Who’s at Risk
An autoimmune disorder is a condition in which the body mistakenly attacks its own healthy cells. And OMS is an autoimmune disorder that occurs when the body produces antibodies (immune proteins) in response to either a viral infection or a tumor called a neuroblastoma.
OMS occurs when the antibodies also attack brain cells in the cerebral cortex and the cerebellum. The resulting damage in the brain produces the symptoms.
While it is rare, OMS affects children more than any other age group. Neuroblastoma occurs during the toddler years, and about 4% of children who have this tumor will develop OMS. Any child who has symptoms of OMS will be tested to see if they have a tumor, even if they are sick with a viral infection.
Treatment
Early diagnosis and treatment are the best ways to achieve neurological remission and recovery. If a child has OMS and has a tumor, the tumor is usually surgically removed. Sometimes this improves or eliminates symptoms.
Typically, these tumors are discovered in the early stages, and chemotherapy or radiation therapy is not required.
In adults, tumor removal often does not help, and the symptoms may even get worse.
Other treatments used for children and adults include:
Adrenocorticotrophic hormone (ACTH) injections Intravenous immunoglobulins, commercial preparations of antibodies from healthy blood donors Imuran (azathioprine), suppresses the immune system, which slows the production of antibodies Oral and intravenous steroids, such as prednisone, dexamethasone, and hydrocortisone Chemotherapy such as cyclophosphamide, doxorubicin, and vincristine for children with neuroblastoma Therapeutic apheresis, exchanging blood plasma Immunoadsorption, cleaning the antibodies out of the blood has been tried in adults with OMS.
Ongoing treatments are often needed to continually manage symptoms and minimize the risk of the tumor returning.
Prognosis
People with the greatest chance of returning to normal after treatment are those who have the mildest symptoms.
Children may have permanent brain damage that may cause physical and mental disabilities. Other problems that come from the inflammatory brain injury can include learning and behavior problems, attention-deficit hyperactivity disorder (ADHD), and obsessive-compulsive disorder. These may need to be managed as well.
Those with more severe symptoms may have relief of muscle twitching (myoclonus) but are more likely to continue to have difficulty with coordination.
Prevalence
Opsoclonus-Myoclonus Syndrome is very rare. It has been estimated to affect between one in 1 million to one in 10 million people. And it is estimated that approximately one to 300 people in the U.S. have OMS. It is typically seen in children, but it can affect adults as well. It occurs slightly more often in girls than in boys and is usually diagnosed between 6 months to two years of age.
