Multiple system atrophy
Updates to Article Attributes
Multiple system atrophy (MSA) is a sporadic neurodegenerative disease (one of the synucleinopathies) characterised by varying degrees of cerebellar ataxia, autonomic dysfunction, parkinsonism and corticospinal dysfunction.
Epidemiology
Multiple systemic atrophy is a sporadic disease, with a prevalence of 4 per 100,000 2. Typically symptoms begin between 40 and 60 years of age 2.
Clinical presentation
Clinical presentation is variable, but typically presents in one of three patterns (initially described as separate entities) 1-2:
- Shy-Drager syndrome is used when autonomic symptoms predominate
- striatonigral degeneration shows predominant parkinsonian features
- olivopontocerebellar atrophy demonstrates primarily cerebellar dysfunction
In a 2007 consensus paper 6 MSA has been divided clinically into 2 forms according to the dominant non-autonomic symptoms:
- MSA-C: predominance of cerebellar symptoms (olivopontocerebellar atrophy)
- MSA-P: predominance of parkinsonian signs and symptoms (striatonigral degeneration)
Some older texts refer to MSA-A to denote Shy-Drager syndrome. In the latest consensus however autonomic symptoms are considered part of both MSA-C and MSA-P and thus the term MSA-A is no longer used.
NB: This is similar to the relationship between Lewy body dementia and Parkinson's disease (also synucleinopathies) where the initial presentation is different despite a similar underlying pathology and similar end stage of disease.
Pathology
Like other synucleinopathies, multiple systemic atrophy results from abnormalities of alpha-synuclein metabolism, resulting in intracellular deposition. Unlike Parkinson disease and Lewy body dementia (two other synucleinopathies) these intracellular deposits are found not only in neurons but also in oligodendroglia 2.
Radiographic features
MRI is the modality of choice for imaging patients with suspected multiple system atrophy (MSA).
MRI
- T2 hyperintensities: typically present in the pontocerebellar tracts
- pons: hot cross bun sign (MSA-C)
- middle cerebellar peduncles
- cerebellum
- putaminal findings in MSA-P 5:
- reduced volume
- reduced GRE and T2 signal relative to globus pallidus
- reduced GRE and T2 signal relative to red nucleus
- abnormally high T2 linear rim surrounding the putamen ("putaminal rim sign"), seen at 1.5T (NB this is normal at 3T) 7(see case 3)
- MSA-C
- disproportionate atrophy of the cerebellum and brainstem (especially olivary nuclei and middle cerebellar peduncle)
- ADC values: higher in the pons, cerebellum, and putamen than in Parkinson disease or controls
- fractional aniosotropy (FA): lower in the pons, cerebellum, and putamen than in Parkinson disease or controls
Treatment and prognosis
Unfortunately no effective treatment is currently available. The disease progresses relentlessly culminating in death usually within 10 years of diagnosis 2.
-<li>abnormally high T2 linear rim surrounding the putamen ("<a title="putaminal rim sign" href="/articles/putaminal-rim-sign">putaminal rim sign</a>"), seen at 1.5T (NB this is normal at 3T) <sup>7</sup>- +<li>abnormally high T2 linear rim surrounding the putamen ("<a href="/articles/putaminal-rim-sign">putaminal rim sign</a>"), seen at 1.5T (NB this is normal at 3T) <sup>7</sup><span style="line-height:13.8666658401489px">(see case 3)</span>
Image 3 MRI (Gradient Echo) ( update )
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