Clinical aspects of a nationwide epidemic of severe haemolytic uremic syndrome (HUS) in children

Diagnosis and Treatment for Shiga Toxin-Producing Escherichia coli Associated Hemolytic Uremic Syndrome

Shiga toxin-producing Escherichia coli (STEC)-associated hemolytic uremic syndrome (STEC-HUS) is a clinical syndrome involving hemolytic anemia (with fragmented red blood cells), low levels of platelets in the blood (thrombocytopenia), and acute kidney injury (AKI). It is the major infectious cause of AKI in children. In severe cases, neurological complications and even death may occur. Treating STEC-HUS is challenging, as patients often already have organ injuries when they seek medical treatment. Early diagnosis is of great significance for improving prognosis and reducing mortality and sequelae. In this review, we first briefly summarize the diagnostics for STEC-HUS, including history taking, clinical manifestations, fecal and serological detection methods for STEC, and complement activation monitoring. We also summarize preventive and therapeutic strategies for STEC-HUS, such as vaccines, volume expansion, renal replacement therapy (RRT), antibiotics, plasma exchange, antibodies and inhibitors that interfere with receptor binding, and the intracellular trafficking of the Shiga toxin.

Dilated cardiomyopathy: A rare and late complication of the hemolytic-uremic syndrome

Hemolytic uremic syndrome (HUS) is a non-exceptional, progressive complication of acute gastroenteritis in children, especially secondary to Escherichia coli infection. It is responsible for significant morbidity and significant mortality (10% of deaths) because of acute renal failure which often complicates it. Dilated cardiomyopathy is a rare but critical extra renal manifestation of the HUS. This article highlights the importance of considering the diagnosis of associated cardiomyopathy in the acute phase of HUS and the following months. A five-year-old boy presented with HUS with acute renal failure requiring peritoneal dialysis for 24 days. No cardiac signs appeared during the acute phase of the disease. After dialysis and normalization of blood pressure, fluid, and electrolyte disturbance, severe dilated cardiomyopathy with cardiac failure appeared three months later without definite etiology. A review of the literature confirmed the rare and severe nature of cardiac lesions occurring in HUS. Dilated cardiomyopathy is a rare but important extra renal manifestation of the HUS and is best demonstrated by echocardiography. A cardiac manifestation should also be screened for in the acute phase of HUS and several months later. <Learning objective: The main message to draw from this case is that despite the rarity of cardiac complications, routine echocardiographic screening of children with hemolytic uremic syndrome should be performed both in the acute phase and during subsequent follow-up even in the absence of clinical signs because of severe prognosis of this complication, and it is therefore the investigation of choice.>.

Outcome and clinical course of EHEC O104 infection in hospitalized patients: A prospective single center study

Objectives

Shiga-toxin producing O157:H7 Entero Haemorrhagic E. coli [STEC/EHEC] are the most common cause of Haemolytic Uraemic Syndrome [HUS] related to infectious haemorrhagic colitis. Nearly all recommendations on long term treatment of EHEC infections refer to this strain. The 2011 outbreak in Northern Europe was the first of this dimension to be caused by the serotype O104:H4. We report on the 3.5 year follow up of 61 patients diagnosed with symptomatic EHEC O104:H4 infection in spring 2011.

Methods

Patients with EHEC O104 infection were followed in a monocentric, prospective observational study at four time points: 4, 12, 24 and 36 months. These data include the patients’ histories, clinical findings, and complications.

Results

Sixty-one patients suffering from EHEC O104:H4 associated enterocolitis participated in the study at the time of hospital discharge. The mean age of patients was 43 ± 2 years, 37 females and 24 males. 48 patients participated in follow up 1 [FU 1], 34 patients in follow up 2 [FU 2], 23 patients in follow up 3 [FU 3] and 18 patients in follow up 4 [FU 4]. Out of 61 patients discharged from the hospital and included in the study, 54 [84%] were examined at least at one additional follow up. Serum creatinine decreased significantly between discharge and FU 1 from 1.3 ± 0.1 mg/dl to 0.7 ± 0.1 mg/dl [p = 0.0045]. From FU 1 until FU 4, no further change in creatinine levels could be observed. The patients need of antihypertensive medications decreased significantly [p = 0.0005] between discharge and FU 1 after four months. From FU 1 until FU 3, 24 months later, no further significant change in antihypertensive treatment was observed.

