Effect of chronic renal failure, dialysis and transplantation on motor nerve conduction velocity in children.

Ulnar and peroneal motor nerve conduction volocities (MNCVs) were measured in 47 children in a dialysis-transplantation program. Mean peroneal MNCV was significantly decreased from normal in children with mild renal failure (serum creatinine concentration, 1.5 to 2.9 mg/dl), whereas ulnar MNCV was significantly decreased only when the serum creatinine value was at least 9 mg/dl. Both ulnar and peroneal MNCVs remained unchanged during long-term hemodialysis or peritoneal dialysis; however, after individual dialyses ulnar MNCV increased. After renal transplantation ulnar MNCV returned to normal within a year and peroneal MNCV within 3 years. Before dialysis was required and during long-term dialysis most plasma magnesium values were elevated; ionized calcium activity was decreased in about 50% of determinations. After transplantation and the concentration of divalent cations rapidly returned to normal. These children differed from adults studied in that (a) there was no correlation between severity of renal failure and MNCV, (b) long-term dialysis did not improve MNCV and (c) peroneal velocities did not recover for 3 years after transplantation.