Epidemiology of hemolytic-uremic syndrome in Canadian children from 1986 to 1988. The Canadian Pediatric Kidney Disease Reference Centre

Haemolytic-uraemic syndrome in childhood: surveillance and case-control studies in Italy. Italian HUS Study Group

Seventy-six cases of haemolytic-uraemic syndrome (HUS) were collected over a 4-year period during a surveillance and case-control study. The annual incidence of 0.2 per 100,000 children aged 0-14 years is lower than in other countries; 34% had no prodromal diarrhoea. Evidence for verocytotoxin-producing Escherichia coli (VTEC) infection was found in 72% of patients and 3% of controls; 88% of patients with bloody diarrhoea, 67% with non-bloody diarrhoea and 55% without diarrhoea were VTEC positive. Seventy-three percent of patients had creatinine clearance > or = 80 ml/min per 1.73 m2, normal blood pressure, no proteinuria and haematuria < 2+ after 1 year of follow-up. One patient died and none had non-renal sequelae. VTEC positivity was significantly correlated with a good outcome, while the absence of diarrhoea and a high total white blood cell count at onset were not predictors of a bad outcome. Household contacts of HUS patients had diarrhoea more frequently than those of the control group, supporting the hypothesis of person-to-person transmission of VTEC infection.

Racial incidence of hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in children and is caused by infection with verotoxin-producing Escherichia coli. There is no consensus on the relative incidence of HUS in blacks and whites. An equal racial incidence has been reported by two centers with small black populations. A series from Washington D.C. reported a low incidence in blacks. The population of Alabama is 32% black and 66% white. The Children's Hospital of Alabama admission rate has a similar racial distribution (35% black, 65% white). A record review from 1980-1992 identified 45 patients with HUS; 43 (96%) were white and only 2 (4%) were black. Based on census data for Alabama in 1980 and 1990, this gives an average annual incidence of HUS of 0.45 per 100,000 in whites and of 0.043 per 100,000 in blacks (P < 0.001, Fischer's exact test). Similar results were found in the group of patients with HUS and a history of diarrhea; whites 0.39 and blacks 0.02 (P < 0.001). However, in those with no history of diarrhea there was no significant racial difference: whites 0.05 and blacks 0.02. There were too few blacks to compare clinical course and outcome. We conclude that typical diarrhea-associated HUS is a relatively rare disease in blacks compared with whites. The reasons are unclear.

Escherichia coli O 157:H7-associated hemolytic-uremic syndrome after ingestion of contaminated hamburgers

We conducted a retrospective analysis of 37 children with Escherichia coli O157:H7-associated hemolytic-uremic syndrome. The infection was traced to contaminated hamburgers at a fast-food restaurant chain. Within 5 days of the first confirmed case, the Washington State Department of Health identified the source and interrupted transmission of infection. Ninety-five percent of the children initially had severe hemorrhagic colitis. Nineteen patients (51%) had significant extrarenal abnormalities, including pancreatitis, colonic necrosis, glucose intolerance, coma, stroke, seizures, myocardial dysfunction, pericardial effusions, adult respiratory disease syndrome, and pleural effusions. Three deaths occurred, each in children with severe multisystem disease. At follow-up two children have significant impairment of renal function (glomerular filtration rate < 80 ml/min/per 1.73 Hm2); both of these children have a normal serum creatinine concentration. Hemolytic-uremic syndrome is the most common cause of acute renal failure in children, and this experience emphasizes the systemic nature of this disease. Clinicians should anticipate that multisystem involvement may occur in these patients, necessitating acute intervention or chronic follow-up. This outbreak of Hemolytic-uremic syndrome also highlights the microbiologic hazards of inadequately prepared food and emphasizes the importance of public health intervention in controlling Hemolytic-uremic syndrome.

Epidemic Escherichia coli O157:H7 gastroenteritis and hemolytic-uremic syndrome in a Canadian inuit community: intestinal illness in family members as a risk factor

OBJECTIVE

To evaluate risk factors for childhood hemolytic-uremic syndrome (HUS) and gastroenteritis during an epidemic of Escherichia coli O157:H7 infection.

DESIGN

Case-control study.

SETTING

Remote Inuit community of Arviat in northern Canada.

