The complex association between pain and neuropathy

Background: Several studies of patients with polyneuropathy failed to show differences between patients with and without pain. In the current study, we aimed to explore the association between neuropathic symptoms, mainly pain, and polyneuropathy characteristics. Methods: A prospective cross-sectional study recruiting 151 patients with non-diabetic polyneuropathy was performed between November 2016 and May 2017. A total of 38 patients with chronic inflammatory demyelinating neuropathy were excluded. Patients underwent clinical, electrophysiological and functional assessments of their polyneuropathy. Polyneuropathy characteristics were compared depending on the presence and severity of neuropathic symptoms. Results: The presence and the severity of weakness were associated with a more severe neuropathy as measured by clinical, electrophysiological and functional assessments, while the presence of pain was associated with higher sural amplitudes, and the severity of pain showed a curvilinear association with neuropathy severity. Conclusions: Our study shows a novel finding of a curvilinear association between pain and polyneuropathy severity.