brain can cause a variety of symptoms, including neurological and psychiatric problems. Symptoms often vary from patient to patient and may appear at different times and different levels of intensity, so that the disease may mimic many other disorders. The symptoms typically develop quickly over weeks to a few months. Long-standing psychiatric issues (for many months or years) are not a sign of autoimmune encephalitis.

Symptoms commonly associated with AE can include:

 ¤ Cognitive impairment

 ¤ Memory difficulties

 ¤ Seizures

 ¤ Involuntary movements

 ¤ Slowed or loss of ability to speak

 ¤ Behavioral changes such as agitation

 ¤ Loss of inhibition

 ¤ Hallucinations (visual or auditory)

 ¤ Paranoid thoughts

 ¤ Severe anxiety

 ¤ Sleep disruption including severe insomnia

 ¤ Decreased level of consciousness

 ¤ Weakness or numbness of part of the body

 ¤ Loss of balance

 ¤ Vision changes

 Although just one of these symptoms does not imply autoimmune encephalitis, an otherwise unexplained mixture of the above neuro-psychiatric symptoms may be a clue that the underlying cause is autoimmune encephalitis.


Most AE patients can expect to see a team of doctors that may include neurologists, rheumatologists, psychiatrists, immunologists and others. Diagnosis requires a thorough history and physical exam, as well as lab studies and imaging. If AE is suspected, a doctor may recommend doing a blood test and a lumbar puncture to evaluate the cerebral spinal fluid for antibodies. An ultrasound of the abdomen may also be performed rule out the possibility of an associated tumor. Diagnostic testing also typically includes a brain MRI with contrast, and an electroencephalogram (EEG) test. 

However, negative test results for autoimmune antibodies does not rule out AE. A significant percentage of AE cases maybe caused by other, still unknown antibodies, or by known antibodies for which a diagnostic test is not yet available. As such, specific diagnostic criteria for “antibody negative” autoimmune encephalitis has been defined. It is very important that in cases who do not fulfill the proposed diagnostic criteria, to remain open to the possibilities of other alternative diagnoses.


Treatment varies depending on the severity of the disease. Corticosteroids and other immunosuppressive medications are typically used to control the inflammation in the brain. Some patients may also require medications for seizures or psychiatric symptoms. If an ovarian or other tumor is found, surgically removing it can significantly improve the patient’s AE. Once the underlying encephalitis is controlled, long-term rehabilitation, including physical, occupational and speech therapy, may help patients regain function.

Just as the diagnosis of autoimmune encephalitis (AE) has evolved over the past several years, so have the treatment options. The following discussion is intended only as an introduction to various treatment options. ONLY your doctor or medical professional can prescribe an appropriate treatment regime.