Epidermal nerve fiber density and sural nerve morphometry in peripheral neuropathies

Area of Science:

• Neurology
• Neuroscience
• Pathology

Background:

• Peripheral neuropathies encompass a range of disorders affecting the peripheral nervous system.
• Accurate diagnosis relies on correlating clinical findings with objective measures of nerve integrity.
• Small fiber sensory neuropathies can be challenging to diagnose using traditional methods.

Purpose of the Study:

• To investigate the relationship between intraepidermal nerve fiber (IENF) density in distal leg skin biopsies and sural nerve morphometry.
• To evaluate the utility of IENF density, sural nerve morphometry, and electrophysiology in characterizing peripheral neuropathies.

Main Methods:

• Studied 26 patients with neuropathic complaints, including clinical evaluation, nerve conduction studies, and skin/sural nerve biopsies.
• Quantified IENF density and myelinated/unmyelinated fiber densities in the sural nerve.
• Examined associations between morphometric measures and sensory nerve action potential (SNAP) amplitudes.

Main Results:

• IENF density correlated significantly with sural nerve myelinated fiber densities (total, small, and large).
• A trend was observed between IENF density and sural nerve unmyelinated fiber densities.
• Sural SNAP amplitude strongly correlated with large myelinated fiber density; IENF density identified small fiber depletion in 23% of cases.

Conclusions:

• Distal leg IENF density may be more sensitive than sural nerve biopsy for identifying small fiber sensory neuropathies.
• Assessing IENF density and large fiber measures via biopsy and electrophysiology aids in characterizing sensory and sensorimotor neuropathies.