Long-term course and mechanisms of progression of renal disease in hemolytic uremic syndrome

Abstract

In the classic form of hemolytic uremic syndrome associated with toxins of gram-negative enterobacteria, mortality in the acute stage has been lower than 5% since 1978 (data from the Nephrology Committee, Argentine Society of Pediatrics). Children usually die because of severe involvement of the central nervous system, intestine, or myocardium and its complications, or because of intercurrent infection. Treatment in this phase is supportive, and efforts should be put into prevention of infection by Shiga-like toxin-producing enterohemorrhagic Escherichia coli. Of the 95% who survive, approximately one third is at risk for having chronic sequelae. Motor, sensory, or intellectual deficits, intestinal strictures, myocardial infarctions, or diabetes are infrequent. The more-frequent chronic renal lesion is characterized by the hyperfunction of nephrons remaining after the acute necrotizing lesion, which leads to progressive scarring, and not by persistence or recurrence of the microangiopathic process. Three courses of progression to end-stage renal failure have been described. Children with most severe forms do not recover from acute renal failure and enter directly into a dialysis and transplantation program. A second group recovers renal function partially, with persistent proteinuria and frequently hypertension; progression to end-stage renal failure occurs in 2 to 5 years. The third group may recover normal serum creatinine and creatinine clearance, with persistent proteinuria. They are at risk of progressing to chronic renal failure and end-stage renal disease after more than 5 years, and sometimes as late as 20 years, after the acute disease. Treatment should aim at preventing the mechanisms associated with progressive renal scarring. Transplantation is indicated in this form of hemolytic uremic syndrome, because there is little, if any, risk of recurrence, and the prognosis is similar to that of transplantation for other diseases.