Clustering of post-diarrheal (Shiga toxin-mediated) hemolytic uremic syndrome in families.

AIMS: 1. To study the epidemiological and clinical features of Shiga toxin (Stx)-mediated (post-diarrheal) hemolytic uremic syndrome (HUS) occurring in more than 1 family member. 2. To compare familial with non-familial episodes, and concurrent familial with non-concurrent familial cases. 3. To determine the likelihood of Stx HUS occurring in a second family member. METHODS: A retrospective review from January 1970 through September 2001 of families in whom Stx HUS occurred in more than 1 family member was conducted using a computerized HUS registry. It contains information on 373 episodes that occurred in 356 families from Utah and neighboring states. Cases were categorized as being either concurrent (i.e., occurring within a month of one another) or non-concurrent, and the study was limited to those with typical (post-diarrheal) episodes. RESULTS: HUS occurred in 2 or more family members in 17 (4.8%) of the families in our registry. In 12 (3.4%) of these families episodes occurred with days to weeks of each other; in 5 families (1.4%) episodes were separated by intervals of several years. There were no statistically significant differences in demographic, seasonal, laboratory, clinical, or outcome variables between familial subsets (concurrent versus non-concurrent) or between familial and non-familial cases. CONCLUSIONS: When a child is diagnosed with D+ HUS, there is an increased risk that a second family member will also develop HUS; most often within days to weeks (i.e., within a month), but in some cases episodes may be separated by intervals of years. Non-concurrent cases suggest common environmental risk factors, or perhaps a genetic predisposition. Concurrent cases suggest a common source of infection or person-to-person transmission; a genetic predisposition cannot be excluded. These observations suggest that siblings of an index case who develop diarrhea should be kept under close surveillance.

Response to Shiga toxin-1, with and without lipopolysaccharide, in a primate model of hemolytic uremic syndrome.

Shiga toxin (Stx) and lipopolysaccharide (LPS) both participate in the pathogenesis of post-diarrheal hemolytic uremic syndrome (HUS), yet little is known about the factors that modulate the host response to these toxins. We have previously shown that the baboon develops HUS if 100 ng/kg of purified Stx-1 is administered rapidly as a single bolus, but not if it is given as four 25-ng/kg doses every 12 h. We therefore used this baboon model to study the response to small intravenous doses of Stx-1, with and without the co-administration of LPS. The co-administration of two 1-mg/kg doses of LPS (given at 0 and 24 h) and four 25-ng/kg doses of Stx-1 (given at 0, 12, 24, and 36 h) resulted in HUS, but the administration of either toxin separately did not. The development of HUS was associated with a rise in urinary, but not plasma concentrations of TNF, and a rise in both urinary and plasma concentrations of IL-6 and IL-8. We speculate that LPS is not required for disease expression in the human, but that it can augment the response to otherwise subtoxic amounts of Stx and this augmentation may be mediated by LPS-induced cytokine release.

Characterization of the baboon responses to Shiga-like toxin: descriptive study of a new primate model of toxic responses to Stx-1.

The baboon response to intravenous infusion of Shiga toxin 1 (Stx-1) varied from acute renal failure, proteinuria, hyperkalemia, and melena with minimal perturbation of host inflammatory and hemostatic systems (high-dose group, 2.0 microg/kg; n = 5) to renal failure with hematuria, proteinuria, thrombocytopenia, schistocytosis, anemia, and melena (low-dose group, 0.05 to 0.2 microg/kg; n = 8). Both groups exhibited renal shutdown and died in 57 hours or less. Both groups produced urine that was positive for tumor necrosis factor and interleukin-6 although neither of these cytokines was detectable (

Hemolytic-uremic syndrome in adolescents.

