Dehydration at admission increased the need for dialysis in hemolytic uremic syndrome children

Volume expansion mitigates Shiga toxin-producing E. coli-hemolytic uremic syndrome in children

BACKGROUND

Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS) is associated with high morbidity and relevant mortality. Previous small studies showed that volume expansion could improve the course and outcome of STEC-HUS. The aim of this single-center study was to evaluate the effect of volume expansion on the clinical course and outcome in STEC-HUS.

METHODS

Data of pediatric patients with STEC-HUS were analyzed retrospectively. Course and outcome of patients treated with volume expansion (VE) from 2019 to 2022 (n = 38) were compared to historical controls (HC) from 2009 to 2018 (n = 111).

RESULTS

Patients in the VE group had a significant relative median weight gain compared to HC (7.8% (3.4-11.3) vs. 1.2% (- 0.7-3.9), p < 0.0001) 48 h after admission. The need for dialysis was not reduced by VE (VE 21/38 (55.3%) vs. HC 64/111 (57.7%), p = 0.8). However, central nervous system involvement (impairment of consciousness, seizures, focal neurological deficits, and/or visual disturbances) was significantly reduced (VE 6/38 (15.8%) vs. HC 38/111 (34.2%), p = 0.039). None of the patients in the VE group died or developed chronic kidney disease (CKD) stage 5, whereas in the HC group, three patients died and three patients had CKD stage 5 at discharge.

CONCLUSIONS

This study suggests that volume expansion may be associated with the mitigation of the acute course of STEC-HUS, especially severe neurological involvement and the development of CKD. Prospective trials should lead to standardized protocols for volume expansion in children with STEC-HUS.

Duration of prodromal phase and severity of hemolytic uremic syndrome

BACKGROUND

Some data have recognized an association between shorter prodromal phase and severe episode of Shiga toxin-producing Escherichia coli-related hemolytic uremic syndrome (STEC-HUS). Our aims were to confirm such association and analyze characteristics of STEC-HUS patients according to duration of the prodromal phase.

METHODS

Patients treated from 2000 to 2022 were compared according to the presence of severe (> 10 days of dialysis and/or extra-renal complications) or non-severe disease. Association between prodromal phase duration and disease severity was assessed by ROC curve and by classifying the cohort in 3 groups according to time to diagnosis.

RESULTS

Non-severe (n = 145) and severe (n = 71) cases were compared. The latter had shorter prodromal phase, higher leukocyte count, hemoglobin, lactic dehydrogenase, liver enzymes, C-reactive protein, urea and creatinine, and lower albumin and sodium; only prodromal phase duration (p = 0.02) and leukocyte count (p = 0.02) remained significant in multivariate analysis. By ROC curve analysis, time to diagnosis resulted in a poor predictor of outcomes (AUC = 0.27). Since prodromal phase duration was 5 days (IQR 3-7), we divided the cohort into Groups A (1-2 days), B (3-7 days), and C (≥ 8 days). Rates of severe disease were 75.8%, 29.6%, and 11.4%, respectively. Taking Group B as reference, Group A patients had higher risk of complications (p = 0.00001; OR 7.4, 95% CI: 2.98-18.7) while Group C ones had significantly less risk (p = 0.02; OR 0.3, 95% CI: 0.1-0.91).

CONCLUSIONS

This study found that duration of prodromal phase is an independent predictor of complicated STEC-HUS and confirms that shorter prodromal phase is associated with worse prognosis. A higher resolution version of the Graphical abstract is available as Supplementary information.

Haemolytic uraemic syndrome in children England, Wales, Northern Ireland, and Ireland: A prospective cohort study

Haemolytic uraemic syndrome (HUS) caused by infection with Shiga toxin-producing Escherichia coli (STEC) is a relatively rare but potentially fatal multisystem syndrome clinically characterised by acute kidney injury. This study aimed to provide robust estimates of paediatric HUS incidence in England, Wales, Northern Ireland, and the Republic of Ireland by using data linkage and case reconciliation with existing surveillance systems, and to describe the characteristics of the condition. Between 2011 and 2014, 288 HUS patients were included in the study, of which 256 (89.5%) were diagnosed as typical HUS. The crude incidence of paediatric typical HUS was 0.78 per 100,000 person-years, although this varied by country, age, gender, and ethnicity. The majority of typical HUS cases were 1 to 4 years old (53.7%) and female (54.0%). Clinical symptoms included diarrhoea (96.5%) and/or bloody diarrhoea (71.9%), abdominal pain (68.4%), and fever (41.4%). Where STEC was isolated (59.3%), 92.8% of strains were STEC O157 and 7.2% were STEC O26. Comparison of the HUS case ascertainment to existing STEC surveillance data indicated an additional 166 HUS cases were captured during this study, highlighting the limitations of the current surveillance system for STEC for monitoring the clinical burden of STEC and capturing HUS cases.

