Neuromyelitis optica spectrum disorder (NMOSD) — also known as neuromyelitis optica (NMO) — is a rare autoimmune disorder that occurs when your immune system mistakenly attacks water channels in your brain and spinal cord, leading to damage to the nerves in your eyes and spinal cord.
Damage to the optic nerve can cause vision problems, including blindness, and damage to the spinal cord can cause muscle weakness, pain, stiffness, and loss of bladder or bowel control.
Although there is currently no cure for NMOSD, UPMC neurology experts can help you manage symptoms with medication, rehabilitation, and supportive care.
On this page:
What Is NMOSD?
Neuromyelitis optica spectrum disorder (NMOSD) — also known as neuromyelitis optica (NMO) — is a rare autoimmune disorder that occurs when your immune system mistakenly attacks water channels in your central nervous system, resulting in damage to the nerves in your eyes and spinal cord.
Damage to the optic nerve can cause vision problems. Damage to your spinal cord causes muscle weakness, pain, stiffness, and loss of bladder or bowel control.
What are the types of NMOSD?
- Seropositive NMOSD — Signs and symptoms of NMO with a positive aquaporin 4 (AQP4) antibody test. About 80% of patients with NMOSD are seropositive, and many standard treatments have the best evidence for this type.
- Seronegative NMOSD — Signs and symptoms of NMO without a positive aquaporin 4 (AQP4) antibody test. This represents about 20% of patients with NMOSD. Some of these patients will be positive for the MOG antibody test and have MOG associated disease (MOGAD). Other patients will not be positive for any known antibody.
How common is NMOSD?
NMOSD is rare, affecting approximately one to 10 people per 100,000 in the U.S. There is a up to a 10:1 female-to-male predominance in NMOSD diagnosis.
What causes NMOSD?
NMOSD occurs when your immune system mistakenly attacks your optic nerve and spinal cord.
In about 80% of cases of NMOSD, aquaporin-4 (AQP4) antibodies in your blood cause your immune system to attack your body’s AQP4 protein — a water channel in your brain and spinal cord — resulting in damage to your nervous system.
Although researchers aren’t sure exactly what causes these antibodies to develop, they believe it could be linked to genetics, a history of infection, or other autoimmune disorders, such as:
- Antiphospholipid syndrome.
- Lupus.
- Sjögren’s syndrome.
NMOSD risk factors
You may be at higher risk of NMOSD if you:
- Are 30 to 40 years of age.
- Are female.
- Are of African or Asian descent.
- Have another autoimmune disorder.
Complications of NMOSD
Complications of NMOSD include:
- Paralysis.
- Treatment-related side effects, such as an increased risk of infection.
- Vision loss.
How can I prevent NMOSD?
There is no way to prevent NMOSD; however, if you develop NMOSD, there are treatments available that help protect you from having disease flare-ups.
What Are the Signs and Symptoms of NMOSD?
NMOSD can cause symptoms ranging from mild to severe and affect the eyes, spinal cord, and brain.
The first attack typically occurs between the ages of 30 and 40. In most cases, symptoms begin suddenly and gradually worsen over days or weeks before improving.
Eye symptoms
Your optic nerve transmits visual information from your eyes to your brain. NMOSD causes inflammation of the optic nerve in one or both eyes, known as optic neuritis.
Optic neuritis may cause symptoms including:
- Blurred vision.
- Complete or partial vision loss.
- Difficulty seeing in low light.
- Pain, especially with eye movement.
Spinal cord symptoms
NMOSD causes inflammation in your spinal cord, known as myelitis.
Myelitis can prevent nerve signals from traveling to the rest of your body, causing symptoms including:
- Loss of bladder or bowel control.
- Muscle stiffness (spasticity).
- Muscle weakness.
- Pain.
- Paralysis.
- Sexual dysfunction.
Can people with NMOSD walk?
Some people with NMOSD can walk independently, whereas others may have difficulty and use a cane or walker for assistance. In other cases, people with NMOSD may experience complete paralysis that requires the use of a wheelchair.
Brain symptoms
NMOSD does not always affect your brain. However, when damage occurs in your brainstem, it can affect your body’s autonomic functions, which are those that occur without you having to think about them.
Symptoms of brainstem involvement include:
- Dizziness.
- Facial nerve pain (trigeminal neuralgia).
- Facial paralysis.
- Frequent, uncontrollable hiccups.
- Hearing loss.
- Loss of balance or coordination.
- Persistent nausea and vomiting.
- Deficient eye movements or double vision.
When should I see a doctor about my NMOSD symptoms?
If you have symptoms of NMOSD, you should schedule an appointment with your doctor right away. Early diagnosis and treatment can reduce the risk of permanent nerve damage.