OBJECTIVE: To compare the epidemiological characteristics, clinical features, and outcome of adolescents with hemolytic-uremic syndrome (HUS) with those of children with HUS. DESIGN: A retrospective descriptive study using data stored in the computerized Utah HUS registry. SETTING: The HUS registry contains data on postdiarrheal and nondiarrheal HUS cases since 1970 in which the patients were younger than 18 years of age at the time of diagnosis and includes virtually all Utah cases as well as those referred from surrounding states. PATIENTS: Seventeen adolescents (age, 12-17 years) and 276 younger patients from September 30, 1970, through December 5, 1993, who met the diagnostic criteria for HUS. MAIN OUTCOME MEASURES: Age, sex, seasonality, prodromal features (eg, antecedent diarrhea), laboratory values, hospital course, outcome, and chronic sequelae. RESULTS: The 17 adolescent patients, who composed 5.8% of the study population, experienced a course of the disease that was similar to that of the younger patients. Diarrhea preceded HUS in approximately 90% of the patients in both groups. Laboratory values were similar in teenagers and younger patients. The hospital courses were also similar; seizures occurred in almost 20%, and hypertension and oligoanuric renal failure occurred in most. Two (12%) of the teenagers and 7 (2.4%) of the younger patients died during the acute phase of the syndrome (P = .09); almost 50% of both groups experienced 1 or more chronic renal sequelae. End-stage renal disease has occurred in 1 (5.8%) of the teenagers and 6 (2.2%) of the children. At follow-up, 1 or more years (median, 5 years) after the onset of HUS, hypertension was present in 22% of the teenagers and 6.7% of the preteens (P = .14). A below-normal glomerular filtration rate was seen in approximately 30% of both groups; proteinuria was noted in approximately 25% of both groups. Approximately 10% of both groups had a combination of proteinuria and a low glomerular filtration rate and are, therefore, at risk for eventual end-stage renal disease. CONCLUSIONS: In our region of the Intermountain West, HUS in adolescents closely resembles that seen in children and the outcome is more favorable than that experienced by adults.

Acute renal failure in idiopathic nephrotic syndrome.

Acute renal failure (ARF) associated with idiopathic nephrotic syndrome has been reported in adults with advanced age but is a rare event in children. We have reviewed the literature on this subject and report an additional pediatric case. The pathogenetic mechanisms which may lead to ARF during the course of idiopathic nephrotic syndrome are reviewed with a brief discussion of the role of angiotensin II and angiotensin converting enzyme inhibition in this setting. Although no consensus has emerged for the prevention and treatment of ARF in patients with nephrotic syndrome, a combination of salt-poor albumin and diuretics to reduce interstitial edema may be beneficial as a preventive measure. Once acute tubular necrosis is diagnosed, dialysis may be indicated. In the majority of reports the prognosis for recovery of renal function has been good even in patients in whom long-term dialysis was required.

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.

The hemolytic uremic syndrome.

HUS is the most common cause of acute renal failure in infants and young children and follows a diarrheal prodrome about 90% of the time. Persuasive evidence shows that virtually all of postdiarrheal cases are caused by EHEC infections, and that the great majority of cases in the United States are caused by the EHEC serotype O157:H7. Mortality is approximately 5%, and approximately 10% of survivors are left with severe sequelae. A much larger number (30%-50%) experience mild chronic renal damage. Public health strategies, including zero tolerance for fecal contamination in slaughter houses and additional public education on proper food handling and cooking, does much to decrease the prevalence of the syndrome. Efforts to further dissect the postdiarrheal pathogenic cascade should continue, and an animal model needs to be developed. Only then will researchers be positioned to develop effective intervention strategies. Preventing life-threatening extrarenal complications, especially of the CNS, is a major challenge. Idiopathic nondiarrheal HUS accounts for approximately 10% of cases and comprises a poorly understood composite of HUS subsets. Research directed toward a better understanding of these mysterious variants also is a priority for the years ahead.

Hemolytic uremic syndrome in children.

The majority of postdiarrheal hemolytic uremic syndrome is caused by Escherichia coli O157:H7. The organisms are carried in the intestines of cattle; partially cooked contaminated hamburger is the single most common vector. The E. coli produce a potent cytotoxin that gains access to the circulation, is taken up by glycolipid receptors on glomerular endothelial cells, is internalized, and causes cell death. Associated phenomena include the activation of platelets, leukocytes, and the coagulation cascade, as well as the production of cytokines. Although some patients experience a mild or incomplete syndrome, life-threatening multisystem involvement can occur. Treatment is supportive, but plasma exchange may be useful in selected high-risk subsets. Efforts to prevent colitis from evolving into hemolytic uremic syndrome include the oral administration of material to bind the toxin in the gut. Mortality remains at 5% to 10%; about 4% are left with end-stage renal failure, and approximately 50% suffer mild chronic kidney damage.

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.

New syndrome involving the visual, auditory, respiratory, gastrointestinal, and renal systems.

A previously undescribed fatal multisystem syndrome involving the eyes, ears, lungs, intestines, and kidneys occurred in sibs. They both presented during early childhood with cataracts, otitis media, intestinal malabsorption, chronic respiratory infection, and failure to thrive. Later, they developed recurrent pneumonia (one was shown to have immotile bronchial cilia) and progressive azotemia leading to end-stage renal disease (ESRD) by late childhood. Both died of overwhelming infection (sepsis, meningitis). An autosomal recessive mode of inheritance is proposed since the normal parents were distant cousins, and 4 other sibs were normal.

Urinary excretion of platelet-activating factor in haemolytic uraemic syndrome.

