Hemolytic Uremic Syndrome (HUS), prognostic factors and follow up of renal function, in Santiago, Chile

Abstract

Introduction: HUS is characterized by acute renal failure (ARF), microangiopathic hemolytic anemia and thrombocytopenia. It is the main cause of ARF in childhood.

Objective: a) To describe clinical characteristics of acute stage HUS in Chile and compare them with previous reports, b) to evaluate follow up of renal function after 12 months and prognostic factors.

Methods: Demographic and clinical characteristics, biochemical and hematological parameters of 374 patients with HUS attended between January 1990 and December 2002 in 9 hospitals of the Metropolitan Region were analyzed, and renal function at 12 months of 213 patients, risk factors for poor renal prognosis and mortality using the logistic regression model were evaluated.

Results: 374 patients were enrolled, 50.5% females, 65.5% from the Metropolitan Region. Mean age was 1.5 ± 1.4 years (0.2 - 8), 91% had diarrhea, 31% occurred in summer, 57% presented with anuria, 43.3% with arterial hypertension and 23% seizures . Renal replacement was done by peritoneal dialysis (50%), hemodiafiltration (6%), hemodialysis (3%) and plasmapheresis (1%). 28% remained hypertensive at discharge. An etiological agent was identified in 17%, enterohaemorrhagic E. Coli was the most frequent. Mortality was 2.7%, multi-organic failure being the principal cause. After 12 months, 80% had normal renal function, 14% chronic renal failure, 6% proteinuria with normal renal function and 4% remained hypertensive. A significant association was found between chronic renal failure and arterial hypertension (p < 0.0001), requirement of peritoneal dialysis or hemodialysis (p < 0.01 and p < 0.0015, respectively), anuria (p < 0.005) and seizures (p < 0.01). A positive correlation with mortality in the acute phase was found with seizures, hemodiafiltration and plasmapheresis requirement (p < 0.0001, p = 0.0001 and p < 0.0001, respectively).

Conclusions: a) Clinical presentation of HUS has not changed during the last 36 years in Santiago, Chile; b) Mortality during the acute phase has decreased; c) Hypertension, dialytic therapy requirement, anuria and neurological involvement were the most significant features associated with morbi-mortality after 1 year of follow-up.