Conclusions

Our findings suggest that patients free of pathological findings at time of discharge do not need a specific follow up. Patients with persistent health problems at hospital discharge should be clinically monitored over four months to evaluate chronic organ damage. Progressive or new emerging renal damage could not be observed over time in any patient.

Postinfectious Hemolytic Uremic Syndrome

Post-infectious hemolytic uremic syndrome (HUS) is caused by specific pathogens in patients with no identifiable HUS-associated genetic mutation or autoantibody. The majority of episodes is due to infections by Shiga toxin (Stx) producing Escherichia coli (STEC). This chapter reviews the epidemiology and pathogenesis of STEC-HUS, including bacterial-derived factors and host responses. STEC disease is characterized by hematological (microangiopathic hemolytic anemia), renal (acute kidney injury) and extrarenal organ involvement. Clinicians should always strive for an etiological diagnosis through the microbiological or molecular identification of Stx-producing bacteria and Stx or, if negative, serological assays. Treatment of STEC-HUS is supportive; more investigations are needed to evaluate the efficacy of putative preventive and therapeutic measures, such as non-phage-inducing antibiotics, volume expansion and anti-complement agents. The outcome of STEC-HUS is generally favorable, but chronic kidney disease, permanent extrarenal, mainly cerebral complication and death (in less than 5 %) occur and long-term follow-up is recommended. The remainder of this chapter highlights rarer forms of (post-infectious) HUS due to S. dysenteriae, S. pneumoniae, influenza A and HIV and discusses potential interactions between these pathogens and the complement system.

Clinical features, therapeutic interventions and long-term aspects of hemolytic-uremic syndrome in Norwegian children: a nationwide retrospective study from 1999-2008

Background

Hemolytic-uremic syndrome (HUS) is a clinical triad of microangiopathic hemolytic anemia, impaired renal function and thrombocytopenia, primarily affecting pre-school-aged children. HUS can be classified into diarrhea-associated HUS (D⁺HUS), usually caused by Shiga toxin-producing Escherichia coli (STEC), and non-diarrhea-associated HUS (D⁻HUS), both with potentially serious acute and long-term complications. Few data exists on the clinical features and long-term outcome of HUS in Norway. The aim of this paper was to describe these aspects of HUS in children over a 10-year period.

Methods

We retrospectively collected data on clinical features, therapeutic interventions and long-term aspects directly from medical records of all identified HUS cases <16 years of age admitted to Norwegian pediatric departments from 1999 to 2008. Cases of D⁺HUS and D⁻HUS are described separately, but no comparative analyses were possible due to small numbers. Descriptive statistics are presented in proportions and median values with ranges, and/or summarized in text.

Results

Forty seven HUS cases were identified; 38 D⁺HUS and nine D⁻HUS. Renal complications were common; in the D⁺HUS and D⁻HUS group, 29/38 and 5/9 developed oligoanuria, 22/38 and 3/9 needed dialysis, with hemodialysis used most often in both groups, and plasma infusion(s) were utilized in 6/38 and 4/9 patients, respectively. Of extra-renal complications, neurological complications occurred in 9/38 and 2/9, serious gastrointestinal complications in 6/38 and 1/9, respiratory complications in 10/38 and 2/9, and sepsis in 11/38 and 3/9 cases, respectively. Cardiac complications were seen in two D⁺HUS cases. In patients where data on follow up ≥1 year after admittance were available, 8/21 and 4/7 had persistent proteinuria and 5/19 and 4/5 had persistent hypertension in the D⁺HUS and D⁻HUS group, respectively. Two D⁺HUS and one D⁻HUS patient were diagnosed with chronic kidney disease and one D⁺HUS patient required a renal transplantation. Two D⁺HUS patients died in the acute phase (death rate; 5 %).

Conclusions

The HUS cases had a high rate of complications and sequelae, including renal, CNS-related, cardiac, respiratory, serious gastrointestinal complications and sepsis, consistent with other studies. This underlines the importance of attention to extra-renal manifestations in the acute phase and in renal long-term follow-up of HUS patients.

Hypertension and mild chronic kidney disease persist following severe haemolytic uraemic syndrome caused by Shiga toxin-producing Escherichia coli O104:H4 in adults

BACKGROUND

Shiga toxin-producing, enteroaggregative Escherichia coli was responsible for the 2011 outbreak of haemolytic uraemic syndrome (HUS). The present single-centre, observational study describes the 1-year course of the disease with an emphasis on kidney function. Outcome data after 1 year are associated with treatment and patient characteristics at onset of HUS.