Since some of the features of haemolytic uraemic syndrome (HUS), such as platelet activation and glomerular injury, could be brought about by platelet-activating factor (PAF), we have studied the urinary excretion of PAF in 10 children with HUS and in 10 healthy age-matched controls. Urinary PAF concentrations, measured by radioimmunoassay, were significantly higher in acute-phase HUS patients than in controls (mean 2.04 [SD 1.66] vs 0.72 [0.43] ng/mg creatinine, p less than 0.05) but were similar to those in controls in samples taken after recovery. High PAF concentrations during the acute phase of HUS may reflect platelet activation and glomerular injury; the lower values after recovery suggest that urinary PAF may be a marker of disease activity.

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.

Hemolytic-uremic syndrome during an outbreak of Escherichia coli O157:H7 infections in institutions for mentally retarded persons: clinical and epidemiologic observations.

PURPOSE: To describe an outbreak of Escherichia coli O175:H7 infection resulting in a high rate of progression to hemolytic-uremic syndrome, and to attempt to identify predictors of and risk factors for progression. DESIGN: Case-control study among employees and comparison of daily clinical features in two groups: infected residents with subsequent development of HUS and those who had no complications. SETTING: Two institutions for retarded persons in Utah. PATIENTS: Twenty residents with E. coli O157:H7 infection (13 culture confirmed, 2 probable, and 5 possible); HUS developed in 8, and 4 died. Thirty-one infected employees (3 with culture-confirmed, 6 with probable, and 22 with possible infection). MEASUREMENTS AND MAIN RESULTS: In a case-control study among employees, infection was independently associated with eating ground beef from a single lot prepared at several barbecues and with close contact with a resident who had diarrhea. Five of eight residents in whom HUS developed had received trimethoprim-sulfamethoxazole, compared with none of seven who had no subsequent complications (p = 0.026); this finding may reflect antimicrobial treatment of patients with more severe illness. Compared with infected residents without complications, persons with HUS were younger (median age 13 vs 27 years, p = 0.043) and, by the third day of illness, had higher leukocyte counts (median 23.7 X 10(9)/L vs 9.1 X 10(9)/L, p = 0.018) and temperature (median 38.5 degrees C vs 37.0 degrees C, p = 0.016). Leukocytosis peaked on day 4, more than 24 hours before signs of HUS appeared. CONCLUSIONS: Food-borne outbreaks of E. coli O157:H7 in institutions may have devastating effects. Leukocytosis and fever may precede and predict HUS in patients with E. coli O157:H7 infection.

A clinicopathological study of 24 children with hemolytic uremic syndrome. A report of the Southwest Pediatric Nephrology Study Group.

This study reports the pattern of renal injury in 24 North American children with hemolytic uremic syndrome (HUS), and the extent of extrarenal involvement in 9 of these children examined at autopsy. Fifteen of the 24 children were studied during the first 16 days of hospitalization; their renal specimens demonstrated glomerular thrombotic microangiopathy (TMA) in 8 children, cortical necrosis in 1, and varying degrees of glomerular TMA and cortical necrosis in 6 children. Nine of the children were studied after 16 or more days of hospitalization; these patients had prominent renal arterial lesions. Of 9 children examined at autopsy, extrarenal microthrombi were identified in 8. In 4 children who died during the acute phase of the disease, hemorrhagic colonic necrosis (3 children) and pancreatic islet cell necrosis (2 children) were the principal extrarenal lesions encountered. Rare microthrombi were present in the brains of the 3 children who manifested seizures.

Hemolytic uremic syndrome associated with glomerular disease.

Secondary hemolytic uremic syndrome (HUS) is uncommon. When it occurs, it is usually in association with pregnancy, malignancy, severe hypertension, drugs, or collagen vascular diseases. It has rarely been reported in patients with glomerular disease. Two such patients with secondary HUS are described. A 17-month-old girl with hematuria and the nephrotic syndrome, negative antistreptolycin O (ASO) titer, and low serum levels of C3 and C4 developed oliguria, progressive azotemia, thrombocytopenia, and microangiopathic hemolytic anemia. A kidney biopsy showed fibrin in glomerular capillaries and cresentic membranoproliferative glomerulonephritis. A 22-year-old man with a 16-year history of relapsing minimal change nephrotic syndrome had been in remission for 5 years when he experienced nephrotic syndrome relapse and developed thrombocytopenia, microangiopathic hemolytic anemia, and renal failure. A kidney biopsy revealed foot process fusion and obstruction of glomerular capillaries with fibrin and platelets. These cases illustrate that HUS can occur in association with other glomerular diseases and should be considered when thrombocytopenia and hemolytic anemia occur in a nephritic or nephrotic patient.