Hyperhydration to Improve Kidney Outcomes in Children with Shiga Toxin-Producing E. coli Infection: a multinational embedded cluster crossover randomized trial (the HIKO STEC trial)

BACKGROUND

Shiga toxin-producing E. coli (STEC) infections affect children and adults worldwide, and treatment remain solely supportive. Up to 15-20% of children infected by high-risk STEC (i.e., E. coli that produce Shiga toxin 2) develop hemolytic anemia, thrombocytopenia, and kidney failure (i.e., hemolytic uremic syndrome (HUS)), over half of whom require acute dialysis and 3% die. Although no therapy is widely accepted as being able to prevent the development of HUS and its complications, several observational studies suggest that intravascular volume expansion (hyperhydration) may prevent end organ damage. A randomized trial is needed to confirm or refute this hypothesis.

METHODS

We will conduct a pragmatic, embedded, cluster-randomized, crossover trial in 26 pediatric institutions to determine if hyperhydration, compared to conservative fluid management, improves outcomes in 1040 children with high-risk STEC infections. The primary outcome is major adverse kidney events within 30 days (MAKE30), a composite measure that includes death, initiation of new renal replacement therapy, or persistent kidney dysfunction. Secondary outcomes include life-threatening, extrarenal complications, and development of HUS. Pathway eligible children will be treated per institutional allocation to each pathway. In the hyperhydration pathway, all eligible children are hospitalized and administered 200% maintenance balanced crystalloid fluids up to targets of 10% weight gain and 20% reduction in hematocrit. Sites in the conservative fluid management pathway manage children as in- or outpatients, based on clinician preference, with the pathway focused on close laboratory monitoring, and maintenance of euvolemia. Based on historical data, we estimate that 10% of children in our conservative fluid management pathway will experience the primary outcome. With 26 clusters enrolling a mean of 40 patients each with an intraclass correlation coefficient of 0.11, we will have 90% power to detect a 5% absolute risk reduction.

DISCUSSION

HUS is a devastating illness with no treatment options. This pragmatic study will determine if hyperhydration can reduce morbidity associated with HUS in children with high-risk STEC infection.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05219110 . Registered on February 1, 2022.

The Prevalence and Incidence of Hemolytic Uremic Syndrome: A Systematic Review

A hemolytic uremic syndrome is an uncommon but severe condition brought on by an overactive alternative complement system, typically involving a hereditary component. It will be crucial to comprehend the epidemiology of hemolytic uremic syndrome as research advances toward bettering its diagnosis and treatment. A systematic review was conducted to evaluate the incidence and prevalence estimates of hemolytic uremic syndrome (HUS) internationally. A thorough literature search was conducted using PubMed, Springer, Cochrane Library for Systematic Reviews, and Embase databases between 2012 and 2023 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations. A further source of data was the PubMed Central search engine. To make sure that the evaluation included just the studies that were the most pertinent, a population, interventions, comparators, and outcomes (PICO) eligibility criterion was also used. Eight articles were included in this review. HUS had an annual crude incidence of 0.66 per 100,000 people and a standard annual incidence of 0.57 per 100,000 people. Females were more likely than males to develop HUS, but only marginally more frequently. Patients under 20 years old were the age group where HUS was most common. HUS had an average cost of $21,500 per patient, which was more expensive than the country's overall inpatient average cost for the same period. This is due to patients requiring supportive care, antibiotics, plasma exchange, plasma infusion, and renal replacement therapy, and it could take multiple courses of treatment before they improve. It was concluded that several variables, including the region, the age group affected, and the frequency of the underlying bacterial infection, determine the prevalence and incidence of HUS. HUS is often more common in children than adults and is more common in some nations. Overall, HUS is an uncommon disorder that can have significant repercussions for people who have it. For better results and fewer consequences, HUS must be diagnosed and treated as soon as possible.

Diarrhoea-associated haemolytic uraemic syndrome and Shiga toxin-producing Escherichia coli infections in New Zealand children: Clinical features and short-term complications from a 23-year cohort study

BACKGROUND

Diarrhoea-associated haemolytic uraemic syndrome (D+HUS) is an important cause of acute kidney injury (AKI) in young children and it is most commonly associated with Shiga toxin-producing Escherichia coli (STEC). Gastrointestinal infections caused by STEC have been increasing in New Zealand over the past two decades, but little is known regarding the acute and short-term outcomes of New Zealand children who develop D+HUS.

AIM

To describe the clinical characteristics, complications and short-term outcomes of New Zealand children with D+HUS identified between 1 January 1998 and 31 December 2020.

METHODS

The New Zealand Paediatric Surveillance Unit sends out a monthly survey to all practising paediatricians regarding conditions under active surveillance. Paediatricians caring for a child aged 0-15 years of age with D+HUS over the prior month were requested to report their patient. Reporting clinicians were then contacted by the principal investigator and sent a questionnaire requesting patient clinical and laboratory information.

RESULTS

Two hundred and twenty-six children had D+HUS; median age 2.8 years (interquartile range 1.7-4.9). Acute dialysis was required in 128/226 (56.2%) of children for a median of 9 days (range 1-38). Children with shorter diarrhoeal prodrome, higher neutrophil count and haemoglobin had a longer duration of dialysis. Seizures occurred in 31/226 (13.7%) and were not associated with a greater HUS severity score. Acute mortality was 1.3%, all resulting from thrombotic microangiopathic cerebral injury.

