DEAR DR. ROACH: My 28-year-old son is in the hospital. He hasn’t been acting like himself for a few weeks (not sleeping nor eating well), and he suddenly had four seizures. The doctors are worried about a condition called autoimmune encephalitis. What can you tell me about it? — J.M. ANSWER: Encephalitis means inflammation of the brain, which is a rare condition. It can be caused by infections (especially viruses) or autoimmune reactions, including antibody-mediated encephalitis. There are only 2,000 cases per year of antibody-mediated encephalitis in the United States.
Several different antibodies can be responsible, and each attacks a specific protein in the brain. At age 28, the most likely type of antibody causing antibody-mediated encephalitis is anti-NMDAR. With this syndrome, children and young adults often develop psychiatric symptoms including insomnia, abnormal movements, agitation, and sometimes hallucinations or delusions. Seizures are common.
The diagnosis is made by finding the antibody in cerebrospinal fluid after a lumbar puncture (“spinal tap”). Antibodies that are found in the blood are not as reliable. An MRI scan is also done to help confirm the diagnosis and exclude other causes.
Some cases of antibody-mediated encephalitis are associated with tumors. For example, young women with anti-NMDAR encephalitis have ovarian tumors over 50% of the time, while young men only have a tumor 5% to 10% of the time. Removing the tumor is important to improve outcomes because it also removes the trigger for the autoimmune disease.
Treatment is best when begun early and, like with many autoimmune diseases, when it is designed to reduce the immune system’s attacks on the body. This may include corticosteroids like prednisone, immune globulin, plasmapheresis (removing antibodies from the blood), or more powerful immune suppressants. With early treatment, most people do well but may still have residual problems.
