Inflamation triggered by infection
Are psychiatric Autoimmune Diseases Caused by Infections?
I read about a newly discovered brain inflammation disease that can make someone have psychiatric symptoms. What can you tell me about this?
A: This sounds like anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, so that will be the topic of today’s column.
Anti-NMDAR encephalitis was first identified in 1997, but further characterized in an evaluation of four patients in 2005 and then a larger study of 100 patients in 2007. Although thousands of patients have now been diagnosed with this disease, it is thought that many more cases have gone undiagnosed due to lack of understanding and suspicion of this condition, as well as the fact that the symptoms can be very variable and mimic those of many other diseases. However, the development of better tests for anti-NMDAR encephalitis has increased the number of people being diagnosed with it.
This disease is most commonly diagnosed in young women (average age early 20s), but it can affect both sexes and patients of any age; it has been diagnosed in infants and in patients in their 80s. It is suspected that some historical cases of "demonic possession" may have actually been patients with this condition.
The classic symptoms of anti-NMDAR encephalitis are a flu-like illness which resolves, however the patient then develops memory loss, sleep disturbance, psychiatric symptoms (such as psychosis, anxiety, paranoia, mania, delusions and/or personality changes), seizures and/or movement disorders (abnormal movements of body parts). The symptoms can progress until the patient is in a coma. When the disease has progressed to this extreme extent, patients may require aggressive supportive care (including breathing support with a ventilator and nutritional support with artificial feedings) for weeks or months.
Anti-NDMAR encephalitis is an autoimmune disease, with the body’s own antibodies attacking some of the NDMA receptors in their own brain. These receptors play a crucial role in learning, memory and many other brain functions. Abnormalities in the NMDA receptor of some patients have been implicated in psychiatric diseases such as schizophrenia.
Over half of the patients with this disease are found to have teratomas, a tumor consisting of different types of tissues (such as skin, hair, muscle, nerve or other), caused by the independent encapsulated development of germ cells (the cells that give rise to the cells involved in sexual reproduction), or other tumors. Teratomas are identified in the testicles of 2 to 3 per 100,000 men, and are four times more common in the ovaries of women; one reason why anti-NDMR encephalitis may be more common in women. One possible explanation for the disease is cross reactivity of antibodies to some of the tissue in the teratoma with the brain receptors; anti-NMDAR antibodies are commonly identified in the tumors of patients with this condition. However, some patients do not have a tumor identified, so there may be other underlying causes as well.