Devic's disease, also known as neuromyelitis optica or NMO, is the simultaneous inflammation of the optic nerve (optic neuritis) and the spinal cord (myelitis).

Discovery

In 1870, Sir Thomas Clifford Allbutt first reported an association between myelitis and an optic nerve disorder. In 1894, Eugène Devic and his student Gault described 16 patients who had lost vision in one or both eyes and within weeks developed severe spastic weakness of the limbs, loss of sensation and often, bladder control. They recognized these were the result of inflammation, respectively of the optic nerve and spinal cord.

Similar instances of optic neuritis and myelitis were reported and many believed it constituted a distinct clinical entity. However some had pathology in other parts of the brain which was more suggestive of acute disseminated encephalomyelitis (ADEM), or multiple sclerosis(MS).

Symptoms

About one third of cases have preliminary symptoms of fever, myalgia, or headache. The typical patient has an acute and severe pastic weakness of the legs (paraparesis) or all four limbs (tetraparesis) with bd sensory signs, often accompanied with loss of bladder control. The disease develops over about one to fourteen days. Neuroimaging(MRI) excludes spinal cord compression. This weakness is preceded or succeeded by an acute unilateral or bilateral optic neuropathy with impaired acuity and colour vision and central hazy or opaque opatches of loss of vision, but there are no signs beyond the spinal cord or optic nerves. Some measure of improvement in a few weeks is the rule, but residual signs and disability may persist, sometimes severely.

The disease can be a single episode, or recurr with relapses and remissions. In about 80% cases, involvements of the cord and optic nerves occur within 3 months of each other.

Treatment

Treatment with short courses of high dosage intravenous steroids (methylprednisolone), plasma exchanges, or immunoglobulins may help to control the acute symptoms, but many trials contain very small numbers, and most are uncontrolled. Some recover, but many are left with impairment of vision and limbs, which can be severe.

Whether NMO is a distinct disease or part of the wide spectrum of multiple sclerosis is debated. Differences are the severe sequelae after an acute episode are more frequent in neuromyelitis optica than in MS. Multiple sclerosis infrequently presents as transverse myelitis. Oligoclonal bands in the CSF and white matter lesions on brain MRI are uncommon in neuromyelitis optica but occur in over 90% of MS patients.

NMO has been associated with many systemic diseases: collagen vascular diseases, autoantibody syndromes, infections——Varicella-zoster virus, Epstein-Barr virus, and HIV, and exposure to Clioquinol and Antituberculous drugs. These should be investigated when clinical features are suggestive.

Neuromyelitis optica emerges as a syndrome rather than a single disease. Separation from classic and variants of multiple sclerosis and variant forms of disseminated encephalomyelitis has been widely, but no certain diagnostic features have been proved. Many sufferers unfortunately are left with significant disabilities, requiring supportive and symptomatic treatment.