Association between severity of gastrointestinal prodrome and long-term prognosis in classic hemolytic-uremic syndrome

Shiga Toxin-Associated Hemolytic Uremic Syndrome: A Narrative Review

The severity of human infection by one of the many Shiga toxin-producing Escherichia coli (STEC) is determined by a number of factors: the bacterial genome, the capacity of human societies to prevent foodborne epidemics, the medical condition of infected patients (in particular their hydration status, often compromised by severe diarrhea), and by our capacity to devise new therapeutic approaches, most specifically to combat the bacterial virulence factors, as opposed to our current strategies that essentially aim to palliate organ deficiencies. The last major outbreak in 2011 in Germany, which killed more than 50 people in Europe, was evidence that an effective treatment was still lacking. Herein, we review the current knowledge of STEC virulence, how societies organize the prevention of human disease, and how physicians treat (and, hopefully, will treat) its potentially fatal complications. In particular, we focus on STEC-induced hemolytic and uremic syndrome (HUS), where the intrusion of toxins inside endothelial cells results in massive cell death, activation of the coagulation within capillaries, and eventually organ failure.

Pediatric Rectal Prolapse

Rectal prolapse is a common and self-limiting condition in infancy and early childhood. Most cases respond to conservative management. Patients younger than 4 years with an associated condition have a better prognosis. Patients older than 4 years require surgery more often than younger children. Multiple operative and procedural approaches to rectal prolapse exist with variable recurrence rates and without a clearly superior operation. These include sclerotherapy, Thiersch's anal cerclage, Ekehorn's rectopexy, laparoscopic suture rectopexy, and posterior sagittal rectopexy.

Haemolytic uraemic syndrome

Haemolytic uraemic syndrome (HUS) is defined by the simultaneous occurrence of nonimmune haemolytic anaemia, thrombocytopenia and acute renal failure. This leads to the pathological lesion termed thrombotic microangiopathy, which mainly affects the kidney, as well as other organs. HUS is associated with endothelial cell injury and platelet activation, although the underlying cause may differ. Most cases of HUS are associated with gastrointestinal infection with Shiga toxin-producing enterohaemorrhagic Escherichia coli (EHEC) strains. Atypical HUS (aHUS) is associated with complement dysregulation due to mutations or autoantibodies. In this review, we will describe the causes of HUS. In addition, we will review the clinical, pathological, haematological and biochemical features, epidemiology and pathogenetic mechanisms as well as the biochemical, microbiological, immunological and genetic investigations leading to diagnosis. Understanding the underlying mechanisms of the different subtypes of HUS enables tailoring of appropriate treatment and management. To date, there is no specific treatment for EHEC-associated HUS but patients benefit from supportive care, whereas patients with aHUS are effectively treated with anti-C5 antibody to prevent recurrences, both before and after renal transplantation.

Enterohemorrhagic Escherichia coli Pathogenesis and the Host Response

Enterohemorrhagic Escherichia coli (EHEC) is a highly pathogenic bacterial strain capable of causing watery or bloody diarrhea, the latter termed hemorrhagic colitis, and hemolytic-uremic syndrome (HUS). HUS is defined as the simultaneous development of non-immune hemolytic anemia, thrombocytopenia, and acute renal failure. The mechanism by which EHEC bacteria colonize and cause severe colitis, followed by renal failure with activated blood cells, as well as neurological symptoms, involves the interaction of bacterial virulence factors and specific pathogen-associated molecular patterns with host cells as well as the host response. The innate immune host response comprises the release of antimicrobial peptides as well as cytokines and chemokines in addition to activation and/or injury to leukocytes, platelets, and erythrocytes and activation of the complement system. Some of the bacterial interactions with the host may be protective in nature, but, when excessive, contribute to extensive tissue injury, inflammation, and thrombosis, effects that may worsen the clinical outcome of EHEC infection. This article describes aspects of the host response occurring during EHEC infection and their effects on specific organs.

