Opsoclonus-Myoclonus Syndrome Symptoms and Treatment

Opsoclonus-myoclonus syndrome (OMS) is an inflammatory neurological disorder. It causes significant issues with motor skills, eye movements, behavior, language disturbances, and sleep problems. It often comes on very suddenly and is typically chronic; if you have been diagnosed with opsoclonus-myoclonus syndrome, it will likely last throughout your whole life. Its name describes its symptoms: opsoclonus is jiggling eye movements and myoclonus means involuntary muscle twitching. It is also known as "Kinsbourne syndrome" or "dancing-eyes-dancing-feet."

Who's at Risk

In an autoimmune disorder, the body attacks its own healthy cells. Opsoclonus-myoclonus syndrome results from an autoimmune disorder in which the body's antibodies are responding to either a viral infection or a tumor called a neuroblastoma. In either case, the antibodies end up attacking the brain cells as well, and this causes the damage that produces the symptoms.

Opsoclonus-myoclonus syndrome occurs most often in children. Toddlers are the age group in which neuroblastoma most often develops; about 4% of these children will develop OMS. Any child who has OMS will be tested to see if she or he has a tumor, even if sick with a viral infection since the two so often go together.

Treatment

The main concern with opsoclonus-myoclonus syndrome is early diagnosis and treatment in order to achieve neurological remission and recovery. If a child has opsoclonus-myoclonus syndrome and has a tumor, the tumor is usually surgically removed. Typically, the tumors are in the early stages and chemotherapy or radiation therapy is not required. Sometimes this improves or eliminates symptoms. In adults, tumor removal often does not help and the symptoms may even get worse.

Other treatments include:

• Adrenocorticotrophic hormone (ACTH) injections
• Intravenous immunoglobulins, commercial preparations of antibodies from healthy blood donors
• Azathioprine (Imuran), suppresses the immune system, which slows the production of antibodies
• Oral and intravenous steroids, such as prednisone, dexamethasone, and hydrocortisone
• Chemotherapy such as cyclophosphamide and methotrexate, 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. Those with more severe symptoms may have relief of their muscle twitching (myoclonus) but have difficulty with coordination. Other problems that come from brain injury, such as learning and behavior problems, attention-deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder, may occur, and these may need their own treatments. Children with the most severe OMS symptoms may have permanent brain damage that may cause physical and mental disabilities.

Prevalence

Opsoclonus-Myoclonus Syndrome is very rare; only 1 million individuals are believed to have the issue in the world. It is typically seen in children and adults, but it can affect adults as well. It occurs slightly more often in girls than in boys and is usually only diagnosed after 6 months of age.