A neurophysiological study of large- and small-diameter nerve fibers in the hands of hemodialysis patients

Abstract

Polyneuropathy in patients with advanced clinical kidney disease is a very disabling condition. The aim of this study was to evaluate neurophysiological abnormalities of large- and small-diameter nerve fibers in the hands of hemodialysis patients. A total of 38 hemodialysis patients and 38 healthy control subjects underwent a conventional electrophysiological examination. The function of small nerve fibers was assessed using cutaneous silent period (CSP) measurement. Slower median nerve motor conduction velocities were recorded in patients with fistula (p < 0.0001) and without fistula (p < 0.001). Sensory median and ulnar nerve conduction velocities were slower in both patient groups compared with the control group (p = 0.001). Median sensory nerve action potential amplitudes were lower in patients with fistulas (p = 0.009) and without fistulas (p = 0.005) compared with the control group. Significantly prolonged F-wave latencies of the median (p = 0.002) and ulnar nerves (p = 0.023) in patients with fistulas hands were observed. In 12/38 (32 %) patients, the onset latencies of CSPs were significantly delayed (p = 0.001). There was an inverse correlation of β2-microglobulin and decreased conduction velocities of the median nerves, while Kt/V was associated with improved sensory nerve conduction velocity of the median nerve. An inverse correlation between motor velocity of both nerves and hemodialysis duration was observed in the patient groups. The measurement of CSPs provides a useful method for assessing small nerve fibers. The role of A-delta fibers is often overlooked.