A SINGLE HEMODIALYSIS IMPROVES TEMPERATUR E AND VIBRATION SENSATION IN CHRONIC UREMIC PATIENTS

Pathophysiology and pathoanatomy of uremic neuropathy are not yet well understood. A single hemodialysis positively increases nerve conducti on velocities of uremic patients, thus demonstrating a functional A al pha-fiber improvement by detoxification. This study tested whether non -invasive Vibrameter and Thermotest studies show a similarly positive effect for A beta-, A delta- and C-fibers and whether the psychophysic al techniques might substitute for nerve conduction studies. 20 uremic patients depending on chronic intermittent hemodialysis were examined shortly before and after a hemodialysis. Using a scaled 128 Hz tuning fork, a Vibrameter (TM) and a ''Marstock''-Thermotest, vibratory and warm and cold thresholds were assessed at both internal malleoli accor ding to the method of limits. In addition, thermal thresholds were det ermined at the volar aspect of the non-shunted wrist. In nine patients the Vibrameter showed elevated thresholds before and after dialysis a s did six patients with the tuning fork. Warm or cold thresholds were abnormal in four patients before treatment and in eight patients after dialysis. This was due to some patients reporting elevated thresholds after dialysis although they had had normal thresholds before the tre atment. Still, the overall sum of abnormal thermal or vibratory thresh olds at the different tested body sites had decreased after treatment. Moreover, mean values of thermal and vibratory thresholds of the 20 p atients improved with dialysis (p<0.05). Tuning fork results were too coarse and failed to show a dialysis effect. Although the results of p sychophysical vibratory and thermal threshold testing; were biased by several un cooperative patients at the end of the dialysis, the study demonstrated improvement not only of large A beta-, but also of small A delta- and C-fiber function. This observation might suggest that det oxification during dialysis primarily affects axonal structures.