Neuromyelitis optica spectrum disorder (NMOSD) is a rare nerve disorder that requires immediate medical attention and treatment. Neuromyelitis optica spectrum disorder is an inflammatory disease that frequently affects the optic nerves and spinal cord. NMOSD often leads to sudden vision loss, paralysis or in some cases both. NMOSD is frequently mistaken for Multiple Sclerosis, as both conditions cause symptoms that may come and go over time. NMOSD is also known as Devic disease or Devic’s disease.
Neuromyelitis optica spectrum disorder is a relatively new term used to describe an emerging group of diseases. NMOSD includes a condition known as neuromyelitis optica, as well as a number of closely related diseases. NMOSD is considered a demyelinating autoimmune disease, which means that the body’s immune system attacks the myelin (or protective sheath) found in and around the nerves.
For 90% of diagnosed patients, NMOSD is a relapsing-remitting illness, akin to the most common forms of Multiple Sclerosis. This means that patients experience attacks (relapses) that can last days at a time. Relapses are often followed by periods of recovery (remissions) that can last weeks, months or even years. Each consecutive relapse can cause lasting damage to the health of the patient, and over time this compounding effect can lead to very serious and often life-altering disability.
Thankfully, NMOSD is a very rare disorder. Estimates vary, but approximately 20,000 people have been diagnosed with NMOSD in the United States, and the numbers are rising as doctors become better informed and equipped to more accurately diagnose the condition. To date, researchers, scientists and medical professionals have made the following observations about this rare nerve disorder:
- Gender: The most common and frequently diagnosed type of NMOSD affects women 4-10x more often than men.
- Age: NMOSD is diagnosed most often in middle aged men and women, generally between the ages of 45-65.
- Race: More white people than people of color have been diagnosed with NMOSD. At the same time, a significant number of people of color, particularly individuals of Asian or African descent, have been affected.
- Family history: Roughly 4% of patients diagnosed with NMOSD have a close relative that has been affected by the disorder. However, approximately ½ of those individuals have a personal or family history of another type of autoimmune disorder.
What causes NMOSD?
The root cause of NMOSD is unknown at this time. However, NMOSD frequently appears after an infection or alongside another type of autoimmune condition. However, researchers and scientists are starting to gain a better understanding of what occurs in the body of those affected. As you are likely aware, your immune system produces antibodies, which are proteins that are released into the bloodstream to fight infection. For individuals suffering from NMOSD, the body produces an antibody called AQP4-IgG, which then attacks a protein that helps distribute water across cell membranes.
What are the Symptoms of NMOSD?
NMOSD attacks can have serious and rather scary effects, including sudden vision loss or partial paralysis. Frequently observed symptoms in those suffering from NMOSD include:
- Blurry vision or blindness in one or both eyes
- Weakness or paralysis in the legs or arms
- Painful spasms
- Numbness or loss of sensation throughout the body
- Persistent nausea
- Uncontrollable vomiting
- Persistent hiccups
- Bladder or bowel dysfunction
- Sleeping problems
How is NMOSD Diagnosed?
Early diagnosis of NMOSD is extremely important, as a single NMOSD attack can increase the chances of lasting damage to your nervous system. Treatment may include a variety of health care specialists, including neurologists, radiologists, imaging specialists and rehabilitation therapists. A thorough diagnostic process includes:
- A full medical history and assessment of recent symptoms.
- A neurologic exam to measure muscle strength and coordination, identify any areas of numbness, and to assess an individual’s speech, vision, memory and mental skills.
- An MRI to look for damage to your optic nerves, spinal cord and brain.
- A spinal tap to examine the fluid surrounding your spinal cord and brain for signs of NMOSD.
- Eye tests to check for blurry vision or loss of color perception.
- Blood tests to look for the AQP4-IgG antibody, which is present in 70% of NMOSD cases.
If a patient tests positive for AQP4-IgG, the doctor may diagnose NMOSD if they have at least one of the following additional symptoms:
- Inflammation of your optic nerve (optic neuritis).
- Inflammation of your spinal cord (transverse myelitis).
- An episode of hiccups or nausea/vomiting with no other cause.
- A brain syndrome with lesions visible on an MRI that are consistent with NMOSD.
If a patient tests negative for AQP4-IgG, they will be diagnosed with NMOSD only if they experience optic neuritis, transverse myelitis and 1 other common NMOSD symptom.
What is the Treatment for NMOSD?
It’s critically important to treat an NMOSD attack as soon as possible, in order to reduce inflammation of the optic nerve and/or spinal cord. After experiencing a flare-up, your health care team will very likely recommend ongoing care to reduce the chances of a relapse. First line treatments may include:
- Anti-inflammatory medication: the doctor may prescribe a course of IV corticosteroids, such as methylprednisolone, to help reduce inflammation.
- Plasma exchange therapy (PLEX): In PLEX, the liquid part of your blood is separated from your blood cells and replaced with artificial plasma, which lowers the amount of AQP4-IgG antibody in your blood.
- Immunosuppression medications: If inflammation persists, medications may change how your immune system reacts to inflammation and prevent new attacks. Your health care providers will closely monitor you during this form of treatment, as immunosuppressants can place you at higher risk for infections and other complications.
Rehabilitation therapy and complementary care plays an important role in the management of NMOSD. Your health care providers can offer rehabilitation services and other therapies to help you manage long-term issues from NMOSD. These specialists and experts can help with issues related to:
Spasticity (muscle stiffness and spasms): They may recommend exercises and daily stretching to keep your muscles more flexible, and they may suggest splints at the ankles, wrists or elbows to help you continue with your daily activities.
Bladder and bowel problems: They can recommend a high-fiber diet and exercise to help with any digestive issues you may be experiencing, and there are medications that can help with issues like constipation or frequent urination.
Nerve pain: NMOSD attacks can cause long-term pain, numbness and other nerve issues. Your health care team can recommend medications and help you find providers of therapies like acupuncture and meditation, which can help NMOSD patients with long-term pain and the mental health issues that often come with it.
Depression: It’s normal to feel upset, sad or stressed after an NMOSD diagnosis. However, if your negative feelings interfere with your relationships or daily life, you may have depression that should be treated. Again, your health care team can help with mental health counselling and discuss with you any potential treatments with medication.