METHODS

Patients were treated according to a standardized approach of supportive care, including a limited number of plasmapheresis. On top of this treatment, patients with severe HUS (n = 35) received eculizumab, a humanized anti-C5 monoclonal antibody inhibiting terminal complement activation. The per-protocol decision--to start or omit an extended therapy with eculizumab accompanied by azithromycin--separated the patients into two groups and marked Day 0 of the prospective study. Standardized visits assessed the patients' well-being, kidney function, neurological symptoms, haematological changes and blood pressure.

RESULTS

Fifty-six patients were regularly seen during the follow-up. All patients had survived without end-stage renal disease. Young(er) age alleviated restoring kidney function after acute kidney injury even in severe HUS. After 1 year, kidney function was affected with proteinuria [26.7%; 95% confidence interval (CI) 13.8-39.6], increased serum creatinine (4.4%, CI 0.0-10.4), increased cystatin C (46.7%, CI 32.1-61.3) and reduced (<90 mL/min) estimated glomerular filtration rate (46.7%, CI 32.1-61.3). Nine of the 36 patients without previous hypertension developed de novo hypertension (25%, CI 10.9-39.1). All these patients had severe HUS.

CONCLUSIONS

Although shiga toxin-producing Escherichia coli (STEC)-HUS induced by O104:H4 was a life-threatening acute disease, follow-up showed a good recovery of organ function in all patients. Whereas kidney function recovered even after longer duration of dialysis, chronic hypertension developed after severe HUS with neurological symptoms and could not be prevented by the extended therapy.

The incidence and aetiology of acute kidney injury in children in Norway between 1999 and 2008

Aim

Primary acute kidney injury (AKI) is a direct cause of hospitalisation in children, but can also result from other conditions. There is limited information on the epidemiology of this condition. Our aim was to describe the national incidence rate and aetiology of acute kidney injury in children under the age of 16 in Norway from 1999 to 2008.

Methods

We carried out a retrospective study of medical records provided by all 18 of the paediatric hospital departments that specialise in treating paediatric patients with AKI.

Results

We identified 315 cases of AKI (53% male), with an estimated average annual incidence rate of 3.3 cases per 100 000 children and a median annual occurrence of 33 cases. Most cases (43%) were in children under five. We identified 53 aetiologies and classified these into 30 aetiological groups: 24% of the cases were prerenal (n = 75), 74% were intrinsic/renal (n = 234) and 2% were postrenal (n = 5). Nephritic syndromes was the major cause (44%) of AKI, followed by haemolytic-uraemic syndrome (HUS) (15%).

Conclusion

Nephritic syndromes and HUS are the most common aetiologies of AKI in Norway. Although our results could indicate a low incidence of paediatric AKI in Norway, the lack of other national studies makes comparisons difficult.

Incidence and etiology of hemolytic-uremic syndrome in children in Norway, 1999-2008--a retrospective study of hospital records to assess the sensitivity of surveillance

Background

Public awareness of hemolytic-uremic syndrome (HUS), especially related to Shiga toxin-producing Escherichia coli (STEC), has increased in Europe in recent years; accentuated in Norway by a national outbreak in 2006 and in a European context especially by the 2011 outbreak originating in Germany. As STEC surveillance is difficult due to diagnostic challenges in detecting non-O157 infections, surveillance of HUS can be used to indicate the burden of STEC infection. Until 2006, notification of HUS to the Norwegian Communicable Disease Surveillance System (MSIS) was based on microbiologically confirmed infection with enterohemorrhagic Escherichia coli (EHEC), humanpathogenic STEC. In 2006, diarrhea-associated HUS (D⁺HUS) was made notifiable based on clinical criteria alone. The incidence and etiology of HUS in children in Norway has not previously been described.

Methods

In order to assess the sensitivity of STEC and D⁺HUS surveillance and describe the incidence and etiology of HUS in children in Norway, we conducted a nationwide retrospective study collecting data from medical records from pediatric departments for the period 1999–2008 and compared them with data from MSIS. Descriptive statistics are presented as proportions, median, average and mean values with ranges and as incidence rates, calculated using population numbers provided by official registries.

Results

Forty-seven HUS cases were identified, corresponding to an average annual incidence rate of 0.5 cases per 100,000 children. Diarrhea-associated HUS was identified in 38 (81%) cases, of which the median age was 29 months, 79% were <5 years of age and 68% were girls. From 1999 to 2006, thirteen more diarrhea-associated HUS cases were identified than had been notified to MSIS. From the change in notification criteria to 2008, those identified corresponded to those notified. STEC infection was verified in 23 (49%) of the HUS cases, in which O157 was the most frequently isolated sporadic serogroup.

