Neuromyelitis Optica Spectrum Disorder: A Rare Illness
Neuromyelitis optica spectrum disorder, also called Devic disease, is a central nervous system disorder that is characterized by optic nerve inflammation (optic neuritis) and spinal cord inflammation (myelitis).
Causes of Neuromyelitis Optica Spectrum Disorder
The cause of neuromyelitis optica spectrum disorder remains unknown; however, in some cases in may appear following an infection or be associated with another autoimmune disease.
It is considered an autoimmune disease, meaning that the immune system mistakenly attacks the body’s healthy tissues. In patients with neuromyelitis optica spectrum disorder, the immune system attacks a protein – aquaporin 4. This protein is found on the surface of astrocytes in the optic nerves, spinal cord and brain. Damage to these cells is believed to cause demyelination (damage to the myelin sheath surrounding the nerve fibers in the spinal cord, optic nerve and brain). In some individuals, the immune system mistakenly attacks a different protein found on the outer layer of myelin – myelin oligodendrocyte glycoprotein (MOG).
Researchers have also found that genetic factors may be involved in this disorder, as 3% of affected individuals have relatives with the condition.
Understanding the Symptoms
Typically, symptoms of neuromyelitis optica spectrum disorder begin during adulthood, although they can start at any age. Symptoms range in severity from mild to severe, and affect individuals differently:
- Optic neuritis (inflammation of the optic nerve)
- Acute transverse myelitis (inflammation of the spinal cord)
- Pain in the spine, arms, and/or legs
- Muscle spasms in the arms, and/or legs
- Weakness of the arms, and/or legs
- Loss of bladder or bowel control
- Nausea and/or vomiting
- Abnormal sensations
- Stiff neck
- Persistent hiccups
- Difficulty breathing (can be life threatening) when the part of the spinal cord responsible for breathing becomes inflamed.
In children, symptoms may look like:
Often people will have episodes of symptoms months, or even years, apart. This is the relapsing form of the disorder, while others will have a single episode of symptoms that persists for several months.
Neuromyelitis optica spectrum disorder progresses differently in each person. As the disease progresses, affected individuals may have short, frequent and painful muscle spasms. Over time, muscle weakness and loss of sensation in the limbs, blindness, and bowel and bladder dysfunction may become permanent, resulting in significant disability and reduced quality of life.
How Is It Diagnosed?
Diagnosis of this disorder begins with a detailed history of symptoms and physical examination, including a thorough neurological exam testing body movement, muscle coordination and strength, sensation, memory and cognitive function, speech, and vision. If neuromyelitis optica spectrum disorder is suspected, additional testing may be recommended:
- Blood tests
- Spinal tap to evaluate levels of proteins, immune cells and antibodies in the cerebrospinal fluid (CSF)
- Imaging studies (x-ray, MRI, and/or CT scan) of the brain, spinal cord and eyes
- Stimuli response test to determine how the body responds to sight, touch, and/or sound
It presents very similar to multiple sclerosis. Distinguishing between the two conditions ensures that the patient receives effective treatment.
There is currently no cure for neuromyelitis optica spectrum disorder, however, there are effective treatment options available to help manage symptoms and prevent future attacks.
High-dose steroids, including methylprednisolone, may be used initially to suppress the immune system to stop and prevent episodes. Pain medications may be used in the early stages to help control pain, and baclofen or tizanidine may be used to relieve muscle spasms. To help individuals with severe symptoms who have not responded to high dose steroids, plasma exchange, which is a procedure for removing excess proteins from the blood, may be utilized.
Various medications have been approved by the FDA for the treatment of adults with neuromyelitis optica spectrum disorder who are anti-aquaporin-4 (AQP4) antibody positive:
- Enspryng (satralizumab)
- Solaris (eculizumab)
- Uplizna (inebilizumab)
Treatment may involve various medical professionals including a neurologist, ophthalmologist, occupational therapy and physical therapist.
Neuromyelitis optica spectrum disorder is a rare disorder characterized by optic nerve and spinal cord inflammation, resulting in an array of disabling symptoms. If you suspect you may suffer from this condition, it is imperative to speak with your doctor to get an early and accurate diagnosis. There are various treatment options available to help get symptoms under control and prevent future episodes to help minimize the chance of severe disability and improve quality of life.