It is also known as Devic’s disease. It is not very common; only about 4,000 people in the United States have it.
Neuromyelitis Optica, or NMO, is a disease that affects the eyes and spinal cord.
NMO occurs because your body’s immune system attacks healthy cells in your central nervous system (your brain and spinal cord).
These attacks can occur over days or weeks, called monophasic NMO. Or it may be a long time between episodes, even months or years. This is called recurrent NMO. With recurrent NMO, symptoms go away, but they can come back and worsen over time.
Men and women are equally likely to get the monophasic type, but women have recurrent NMO much more often than men. Children can get the disease too.
The NMO is not EM
Another condition that causes inflammation and can make movement difficult is multiple sclerosis (MS). Doctors used to think that NMO was a type of MS. Now research shows that they are different:
- MS usually occurs more slowly and for a longer time.
- There is a blood test for NMO, but there is no blood test for MS.
- With NMO, you may have nausea, vomiting, and hiccups. This usually does not happen with MS.
Causes of neuromyelitis optica
Doctors are not sure what causes NMO. It does not appear to be inherited, but many people who have it also have other autoimmune diseases, in which their body mistakenly attacks healthy cells.
Or they may have family members who do. Some examples of autoimmune diseases are type 1 diabetes, rheumatoid arthritis, psoriasis, and vitiligo.
Symptoms of neuromyelitis optica (NMO) can include all of the following, although visual symptoms and spinal cord inflammation ( transverse myelitis ) are primary. Sudden vision changes caused by optic neuritis include:
- Loss or blurriness of vision in one or both eyes.
- Loss of color vision.
- Eye pain.
Changes in sensation and function in the extremities caused by transverse myelitis, which generally affects multiple levels in the spinal cord, include:
- Soft spot.
- Numbness (loss of sensation).
- Loss of function (paralysis).
- Loss of bladder control.
- Retention of urine or difficulty emptying the bladder.
- Spasticity (increased tone or stiffness in the extremities).
- Shooting or tingling pain in the neck, back, or abdomen.
- Uncontrollable nausea and vomiting.
- Confusion, seizures, or coma can occur in children.
Diagnosis of neuromyelitis optica
Early diagnosis of NMO is critical. Unlike MS, episodes of NMO are usually quite severe. If left untreated, these episodes can have devastating and irreversible effects.
The diagnosis of NMO requires evidence of optic neuritis and transverse myelitis. Additional findings supporting the diagnosis of NMO include:
- MRI findings of the brain that do not meet the criteria for MS.
- Distinctive and elongated lesions in the spinal cord (called extensive longitudinal transverse myelitis (MTLE)).
The diagnostic process includes:
- Medical history.
- Neurological examination: A neurologist examines the person’s mobility, muscle strength, coordination, sensation, memory, and the functions of thinking, speech, and vision.
- Magnetic resonance imaging (MRI) of the brain, optic nerves, and spinal cord.
- Spinal tap (lumbar puncture) to examine the cerebrospinal fluid.
- Ophthalmology studies (eyes and vision); Optical coherence tomography (OCT).
- Blood tests for NMO-IgG. 70% of people with NMO test positive for aquaporin antigen 4 (NMO-IgG) antibodies. The percentage of positive results is lower in people with more limited forms of NMO, such as isolated optic neuritis or transverse myelitis.
- Evoked potential (EP) tests help detect lesions or damaged areas in the nerves, spinal cord, optic nerve, or brainstem.
There is no cure for neuromyelitis Optica (NMO), and no medications have been specifically approved to treat it. The standard of care for an initial NMO attack includes the following:
- High-dose intravenous corticosteroids (methylprednisolone).
- Plasma exchange (PLEX) if no improvement with corticosteroids. The goal of PLEX is to lower the level of NMO-IgG in the blood. PLEX involves drawing blood from the body through a needle and tube.
Because the probability of recurrence is greater than 90% and the attacks are generally severe, continuous treatment is considered necessary to suppress the immune system. The following medications are used for maintenance therapy:
- Mycophenolate mofetil (CellCept).
- Rituximab (Rituxan).
- Azatioprina (Imuran, Azasan).