CONCLUSION

D+HUS is a major cause of AKI in previously healthy young children. Earlier recognition of STEC infections in young children may reduce the need for dialysis and other extra-renal complications. The New Zealand incidence of acute dialysis, other major complications and mortality are consistent with other reported studies.

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.

Hyperuricemia: an unrecognized risk factor for kidney-related sequelae in children with hemolytic uremic syndrome

BACKGROUND

Chronic kidney-related sequelae after STEC-HUS occur in 20-40% of patients. Hyperuricemia (HU) may cause acute and chronic toxicity involving the kidneys. We retrospectively assessed if there was an association between the presence of HU during the acute illness and that of kidney-related sequelae in children with STEC-HUS.

METHODS

Children with STEC-HUS who had clinical and laboratory data at 2 years of follow-up were included in this case-control study. Univariate and multivariate analyses were performed between patients with (cases) or without (controls) kidney-related sequelae to identify factors associated with outcomes, including different measures of serum uric acid (sUA) (baseline level, peak, and duration of HU). HU was defined as sUA > 8 mg/dL.

RESULTS

Of 86 patients included, 77.9% had HU. Patients with sequelae (n = 41) had a higher prevalence of HU (41/41 vs. 26/45, p < 0.01), higher baseline leukocyte count, serum creatinine (sCr), and sUA levels as well as lower sodium than controls. During hospitalization, cases also had higher sCr peak, sUA peak and duration of HU, requirement and duration of dialysis, extrarenal complications, and hypertension. By multivariate analysis, after adjusting for length of dialysis, only duration of HU (p = 0.0005; OR 1.7, 95% CI 1.27-2.36) remained as an independent predictor of sequelae, with a best cutoff of 5.5 days (AUC 0.95, specificity 80%, sensitivity 100%).

CONCLUSIONS

The presence of HU is a common finding in children with STEC-HUS and its duration during the acute stage was associated with kidney-related sequelae, regardless of the duration of dialysis. A higher resolution version of the Graphical abstract is available as Supplementary Information.

Microfluidic-Based Novel Optical Quantification of Red Blood Cell Concentration in Blood Flow

The optical quantification of hematocrit (volumetric percentage of red blood cells) in blood flow in microfluidic systems provides enormous help in designing microfluidic biosensing platforms with enhanced sensitivity. Although several existing methods, such as centrifugation, complete blood cell count, etc., have been developed to measure the hematocrit of the blood at the sample preparation stage, these methods are impractical to measure the hematocrit in dynamic microfluidic blood flow cases. An easy-to-access optical method has emerged as a hematocrit quantification technique to address this limitation, especially for the microfluidic-based biosensing platform. A novel optical quantification method is demonstrated in this study, which can measure the hematocrit of the blood flow at a targeted location in a microchannel at any given instant. The images of the blood flow were shot using a high-speed camera through an inverted transmission microscope at various light source intensities, and the grayscale of the images was measured using an image processing code. By measuring the average grayscale of the images of blood flow at different luminous exposures, a relationship between hematocrit and grayscale has been developed. The quantification of the hematocrit in the microfluidic system can be instant and easy with this method. The innovative proposed technique has been evaluated with porcine blood samples with hematocrit ranging from 5% to 70%, flowing through 1000 µm wide and 100 µm deep microchannels. The experimental results obtained strongly supported the proposed optical technique of hematocrit measurement in microfluidic systems.

Prodromal Phase of Hemolytic Uremic Syndrome Related to Shiga Toxin-Producing Escherichia coli: The Wasted Time

OBJECTIVES

This study aimed to evaluate practice patterns during prodromal phase of hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS).

METHODS

Trajectories of children from first symptoms until STEC-HUS admitted consecutively at our center (period 2000-2017) were retrospectively reviewed. Early recommended practices include identification of STEC infections, antibiotics and antiperistaltic avoidance, and administration of anticipatory intravenous fluids; therefore, implementation and changes over time (before and after 2011) of such interventions were assessed. In addition, early management was correlated with acute disease outcomes.

RESULTS

Of 172 patients, 98 (57%) had early consults, 75 of them visit the pediatric emergency department. Those seen with watery diarrhea (n = 74) were managed as outpatients, whereas 27 of the 45 assisted with bloody diarrhea were hospitalized for diagnosis other than STEC-HUS. Stool cultures were performed in 13.4% (23/172), 18% (31/172) received antibiotics, and 12.8% (22/172) received endovenous fluids; none received antiperistaltic agents. Shiga toxin-producing E. coli infection was proven in 4% (7/172) before HUS. Rate of cultured patients and treated with intravenous fluids remained unchanged over time (P = 0.13 and P = 0.48, respectively), whereas antibiotic prescription decreased from 42.8% to 16.6% (P = 0.005). Main acute outcomes (need for dialysis, pancreatic compromise, central nervous system involvement, and death) were similar (P > 0.05) regardless of whether they received antibiotics or intravenous fluids.

