Sural nerve conduction studies and late responses in children undergoing hemodialysis

Physiologic evidence of peripheral neuropathy has been described previously in children undergoing hemodialysis. In order to detect early or subclinical evidence of peripheral neuropathy, several newer electrophysiologic techniques, including latencies of late responses (H reflex and F response) and sural nerve sensory studies, were evaluated in addition to routine motor and sensory conduction in 17 randomly selected children (mean age 14.2 years) undergoing hemodialysis (12 of whom had no clinical evidence of peripheral neuropathy) and 20 age-matched normal control subjects. Conventional motor and sensory conduction studies of median and ulnar nerves and motor conduction of peroneal and tibial nerves showed abnormalities of motor conduction in 5 (29%) and abnormalities of sensory conduction in 2 (12%). Sural nerve sensory potentials were abnormal in 10 (59%) patients. Late response were significantly abnormal in 10 (59%) patients, 5 (29%) of whom had normal routine motor conduction studies in the same nerve distribution. The abnormalities of late responses and motor and sensory conduction were more evident in lower limbs. Studies of late responses and sural sensory conduction provide a method of detecting subclinical neuropathy in this patient population at a time when results of conventional motor and sensory conduction tests are within normal limits. Effects of dialysis may then be followed quantitatively in patients whose neuropathy would otherwise be undetectable.