Development of focal segmental sclerosis and hyalinosis in hemolytic uremic syndrome

Renal biopsies from 19 boys and 11 girls, most with moderate or severe forms of hemolytic uremic syndrome (HUS) of the classic diarrhea-associated type, were analyzed as part of their long-term follow-up. Patients were biopsied because of late or persistent proteinuria, hypertension, and prolonged renal failure. The median length of follow-up was 11.2 years (range 0.9-22.0 years). Four histological groups were identified: focal segmental glomerulosclerosis and hyalinosis (FSGSH) (17 patients), diffuse mesangial proliferative glomerulonephritis (DMPGN) (9 patients), diffuse glomerulosclerosis (2 patients), and minimal glomerular changes (2 patients). The median interval between the onset of disease and renal biopsy was significantly shorter in DMPGN than in FSGSH (P < 0.001). The pathological findings may be the expression of two different stages of the same dynamic process: a regular sequence of glomerular lesions consisting of early DMPGN, followed by FSGSH. This lesion would ultimately lead to the final stage of global glomerulosclerosis. At the last examination, only a quarter of the patients had normal renal function. These observations also confirm that prolonged oligoanuria during the acute stage of HUS frequently results in an unfavorable long-term prognosis.