Transient changes of sensory nerve functions in uraemia.

The neurophysiological parameters (conduction velocity, amplitude and rise time of the compound action potential) of two sensory nerves of the lower limb (N. suralis and peronaeus superficialis) were determined bilaterally in five patients. Measurements were carried out at least twice in each subject during a time of great metabolic change. Two patients were recovering from acute renal failure (a single haemodialysis had to be performed on one of them) and three were under chronic maintenance haemodialysis. In the case of the haemodialysis patients, measurements were performed on two successive days, before and after one haemodialysis session. All the neurophysiological parameters showed significant improvement in successive measurements. In one patient the follow-up after acute renal failure revealed a delayed deterioration of the nerve functions, but after one year the values were normal. From the results it seems probable that an acute metabolic disturbance may cause transient inhibition of nerve functions without morphological changes in the nerve fibres.