Neuromyelitis optica causes symptoms similar to those of multiple sclerosis and used to be considered a variant of multiple sclerosis. However, neuromyelitis optica typically affects only the eyes and the spinal cord, and multiple sclerosis also affects the brain.
Neuromyelitis optica causes inflammation of the optic nerve (optic neuritis). One or both eyes may be affected. The disorder causes episodes of eye pain and dim, blurred, or lost vision. Days to weeks (sometimes years) later, the limbs are affected. People may temporarily lose sensation, and the arms and legs may become weak and sometimes paralyzed. People may be unable to control bladder and bowel function.
In some people, the part of the spinal cord that controls breathing is inflamed, leading to difficulty breathing, which is life threatening.
The disorder progresses differently in each person. As the disorder progresses, people may have brief, frequent, painful muscle spasms. Eventually, blindness, loss of sensation and muscle weakness in the limbs, and bladder and bowel dysfunction may become permanent.
To diagnose the disorder, doctors evaluate the nervous system (neurologic examination) during a physical examination (see Physical Examination). The optic nerve is examined with an ophthalmoscope (see What Is an Ophthalmoscope?). Tests include magnetic resonance imaging (MRI), evoked responses (see Evoked Responses), and a blood test to detect specific antibodies in people with neuromyelitis optica.
There is no cure. However, treatments can stop episodes, control symptoms, and prevent episodes from recurring. A corticosteroid (such as methylprednisolone) and a drug that suppresses the immune system (an immunosuppressant, such as azathioprine) are often used to stop and prevent episodes. Rituximab may be used to reduce the number of abnormal antibodies and to control the disorder. Plasma exchange may help people who do not respond to corticosteroids. For this treatment, blood is removed, then abnormal antibodies are removed, and the blood is returned to the person (see Sidebar 2: Controlling Diseases by Purifying the Blood).
Treatment of symptoms is similar to that for multiple sclerosis (see Treatment). Baclofen or tizanidine may relieve muscle spasms.
Last full review/revision April 2014 by Brian R. Apatoff, MD, PhD