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Neuromyelitis Optica Spectrum Disorder (NMOSD)

(Neuromyelitis Optica; Devic Disease)


Michael C. Levin

, MD, College of Medicine, University of Saskatchewan

Reviewed/Revised May 2023
Topic Resources

Neuromyelitis optica spectrum disorder affects mainly the nerves in the eyes and spinal cord, causing patches of myelin (the substance that covers most nerve fibers) and the nerve fibers under them to be damaged or destroyed.

Nerve Cells and Fibers

The risk of becoming disabled is greater with neuromyelitis optica spectrum disorder than with multiple sclerosis. Thus, people with symptoms suggesting neuromyelitis optica spectrum disorder should see a doctor promptly.

Insulating a Nerve Fiber

Most nerve fibers inside and outside the brain are wrapped with many layers of tissue composed of a fat (lipoprotein) called myelin. These layers form the myelin sheath. Much like the insulation around an electrical wire, the myelin sheath enables nerve signals (electrical impulses) to be conducted along the nerve fiber with speed and accuracy. When the myelin sheath is damaged (called demyelination), nerves do not conduct electrical impulses normally.

Insulating a Nerve Fiber

Neuromyelitis optica spectrum disorder is also an autoimmune disorder Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers an autoimmune disorder is not known. Symptoms vary depending... read more . Autoimmune disorders occur when the immune system malfunctions and attacks the body’s own tissues. In neuromyelitis optica spectrum disorder, the target of the autoimmune attack is one of the following proteins:

Damage to astrocytes or oligodendrocytes is thought to lead to demyelination. In some people with neuromyelitis optica spectrum disorder, the immune system targets another protein called myelin oligodendrocyte glycoprotein (MOG), which is present on the outer layer of myelin.

Symptoms of NMOSD

Neuromyelitis optica spectrum disorder causes inflammation of the optic nerve (optic neuritis Optic Neuritis Optic neuritis is inflammation of the optic nerve. Multiple sclerosis is the most common cause. Loss of vision may develop, and there may be pain with eye movement. Magnetic resonance imaging... read more ). One or both eyes may be affected. The disorder causes episodes of eye pain and dim, blurred, or lost vision.

Some people have hiccups that will not stop (persistent or intractable hiccups Causes ) or nausea and vomiting.

In some people, the part of the spinal cord that controls breathing is inflamed, leading to difficulty breathing, which is life threatening.

Neuromyelitis optica spectrum 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.

Diagnosis of NMOSD

  • A doctor's evaluation

  • Magnetic resonance imaging

  • Visual evoked responses

  • Blood tests

When the visual evoked responses test is used to diagnose neuromyelitis optica spectrum disorder, stimuli for sight (such as a flashing light) are used to activate certain areas of the brain. Then, electroencephalography Electroencephalography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more Electroencephalography is used to detect the response to the stimuli. Based on these responses, doctors can tell how well the optic nerve is working.

Blood tests to detect specific antibodies to aquaporin 4 and to myelin oligodendrocyte glycoprotein may be done to distinguish neuromyelitis optica spectrum disorder from multiple sclerosis. (Antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more Antibodies are proteins produced by the immune system to help defend the body against a particular attacker.)

Treatment of NMOSD

  • Corticosteroids

  • Plasma exchange

  • Medications that suppress the immune system

There is no cure for neuromyelitis optica spectrum disorder. However, treatments can stop episodes, control symptoms, prevent episodes from recurring, and may help delay disability in the short term.

A corticosteroid (such as methylprednisolone) and a medication that suppresses the immune system (an immunosuppressant, such as azathioprine) are often used to stop and prevent episodes.

Eculizumab (another monoclonal antibody) can sometimes help. This medication suppresses complement, which is a component of the immune system. Side effects of this medication include life-threatening meningococcal meningitis Meningococcal Infections Meningococcal infections are caused by the bacteria Neisseria meningitidis (meningococci) and include meningitis and sepsis. Infection is spread by direct contact with nasal and throat... read more Meningococcal Infections , pneumonia, upper respiratory infections, and headache. Doctors usually give people who take eculizumab the meningococcal vaccine Meningococcal Vaccine The meningococcal vaccine protects against infections caused by the bacteria Neisseria meningitidis (meningococci). Meningococcal infections can lead to meningitis (an infection of tissue... read more and closely monitor them.

Satralizumab and inebilizumab (both monoclonal antibodies) can be used to treat neuromyelitis optica spectrum disorder when aquaporin-4 antibodies are present. People taking these medications are closely monitored for infections, such as urinary tract and respiratory infections.

Drugs Mentioned In This Article

Generic Name Select Brand Names
A-Methapred, Depmedalone-40, Depmedalone-80 , Depo-Medrol, Medrol, Medrol Dosepak, Solu-Medrol
Azasan, Imuran
RIABNI, Rituxan, RUXIENCE, truxima
ED Baclofen, FLEQSUVY, Gablofen, Lioresal, Lioresal Intrathecal, LYVISPAH, OZOBAX, OZOBAX DS
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