Neuromyelitis optica

By Mayo Clinic Staff

Neuromyelitis optica (NMO) is a rare central nervous system condition. It causes inflammation in nerves of the eye and the spinal cord.

NMO also is called neuromyelitis optica spectrum disorder (NMOSD) or Devic disease. It happens when the immune system reacts to the body's own cells. That type of condition is called an autoimmune disease. NMO typically affects the spinal cord and the optic nerves that connect the retinas of the eyes to the brain. Sometimes it also can happen within the brain.

NMO may appear after an infection. Or it may be linked to another autoimmune condition. Neuromyelitis optica used to be considered a form of multiple sclerosis (MS), and it still sometimes may be diagnosed incorrectly as MS. But NMO is a condition separate from MS.

Neuromyelitis optica can cause blindness, weakness in the legs or arms, and painful spasms. It also can cause loss of feeling, vomiting, hiccups, and bladder or bowel symptoms.

Symptoms may get better and then get worse again. This is called a relapse. Treatment to prevent relapses is important to help prevent long-term health issues related to NMO.

Symptoms of neuromyelitis optica are caused by inflammation in the nerves of the eye and spinal cord.

Together, symptoms that affect the eye due to inflammation of the optic nerves are called optic neuritis. They may include:

• Blurred vision or loss of vision in one or both eyes.
• Not being able to see color.
• Eye pain.

Symptoms related to the spinal cord are collectively called transverse myelitis. These may include:

• Stiffness, weakness or numbness in the legs and sometimes in the arms.
• Loss of feeling in the arms or legs.
• Not being able to empty the bladder or trouble managing bowel or bladder function.
• A tingling feeling or shooting pain in the neck, back or stomach.

Other symptoms of NMO may include:

• Hiccups.
• Nausea and vomiting.

Children with NMO can have confusion, seizures or coma. But these symptoms in children are more common in a related condition called myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

Symptoms may get better and then get worse again. This is called a relapse. Relapses can happen after weeks, months or years. Over time, relapses can lead to total blindness or loss of feeling and mobility, known as paralysis.

Experts don't know exactly what causes neuromyelitis optica. In people who have this condition, the immune system attacks healthy tissues in the central nervous system. The central nervous system includes the spinal cord and brain, as well as the optic nerves that connect the retinas of the eyes to the brain. The immune system attack happens when an antibody called aquaporin-4-immunoglobulin G (AQP4-IgG) binds to proteins in the central nervous system. That causes swelling and inflammation. The inflammation then damages nerve cells.

Neuromyelitis optica is rare. Some factors that may raise the risk of getting NMO include:

• Sex assigned at birth. Those assigned female at birth have NMO more often than those assigned male at birth.
• Age. The average age at diagnosis is 40. But children and older adults also can have neuromyelitis optica.
• Race or ethnicity. People of Hispanic, Asian, African or Afro Caribbean descent have NMO at higher rates than do other people.

Some research suggests that not having enough vitamin D in the body, smoking and having few infections early in life also may raise the risk of neuromyelitis optica.

To diagnose neuromyelitis optica, a healthcare professional first reviews your medical history and symptoms and does a physical exam. That may include a neurological exam, which involves checking movement, muscle strength, coordination, sensation, memory, thinking, vision and speech.

If your healthcare professional suspects NMO based on symptoms, then you may have various tests. The diagnosis process includes ruling out other nervous system conditions that have similar symptoms.

Tests to diagnose neuromyelitis optica may include:

• Blood tests. A blood test can be done to look for the antibody that binds to proteins and causes NMO. That antibody is called aquaporin-4-immunoglobulin G (AQP4-IgG). Testing for this antibody can tell the difference between NMO and MS and make an early diagnosis of NMO.

  Blood tests also may be done to diagnose an NMO relapse. Those tests look for substances, called biomarkers, such as serum glial fibrillary acidic protein (GFAP) and serum neurofilament light chain. A test for myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) antibody also might be used to check for another inflammatory condition that has symptoms like those of NMO.

