Multiple system atrophy manifested as dizziness and imbalance: a report of two cases.

Multiple system atrophy (MSA) is a progressive neurodegenerative disease of undetermined origin that occasionally manifests as dizziness and imbalance. It is not often considered in clinical situations, especially not by neuro-otological consultants. Hence, we report our recent experience with two cases of MSA. One is that of a 62-year-old man with MSA with a predominant cerebellar feature, and the other is that of a 72-year-old man with MSA with a predominant parkinsonian feature. The results of the syncopic study correlated with orthostatic hypotension. The neuro-otological study in both patients revealed an abnormal eye tracking test, abnormal optokinetic nystagmus test and loss of visual suppression in the caloric nystagmus. These indicate that the central vestibular system, e.g., the cerebellum or brain stem, is affected by MSA, contributing to dizziness and imbalance. Therefore, diagnosis of MSA should be kept in mind by neuro-otological consultants when dealing with patients with dizziness and imbalance, especially when this is accompanied by orthostatic hypotension.