PARTICIPANTS

Of the 565 Arviat residents less than 15 years of age, 19 had HUS and 65 more had E. coli O157:H7 gastroenteritis. The 19 children with HUS were compared with 19 age- and gender-matched children with uncomplicated E. coli O157:H7 gastroenteritis, and both HUS and gastroenteritis patients were compared with 19 healthy control subjects.

INTERVENTIONS

Questionnaire administered face-to-face to parents of participants in the home.

MAIN OUTCOME MEASURES

Rates of exposure to foods, travel, sources of water, and gastrointestinal illness in family members.

RESULTS

Patients with HUS and those with uncomplicated E. coli O157:H7 gastroenteritis differed only on measures of clinical severity. In the 7 days before the onset of gastrointestinal symptoms, children with HUS and those with uncomplicated gastroenteritis were more likely to have been exposed to a family member with diarrhea than were the healthy control subjects (odds ratio = 9 for HUS vs healthy control subjects; 95% confidence interval 2 to 43; p < 0.01). Undercooked ground meat and foods traditionally consumed by the Inuit were not implicated as risk factors in E. coli O157:H7 infection.

CONCLUSIONS

These findings emphasize the potential for extensive intrafamilial transmission of verotoxin-producing E. coli once infection is introduced into certain communities.

Shiga-like toxin-producing Escherichia coli in Seattle children: a prospective study

BACKGROUND

The frequency with which stools contain Shiga-like toxin producing Escherichia coli not belonging to serotype O157:H7 is unknown in the United States. The aim of this study was to determine the frequency with which these E. coli are present in stools from children from Seattle submitted for bacteriologic analysis.

METHODS

2225 coliform colonies from 445 stools submitted for bacterial culture from Seattle children were probed with the structural genes of Shiga-like toxins I and II in a 1-year prospective study. The adherence and actin aggregating characteristics of these E. coli were subsequently determined.

RESULTS

Five (1.1%) patients had non-O157:H7 Shiga-like toxin producing E. coli, a rate of isolation higher than Shigella or Yersinia (0.2% each) but lower than Campylobacter (2.5%), E. coli O157:H7 (2.9%), or Salmonella (3.4%). Only one of the five patients had bloody diarrhea. None developed hemolytic uremic syndrome. All strains adhered in a localized pattern to, and induced actin aggregation in, HeLa cells, and produced a toxin that was lethal to Vero cells.

CONCLUSIONS

Non-O157:H7 Shiga-like toxin producing E. coli are present in stools submitted for bacterial culture in a North American childhood population. Their role in childhood diarrhea warrants better definition.

Plasma exchange in children with hemolytic-uremic syndrome at risk of poor outcome

A retrospective study on the use of plasma exchange in children with hemolytic-uremic syndrome was conducted to compare the renal outcome in treated and nontreated patients. Only children over 5 years of age were selected because they seem to be at major risk of bad renal prognosis. The evolution of renal function in the two populations is not significantly different, but chronic renal failure (clearance < 60 mL/min/1.73 m2) and end-stage renal failure were present only in untreated patients.

The role of Escherichia coli O 157 infections in the classical (enteropathic) haemolytic uraemic syndrome: results of a Central European, multicentre study

To assess the importance of infection by Verotoxin (VT) producing Escherichia coli (VTEC) in children with HUS in Central Europe, stool and/or serum samples obtained from 147 patients from 28 paediatric centres were prospectively examined for the presence of VTEC and the kinetics of faecal VT titres (FVT), and for VT neutralization titres and antibodies against E. coli O 157 lipopolysaccharide, respectively. Ninety-two percent of the patients had classic (enteropathic) HUS (E+ HUS). Evidence of VTEC infection was obtained in 86% of them. VTEC/FVT were identified in 55/118 E+ cases (47%). A prominent feature was the frequent isolation of sorbitol-fermenting, VT2-producing E. coli O 157.H-.VT1 (C600/H19) was neutralized by 9%, and VT2 (C600/933W) by 99% of the initial serum samples from E+ patients, compared to 3% (VT1) and 100% (VT2) from age-related controls. Fourfold titre rises against VT1 and/or VT2 were observed in 13/70 (19%), and significantly elevated O 157 LPS IgM and/or IgA antibodies in 106/128 (83%) of the E+ patients. The ubiquitous VT2 neutralizing principle in the serum of HUS patients as of healthy controls warrants further investigations.