CONCLUSIONS

During the diarrheal phase, 57% of patients consulted; three-quarters of them consulted to the pediatric emergency department. Shiga toxin-producing E. coli detection was poor, antibiotic use remained high, and anticipatory volume expansion was underused. These findings outline the critical need to improve the early management of STEC-HUS.

Hemoglobinuria for the early identification of STEC-HUS in high-risk children: data from the ItalKid-HUS Network

Hemolytic uremic syndrome (HUS) represents one of the main causes of severe acute kidney injury in children. The most frequent form of HUS is caused by Shiga toxin-2 (Stx2)-producing Escherichia coli. Hemoglobinuria and hematuria are markers of glomerular damage, but their use has never been validated in HUS. We retrospectively analyzed the presence of hemoglobinuria/urinary red blood cells (RBCs) in children with Stx2-positive bloody diarrhea (BD) or with already ongoing STEC-HUS with the aim of validating its role in early identifying HUS. We reviewed all the pediatric patients with Stx2+ BD (group 1) and with ongoing HUS (group 2) referred to our center from 2010 to 2019. A total of 100 children were eligible for the study. In group 1, 22 patients showed hemoglobinuria/hematuria, while 41 remained negative. In 15/22 positive patients (68.2%), blood tests ruled in HUS, while in 7 (31.8%), HUS was excluded. Among the 41 patients persistently negative for hemoglobinuria/hematuria, no one developed HUS. The 37 STEC-HUS children (group 2) all had hemoglobinuria/RBCs at admission.Conclusion: Hemoglobinuria/hematuria for the diagnosis of HUS in children with Stx2+ BD showed a sensitivity of 100% and a specificity of 85%. We strongly recommend patients with BD carrying Stx2 in stools to be closely monitored with urine dipstick/urinalysis to early identify HUS. What is Known • Children with bloody diarrhea secondary to Shiga toxin 2 are at high risk of hemolytic uremic syndrome, thus have to be carefully monitored for the development of the disease, in order to early be hospitalized and treated. What is New • Urine dipstick for hemoglobinuria can be used as an easy, inexpensive, and repeatable tool to early diagnose children with bloody diarrhea secondary to Shiga toxin 2 to have developed hemolytic uremic syndrome, with no risk of false-negative results.

Fluid restriction versus volume expansion in children with diarrhea-associated HUS: a retrospective observational study

BACKGROUND

Fifty percent of patients with typical diarrhea-associated hemolytic uremic syndrome (D+HUS) require kidney replacement therapy (KRT). In these patients, dehydration worsens disease prognosis. We evaluated dialysis requirement, presence of seizures, and mortality rate among patients diagnosed with D+HUS treated with volume expansion (VE) versus fluid restriction (FR).

METHODS

Thirty-five patients with D+HUS were enrolled; 16 received VE and 19 were historical patients who received conventional FR.

RESULTS

Upon admission or during treatment, neither group presented evidence of fluid overload. The VE group received higher volumes of saline (VE 27 ml/kg [10-30] over a 3-h period vs. FR 0 ml), had higher urine output after 12 h (VE vs. FR: OR 6.2 [1.2-41.6], P = 0.03), and required less dialysis (VE 2 [12.5%, CI 95% 0-29] vs. FR 9 [47.4%, CI 95% 24-70], P = 0.035). The VE group had an absolute risk reduction of 0.34 (CI 95% 0.07-0.63); hence, three patients treated with VE were required to avoid one KRT. VE also corrected initial hyponatremia and maintained serum sodium within normal ranges. No statistical differences were observed regarding number of patients with seizures (P = 0.08) or mortality (P = 1.0).

CONCLUSIONS

VE markedly reduces the number of patients requiring KRT and keeps serum sodium within a normal range. We propose to initially hydrate every patient with D+HUS and without signs of fluid overload, with 10 ml/kg/h 0.9% saline solution IV, over a 3-h period. Afterwards, if urine output is ≥ 0.5 ml/kg/h, it is recommended to not dialyze and continue IV hydration schedule with isotonic (D5) saline solution, according to their needs.

Hemoconcentration and predictors in Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS)

BACKGROUND

Hemoconcentration has been identified as a risk factor for a complicated course in Shiga toxin-producing E. coli-hemolytic uremic syndrome (STEC-HUS). This single-center study assesses hemoconcentration and predictors at presentation in STEC-HUS treated from 2009-2017.

METHODS

Data of 107 pediatric patients with STEC-HUS were analyzed retrospectively. Patients with mild HUS (mHUS, definition: max. serum creatinine < 1.5 mg/dL and no major neurological symptoms) were compared to patients with severe HUS (sHUS, definition: max. serum creatinine ≥ 1.5 mg/dL ± major neurological symptoms). Additionally, predictors of complicated HUS (dialysis ± major neurological symptoms) were analyzed.

