Multiple system atrophy: new developments in pathophysiology and therapy

There have been substantial advances in the last five years in understanding the basic and clinical pathophysiology underlying multiple system atrophy (MSA). Identification of glial cytoplasmic inclusions has been the most important organizing principle for further elucidation of underlying mechanisms. Recently, several unexpected developments at the clinical level have been reported. In this article, we will focus on two of these: (1) the recognition that substantial autonomic function is retained in MSA but not modulated appropriately, and (2) a potent pressor effect from ingestion of water, which cannot be explained by currently understood physiologic and pathophysiologic mechanisms. In some patients, water has elicited a 50% increase in blood pressure and been more therapeutically effective than any available pressor drug. By careful coordination of the pressor effect of water and the depressor effect of carbohydrate-rich food, many patients with MSA can now have their blood pressure controlled without pharmacological intervention.