Early erythropoietin in post-diarrheal hemolytic uremic syndrome: a case-control study

BACKGROUND

Although erythropoietin (EPO) deficiency has been reported in children with post-diarrheal hemolytic uremic syndrome (D + HUS), very limited clinical data on EPO use in this disease are currently available. In this case-control study we examined whether EPO administration would reduce the number of red blood cell (RBC) transfusions in D + HUS patients under our care.

METHODS

Data from children treated exclusively with RBC transfusions (controls; n = 21) were retrospectively compared with data on those who also received EPO for the treatment of anemia (cases; n = 21).

RESULTS

Both patient groups were similar in age (p = 0.9), gender (p = 0.12), weight (p = 1.00) and height (p = 0.66). Acute phase severity was also comparable, as inferred by the need for dialysis (p = 0.74), the duration of dialysis (p = 0.3), length of hospitalization (p = 0.81), presence of severe bowel (p = 1.00) or neurological injury (p = 0.69), arterial hypertension (p = 1.00) and death (p = 1.00). No differences in the hemoglobin level at admission (p = 0.51) and discharge (p = 0.28) were noted. Three children treated with EPO and two controls did not require any RBC transfusion (p = 1.00). Median number of RBC transfusions needed by cases and controls was 2 (p = 0.52).

CONCLUSION

Treatment with EPO did not reduce the number of RBC transfusions in D + HUS children. Assessment of EPO efficacy in D + HUS merits further studies.

Long-term outcomes of Shiga toxin hemolytic uremic syndrome

Shiga toxin-producing Escherichia coli (STEC) hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury (AKI). The outcomes of STEC HUS have improved, and the acute mortality rate in children is 1-4%. About 70% of patients recover completely from the acute episode and the remainder have varying degrees of sequelae. Only a few retrospective studies have reviewed these patients over long periods. Methodological flaws include a lack of strict definitions, changing modes of treatment, ascertainment bias and loss of subjects to follow-up. The kidneys bear the brunt of the long-term damage: proteinuria (15-30% of cases); hypertension (5-15%); chronic kidney disease (CKD; 9-18%); and end-stage kidney disease (ESKD; 3%). A smaller number have extra-renal sequelae: colonic strictures, cholelithiasis, diabetes mellitus or brain injury. Most renal sequelae are minor abnormalities, such as treatable hypertension and/or variable proteinuria. Most of the patients who progress to ESKD do not recover normal renal function after the acute episode. Length of anuria (more than 10 days) and prolonged dialysis are the most important risk factors for a poor acute and long-term renal outcome. After the acute episode all patients must be followed for at least 5 years, and severely affected patients should be followed indefinitely if there is proteinuria, hypertension or a reduced glomerular filtration rate (GFR).

Hemolytic uremic syndrome: pathogenesis and update of interventions

The typical form of hemolytic uremic syndrome (HUS) is the major complication of Shiga toxin-producing Escherichia coli infections. HUS is a critical health problem in Argentina since it is the main cause of acute renal failure in children and the second cause of chronic renal failure, accounting for 20% of renal transplants in children and adolescents in Argentina. Despite extensive research in the field, the mainstay of treatment for patients with HUS is supportive therapy, and there are no specific therapies preventing or ameliorating the disease course. In this review, we present the current knowledge about pathogenic mechanisms and discuss traditional and innovative therapeutic approaches, with special focus in Argentinean contribution. The hope that a better understanding of transmission dynamics and pathogenesis of this disease will produce better therapies to prevent the acute mortality and the long-term morbidity of HUS is the driving force for intensified research.