RESULTS

Sixteen of one hundred seven (15%) patients had mHUS. Admission of patients with sHUS occurred median 2 days earlier after the onset of symptoms than in patients with mHUS. On admission, patients with subsequent sHUS had significantly higher median hemoglobin (9.5 g/dL (3.6-15.7) vs. 8.5 g/dL (4.2-11.5), p = 0.016) than patients with mHUS. The product of hemoglobin (g/dL) and LDH (U/L) (cutoff value 13,302, sensitivity 78.0%, specificity of 87.5%) was a predictor of severe vs. mild HUS. Creatinine (AUC 0.86, 95% CI 0.79-0.93) and the previously published score hemoglobin (g/dL) + 2 × creatinine (mg/dL) showed a good prediction for development of complicated HUS (AUC 0.87, 95% CI 0.80-0.93).

CONCLUSIONS

At presentation, patients with subsequent severe STEC-HUS had a higher degree of hemoconcentration. This underlines that fluid loss or reduced fluid intake/administration may be a risk factor for severe HUS. The good predictive value of the score hemoglobin (g/dL) + 2 × creatinine (mg/dL) for complicated HUS could be validated in our cohort. A higher resolution version of the Graphical abstract is available as Supplementary Information.

Late onset of hemolytic uremic syndrome after the appearance of prodromal gastrointestinal tract symptoms

Hemolytic uremic syndrome (HUS) may occur late after the onset and improvement of gastrointestinal tract symptoms. Clinicians need to carefully monitor for the onset of HUS, even if the patients have few symptoms.

Low C3 Serum Levels Predict Severe Forms of STEC-HUS With Neurologic Involvement

Background: The correlation between the severity of hemolytic uremic syndrome related to Shiga toxin–producing Escherichia coli (STEC-HUS) and involvement of the complement system has been examined in a small number of studies, with conflicting results. In the present study, we investigated whether serum C3 levels on admission are associated with neurologic involvement.

Methods: To this purpose, 68 consecutive STEC-HUS patients were recruited and main clinical and laboratory variables ad hospital admission were compared between those with or without neurologic involvement.

Results: STEC-HUS patients who developed neurologic involvement (NI) showed significant higher leukocyte count, C-reactive protein and hemoglobin, and lower sodium levels as compared with those without. Interestingly, baseline serum levels of C3 were significantly lower in patients with NI as compared with those without (p < 0.001). Moreover, when stratified according to need of Eculizumab rescue therapy due to severe NI, patients treated with this drug showed baseline C3 serum levels significantly lower than those who were not (p < 0.001).

Low C3 was independent risk factor for NI in our patients' population when entered as covariate in a multivariate logistic regression analysis including other major variables previously proposed as possible predictors of poor prognosis in STEC-HUS (for instance, leukocyte count, c-reactive protein, sodium levels) (HR 6.401, 95%CI 1.617–25.334, p = 0.008 for C3).

To underline the role of complement in the worsening of STEC-HUS patients' clinical conditions and outcomes, all patients were divided into two groups according to the baseline lower vs. normal serum levels of C3 and the main data on care needs were assessed. Interestingly more patients with lower C3 serum levels required renal replacement therapy (p = 0.024), anti-hypertensive therapy (p = 0.011), Intensive Care Unit admission (p = 0.009), and longer hospitalization (p = 0.003), thus displaying significantly more severe disease features as compared with those with normal C3 serum levels.

Conclusions: Our data suggests that children with STEC-HUS with decreased C3 concentrations at admission are more likely to develop neurologic involvement and are at increased risk of having severe clinical complications.

C3 levels and acute outcomes in Shiga toxin-related hemolytic uremic syndrome

BACKGROUND

The correlation between complement activation and severity of hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS) has been examined in few studies, with conflicting results. We investigated whether C3 levels on admission are associated with worse acute outcomes.

METHODS

Demographic, clinical, and laboratory variables were compared between dialyzed and non-dialyzed patients and between those with or without extrarenal complications. Univariate and multivariate analyses were performed; odds ratio (OR) and 95% confidence interval (95%CI) were calculated. C3 concentrations were correlated with dialysis length (Spearman test) and ROC curves with area under the curves (AUC) were calculated to identify C3 concentrations able to discriminate patients with dialysis requirements and complicated course.

RESULTS

Among 49 children, 33 had normal and 16 had decreased C3 concentrations. Higher hemoglobin, lactic dehydrogenase, urea and creatinine and lower albumin, sodium, and C3 and C4 concentrations at admission were associated with dialysis requirement; only creatinine remained significant (p = 0.03, OR 2.1, 95%CI 1.34-2.7) by multivariate analysis. Patients with a complicated course presented higher leukocyte count, hemoglobin and lactic dehydrogenase and lower albumin, sodium, and C3 and C4. In the multivariate analysis, leukocyte count (p = 0.02, OR 2.6, 95%CI 1.4-4.3) and C3 concentration (p = 0.039, OR 1.7, 95%CI 1.1-2.73) were independently associated with a complicated disease. C3 levels correlated with dialysis length (r = - 0.42, p = 0.002); nevertheless, they were unable to discriminate dialysis requirement (AUC = 0.25, 95%CI 0.11-0.38) and extrarenal complications (AUC = 0.24, 95%CI 0.11-0.4).

CONCLUSIONS

Our study suggests that decreased C3 levels at admission are associated with a more complicated STEC-HUS episode.

