The late histologic findings in diarrhea-associated hemolytic uremic syndrome
The late histologic findings in diarrhea-associated hemolytic uremic syndrome. Moghal, NE, Ferreira MAS, Howie AJ, Milford DV, Raafat F, Taylor CM. Journal of Pediatrics 1998;133(2):220-223.
Although survivors of diarrhea-associated hemolytic uremic syndrome (D+HUS) may initially appear to have made a full recovery, long-term studies reveal a significant number have renal sequelae. This paper examines the histologic findings in children with persistent proteinuria after D+HUS and discusses the importance of long-term follow-up of these patients. Kidney biopsies were undertaken for persisting proteinuria (mean 5.4 years) from the onset of D+HUS in five boys and two girls (mean age at onset 3 years). At one year the mean early morning urine protein/creatinine ratio was 100 mg/mmol, and the mean glomerular filtration rate (GFR) was 65 mL/min/1.73m2 . At five years the mean early morning urine protein/creatinine ratio was 81 mg/mmol, and the mean GFR was 73 mL/min/1.73m2. The biopsy specimens were compared with those of seven age- and sex-matched children who were investigated for isolated persistent microscopic hematuria but in whom no abnormality was detected. Global glomerulosclerosis was noted in six patients with D+HUS, and two of these had segmental sclerosing lesions. Tubular atrophy and interstitial scarring were seen in all but one patient. The glomeruli in the D+HUS group were significantly larger than in the control group. These findings are typically found in kidneys with reduced nephron numbers and are compatible with changes of hyperperfusion and hyperfiltration in surviving nephrons. Measuring GFR and blood pressure at five years from illness alone would have deemed four children to have a good outcome. It is clear from the histologic findings that that is incorrect. In addition, two children with global sclerosis and moderate to severe interstitial changes had well-preserved GFRs. These children may progressively lose renal function due to damage caused by hyperfiltration, and this may be accompanied by hypertension. These findings suggest that long-term follow-up of patients with D+HUS and proteinuria is advisable.