--the causes of which range from diabetes (the most common cause) to autoimmune disorders to "idiopathic", often get some degree of autonomic dysfunction as time progresses, although for many this is subclinical and hard to spot. The most common disruptions are to orthostatic blood pressure control and to sweating.

This likely is due to the fact that the autonomic nervous system is made up primarily of unmyelinated small fibers similar to those that sense pain and temperature in the skin.

Diabetics, of course, are well known for autonomic problems such as delayed stomach emptying (diabetic gastropathy) and constipation, among others.