• MRI. This imaging test uses a magnetic field and radio waves to create a detailed view of organs inside the body. The results may show lesions or damaged areas in the brain, optic nerves or spinal cord.
• Lumbar puncture, also called a spinal tap. During this test, a needle is put into the lower back to remove a small amount of spinal fluid. This test shows the levels of immune cells, proteins and antibodies in the fluid. The test can help show whether symptoms are being caused by NMO or by MS.
• Optical coherence tomography. This test looks at the retinal nerve fiber layer and its thickness. People who have inflamed optic nerves from NMO have more vision loss and retinal nerve thinning than do people with MS.

• Stimuli response test. To learn how well the brain responds to stimuli such as sounds, sights or touch, a test called an evoked potentials test or evoked response test may be used.

  For this test, wires called electrodes are attached to the scalp and, sometimes, the earlobes, neck, arms, legs and back. Equipment attached to the electrodes records the brain's responses to stimuli. These tests help find lesions or damaged areas in the nerves, spinal cord, optic nerve, brain or brainstem.

Neuromyelitis optica can't be cured. But treatment sometimes can lead to long periods with no symptoms, called remission. NMO treatment involves therapies to ease symptoms and lower the risk of relapse.

• Easing symptoms. In the early stage of an NMO attack, a healthcare professional might give a corticosteroid medicine such as methylprednisolone (Solu-Medrol) to reduce symptoms. It's given through a vein in the arm. The medicine is taken for about five days. Typically, it's then tapered off slowly over several days.

  Plasma exchange often is recommended as treatment, usually in addition to corticosteroids. In this procedure, some blood is taken from the body, and blood cells are mechanically separated from the fluid in the blood called plasma. The blood cells are mixed with a replacement fluid, and the blood is returned to the body. This process can remove harmful substances from the blood.

• Lowering the risk of relapses. A lower dose of corticosteroids taken over time may help prevent future NMO attacks.

  Medicines called monoclonal antibodies have been shown to be effective in lowering the risk of NMO relapses in adults. These medicines include:

  • Eculizumab (Soliris).
  • Inebilizumab (Uplizna).
  • Ravulizumab (Ultomiris).
  • Rituximab (Rituxan).
  • Satralizumab (Enspryng).

  Medicines that suppress the immune system also may help prevent relapses. Those medicines include:

  • Azathioprine (Imuran, Azasan).
  • Mycophenolate mofetil (Cellcept, Myhibbin).
  • Methotrexate (Trexall, Xatmep, others).
  • Tocilizumab (Actemra).

  Medicine called intravenous immunoglobulins (IVIg) also may lower the number of NMO relapses.

You're likely to start by seeing your primary healthcare professional. But when you call to make an appointment, you may be referred to a doctor trained in brain and nervous system conditions, called a neurologist.

When you make the appointment, ask if there's anything you need to do beforehand, such as not eat or drink before a test. Make a list of:

• Your symptoms, including any that don't seem related to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins and other supplements you take, including the doses.
• Questions to ask your healthcare professional.

Take a family member or friend along, if possible, to help you remember the information you're given.

For neuromyelitis optica, some basic questions to ask your healthcare professional include:

• What's likely causing my symptoms?
• Other than the most likely cause, what are other possible causes for my symptoms?
• What tests do I need?
• What's the best course of action?
• What are the alternatives to the primary approach you're suggesting?
• I have other health conditions. How can I best manage them together?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Are there brochures or other printed material I can have? What websites do you recommend?

Be sure to ask any other questions you may have.

Your healthcare professional is likely to ask you some questions, such as:

• When did your symptoms begin?
• Do you have symptoms all the time or do they come and go?
• How bad are your symptoms?
• What, if anything, seems to make your symptoms better?
• What, if anything, seems to make your symptoms worse?