Frequently Asked Questions – NMO FAQs

Based on years of funding basic and clinical scientific research, we’ve collected answers to some of the most frequently asked questions about neuromyelitis optica (NMO). Many of the topics here feature video interviews with leading scientists from organizations like Harvard University, Johns Hopkins, Mayo Clinic, UC San Francisco, UC Denver, and more.

What is NMO?

NMO stands for neuromyelitis optica. Once thought to be a type of multiple sclerosis (MS), neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorder (NMOSD) are variants of a distinctive but rare autoimmune disease. NMO is an inflammatory disease of the central nervous system (CNS) characterized mainly by attacks (relapses) of swelling and damage in the optic nerves (optic neuritis or ON) and spinal cord (transverse myelitis or TM). It can cause temporary or permanent blindness and/or paralysis, and may have periods of remission and relapse.

What causes NMO?

At present, the specific cause(s) of NMO are unknown. However, most experts believe that NMO results from a dysfunction in immune tolerance, which is the immune system’s ability to distinguish one’s own cells or proteins from potentially foreign materials. It is believed that autoreactive T and B cells, autoantibody, complement and leukocytes play a role in NMO.

How common is NMO?

This answer remains difficult to know precisely. However there is emerging evidence that the number of cases is considerably higher than known to date. This situation may be due to a previous lack of awareness of the disease, limited test methods that did not allow accurate diagnosis, and similarities that NMO shares with other autoimmune and neurologic conditions. Current studies indicate that the incidence (number of new cases) and prevalence (total number of known active cases) of NMO are significantly greater than originally estimated. Importantly, NMO is now becoming more effectively diagnosed thanks to new diagnostic methods, laboratory tests, and special imaging methods. Many of these tools have emerged in just the past several years, so the current estimates of NMO disease almost certainly do not reflect the actual incidence and prevalence of NMO worldwide.
Historically, the prevalence of NMO was estimated to be approximately 1-4 per 100,000. Today, due to improved awareness and advances in clinical diagnosis, research data estimate that NMO afflicts up to 10 in 100,000 persons. This rate suggests nearly 15,000 NMO patients in the U.S. alone, and hundreds of thousands of patients worldwide. Interestingly, the prevalence of NMO appears to vary in different regions and among distinct populations around the world. Because such population effects may result from heritable or environmental factors, this observation may provide new insights into the genetic contributions to NMO. NMO is more common in women than men, with a ratio of up to 7:1. NMO also appears to be more common among individuals having genetic ancestry including African, Asian, Pacific Island, Polynesian or Caribbean descent. However, all peoples can be affected by NMO and NMOSD.

How frequent are NMO relapses?

The time interval between relapses or attacks can range from days, weeks, months or even years apart. Some cases have been known to have attacks 15 years apart. In some patients there is only one episode (no relapses), but such cases are relatively uncommon.
Relapsing NMO is most common and identified by recurrent attacks separated by months or years. Attacks are usually followed by partial or complete recovery during periods of remission. This relapsing form of NMO appears to affect women 4 times more commonly than men. Unfortunately, in some severe cases of relapsing NMO, recovery may not occur following a relapse, causing permanent disability.
Monophasic NMO is less common and is usually characterized by a single, severe attack over a short period of time (days or weeks). As a rule, relapses do not occur in monophasic NMO. This form of NMO typically affects optic nerve(s) and the spinal cord. Interestingly, women and men tend to be equally affected by this form of NMO.
When a patient is first diagnosed with NMO, it is unclear whether they will experience a monophasic or relapsing course. In either scenario, accurate and rapid diagnosis of relapses is a key to minimizing severity and promoting recovery.

What are NMO symptoms?

NMO symptoms can vary from person to person and may resemble MS symptoms in many ways. NMO is most commonly characterized by inflammation of the spinal cord and/or optic nerves, causing any one or more of the following symptoms:

  • Rapid onset of eye pain or loss of vision (optic neuritis).
  • Limb weakness, numbness, or partial paralysis (transverse myelitis).
  • Shooting pain or tingling in the neck, back or abdomen.
  • Loss of bowel and bladder control.
  • Prolonged nausea, vomiting or hiccups.
  • Sometimes these symptoms are temporary, and resolve on their own. In any case, it is important to discuss these symptoms with your doctor to help consider NMO in your diagnosis.

