Multiple system atrophy is a relentlessly progressive neurodegenerative disorder causing pyramidal, cerebellar, and autonomic dysfunction. It includes 3 disorders previously thought to be distinct: olivopontocerebellar atrophy, striatonigral degeneration, and Shy-Drager syndrome. Symptoms include hypotension, urinary retention, constipation, ataxia, rigidity, and postural instability. Diagnosis is clinical. Treatment is symptomatic, with volume expansion, compression garments, and vasoconstrictor drugs.
Multiple system atrophy affects about twice as many men as women. Mean age at onset is about 53 yr; after symptoms appear, patients live about 9 to 10 yr.
Etiology is unknown, but neuronal degeneration occurs in several areas of the brain; the area and amount damaged determine initial symptoms. A characteristic finding is cytoplasmic inclusion bodies containing α-synuclein within oligodendroglial cells.
Symptoms and Signs
Initial symptoms vary but include a combination of parkinsonism unresponsive to levodopa, cerebellar abnormalities, and symptoms due to autonomic insufficiency.
These symptoms predominate in striatonigral degeneration. They include rigidity, bradykinesia, postural instability, and jerky postural tremor. High-pitched, quavering dysarthria is common. In contrast to Parkinson disease, multiple system atrophy usually does not cause resting tremor and dyskinesia, and symptoms respond poorly and transiently to levodopa.
These abnormalities predominate in olivopontocerebellar atrophy. They include ataxia, dysmetria, dysdiadochokinesia (difficulty performing rapidly alternating movements), poor coordination, and abnormal eye movements.
Typically, autonomic insufficiency causes orthostatic hypotension (symptomatic fall in BP when a person stands, often with syncope—see Orthostatic Hypotension), urinary retention or incontinence, constipation, and erectile dysfunction.
Other autonomic symptoms, which may occur early or late, include decreased sweating, difficulty breathing and swallowing, fecal incontinence, and decreased tearing and salivation. REM sleep behavior disorder (eg, speech or skeletal muscle movement during REM sleep) and respiratory stridor are common. Patients are often unaware of REM sleep behavior disorder. Patients may have nocturnal polyuria; contributing factors may include a circadian decrease in argininevasopressin and treatments used to increase blood volume.
Diagnosis is suspected clinically, based on the combination of autonomic insufficiency and parkinsonism or cerebellar symptoms. Similar symptoms may result from Parkinson disease, Lewy body dementia, pure autonomic failure, autonomic neuropathies, progressive supranuclear palsy, multiple cerebral infarcts, or drug-induced parkinsonism.
No diagnostic test is definitive, but some (eg, MRI, nuclear imaging with 123I-metaiodobenzylguanidine [MIBG], autonomic tests) help confirm clinical suspicion of multiple system atrophy—for example, if
There is no specific treatment, but symptoms are managed as follows:
Last full review/revision April 2013 by Phillip Low, MD
Content last modified July 2013