[Multiple system atrophy].

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder of unknown etiology. It is the most frequent disorder among atypical parkinsonism with an estimated prevalence of 2 to 5 per 100 000 inhabitants. The clinical symptoms are rapidly progressing with a mean survival ranging between 6 to 9 years. The diagnosis is based on consensus criteria that have been revised in 2008. The diagnostic criteria allow defining "possible", "probable" and "definite" MSA. The latter requires post mortem confirmation of striatonigral and olivopontocerebellar degeneration with alpha-synuclein containing glial cytoplasmic inclusions. The diagnosis of "possible" and "probable" MSA is based on the variable presence and severity of parkinsonism, cerebellar dysfunction, autonomic failure and pyramidal signs. According to the revised criteria, atrophy of putamen, pons, middle cerebellar peduncle (MCP) or cerebellum on brain magnetic resonance imaging are considered to be additional features for the diagnosis of "possible" MSA. T2-weighted brain imaging may further reveal a putaminal hypointensity, a hyperintense lateral putaminal rim, the so called "hot cross bun sign" and MCP hyperintensities. Cardiovascular examination, urodynamic testing and anal sphincter electromyography may be helpful for the diagnosis of autonomic failure. Some patients may respond to levodopa, but usually to a lesser extent than those suffering from Parkinson's disease, and high doses are already required in early disease stages. No specific therapy is available for cerebellar dysfunction, while effective treatments exist for urinary and cardiovascular autonomic failure. Physical therapy may help to improve the difficulties of gait and stance, and to prevent their complications. In later disease stages, speech therapy becomes necessary for the treatment of dysarthria and dysphagia. Percutaneous gastrostomy is sometimes necessary in patients with severe dysphagia. Beyond these strategies, psychological support, social care and occupational therapy to adapt the environment to the patient's disability are prerequisites for improving the quality of life in MSA patients.