Devic’s disease is an inflammatory condition that affects the protective covering of spinal cord and optic nerves. It is also known as neuromyelitis optica (NMO).
Due to the part of the nerve affected by the condition, NMO is classified as a demyelinating disease. The protective covering of a nerve is formed from a substance called myelin. Demyelinating diseases target this covering.
The condition is extremely rare, affecting between 0.052 and 0.44 in every 100,000 people worldwide.
The disease is more common in people over 40 years of age.
This MNT Knowledge Center article will explain the types, causes, symptoms, and treatments for NMO, as well as explaining how the condition is diagnosed and ways it can complicate.
Fast facts on Devic’s disease
The two types of Devic’s disease, or neuromyelitis optica (NMO) are relapsing NMO and monophasic NMO, and the type depends on the frequency of attacks.
Symptoms can include a temporary loss of eyesight, eye pain, and altered sensations in the limbs.
The cause is unknown, and there is no cure.
Treatment aims to prevent relapses and control symptoms.
NMO damages the protective covering of the optic nerve and nerves in the spinal cord.
There are two types of NMO: Relapsing, which is the most common, and monophasic, which is rare.
With this type, there is an initial attack of inflammation in the optic nerve and spinal cord followed by attacks over a period of several years. Further research is required to confirm what triggers these attacks.
The individual may not be able to fully recover from the nerve damage caused by these attacks cause, and the damage is often permanent. This can cause disability and affects females more frequently than males.
A limited number of attacks is experienced over a period of days or weeks. There are no subsequent attacks. This form of NMO affects both sexes equally.
It is easier for an individual to recover from monophasic NMO.
The type of NMO will affect how severe symptoms are as well as the likelihood of complications and disability. Relapsing NMO is by far the most common, with 90 percent of people experiencing more than one attack.
Signs and symptoms of NMO vary. A person with NMO will experience at least one bout of inflammation of the optic nerve and spinal cord.
Symptoms of optic nerve inflammation, termed optic neuritis (ON), include:
temporary loss of eyesight affecting at least one eye, with a risk of permanent vision loss
swelling of the optic disc
pain in the eye that generally gets worse with movement, and tends to become more severe after a week then resolve in a few days
reduced sensitivity to color
People who develop optic neuritis should not drive a vehicle due to reduced vision. They may also develop symptoms in the spinal cord from a process called transverse myelitis (TM) including:
altered sensations, with sensitivity to temperature, numbness, tingling, and a sensation of coldness or burning
weak, heavy limbs, sometimes leading to total paralysis
changes in urination patterns, including urinary incontinence, difficulty urinating, and more frequent urination
fecal incontinence or constipation
A person with NMO may have just one mild attack of ON and one episode of TM, recover completely, or almost completely, and have no more relapses ever. Others may have several attacks throughout their life and experience lifelong disability.
NMO spectrum disorder is a term used for individuals who experience inflammation of either the optic nerve or spinal cord but not both.
In most cases, just the optic nerve and spinal cord are affected. In very rare cases, parts of the brain may also be affected. When the brain stem is affected, an individual may experience uncontrollable hiccups or vomiting.