Atypical hemolytic-uremic syndrome: a comparison with postdiarrheal disease.

OBJECTIVES: To compare the epidemiologic, laboratory, clinical, and outcome variables of atypical (nondiarrheal) hemolytic-uremic syndrome with those of classic postdiarrheal disease. METHODS: A 24-year retrospective review of 28 episodes of atypical HUS that occurred in 22 children compared with 266 episodes of typical postdiarrheal disease in 265 children treated during the same period. RESULTS: Of the 294 episodes of HUS, 9.5% were atypical (nondiarrheal), and 18% of the patients in the atypical disease group had recurrences. Prodromal features (other than the presence or absence of diarrhea) were similar between the groups. White blood cell count and serum creatinine concentration on admission to the hospital and most abnormal blood urea nitrogen values during hospitalization were significantly lower (p = 0.02) in the patients with atypical HUS. Oliguria, anuria, and the need for dialysis were also less common (p = 0.02) in the atypical disease group. There were no deaths in the subset of patients with atypical disease; 3.4% of the patients in the typical disease group died. Although there were no statistically significant differences in the incidence of end-stage renal disease between the atypical and typical disease groups, two of the four patients with atypical disease who had recurrences also had end-stage renal disease. There were no significant differences in chronic renal sequelae between the groups one or more years after HUS. CONCLUSIONS: In contrast to reports from most other regions, patients with atypical disease in our area of the western United States have milder acute nephropathy and, with the exception of those with recurrence, do not experience worse outcomes.

A 20-year population-based study of postdiarrheal hemolytic uremic syndrome in Utah.

OBJECTIVE: To determine epidemiologic features, trends in frequency, and predictors of clinical outcome of postdiarrheal hemolytic uremic syndrome (HUS) in Utah. DESIGN: A 20-year population-based study of HUS with a review of the HUS registry, hospital records, transplant registry, and a survey of pediatricians and pediatric nephrologists to ensure completeness of ascertainment. POPULATION: All Utah residents under 18 years of age with HUS occurring after a diarrheal prodrome between 1971 and 1990. OUTCOME MEASURES: Incidence of HUS, severity, complications, and long-term sequelae. RESULTS: There were 157 cases during 20 years; 140 (89%) occurred after a diarrheal prodrome. The mean annual incidence was 1.42/100,000 children (range 0.2 to 3.4/100,000 children/year). Periods of high incidence occurred; however, there was no overall sustained increase in incidence. Escherichia coli O157:H7 was isolated from the stool of 62% of children who had specimens submitted. There were no differences between the first and second decade in the proportion with diarrheal prodrome, bloody diarrhea, most abnormal laboratory values, hospital course, or outcome. However, admission laboratory abnormalities were more severe during the first decade suggesting a delay in diagnosis. Age < 2 years, anuria before admission, and higher white blood cell counts on admission predicted severe disease. Bad outcome (death, end-stage renal disease, or stroke) occurred in 11%; 5% died. Chronic renal sequelae, usually mild, were found on follow-up (median 6.5 years) in 51% of survivors. CONCLUSIONS: HUS has been an important clinical and public health problem in Utah for 20 years. The consistency of the clinical and epidemiologic features over 2 decades suggests that a common etiologic agent has accounted for most cases of HUS in this region since 1971.

Long-term outcome and prognostic indicators in the hemolytic-uremic syndrome.

We examined 61 patients an average of 9.6 years (range 5 to 18 years) after an episode of childhood hemolytic-uremic syndrome. Twenty-four (39%) had one or more abnormalities. Seven (11%) had proteinuria and six (10%) had low creatinine clearance as solitary abnormalities. Eight (13%) had both proteinuria and reduced creatinine clearance; three (5%) had a combination of hypertension, proteinuria, and low creatinine clearance. Abnormalities sometimes appeared after an interval of apparent recovery. Logistic regression analysis showed that duration of anuria was the best predictor of disease at follow-up. No patients who had anuria lasting longer than 8 days or oliguria exceeding 15 days escaped chronic disease. However, 45% of those with disease had no anuria, and a third had no oliguria. Physicians should therefore be cautious in assuming recovery from HUS on the basis of a single evaluation and should periodically evaluate patients for an extended period.