How is NMO diagnosed?

There are currently several methods that can be utilized alone or together to diagnose NMO:

  • Specific laboratory tests that detect hallmark NMO IgG antibody (simple blood test).
  • Magnetic resonance imaging (MRI) to check for spinal cord lesions.
  • Ophthalmology studies such as optical coherence tomography (OTC) to check for telltale damage to the optic nerve or retina.
  • Tests to rule out other closely related disorders such as multiple sclerosis.

Is the NMO IgG antibody test foolproof?

No. Most NMO IgG tests list a 5-10% chance of a false-positive result, or a 20-30% chance of false negative result. The most commonly used laboratory test for NMO antibody was created in 2000 at the Mayo Clinic.

How do I get the NMO IgG antibody test?

Your primary care physician or neurologist can order the NMO IgG antibody test.

How can I help my primary care physician to consult with an NMO specialist?

The GJCF Connect the Docs webpage provides contact information for neurologists and other clinicians in the U.S. and throughout the world who specialize in diagnosing and treating NMO. Click here to view now.

My primary care physician has never heard of NMO. Does this make him/her a bad clinician?

No. Many clinicians and neurologists have never seen an NMO patient and are not aware of this rare disease. To view physicians that treat NMO, please visit Mapping NMO for more information.

Is there a possibility that NMO may be misdiagnosed as Multiple Sclerosis (MS)?

Yes. NMO is sometimes misdiagnosed as MS. The treatments for these distinct conditions can be very different, and recent reports suggest that some agents used to treat MS may be ineffective in NMO or actually make NMO symptoms worse.

Is NMO a form of Multiple Sclerosis (MS)?

Until recently, NMO was thought to be a type of Multiple Sclerosis. However, recent discoveries indicate that NMO and MS are distinct diseases. With so many symptoms in common, NMO can sometimes be confused with MS or other diseases. But these diseases are treated in different ways and early detection and treatment help ensure best outcomes. For these reasons, it is important to seek clinical care as soon as possible if symptoms occur.

How do clinicians treat NMO?

At present, treatment of NMO is targeted at two facets of the disease:

  • Control tissue inflammation and damage at onset or during relapse
  • Prevent further tissue damage by reducing the frequency of relapse

What are the treatments for NMO relapses?

Acute NMO relapses or attacks are often treated with: – Corticosteroids (steroid treatment) – Plasmapheresis (the removal of antibodies from the blood stream) Plasmapheresis is often used if steroid treatment is ineffective. Some clinicians use plasmapheresis on a limited scale in cases where patients show poor tolerance for other agents used to prevent relapses.

How are NMO relapses prevented?

The most common immunosuppressive agents used by NMO specialists to prevent NMO relapses include:

  • Azathioprine (trade name, Immuran; oral)
  • Mycophenolate (trade name, CellCept; oral)
  • Rituximab (trade name, Rituxan; intravenous infusion)
    Relapse prevention medications can be very helpful but may not be 100% effective.

Do clinicians prefer one drug treatment over another?

As with many aspects of medicine, neurologists including NMO specialists may have certain preferences for one treatment regimen over another. Selection of a treatment regimen depends on many individual factors such as symptoms, disease severity, whether the treatment is well-tolerated, cost, and other factors.

Do these treatments have dangerous side effects?

As with the treatment of any disease, certain NMO treatments can have side effects, including serious adverse events such as infection. However, recent reports suggest that treatment efficacy is improving, and the benefits far outweigh the negative side effects in preventing or resolving severe attacks. It is always best to consult with your physician and/or an NMO specialist to determine which treatment regimen may be best for you.

If taking immunosuppressive therapy, is it OK to take over-the-counter herbal remedies and/or vitamin supplements?

It is always best to consult with your physician and/or an NMO specialist regarding over-the-counter herbal remedies and/or vitamin supplements in relation to your NMO treatment regimen.

What are key points to keep in mind if I am taking immunosuppressive therapy?