Long-term course and mechanisms of progression of renal disease in hemolytic uremic syndrome

In the classic form of hemolytic uremic syndrome associated with toxins of gram-negative enterobacteria, mortality in the acute stage has been lower than 5% since 1978 (data from the Nephrology Committee, Argentine Society of Pediatrics). Children usually die because of severe involvement of the central nervous system, intestine, or myocardium and its complications, or because of intercurrent infection. Treatment in this phase is supportive, and efforts should be put into prevention of infection by Shiga-like toxin-producing enterohemorrhagic Escherichia coli. Of the 95% who survive, approximately one third is at risk for having chronic sequelae. Motor, sensory, or intellectual deficits, intestinal strictures, myocardial infarctions, or diabetes are infrequent. The more-frequent chronic renal lesion is characterized by the hyperfunction of nephrons remaining after the acute necrotizing lesion, which leads to progressive scarring, and not by persistence or recurrence of the microangiopathic process. Three courses of progression to end-stage renal failure have been described. Children with most severe forms do not recover from acute renal failure and enter directly into a dialysis and transplantation program. A second group recovers renal function partially, with persistent proteinuria and frequently hypertension; progression to end-stage renal failure occurs in 2 to 5 years. The third group may recover normal serum creatinine and creatinine clearance, with persistent proteinuria. They are at risk of progressing to chronic renal failure and end-stage renal disease after more than 5 years, and sometimes as late as 20 years, after the acute disease. Treatment should aim at preventing the mechanisms associated with progressive renal scarring. Transplantation is indicated in this form of hemolytic uremic syndrome, because there is little, if any, risk of recurrence, and the prognosis is similar to that of transplantation for other diseases.

Not All Inflammation in the Right Lower Quadrant is Appendicitis: A Case Report of Escherichia coli O157:H7 with a Review of the Literature

Although significant work has been presented on this subject in pediatric, infectious disease, and epidemiologic literature, there is a noteworthy lack of information on Escherichia coli O157:H7 in any surgical journals. As this disease can present with signs and symptoms often ascribed to the acute abdomen, it is imperative that the general surgeon, pediatric surgeon, and colorectal surgeon are all familiar with this infection and its clinical ramifications. A case report followed by a review of the literature is presented.

The role of Shiga-toxin-producing Escherichia coli in hemorrhagic colitis and hemolytic uremic syndrome

The Shiga-toxin-producing E. coli represent a major class of pathogens that have been defined over the last twenty years. They cause distinctive clinical manifestations such as afebrile bloody diarrhea with severe abdominal pain (hemorrhagic colitis) and microangiopathic hemolytic anemia with renal failure (hemolytic uremic syndrome). The most common Shiga-toxin-producing E. coli is serotype O157:H7, although at least one hundred different serotypes share the virulence traits and clinical manifestations with this organism. Understanding the pathophysicology, improving diagnostic tools, and developing a treatment strategy are important areas of ongoing investigations.

Nationwide study of haemolytic uraemic syndrome: clinical, microbiological, and epidemiological features

AIMS

To establish the incidence and aetiology of haemolytic uraemic syndrome (HUS) in Australia and compare clinical and microbial characteristics of sporadic and outbreak cases.

METHODS

National active surveillance through the Australian Paediatric Surveillance Unit with monthly case notification from paediatricians, July 1994 to June 1998. Children under 15 years presenting with microangiopathic haemolytic anaemia, thrombocytopenia, and acute renal impairment were identified.

RESULTS

Ninety eight cases were identified (incidence 0.64 per 10(5) children <15 years/annum and 1.35 per 10(5) children <5 years/annum). Eighty four were associated with diarrhoea (64 sporadic, 20 constituting an outbreak) and 14 were atypical. Shiga toxin producing Escherichia coli (STEC) O111:H- was the most common isolate in sporadic HUS and caused the outbreak. However O111:H- isolates from outbreak and sporadic cases differed in phage type and subtyping by DNA electrophoresis. STEC isolates from sporadic cases included O26:H-, O113:H21, O130:H11, OR:H9, O157:H-, ONT:H7, and ONT:H-. STEC O157:H7 was not isolated from any case. Only O111:H- isolates produced both Shiga toxins 1 and 2 and possessed genes encoding E coli attaching and effacing gene (intimin) and enterohemolysin. Outbreak cases had worse gastrointestinal and renal disease at presentation and more extrarenal complications.

