[Raynaud's phenomenon in dialysed patients (author's transl)]. / Raynaud-Phänomen bei Dialysepatienten

In 158 uraemic patients on haemodialysis complaints resembling Raynaud's disease were observed more frequently (85 patients = 54%) than in an equal number of age and sex matched control persons (10 probands = 6%). The complaints were also registered in the arm without the fistula. Triggering causes were exposure to cold or isometric muscular exercise. The complaints were slightly more frequent in women and occurred in 28% prior to dialysis in the terminal stage of renal insufficiency. They were improved only in a minority of those treated with haemodialysis, however they disappeared after successful renal transplantation. Veno-occlusive plethysmographic investigations showed that in asympatomatic patients the resting perfusion at room temperature, the perfusion in reactive hyperaemia, and perfusion at 0 degrees C were not different from control persons. Patients with Raynaud's phenomenon had on average a diminished resting perfusion and a normal perfusion after reactive hyperaemia. The perfusion at 0 degrees C was lower than in asymptomatic patients but still higher than in patients with Raynaud's disease. Increased cooling of the skin and delayed rewarming were objectively measured by using skin temperatures. There was not correlation between the complaints or perfusion values and the vibration threshold.

Changes in peripheral nerve function with long-term hemofiltration treatment.

The changes in the peripheral nerve function of three patients with chronic renal failure who were treated over a period of 1-1/2 to 2 years by hemofiltration have been analyzed in the form of a longitudinal study by quantitative measurements of vibratory perception threshold and nerve conduction velocity. Changes in vibratory perception threshold were measured in six patients both before and after treatment. Despite increased values of creatinine and BUN, an improvement in the peripheral nerve function of all patients undergoing hemofiltration could be observed, although vibratory perception and nerve conduction velocity did not return to normal. All of the vibratory perception threshold measurements made directly after hemofiltration showed an improved vibratory perception in comparison to the original values. A comparison of the measurement methods showed a good correlation and clearly indicated the advantage of vibratory perception threshold measurements as a means for the routine diagnosis of nephrogenic polyneuropathy.

[Correlation between sensory action potentials and vibratory perception in uremic polyneuropathy (author's transl)]. / Korrelationen zwischen Veränderungen des sensiblen Nervenaktionspotentials und gestörter Vibrationsempfindung bei urämischer Polyneuropathie

1. The sensory action potentials of the tibial nerve at the medial malleolus were studied by averaging in 51 patients with chronic renal failure treated by hemodialysis. Vibratory sense was also tested quantitatively on the dorsum of the foot with a pallesthesiometer. 2. Good correlation was found between sensory tibial nerve potentials and vibration sense in subclinical as well as in clinical uremic polyneuropathy. A biphasic potential correlated with unaffected vibration sense in 18 out of 23 patients, and impaired vibratory sense with a polyphasic response in 20 of 28 patients. Maximal nerve conduction of sensory fibres was faster (mean 37.4 m/sec) in cases with normal vibratory sense, but slower (mean 31.3 m/sec), when vibratory sense was impaired. Furthermore there was a correlation between the threshold of vibratory perception and sensory nerve conduction. 3. Sensory function, tested with conventional methods, was impaired only 5 times in 28 patients with altered vibratory perception. 4. The earlier impairment, especially of the vibratory sense, may be explained by the following neurophysiological mechanisms: a) Because of the polyphasic prolonged response of the sensory potentials, no rhythmical groups of impulses reach the central nervous system, but only a continual stream of small peaks arrives, so that vibration perception does not develop. b) A multiplication of the frequency of discharges caused by alternating firing of different sensory fibres is impossible due to the reduction of the number of axons. c) The prolongation of the relatively refractory period due to demyelinization of the surviving fibres prevents the transmission of frequent impulses. 5. Alterations of the sensory action potentials of the tibial nerve, as well as of vibratory perception tested quantitatively, are earlier signs of uremic polyneuropathy than the prolonged motor nerve conduction velocity. Since not all patients give accurate information when tests of vibratory sense are performed both methods should be applied. Physiological polyphasia of sensory action potentials and diminishing vibration perception in advanced age must be taken into account.