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.

Shiga-Toxin E. coli Hemolytic Uremic Syndrome: Review of Management and Long-term Outcome

Purpose of Review

We review the pathophysiology of Shiga-Toxin Enteropathogenic–Hemolytic Uremic Syndrome (STEC-HUS), strategies to ameliorate or prevent evolution of STEC-HUS, management and the improved recognition of long-term adverse outcomes.

Recent Findings

Following on from the preclinical evidence of a role for the complement system in STEC-HUS, the use of complement blocking agents has been the major focus of most recent clinical research. Novel therapies to prevent or lessen HUS have yet to enter the clinical arena. The long-term outcomes of STEC-HUS, similarly to other causes of AKI, are not as benign as previously thought.

Summary

Optimizing supportive care in STEC-HUS is the only current recommended treatment. The administration of early isotonic fluids may reduce the severity and duration of STEC-HUS. The role of complement blockade in the management of STEC-HUS remains unclear. The long-term sequelae from STEC-HUS are significant and patients with apparent full renal recovery remain at risk.

Case-management protocol for bloody diarrhea as a model to reduce the clinical impact of Shiga toxin-producing Escherichia coli infections. Experience from Southern Italy

To describe an operating protocol for bloody diarrhea (BD) in a pediatric population as a rapid response to a public health threat represented by an excess of pediatric HUS cases in the Apulia region (Southern Italy) starting from 2013. The protocol was set up with the goal of correct clinical management of Shiga toxin-producing Escherichia coli (STEC) infections, reductions in subsequent cases of hemolytic uremic syndrome (HUS), and improved short- and long-term disease outcomes. The protocol consisted of rapid hospitalization of children with bloody diarrhea (BD), hematochemical laboratory tests every 12–24 hours, and prompt laboratory diagnosis of STEC. No antibiotics were recommended until diagnosis. Children positive for STEC infections underwent early vigorous volume expansion. In June–December 2018, 438 children with BD were hospitalized, of which 53 (12.1%) had a STEC infection. The most common serogroups were O26 (36.1%), O111 (23.0%), and O157 (14.8%). Thirty-one samples carried the stx2 gene. Four cases evolved into HUS (7.5%), all with favorable outcome despite neurological involvement in two cases. Prompt and accurate laboratory diagnosis of STEC infections is of the utmost importance in patients with BD for correct clinical management. The strict adherence to the protocol could reduce the progression rate of STEC infections to HUS and prevents complications. Enhanced BD surveillance may help reduce cases of pediatric HUS in Southern Italy.

Hemolytic uremic syndrome in a developing country: Consensus guidelines

BACKGROUND

Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country.

METHODS

Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017.

RESULTS

An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted.

CONCLUSIONS

Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.

Risk Factors for Short- and Long-Term Outcomes in Children With STEC-HUS/D+ HUS: A Single-Center Experience

Background. Hemolytic uremic syndrome (HUS) is one of the common causes for acute kidney injury in childhood. Objective. The goals of our study were to identify risk factors for short-term complications and long-term outcomes of chronic kidney disease (CKD) in Shiga toxin-producing Escherichia coli (STEC)-HUS and other diarrhea positive (D⁺) HUS. Methods. Retrospective chart review was obtained of 58 pediatric patients treated for STEC-HUS and other D⁺ HUS between February 2002 and January 2011. Results. Thirty-three patients (56.9%) required dialysis. Dialysis was more likely initiated if a patient was a female (P < .012), oliguric (urine output < 0.5 mL/kg/h, P < .0005), or hemoglobin (HGB) level >10 g/dL (P = .009) at admission. Neurological complications developed only among 5 dialyzed patients (P < .042), and were more common if the patient received hemodialysis (HD) compared with peritoneal dialysis (P < .0005). CKD was noted during the subsequent follow-up clinic visits in 5 patients (8.6%). Those who developed CKD received HD (P = .002), dialysis for >10 days (P = .0004), or HGB level >10 g/dL (P = .034) at admission. Conclusions. Children with STEC-HUS/D⁺ HUS who may need dialysis are identified by female gender, lower urine output, higher serum creatinine level, and higher HGB at admission. They are at higher risk developing central nervous system complications especially if they needed HD. Children requiring >10 days of dialysis are at risk for development of CKD.

A simple prognostic index for Shigatoxin-related hemolytic uremic syndrome at onset: data from the ItalKid-HUS network

