Evaluation of the Relationship Between Serum Zinc and Peripheral Neuropahty in Chronic Hemodialysis Patients

Zinc deficiency is a common finding in hemodialysis patients. This element is an essential constituent of some intracellular enzymatic systems, so zinc deficiency is associated with several disorders. Some neurologic distrubances as peripheral neuropathy associated with zinc deficiency have been described in human. At present there is no sufficient data to recommend the measurement of zinc level or routine use of its supplements in all hemodialysis patients. This study was done to evaluate the relationship between zinc deficiency and peripheral neuropathy. If this relationship can be confirmed, the improvement of plasma zinc by zinc supplementation may provide an effective therapy for uremic neuropathy. In this cross-sectional study, the electrophysiologic evaluation of sensory and motor nerves, were done in 67 nondiabetic chronic hemodialysis patients in Kerman, Rafsanjan, Sirjan and Jiroft. All cooperative patients with stable catabolic states were included in this study. At first, zinc level of these 67 patients was compared with its level in 72 healthy control persons. Then, for each nerve in lower limbs, the relationship between serum zinc and nerve conduction velocity(NCV) and distal latency(DL) was evaluated. The intervention effect of dialysis adequacy(KT/V), protein catabolic rate(PCR), serum PTH, dialysis interval and dialysis treatment duration was eliminated in this analysis. Serum zinc concentration was significantly low in 67 hemodialysis patients compared to 72 healthy controls(94.13±30.05 versus 104.53±42.8) (P<0.05). Fifty-seven percent of cases had electrophysiologic findings of peripheral neuropathy and 33% of them had clinical findings of it. Superficial peroneal nerve was the most common involved nerve in these patients. In 38 cases sup peroneal NCV was lower than normal. Zinc level of these patients was significantly lower than other 29 cases(88.9±25.1 versus 105.99±34.9) (P<0.03). On the other hand the relationship between serum zinc and NCV was significant for sural(P<0.01) and sup peroneal(P<0.05). The relationship between serum zinc and DL was also significant for sup peroneal(P<0.01). In conclusion, zinc deficiency and peripheral neuropathy are two common findings in hemodialysis patients. This study can confirm the relation between zinc deficiency and peripheral neuropathy in sensory nerves. Absence of this relation for motor nerves may be due to less severe involvement of them during uremic neuropathy.