All immunosuppressive therapies reduce the ability of your immune system to fight against infection and cancer. In addition, wound healing may be slower, and dental health compromised. Preventative exams such as mammograms, pap smears, dermatology full-body exams, and dental hygiene should be done regularly. It is also important to pay attention to public health hygiene by considering the basic rules of protecting yourself against transmissible diseases:

  • Wash your hands regularly and thoroughly with soap and water
  • Avoid touching your eyes, nose, mouth, or face
  • Avoid interacting with people who may be sick, coughing or sneezing
  • If you feel a cold or fever coming on, consult your physician immediately

How broken is my immune system if I have NMO?

The immune system is one of the most powerful yet mysterious of all the systems in the human body. Intensive research is being conducted to understand the specific causes of NMO, identify new and more effective treatments that prevent relapses, and ultimately find ways to reset the immune system with the intention to solve NMO. It may even be possible to use the immune system itself to do so.

Can tissues injured by NMO be repaired?

It is not known if the body can heal damage to the spinal cord, optic nerves or brain caused by NMO. It is possible that by preventing relapses, these tissues may repair themselves over time. However, it is also possible that tissue caused by NMO may be irreversible. Ongoing studies are being conducted to find ways to repair tissue damaged by NMO.

I haven’t had an NMO relapse for a long time, can I stop taking my medication or decrease its dosage?

Because NMO can stay in remission for long periods of time, even years, it is important to consult with your physician and/or an NMO specialist to determine ongoing therapy.

Should NMO patients receive vaccinations against COVID-19?

There are several good reasons why NMOSD patients should be vaccinated against COVID-19. Click here to learn more.

Should NMO patients receive standard vaccinations against infectious diseases?

Vaccinations are not known to cause NMO, and the benefits of immunization to protect against infection far outweigh risks. However, certain vaccines may not be advisable in the setting of specific types of immunosuppressive therapy. It is always best to consult with your physician and/or an NMO specialist to determine the best vaccine schedule in your case.

Are there specific agents approved by the Food and Drug Administration (FDA) to treat NMO?

After more than 100 years with no approved treatment, today there are three therapeutics for NMOSD which have been regulatory approved in the U.S. and other regions of the world. The Guthy-Jackson Charitable Foundation invites you to learn more about approved therapeutics for NMOSD from industry partners Alexion, Genentech, and Horizon Therapeutics (previously Viela Bio). Click here to learn more.

What are B cells and why are they important?

B cells are a special type of white blood cell that produces antibody. Because the NMO-IgG antibody is believed to play a role in causing NMO disease or relapse, B cells that make NMO-IgG are considered targets for NMO therapy. For example, rituximab targets and eliminates certain types of B cells that may produce NMO-IgG antibody. B cell monitoring is often used for patients after receiving rituximab infusions, which are often four-to-six months apart.

Can I get Stem-Cell treatment for NMO?

At the present time, the effectiveness of stem cell therapies for NMO is unknown. Consult with your physician and/or an NMO specialist.

Does one-step or monophasic NMO exist?

Usually NMO occurs as a series of episodes or relapses. However, in approximately 10% of patients, it appears that a form of monophasic NMO exists. These patients may suffer from an acute episode of optic neuritis in one or both eyes, and have other hallmark signs such as transverse myelitis, but have no relapses. However, it is difficult to tell if such patients are in a long remission period, or have the monophasic form of disease, so drug treatment is usually continued.

What is transverse myelitis?

Transverse myelitis is a medical term describing a condition in which inflammation is seen by MRI or other imaging methods to affect a section of the spinal cord. Inflammation can damage or destroy spinal cord, optic nerve, or brain tissue, including the protein insulation (myelin) that covers nerve cells.

What is optic neuritis?

Optic neuritis is caused by damage to the optic nerve due to acute or chronic inflammation. The optic nerve carries visual information from the eye to the brain. Inflammation of the optic nerve can cause damage to the myelin sheath covering it. Optic neuritis may occur in the form of loss of color vision, reduced visual field, and other symptoms. Optic neuritis is a serious condition that can lead to progressive vision loss or even blindness. Minimizing or preventing damage to the optic nerve is one of the primary reasons to seek medical care immediately if symptoms of optic neuritis occur or relapse.