CONCLUSIONS

Linking national surveillance with a specialised laboratory service allowed estimation of HUS incidence and provided information on its aetiology. In contrast to North America, Japan, and the British Isles, STEC O157:H7 is rare in Australia; however, non-O157:H7 STEC cause severe disease including outbreaks. Disease severity in outbreak cases may relate to yet unidentified virulence factors of the O111:H- strain isolated.

Haemolytic uraemic syndrome

Diarrhoea-associated haemolytic uraemic syndrome develops in about 5 to 10% of children with haemorrhagic colitis due to Escherichia coli (E. coli) O157:H7 and is a common cause of acute renal failure in childhood. Endothelial cell damage, white blood cell activation and platelet-endothelial cell interactions are important in the pathogenesis. Meticulous supportive care, with attention to nutrition and fluid, and electrolyte balance, is important. Dialysis is necessary in many children. Public health follow-up is important to minimise the spread of E. coli O157:H7, which is transmitted by person-to-person, as well as through contaminated food products. 20-year follow-up studies report that 75% of children recover without any clinically significant long term sequelae. Chronic renal failure is reported in about 5% of children.

Shigella and Shiga toxin-producing Escherichia coli causing bloody diarrhea in Latin America

In Latin America, Shigella and shiga toxin-producing Escherichia coli are the two leading agents in the cause of bloody diarrhea. The already high and increasing antimicrobial resistance of Shigella also is a significant problem. Shiga toxin-producing E. coli is an emerging disease with life-threatening complications: hemolytic uremic syndrome. Although E. coli O157:H7 remains the most commonly recognized serotype, recently emerging, non-O157 bacteria may be the cause of a similar spectrum of disease in humans.

Rectal prolapse in pediatrics

Rectal prolapse in pediatrics has its highest incidence in infancy and is uncommonly seen in industrialized countries. The prolapse may involve only the mucosa (mucosal prolapse) or all layers of the rectum (complete prolapse or procidentia). It is usually detected by the child's parents and is brought urgently to medical attention; however, it is usually spontaneously reduced by the time they reach the practitioner's office. Rectal prolapse should be viewed as a symptom of an underlying condition rather than a discrete disease entity. Potential causes are increased intraabdominal pressure, diarrheal and neoplastic diseases, malnutrition, and conditions predisposing to pelvic floor weakness. Its strong association with cystic fibrosis makes the sweat test mandatory for infants and children with recurrent rectal prolapse. Of particular importance are three entities related to rectal prolapse that may easily escape diagnosis by practitioner: occult rectal prolapse, solitary ulcer of the rectum syndrome, and inflammatory cloacogenic polyps. The treatment of rectal prolapse is mainly conservative and is directed at the underlying conditions. Surgical intervention may be required for recurrent rectal prolapse refractory to conservative measures. The simplest, less invasive, yet highly effective approach, appears to be perirectal injection with a sclerosing agent. While the majority of children experience spontaneous resolution of the prolapse, the prognosis is worse when presentation occurs after the age of 4 years.

Survey of haemolytic-uraemic syndrome in Queensland 1979-1995

OBJECTIVE

To review the clinical course of haemolytic-uraemic syndrome (HUS) in children admitted to Brisbane children's hospitals between April 1979 and October 1995.

DESIGN

Retrospective case survey.

SETTING

Royal Children's Hospital and Mater Misericordiae Children's Hospital (the two major children's hospitals in Brisbane).

SUBJECTS

All children hospitalised for HUS.

OUTCOME MEASURES

Clinical and laboratory features on presentation (including typical [diarrhoea-positive, D+] or atypical [diarrhoea-negative, D-] presentation), clinical course, treatment and features on subsequent outpatient follow-up (1, 3, 6 and 12 months later), renal outcome on long term follow-up (3-16 years later).

RESULTS

55 children (aged 2 months to 13 years) were hospitalised for HUS, but no epidemic was detected. Seven children (13%) had D- presentations, including three (5%) with T-activation caused by pneumococcal pneumonia. Thrombocytopenia was more severe and prolonged in D- patients (P < 0.01). Major complications occurred only in the D+ group (one patient died, and two had recurrences). Chronic renal failure was significantly more likely in patients with prolonged oliguria or hypertension in the acute illness and proteinuria or hypertension on follow-up.

