RESUMO
BACKGROUND Biocompatible hemodialysis membranes have greatly advanced the treatment of renal failure. Synthetic polysulfone dialysis membranes are considered to be very biocompatible because of their low propensity to activate complement. However, these membranes can reduce platelet count through platelet activation, although the mechanism of this activation is unknown. CASE REPORT We report the case of an 82-year-old man with a history of chronic kidney disease with recurrent gastrointestinal bleeding and worsening renal function who was initiated on renal replacement therapy with polysulfone dialysis membranes. On admission, the patient's platelet count was normal at 233×10³/µL. A significant fall in platelet count was observed following most dialysis treatments, reaching a nadir of 37×10³/µL. With occasional dialysis treatments, his platelet count did not change. This dialysis-induced thrombocytopenia resolved following substitution with Cellentia-H cellulose triacetate single-use, hollow-fiber, high-flux hemodialyzer membrane. CONCLUSIONS Polysulfone membranes are capable of activating platelets, which can result in severe thrombocytopenia. However, the magnitude of dialysis-induced thrombocytopenia varies from treatment to treatment. As such, it may not be evident when the pre- and postdialysis platelet counts are measured for a single treatment. Because the etiology of this platelet activation is unknown, substitution with cellulose triacetate membranes should be considered. These membranes have an unrelated chemical composition and a very low propensity to activate platelets.
