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. Symptoms typically begin between 40 and 60 years of age 2.
Clinical presentation
Clinical presentation is variable, but the disease 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 was divided clinically into two forms, according to the dominant non-autonomic symptoms:
-
MSA-C: predominance of
cerebellar -
MSA-P: predominance of
parkinsonian
Some older texts refer to MSA-A (where A stood for autonomic) to denote Shy-Drager syndrome. In the latest consensus, however, autonomic symptoms are considered part of both MSA-C and MSA-P, thus the term MSA-A is no longer used.
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 neurones 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 the globus pallidus and the red nucleus
- abnormally high T2 linear rim surrounding the putamen (putaminal rim sign), seen at 1.5 T (this is normal at 3 T) 7 (see case 3)
- MSA-C
- disproportionate atrophy of the cerebellum and brainstem (especially olivary nuclei and middle cerebellar peduncles)
- ADC values: higher in the pons, cerebellum, and putamen compared with Parkinson disease or controls
- fractional anisotropy (FA): lower in the pons, cerebellum, and putamen compared with Parkinson disease or controls
Nuclear medicine
On SPECT/CT with I-123 ioflupane, there is loss of the normal comma- or crescent-shaped tracer uptake in the striatum. Instead, a period- or oval-shaped uptake is seen within the caudate nucleus head, without tracer uptake in the putamen. Quantitative assessment reveals reduced uptake in the putamen compared with norms.
Treatment and prognosis
Unfortunately, no effective treatment is currently available. The disease progresses relentlessly, culminating in death, usually within 10 years of diagnosis 2.
-<strong>MSA-C:</strong> predominance of <strong>c</strong>erebellar symptoms (<a href="/articles/multiple-system-atrophy-cerebellar-type-msa-c">olivopontocerebellar atrophy</a>)</li>- +<strong>MSA-C:</strong> predominance of cerebellar symptoms (<a href="/articles/multiple-system-atrophy-cerebellar-type-msa-c">olivopontocerebellar atrophy</a>)</li>
-<strong>MSA-P:</strong> predominance of <strong>p</strong>arkinsonian signs and symptoms (<a href="/articles/multiple-system-atrophy-parkinsonian-type-msa-p-2">striatonigral degeneration</a>)</li>- +<strong>MSA-P:</strong> predominance of parkinsonian signs and symptoms (<a href="/articles/multiple-system-atrophy-parkinsonian-type-msa-p-2">striatonigral degeneration</a>)</li>
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