How Do You Diagnose NMOSD?
To diagnose NMOSD, your doctor will perform physical and neurological examinations and review your symptoms and medical history. Your doctor will also order tests to confirm your diagnosis and rule out other problems.
What to expect during your visit
During your visit, your doctor will:
- Ask you about your symptoms.
- Order tests.
- Perform a physical and neurological exam.
- Review your medical history.
Tests to diagnose NMOSD
Your doctor may order tests to provide information or rule out other problems, including:
- Blood tests — Checks for AQP4 antibodies and rules out other conditions.
- Cerebral spinal fluid analysis (spinal tap or lumbar puncture) — Involves inserting a needle into your lower back to collect a sample of cerebrospinal fluid (CSF) for analysis in a lab.
- CT scan — Creates images of bones, organs, and tissues inside your body.
- Evoked potential test — Measures how quickly your brain responds to sights, sounds, and sensations.
- Magnetic resonance imaging (MRI) — Creates images of your brain and spine using contrast dye to look for damaged or abnormal areas.
- Neurological examination — Checks your reflexes, balance, movement, memory, and ability to think.
- Neuropsychological examination — Checks your ability to think, reason, and remember.
- Optical coherence tomography (OCT) — A noninvasive imaging test that uses reflected light to create images of nerve layers in the back of your eye.
NMOSD prognosis
Currently, there is no cure for NMOSD, and for most people, it is a lifelong condition. In severe cases, or if left untreated, it can cause permanent vision loss and movement problems. However, medications can reduce the risk of permanent damage and recurrence.
After receiving initial treatment for acute symptoms, most people need long-term treatment to reduce the risk of recurrence. You will need routine follow-up care and monitoring to reduce your risk of treatment-related side effects.
What is the life expectancy of a person with NMOSD?
Life expectancy with NMOSD is slightly lower than that of the general population, but it can vary depending on the severity of your condition, how soon you receive treatment, your overall health, and other factors.
How Do You Treat NMOSD?
Currently, there is no cure for NMOSD. Treatment typically includes:
- Acute treatment — Addresses immediate symptoms of an attack to reduce your risk of permanent damage.
- Long-term treatment — Reduces your risk of recurrence.
Treatment options may include:
Medications
Your doctor may prescribe corticosteroid or immunosuppressive medications to stop your immune system from attacking your nerves. These medications may be given through an IV or orally and can be used for both acute and long-term treatment.
Long-term treatment for NMOSD focuses on preventing relapses.
Before 2019, NMSOD was treated off-label with immunosuppressants and monoclonal antibodies to prevent relapses. Rituximab, a B-cell depleting antibody, was the most commonly used medication, as were azathioprine, mycophenolate mofetil, and long-term corticosteroids.
Now, newer FDA-approved medications have shown excellent effectiveness in treating NMSOD, with up to 100% of patients remaining relapse‑free for five years.
FDA‑approved medications for NMOSD include:
- Eculizumab
- Ravulizumab
- Satralizumab
However, these drugs are costly, so rituximab is still widely used as a more affordable off‑label option, even though it carries a higher risk of relapse. Compared with the FDA-approved drugs, which showed 100% effectiveness, 70% were relapse-free on rituximab, with even lower rates for mycophenolate mofetil and azathioprine.
Although these medications can treat symptoms and reduce your risk of NMOSD attacks, they also suppress your immune system. As a result, you may be at higher risk of infection, certain cancers, or other side effects.
Intravenous immunoglobulin therapy (IVIG)
During IVIG, you will receive an intravenous injection of donor immunoglobulins or antibodies. Immunoglobulins are a natural part of your immune system and protect your body by attacking foreign organisms. Immunoglobulins may prevent your immune system from further damaging your nerves.
Plasma exchange (plasmapheresis)
Plasmapheresis involves using a machine to separate the liquid part of your blood, called plasma, from your blood cells. Your plasma is then filtered to remove the antibodies that are causing nerve damage before being returned to your body.
Clinical trials
You may be eligible to participate in a clinical trial studying new treatments for NMOSD. Your doctor will let you know if you qualify for a clinical trial.
Why Choose UPMC for NMOSD Care?
When you choose UPMC for NMOSD care, you will receive:
- Multidisciplinary care — Our team of neurologists and autoimmune disease experts will work together to develop a customized treatment plan that reduces your risk of complications.
- Access to advanced clinical trials — Our team participates in national multicenter clinical trials evaluating new treatment options, allowing you to contribute to research that advances care for autoimmune disorders.
- Seamless, ongoing treatment — If you are diagnosed with NMOSD, our team will develop a plan for your follow-up care.
- Bench-to-bedside research — We have faculty members who are actively researching NMOSD and other neuroimmunologic disorders.