Shigatoxin Escherichia coli-related hemolytic uremic syndrome (eHUS) is a severe thrombotic microangiopathy (TMA) burdened by life-threatening complications and long-term sequelae. Since hemoconcentration is associated with worse outcome, we tried to develop a reliable and easy-to-calculate index for predicting complications and sequelae based on hemoglobin (Hb) at presentation. The first laboratory examinations with signs of TMA in eHUS patients were analyzed in relation to the outcomes with the receiver operating characteristic curves and their areas under the curve (AUC) for Hb and creatinine (sCr). A total of 197 eHUS patients were identified of whom 24% did not have anemia at presentation. Hb level was the best predictor of a poor outcome (AUC 0.67) but the combination of Hb with sCr, in the formula [(Hb in g/dL + (sCr in mg/dL × 2)], showed an even better AUC of 0.75. The described scoring system was also strongly associated and predictive of all complications and health care needs (8% of patients with scoring > 13 died or entered a permanent vegetative state compared with 0% of those with ≤ 13).Conclusion: The presented score is a simple and early predictor of both short- and long-term outcomes and identifies patients who should undergo rapid volume expansion to counteract hemoconcentration, the spreading of microvascular thrombosis, and the consequent increased organ damage. What is Known: • In eHUS, hemoconcentration is associated with worse short- and long-term outcome. • A prognostic index to identify patients at higher risk for complications at presentation is not available. What is New: • We developed a simple and early prognostic index for eHUS outcome with the combination of Hb and sCr at onset, in the following formula [(Hb in g/dL + (sCr in mg/dL × 2)]. • The proposed HUS Severity Score can promptly identify patients with good outcome and those with high risk of worse short- and long-term outcome.

Hyponatremia: a new predictor of mortality in patients with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome

OBJECTIVES

(1) Evaluate mortality rate in patients with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome, (2) determine the leading causes of death, and (3) identify predictors of mortality at hospital admission.

METHODS

We conducted a multicentric, observational, retrospective, cross-sectional study. It included patients under 18 years old with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome hospitalized between January 2005 and June 2016. Clinical and laboratory data were obtained from the Argentine National Epidemiological Surveillance System of Hemolytic Uremic Syndrome. Clinical and laboratory variables were compared between deceased and non-deceased patients. Univariate and multivariate analyses were performed. ROC curves and area under the curve were obtained.

RESULTS

Seventeen (3.65%) out of the 466 patients died, being central nervous system involvement the main cause of death. Predictors of death were central nervous system involvement, the number of days since the beginning of diarrhea to hospitalization, hyponatremia, high hemoglobin, high leukocyte counts, and low bicarbonate concentration on admission. In the multivariate analysis, central nervous system involvement, sodium concentration, and hemoglobin were independent predictors. The best cut off for sodium was ≤ 128 meq/l and for hemoglobin ≥ 10.8 g/dl.

CONCLUSIONS

Mortality was low in children with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome, being central nervous system involvement the main cause of death. The best mortality predictors found were central nervous system involvement, hemoglobin, and sodium concentration. Hyponatremia may be a new Shiga toxin-producing Escherichia coli hemolytic uremic syndrome mortality predictor.

Clinical and Laboratory Predictors of Shiga Toxin-Producing Escherichia coli Infection in Children With Bloody Diarrhea

OBJECTIVES

Children with acute bloody diarrhea are at risk of being infected with Shiga toxin-producing Escherichia coli (STEC) and of progression to hemolytic uremic syndrome. Our objective was to identify clinical and laboratory factors associated with STEC infection in children who present with acute bloody diarrhea.

METHODS

We performed a prospective cohort study of consecutive children younger than 18 years who presented with acute (<2-week duration) bloody diarrhea between August 1, 2013, and August 1, 2014. We excluded patients with a chronic gastrointestinal illness and/or an obvious noninfectious source of bloody stool. We obtained a standardized history and study laboratory tests, performed physical examinations, and recorded patient outcomes.

RESULTS

Of the 135 eligible patients, 108 were enrolled; 27 declined consent. The median patient age was 3 years, and 56% were male. Ten (9%) patients tested positive for STEC (E coli O157:H7, n = 8; E coli O111, n = 1; E coli O103, n = 1), and 62 had negative stool culture results. Children infected with STEC were older (8.5 vs 3 years, respectively) (P < .001) and more likely to have abdominal tenderness (83% vs 17%, respectively) than those in the other groups. D-Dimer concentrations had a 70% sensitivity and 55% specificity for differentiating children with STEC from those with another cause of bloody diarrhea and 75% sensitivity and 70% specificity in differentiating children with a bacterial etiology from those with negative stool culture results.

CONCLUSION

Clinical assessment and laboratory data cannot reliably exclude the possibility that children with bloody diarrhea have an STEC infection and are at consequent risk of developing hemolytic uremic syndrome. Abnormal D-dimer concentrations (>0.5 μg/mL) were insufficiently sensitive and specific for distinguishing patients with STEC from those with another bacterial cause of bloody diarrhea. However, this marker might be useful in identifying children whose bloody diarrhea is caused by a bacterial enteric pathogen.

Blood urea nitrogen to serum creatinine ratio as a prognostic factor in diarrhea-associated hemolytic uremic syndrome: a validation study

Identifying those children with complicated forms of diarrhea-associated hemolytic uremic syndrome (D+HUS) on admission can optimize their management. Recently, the blood urea nitrogen to serum creatinine ratio (BCR) at admission has been proposed as a novel and accurate predictor of complicated clinical outcome in D+HUS; therefore, we performed this retrospective study aimed to validate such observation in a larger series of patients. A complicated course was defined as developing one or more of the following: severe neurological or bowel injury, pancreatitis, cardiac or pulmonary involvement, hemodynamic instability, hemorrhage, and death. Data from 161 children were reviewed, 50 of them with a complicated disease including five deaths. Those with worse evolution presented a lower admission BCR than those with good outcome (22.5 vs. 30.8; p = 0.005). BCR at admission showed a limited ability to identify children at risk of a complicated course, with an AUC of 0.63 (95% CI 0.58-0.71) and an optimal cutoff point of ≤ 26.7, which achieves a sensitivity of 70% (95% CI 55.2-81.7) and a specificity of 56.7% (95% CI 47-66).

