Is pruritus in chronic uremic patients related to peripheral somatic and autonomic neuropathy? Study by R-R interval variation test (RRIV) and by sympathetic skin response (SSR)

The problem of pruritus in uremic dialysed patients remains unsolved. The e tiology of pruritus has not been precisely explained, and sometimes no effi cient treatment is available. The aim of this study was to analyse the rela tionship between somatic neuropathy and pruritus as well as the relationshi p between pruritus and dysautonomia. Fifty-one patients with end-stage rena l failure underwent basic neurological examination, nerve conduction veloci ty studies, and pruritus assessment by means of a questionnaire. Two tests were used to assess the autonomic nervous system, namely the R-R interval v ariation test in basal and profound breath conditions (RRIV) and the sympat hetic skin response (SSR). Pruritus was found in 63% patients of the sample . Most of them had clinical symptoms and signs of peripheral sensorimotor n europathy and dysautonomia. About 59% of uremic patients revealed abnormall y reduced RRIV. About 45% of patients had abnormal (delayed or absent) SSR. The pruritus in uremic patients occurred significantly more frequently (P < 0.01) in patients with paresthesia. A nonsignificant but sizeable trend t owards a relationship of pruritus with hypohidrosis and pathological SSR re sults was also observed. There was no relationship between the pruritus pre sence and RRIV results. According to our results the activity of the nervou s system might play an important role in the mechanism of uremic pruritus, but paradoxically this latter appeared more tightly related to somatic neur opathy than to autonomic dysfunction. Our results also suggest that SSR may become a useful technique for the assessment of autonomic dysfunction in u remic patients. (C) 2001 Editions scientifiques et medicales Elsevier SAS.