ABSTRACT
Uremic pruritus is a common cause of morbidity for both hemodialysis [HD] and peritoneal dialysis patients. The pathogenesis is still conflicting. This work was planned to study skin ultrastructure and some biochemical parameters with possible relevance to pruritus including serum urea, creatinine, calcium, phosphorus, alkaline phosphatase, parathyroid hormone [PTH], and calcium-phosphorus products. The effects of dialysis duration, frequency, adequacy, and dialysate buffer were also studied. The study was conducted on 45 persons divided into three groups. Group 1 included 15 patients with CRF on HD with severe pruritus. Group II included 15 patients without pruritus on HD. Group III included 15 normal persons as control. Skin biopsy was performed for ten patients from each of group I and group II patients for electrom microscopic [EM] examination. Uremic pruritus was neither correlated to dialysis duration, frequency, adequacy, nor to dialyste buffer. The serum levels of urea, creatinine, calcium, alkaline phosphatase, and calcium-phosphorus products showed no significant difference between both HD groups. Whereas, serum phosphorus and PTH were significantly higher in both patient groups than controls, and in the pruritic than the non-pruritic HD patients. The present EM study demonstrated increased density of mast cells as well as an increase of mast cell granule size and number. These mast cell changes were common for both patient groups. Sweat glands in the pruritic, but not the non-pruritic group, revealed non-uniform cell morphology with altered villi. The nuclear envelope was irregular with segregation of nucleoli. The skin nerve endings, sebaceous glands and blood vessels were normal in both patient groups. It was concluded that the markedly elevated serum levels of phosphorus and PTH might play a crucial role in the development of pruritus in maintenance HD patients. Also, the co-occurrence of sweat gland changes with increased mast cell number; granularity and granule size could be a marker of uremic pruritus