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Multiple system atrophy (MSA) is a degenerative disease of the central nervous system. Dejerine and Thomas in 1900 were the first to use the term olivopontocerebellar atrophy (OPCA) in two sporadic cases, 1 although Menzel described the first case in 1891. Shy and Drager in 1960 described four cases of a "neurological syndrome with orthostatic hypotension". 2 They defined the full syndrome comprising of orthostatic hypotension, urinary and rectal incontinence, loss of sweating, iris atrophy, external ocular palsies, rigidity, tremor, loss of associated movements, impotence, atonic bladder, loss of rectal sphincter tone, fasciculations, wasting of distal muscles, evidence of a neuropathic lesion in the electromyogram suggesting involvement of the anterior horn cells, and the finding of a neuropathic lesion in the muscle biopsy. Adams et al first described a syndrome designated striatonigral degeneration in the early 1960s. 3 These patients had mild autonomic failure and ataxia and were shown to have lesions in the olivopontocerebellar system. Graham and Oppenheimer first proposed the term multiple system atrophy in 1969 and suggested that OPCA, idiopathic orthostatic hypotension, the Shy-Drager syndrome, and striatonigral degeneration "are merely the expression of neuronal atrophy in a variety of overlapping combinations". 4
MSA is a sporadic disease. MSA was considered a rare disease but many patients with MSA are misdiagnosed as suffering from idiopathic Parkinson's disease. It is clear from a large postmortem series of parkinsonian brains that cases of MSA are more common than previously thought. Between 4% and 22% of the brains in parkinsonian brain banks have MSA. 5 According to one estimate the prevalence of MSA is 16.4 per 100000 population. Mean age of disease onset is 53 years (range 36-74) and the median disease duration to death is five years (range 1-11). Both sexes are affected equally. 6
Clinical features
MSA can cause any combination of parkinsonian, autonomic, pyramidal, and cerebellar signs. When parkinsonian features predominate, the term striatonigral degeneration is often used. When cerebellar features predominate, sporadic OPCA is often used. When autonomic failure predominates, the term Shy-Drager syndrome is often used. These manifestations may occur in various combinations and evolve with time.
"Red flags"-clinical features raising doubts about the diagnosis of idiopathic Parkinson's disease
Poor or absent levodopa response.
Lack of typical levodopa induced dyskinesias.
Atypical...