Conclusions

Our results show that the incidence of HUS in children in Norway is low and suggest that D⁺HUS cases may be underreported when notification requires microbiological confirmation. This may also indicate underreporting of STEC infections.

Synthetic brominated furanone F202 prevents biofilm formation by potentially human pathogenic Escherichia coli O103:H2 and Salmonella ser. Agona on abiotic surfaces

AIMS

Investigate the use of a synthetic brominated furanone (F202) against the establishment of biofilm by Salmonella ser. Agona and E. coli O103:H2 under temperature conditions relevant for the food and feed industry as well as under temperature conditions optimum for growth.

METHODS AND RESULTS

Effect of F202 on biofilm formation by Salmonella ser. Agona and E. coli O103:H2 was evaluated using a microtiter plate assay and confocal microscopy. Effect of F202 on bacterial motility was investigated using swimming and swarming assays. Influence on flagellar synthesis by F202 was examined by flagellar staining. Results showed that F202 inhibited biofilm formation without being bactericidal. F202 was found to affect both swimming and swarming motility without, however, affecting the expression of flagella.

CONCLUSIONS

F202 showed its potential as a biofilm inhibitor of Salmonella ser. Agona and E. coli O103:H2 under temperature conditions relevant for the feed and food industry as well as temperatures optimum for growth. One potential mode of action of F202 was found to be by targeting flagellar function.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study gives valuable new knowledge to the potential use of furanones as a tool in biofilm management in the food and feed industry.

Renal and neurological involvement in typical Shiga toxin-associated HUS

Shiga toxin-producing Escherichia coli-associated haemolytic uraemic syndrome (STEC-HUS) is one of the most important causes of acute kidney injury in patients of all ages, especially in children. It can occur sporadically or in outbreaks. STEC-HUS is a systemic illness caused by toxin-mediated injury to the vascular endothelium and a generalized inflammatory response. The kidney and the brain are the two primary target organs. Nearly 40% of patients with STEC-HUS require at least temporary renal replacement therapy and up to 20% will have permanent residual kidney dysfunction. Neurological injury can be sudden and severe and is the most frequent cause of acute mortality in patients with STEC-HUS. Over the past 30 years, a wide range of inflammatory mediators have been linked to the pathogenesis of STEC-HUS and associated renal and neurological complications. Recently, evidence has accumulated that abnormal activation of the alternative pathway of complement occurs in patients with STEC-HUS. In the large outbreak of STEC-HUS caused by E. coli O104:H4 that occurred in Germany in May 2011, a large number of patients received eculizumab, a monoclonal antibody directed against C5, in an open-label manner. We describe the experience with eculizumab under these emergent circumstances at one large centre.

An outbreak of Shiga toxin-producing Escherichia coli O104:H4 hemolytic uremic syndrome in Germany: presentation and short-term outcome in children

BACKGROUND

In May and June 2011 the largest known outbreak of hemolytic uremic syndrome (HUS) occurred in northern Germany. Because, quite unusually, a large number of adults was affected and the causative Escherichia coli strain, serotype O104:H4, showed an atypical virulence factor pattern, it was speculated that this outbreak was associated with an aggressive course and an unfavorable prognosis also in children.

METHODS

Retrospective analysis of medical records of 90 children and comparison to previous outbreak and sporadic case series.

RESULTS

Median age was unusually high (11.5 years) compared with that in historical series. Only 1 patient (1.1%) died in the acute phase. Most patients (67/90 [74%]) received supportive care only. Renal replacement therapy was required in 64 of 90 (71%) of the children. Neurological complications, mainly seizures and altered mental stage, were present in 23 of 90 (26%) patients. Ten patients received plasmapheresis, 6 eculizumab, and 7 a combination of both. After a median follow-up of 4 months, renal function normalized in 85 of 90 (94%) patients, whereas 3 patients had chronic kidney disease stage 3 or 4, and 1 patient (1.1%) still requires dialysis. Complete neurological recovery occurred in 18 of 23 patients. Mild to moderate and major residual neurological changes were present in 3 patients and 1 patient, respectively, although all patients were still improving.

CONCLUSIONS

E. coli O104:H4 caused the largest HUS outbreak in children reported in detail to date and most patients received supportive treatment only. Initial morbidity, as well as short-term outcome, due to this pathogen, is comparable to previous pediatric series of Shiga toxin-producing E. coli HUS.