Diarrhoea in close contacts as a risk factor for childhood haemolytic uraemic syndrome. The CPKDRC co-investigators

To determine whether the risk factors for childhood haemolytic uraemic syndrome (HUS) are similar to risk factors previously reported for Escherichia coli O 157. H7 gastroenteritis, we conducted a case-control study at eight paediatric hospitals in the summer of 1990. Thirty-four consecutive children with HUS were prospectively enrolled; all had diarrhoea and 88% had laboratory evidence of exposure to verotoxin-producing E. coli (VTEC). The 102 controls were otherwise healthy children with minor acute injuries. Parents of all subjects responded to a questionnaire about each child's exposure to various foods, methods of food preparation, sources of water, travel, and individuals with diarrhoea. Children with HUS were significantly more likely than controls to have had close contact with an individual with diarrhoea in the 2 weeks before the onset of illness (74 v. 29%, P < 0.00001; odds ratio 7.0, 95% CI 2.7-18.5). The onset of diarrhoea in the contacts occurred a median of 6 days (range, 1- > 14 days) before the onset of diarrhoea in the HUS patients. Exposure to undercooked ground meat was not significantly more common in the patients with HUS (15 v. 8%; P = 0.05). These data provide evidence consistent with person-to-person transmission of VTEC in a substantial proportion of episodes of childhood HUS.

A prospective study of exposure to verotoxin-producing Escherichia coli among Canadian children with haemolytic uraemic syndrome. The CPKDRC co-investigators

Haemolytic uraemic syndrome (HUS) is a leading cause of acute renal failure in childhood. Although infection with Escherichia coli O 157. H7 has been associated with HUS in North America and Europe, only a limited number of studies have examined the role of other verotoxin-producing E. coli (VTEC) serotypes in this condition. To address this issue, we conducted a comprehensive, prospective microbiological study of patients treated for HUS at eight Canadian hospitals in the summer of 1990. Of the 34 consecutive patients with HUS enrolled over 4 months, E. coli O 157. H7 was isolated from the stools of 26, and other E. coli serotypes were isolated from four patients. In four subjects no pathogenic E. coli serotypes were identified on stool culture. Using oligonucleotide probes specific for VT-1 and VT-2, verotoxin genes were detected in the stool isolates of all patients with E. coli O 157. H7, and from two with other E. coli serotypes. Two other patients had at least a fourfold rise in anti-verotoxin antibodies. Strong evidence of exposure to a verotoxin was present in 30/34 (88%). Patients with E. coli O 157. H7 infection were more likely to develop an antibody response to VT-2 than to VT-1 (22/22 vs 12/22; P = 0.002). These results further strengthen the association of HUS with verotoxin-producing E. coli in North America, and confirm that E. coli serotypes other than O 157.H7 are isolated in a small proportion of summertime HUS episodes.

Hemolytic-uremic syndrome

HUS is one of the most common causes of acute renal failure in childhood. D+ HUS is the most common form and usually follows an episode of hemorrhagic colitis due to VTEC or S. dysenteriae type 1. The SLT elaborated by these organisms is responsible for the endothelial damage that is the initial insult in the pathogenesis of the acute renal failure. Excellent supportive care is necessary to reduce the mortality and morbidity due to HUS.

Sequelae of haemolytic uraemic syndrome

Twenty two patients with previous episodes of haemolytic uraemic syndrome (HUS) were investigated for evidence of deficits in cognitive, behavioural, and academic function. Patients were pair matched with 22 controls for age (+/- 1 year), gender, and socioeconomic status. HUS patients had numerically lower cognitive and achievement scores and higher behavioural problem ratings than their controls on every measure. None of the group differences was significant at the 0.01 level. Significance values between 0.10 and 0.01 were obtained for the Wechsler full scale and verbal intelligence quotient scores and for several of the achievement measures and behaviour ratings. These results were conservatively interpreted as trends and are considered to provide preliminary indications of a post-HUS deficit in behaviour, verbal intelligence, and the verbally based skills of reading comprehension and vocabulary. The findings provide interim guidelines for follow up care but require confirmation and elaboration in a larger study.