Background: We aimed to evaluate the significance of electromyographic findings in the intrinsic foot muscles (IFMs) of patients with skin biopsy proven small fiber neuropathy (SFN).
Methods: This was a single-center retrospective analysis of patients who underwent skin biopsy for intra-epidermal nerve fiber density (IENFD) measurement and electrodiagnostic (EDX) study for evaluation of polyneuropathy.
Results: A total of 1416 patents with normal lower extremity EDX studies proximal to the foot were included. Active denervation was seen in 16.1% of IFMs in patients with skin biopsy proven SFN and 4.1% of patients without SFN (P < .0001). Reinnervation changes without active denervation were observed in 30.4% of SFN patients and 23.8% of patients without SFN (P = .01). IENFD was lower in SFN patients with active denervation in IFMs than without (P < .0001).
Conclusions: Evaluation of active denervation in the IFMs can reveal large fiber dysfunction in SFN patients with otherwise normal routine EDX findings.
Keywords: denervation; electromyography; intra-epidermal nerve fiber density; large fiber neuropathy; skin biopsy; small fiber neuropathy.
© 2020 Wiley Periodicals, Inc.