What Is Neuromyelitis Optica?

Medically Reviewed by Christopher Melinosky, MD on October 25, 2023
Written by WebMD Editorial Contributors
3 min read

Neuromyelitis optica, or NMO,  is also called neuromyelitis optica spectrum disorder (NMOSD) and Devic disease. It is a disease that affects your eyes and spinal cord. It's not very common -- only about 4,000 people in the United States have it.

NMO happens because your body's immune system attacks healthy cells in your central nervous system (your brain and your spinal cord). These attacks can happen over days or weeks -- this is called monophasic NMO. Or you may go a long time between attacks, even months or years. This is called relapsing NMO. With relapsing NMO, symptoms go away but can come back and get worse over time.

Men and women are equally likely to get the monophasic type, but women get relapsing NMO much more often than men. Children also can get the disease.

The signs of NMO fall into two categories. See your doctor if you have any of these symptoms:

  • Optic neuritis: inflammation of the optic nerve (this carries information from your eye to your brain). You might feel sudden pain inside your eye. That can be followed by problems like not seeing clearly or even blindness. It usually happens only in one eye, but it can happen in both.
  • Transverse myelitis: inflammation of the spinal cord. This can cause problems with your arms and legs, including pain, weakness, numbness, or paralysis. It also can lead to loss of control of your bladder and bowel. You could have nausea, vomiting, hiccups, a stiff neck, or a headache.

Children who have NMO may seem confused, have seizures, or fall into a coma.

Another condition that also causes inflammation and can make it hard to move is multiple sclerosis (MS). Doctors used to think NMO was a type of MS. Now research shows they're different:

  • MS usually happens more slowly and over a longer time.
  • There is a blood test for NMO, but there is no blood test for MS.
  • An MRI of the brain usually looks normal when you first get NMO but not with MS.
  • With NMO, you might have nausea, vomiting, and hiccups. This doesn't usually happen with MS.

Doctors aren't sure what causes NMO. It doesn't seem to run in families, but many people who have it also have other autoimmune diseases, in which your body mistakenly attacks healthy cells. Or they may have family members who have them. Some examples of autoimmune diseases are type 1 diabetes, rheumatoid arthritis, psoriasis, and vitiligo.

Your doctor will examine you and check your thinking, vision, speech, strength, and reflexes. They may want to test fluid from your spine and your blood. More than 70% of people who have NMO have a certain protein in their blood called an antibody.

Your doctor also may want to look at your spine to see if it's inflamed. One way to do that is with a test called an MRI (magnetic resonance imaging). It uses a large magnet and a computer to create an image of your spinal cord.

You also might need to see a doctor who specializes in treating eyes (ophthalmologist) and have an optical coherence tomography (OCT) to check for damage to the optic nerve.

There's no cure for NMO, but there are medicines and other treatments that can help ease your symptoms, including:

Drugs to prevent attacks. The FDA has recently approved three drugs to treat it. Eculizumab (Soliris), inebilizumab-cdon (Uplizna), and satralizumab-mwge (Enspryng) work by targeting the defective antibodies that attack the healthy cells in your body, triggering NMO. Your doctor may prescribe you other drugs to suppress your immune system. 

Steroids. Your doctor will likely give you steroids or corticosteroids that help with inflammation. Other drugs may help keep your body from fighting off the good cells and prevent future attacks. You'll get them into a vein in your arm through an IV.

Plasma exchange. Called plasmapheresis., this removes harmful antibodies from the blood. A machine separates the different parts of your blood, then your plasma is replaced with a substitute. After that, the new blood is put back into your body.