Devic's disease
From Wikipedia, the free encyclopedia
| ICD-10 | G36.0 |
|---|---|
| ICD-9 | 341.0 |
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).
Devic's disease is an inflammatory disease of the central nervous system in which there are episodes of inflammation and damage to the myelin (fatty, protective covering of nerves) that almost exclusively affect the optic (eye) nerves and spinal cord. It usually causes temporary blindness, occasionally permanent, in one or both eyes. It can also lead to varying degrees of weakness or paralysis in the legs or arms, loss of sensation, and/or bladder and bowel dysfunction from spinal cord damage. A rare disorder which resembles multiple sclerosis (MS) in several ways, but requires a different course of treatment for optimal results.
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[edit] 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 this was the result of inflammation of the optic nerve and of spinal cord respectively.
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).
[edit] Diagnosis
The Mayo Clinic's new NMO guidelines:
Diagnosis requires absalute criteria PLUS at least two of three supportive criteria
Table 1.
ABSOLUTE CRITERIA
1. Optic Neuritis 2. Acute myelitis
SUPPORTIVE CRITERIA
1. Negative brain MRI at disease onset 2. Spinal cord MRI with contiguous T2-weighted signal abnormality extending over 3 or more vertebral segments 3. NMO-IgG seropositive status
Table 2.
NMO Spectrum Disorders (This means that ALL will fall under NMO umbrella)
- Neuromyelitis optica (2006 definition)
- Limited forms of NMO:
"Idiopathic" single or recurrent events of longitudinally extensive (3 or more vertebral segment spinal cord MRI lesion) Bilateral simultaneous or recurrent optic neuritis
- Asian optic-spinal MS
- Optic neuritis OR longitudinally extensive myelitis associated with systemic auto-immune disease
- Optic neuritis OR myelitis associated with "specific" NMO brain
lesions (hypo-thalamic, periventricular, brainstem)
TREATMENT
Acute optic neuritis OR myelitis:
1) Corticosteroids: IV methylprednisone 1000mg/d (or equivalent) for 5 or more days
2) Plasmapheresis for attacks that progress or are refractory to corticosteroid therapy
ATTACK PREVENTION
1) There no preventative therapies with efficacy demonstrated by controlled trials in NMO.
Most agree that long term immunosuppression is required for established NMO. It has also been recommended for NMO-IgG seropositive patients with single LETM episodes because of the high risk for relapse.
Current options include:
1) Azathioprine (2.5-3.0 mg/kg/d) plus prednisone (~1mg/kg/d to be tapered after azathioprine (imuran) is fully effective)
2) Mycophenolate mofetil 1000 mg BID plus prednisone as above
3) Rituximab (chimeric anti-CD20 monoclonal antibody)
4) Mitoxantrone
5) Intravenous immune globulin (IVIG)
6) Cyclophosphamide
The absolute and relative efficacy of these therapies have not been established, though promising results have been seen with one completed and one on-going Rituximab trial.
[edit] Symptoms
About one third of cases have preliminary symptoms of fever, myalgia, or headache. The typical patient has an acute and severe spastic weakness of the legs (paraparesis) or all four limbs (tetraparesis) with sensory signs, often accompanied by 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 visual acuity and colour vision and central hazy or opaque patches 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 recur with relapses and remissions. In about 80% cases, involvement of the cord and optic nerves occur within 3 months of each other.
[edit] 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, which are more frequent in neuromyelitis optica than in MS. Multiple sclerosis infrequently presents as transverse myelitis. Oligoclonal bands in the CSF, as well as 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 proposed, but no certain diagnostic features have been proved. Many sufferers are left with significant disabilities, requiring supportive and symptomatic treatment.
