If autonomic nerves are affected, signs and symptoms might include:
- Heat intolerance and altered sweating
- Bowel, bladder or digestive problems
- Changes in blood pressure, causing dizziness or lightheadedness
This intriguing study demonstrates a somewhat unexpectedly high prevalence of PN in IPD patients and cites an association with elevated MMA levels, perhaps mediated by exposure to L-dopa. L-dopa may indeed interact with methylation pathways involved in folate metabolism, providing a mechanism for MMA elevation. Although causation is not proven here, if verified, this study may change the way we care for patients with IPD. PN in IPD could substantially contribute to gait disturbance and disability in some patients with IPD, and prevention of PN would be an important advance. Exposure to L-dopa is inevitable in most IPD patients at some point during their course, but perhaps we should be measuring MMA levels in these patients and treating with cobalamin supplementation to reduce MMA levels and prevent neuropathy. Further studies, including treatment trials, seem warranted.