CONCLUSIONS

The clinical course and outcome in childhood HUS vary greatly and D- HUS is not invariably associated with a poorer prognosis than D+ HUS. Pneumococcal-associated T-activation is an important cause of D- HUS and should be actively sought to allow for appropriate therapy.

[Digestive manifestations in hemolytic uremic syndrome in children]

BACKGROUND

Gastro-intestinal manifestations are relatively frequent during the course of hemolytic uremic syndrome (HUS), some of them requiring special supportive care. This work was aimed at retrospectively studing gastrointestinal manifestations of HUS and determining their place in the prognosis.

PATIENTS

Thirty-seven children aged 4 months to 11 years (22 girls and 15 boys) were included in the study.

RESULTS

All children but one had gastrointestinal prodromes. During the course of HUS, various manifestations were seen: bloody diarrhea in 32% of patients, ileo-ileal intussusception in 3%, rectal prolapse in 8% and hepatic cytolysis in 38%. Seven patients with bloody diarrhea had a complicated course, lethal in one. Comparison between these seven children and the 30 others revealed some indicators of severe gut involvement: female sex, short duration of gastrointestinal prodromes, hemorrhagic colitis with rectal prolapse, high WBC count, high neutrophils count and less important degree of anemia at admission. Severity of the gastrointestinal lesions was correlated with that of the outcome of the renal disease.

CONCLUSION

Gastrointestinal tract is frequently affected in HUS and severe complications can appear, potentially leading to death. Total parenteral nutrition could prevent occurrence of gastrointestinal complications. Severe gastrointestinal lesions are associated with a poor renal outcome.

Hemolytic uremic syndrome - clinical aspects and outcome of an outbreak: Report of 28 cases

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. There are two main subgroups: the typical form of HUS follows a diarrheal prodrome (D+HUS) and the atypical form is without the diarrheal prodrome (D-HUS). We have studied 28 children with HUS over a period of 15 months between 1992 and 1993. The median age was 2.2 years (range from six months to six years). All children had prodromal diarrhea. Hypertension was present in 71% and neurological complications in 39%. All the patients had oliguria or anuria (16 oliguric and 12 anuric). The mean duration of anuria was 16 days (range seven to 42 days). Serum creatinine on admission ranged between 112 and 1064 Amicromol/L (mean 453 Amicromol/L). The lowest hemoglobin level and platelet count during hospitalization ranged between 38 and 87 g/L and 7 to 147x109/L respectively. Leukocytosis on admission was present in 22 patients, low C3 was documented in 11 patients (34%), and four patients had low C4. All patients received fresh frozen plasma transfusion, a total of 25 patients received dialysis therapy, 19 patients were treated with peritoneal dialysis (PD), one patient had hemodialysis (HD), and five patients had both HD and PD. The mean duration of dialysis was 18 days (range three to 56 days). Only one patient died (mortality rate 3%). The median duration of hospital stay was 28 days (range eight to 90 days). We conclude that HUS is emerging as an important clinical and public health problem and that early comprehensive management including dialysis therapy, aggressive management of hypertension, fresh frozen plasma transfusion, and nutritional support all improve the outcome and decrease the mortality and morbidity in patients with HUS.

Extrarenal involvement in diarrhoea-associated haemolytic-uraemic syndrome

A review of extrarenal involvement in diarrhoea-associated haemolytic-uraemic syndrome (HUS) is based on 64 of our autopsied patients and an update of the literature. Large bowel pathology was the commonest (29 cases), followed by the central nervous system (21 cases), the heart (19 cases) and the pancreas (19 cases). The severity of systemic involvement was associated with the magnitude of renal compromise and the prognosis of the acute phase. Diarrhoea-associated HUS is described as a multiorgan entity, due to extensive microvascular damage and thrombosis. At present mortality during the acute phase is not confined to renal failure; systemic involvement can also lead to death.

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.

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.