The Pathogenesis of Typical, Diarrhea-Associated, Hemolytic Uremic Syndrome

Abstract

Hemolytic uremic syndrome (HUS) is an important cause of renal failure, morbidity and mortality and is classified broadly into typical (epidemic, diarrheaassociated or D+) and atypical (sporadic or D-) forms (1, 2). Atypical forms more closely resemble thrombocytopenic thrombotic purpura (TTP) than do typical forms. There is a distinctive form of HUS (typical, D+, Shiga-like toxin-associated HUS) (1–3) which occurs mainly in childhood and is characterized by the rapid onset of acute hemolysis, thrombocytopenia, and acute renal injury. These are preceded by a prodromal illness of acute gastroenteritis, usually with bloody diarrhea. Renal failure predominates over brain involvement. Typical HUS is uncommon in blacks. Typical HUS is associated with infection by organisms that produce Shiga-like toxins (SLT), especially Escherichia coli 0157:H7 (3). Most cases have a neutrophilia. The endothelial injury and thrombotic microangiopathy predominantly involve glomeruli (4). The immediate prognosis is excellent and recurrences are rare (1, 2, 5, 6).