Is uremic neuropathy related to adequacy and duration of hemodialysis therapy? A cross-sectional analysis of neurophysiologic parameters in long term hemodialysis patients

Abstract

Background: Uremic polyneuropathy is the most common type of peripheral nerve involvement in chronic hemodialysis patients. However, its incidence was variable and ranged from 18–83%. The aim of the present study was to evaluate the prevalence of uremic neuropathy in chronic hemodialysis patients both clinically and electrophysiologically. In addition, the effects of dialysis adequacy and duration on the extent of peripheral nerve involvement were further examined.

Patients and methods: Thirty stable chronic non-diabetic hemodialysis patients (13 males, 17 females, mean age 39.17±11.52 years) were divided into three groups according to the duration of hemodialysis. Careful neurological examination as well as nerve conduction studies of both extremities were done and the results were compared to healthy control measurements. Hemodialysis adequacy was assessed through the calculation of single (spKt/V) and equilibrated Kt/V (eqKt/V) in order to examine the effect of dialysis adequacy on nerve conduction measurements.

Results: Clinical neurological examination revealed the presence of peripheral neuropathy in 57% of hemodialysis patients. There were significant reductions in the left common peroneal nerve and the right posterior tibial nerve conduction velocities as well as prolongation of the distal motor latency of the previously mentioned nerves (P<0.05). Sensory conduction studies revealed reduction in the conduction velocity of the left medial plantar nerve besides prolongation of its distal motor latency (P<0.05). There were no significant correlations between all neurophysiologic measurements and either spKt/V or eqKt/V. Similarly, no significant correlation was demonstrated between neurophysiologic measurements of the lower extremities and the duration of hemodialysis. In the upper extremities, there was a significant positive correlation between the left median nerve distal motor latency and the duration of hemodialysis (P<0.05).

Conclusion: Our data confirm the high prevalence of uremic neuropathy in hemodialysis patients. However, adequacy of dialysis, as indicated by urea clearance, probably doesn't play a major role in the development and progression of uremic neuropathy. Care should be exercised in interpreting the findings of nerve conduction studies of the upper extremities so as to eliminate the effect of entrapment neuropathy, particularly in long standing hemodialysis.