What is multiple system atrophy (MSA)?
Multiple system atrophy was once considered to be three separate clinicopathological disorders termed olivopontocerebellar atrophy (OPCA), striatonigral degeneration (SND), and Shy–Drager syndrome (SDS).
Currently the motor phenotype of Multiple system atrophy is clinically stratified into those with predominant parkinsonism (MSA-P) or cerebellar ataxia (MSA-C).
MSA-P is characterized by parkinsonism, which occasionally responds to dopaminergic therapy, and dysautonomia.
Although cerebellar findings dominate in MSA-C, mild parkinsonism and pyramidal signs are also usually recognized.
Patients with MSA-P, typically have parkinsonism and pyramidal signs with laryngeal stridor, although in some cases, MSA-P, is indistinguishable from Parkinsons Disease. The division of MSA into SDS, OPCA, and SND is controversial, with some authorities grouping the spectrum into the prominence of either cerebellar or parkinsonisms designated as MSA-C, or MSA-P, respectively.
Although usually clinically distinct at onset, with progression symptoms overlap substantially.
The two syndromes have a common pathologic substratum consisting of cell loss and gliosis in the striatum, SN, locus ceruleus, inferior olive, pontine nuclei, dorsal vagal nuclei, cerebellar Purkinje cells, and intermediolateral cell columns of the spinal cord.
The characteristic histologic marker—glial cytoplasmic inclusions, which are seen particularly in oligodendrocytes—has helped to distinguish Multiple system atrophy as a clinicopathologic entity.
The presence of autonomic dysfunction early on is thought to predict a poor prognosis.