Central or peripheral autonomic dysfunction in Parkinson disease: Does it matter?

In the early 19th century, James Parkinson captured with dazzling lucidity several clinical aspects of the disease that would bear his name, including some of its nonmotor autonomic features such as constipation, urinary dysfunction, and dysphagia. During most of the 20th century, autonomic dysfunction in patients with Parkinson disease (PD), neurogenic orthostatic hypotension (nOH) in particular, was considered a side effect of l-dopa, a late stage in the disease progression, or, if prominent, a red flag suggesting multiple system atrophy (MSA). In the early 21st century, autonomic dysfunction is a well-recognized, characteristic nonmotor feature of PD, occurring in most patients at all stages of the disease. Indeed, autonomic dysfunction can be a prodromal manifestation of the disease, occurring years, or even decades, before any of the defining motor features are evident.^1,2