Neuromyelitis Optica (NMO)
Neuromyelitis optica (NMO) is a rare autoimmune disease that primarily damages the optic nerves (sight) and spinal cord but may also damage the brain.
What is Neuromyelitis Optica (NMO)?
This autoimmune, brain disease can occur in children when the body’s immune system mistakenly attacks its own optic nerves and spinal cord. These attacks cause inflammation (swelling) that primarily affects how sight is transmitted and understood by the brain.
NMO (also known as Devic’s disease) was once thought to be a symptom of multiple sclerosis (MS). However, recent research has shown that the autoimmune attack that triggers NMO is specific to a molecule (aquaporin 4), which is different than the MS trigger.
Approximately 4,000 people in the U.S. and 250,0000 worldwide have NMO. It can occur at any age (as young as age 3), although it is typically diagnosed between the ages of 40 and 50. It is also the most common type of demyelinating disease (damage to the myelin around the nerves) in those of African, Asian and Native American descent. Myelin acts as insulation (like a plastic covering on electrical wires), allowing the body’s electrical impulses that control normal functions to activate. When the myelin is damaged, it can slow down the body’s internal communication that manages movements and reactions.
What are the different types of Neuromyelitis Optica (NMO)?
Neuromyelitis optica has two forms.
This is the most common form and means symptoms are worse at times (relapse); this occurs in 70% of patients after the initial physical signs. Symptoms can disappear or improve at other times (remitting). It most often occurs in women (at least 80% of cases).
Causes a single (mono) symptom period (phase) that can last several months. It equally impacts men and women.
What are the signs and symptoms of Neuromyelitis Optica (NMO)?
Symptoms of NMO can range in frequency and severity. New, repeated or continual damage from long-lasting episodes can occur in the optic nerve and/or the spinal cord, which can lead to long-term health challenges.
- Bladder and bowel problems
- Blurry, loss of color or loss of vision (can be in one or both eyes)
- Eye pain and swelling
- Numbness in the extremities (arms, fingers, legs and toes)
- Nausea and vomiting
- Paraparesis (weakness or paralysis in the legs or arms)
- Spasticity (involuntary, continually tense muscles)
- Uncontrollable hiccups
What are the causes of Neuromyelitis Optica (NMO)?
The exact cause of NMO is unknown, but scientists believe there may be a combination of factors that trigger the autoimmune responses that cause damage.
- Viral and bacterial diseases – In some cases, tuberculosis (TB) and other infections like varicella (chicken pox), syphilis and Epstein-Barr virus (mono) have also been linked with NMO.
- Genetics – If someone in a family has NMO, it is not guaranteed that family members will inherit it, but there is an increased risk of developing it.