Detection of uremic neuropathy by reflex response latency

Dialysis time necessary for treatment of terminal renal failure is very different in different patients. Adequacy of therapy cannot be controlled by laboratory measures but only clinical means. Uremic peripheral neuropathy is regarded as the most reliable indicator of insufficient dialysis treatment. Serial measurements of peripheral nerve function therefore make individual adjustment of dialysis schedule possible. In some cases motor nerve conduction velocity is not sensitive enough for this purpose, as conduction velocity in afferent nerve fibers is disturbed at an earlier stage of uremic intoxication. Measurement of sensory nerve conduction velocity is time consuming and afferent fibers can also be examined in proprioceptive reflexes. Ths suitability of H-reflex response latency (RRL) for detection of slight uremic neuropathy was analysed. The wide range of RRL in healthy subjects can be explained by the different length of neural pathway in different subjects. A strong correlation between RRL and body height was found in healthy subjects. Relating RRL to the body height gives a highly sensitive measure of peripheral nerve function. Asymptomatic uremic neuropathy was detected very much earlier by RRL than by motor nerve conduction velocity. The method proved to be well suited for routine monitoring of uremic neuropathy in patients on dialysis.