CONCLUSION

In this validation study, the BCR at admission provided a limited value to predict severe forms of D+HUS. What is Known: • BCR at admission has been proposed as an accurate predictor of complicated clinical course in children with D+HUS. What is New: • In a larger series of children with D+HUS, we were unable to confirm the usefulness of the admission BCR to early identify those at risk of complicated forms of the disease. • Further research is warranted to improve the optimal detection of these high-risk patients.

2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea

These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea.

Escherichia coli Complications in Pediatric Critical Care

Escherichia coli is a bacterium that is an important part of the intestinal tract; however, it has the potential to become pathogenic. Shiga toxin-producing E coli (STEC) is a leading cause of E coli infections and has led to outbreaks in North America. Transmission is through ingestion of contaminated food sources, and via infected humans and animals. Young children infected with STEC are at high risk for developing hemolytic uremic syndrome (HUS). HUS is a clinical syndrome characterized by macroangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Early diagnosis and supportive treatment of HUS are essential to limit complications.

Province-Wide Review of Pediatric Shiga Toxin-Producing Escherichia coli Case Management

OBJECTIVE

To identify the gaps in the care of children infected with Shiga toxin-producing Escherichia coli (STEC), we sought to quantitate care received and management timelines. Such knowledge is crucial to the design of interventions to prevent the development of hemolytic uremic syndrome (HUS).

STUDY DESIGN

We conducted a retrospective case-series study of 78 children infected with STEC in Alberta, Canada, through the linkage of microbiology and laboratory results, telephone health advice records, hospital charts, physician billing submissions, and outpatient antimicrobial dispensing databases. Outcomes were the time intervals between initial presentation and reporting of positive culture result and symptom onset to HUS and to describe the proportions that had baseline blood work performed and received antibiotics.

RESULTS

Seventy-eight children infected with STEC were identified; 13% (10/78) developed HUS. Median time from initial presentation to laboratory stool sample receipt was 33 hours (IQR 18, 42); time to positive culture was 120 hours (IQR 86, 205). Time from symptom onset to HUS diagnosis was 188 ± 37 hours. Baseline blood tests were obtained in 74% (58/78) of infected children. Antibiotics were administered to 50% (5/10) of those who developed HUS and 22% (15/78) of those who did not; P = .11. The provincial telephone advice system received 31 calls regarding 24 children infected with STEC; 23% (7/31) of callers were recommended to seek emergency department care.

CONCLUSIONS

A significant proportion of children developed HUS following multiple interactions with the health care system. Delays in the confirmation of STEC infection occurred. There are numerous opportunities to improve the timing, monitoring, and interventions in children infected with STEC.

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.

Early Volume Expansion and Outcomes of Hemolytic Uremic Syndrome

BACKGROUND

Hemolytic uremic syndrome associated with Shiga toxin-producing Escherichia coli (STEC-HUS) is a severe acute illness without specific treatment except supportive care; fluid management is concentrated on preventing fluid overload for patients, who are often oligoanuric. Hemoconcentration at onset is associated with more severe disease, but the benefits of volume expansion after hemolytic uremic syndrome (HUS) onset have not been explored.

METHODS

All the children with STEC-HUS referred to our center between 2012 and 2014 received intravenous infusion targeted at inducing an early volume expansion (+10% of working weight) to restore circulating volume and reduce ischemic or hypoxic tissue damage. The short- and long-term outcomes of these patients were compared with those of 38 historical patients referred to our center during the years immediately before, when fluid intake was routinely restricted.

RESULTS

Patients undergoing fluid infusion soon after diagnosis showed a mean increase in body weight of 12.5% (vs 0%), had significantly better short-term outcomes with a lower rate of central nervous system involvement (7.9% vs 23.7%, P = .06), had less need for renal replacement therapy (26.3% vs 57.9%, P = .01) or intensive care support (2.0 vs. 8.5 days, P = .02), and needed fewer days of hospitalization (9.0 vs 12.0 days, P = .03). Long-term outcomes were also significantly better in terms of renal and extrarenal sequelae (13.2% vs 39.5%, P = .01).

CONCLUSIONS

Patients with STEC-HUS had great benefit from early volume expansion. It is speculated that early and generous fluid infusions can reduce thrombus formation and ischemic organ damage, thus having positive effects on both short- and long-term disease outcomes.

Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE): epidemiology, emerging organisms, and economics

Background

Each year in Canada there are 5 million episodes of acute gastroenteritis (AGE) with up to 70 % attributed to an unidentified pathogen. Moreover, 90 % of individuals with AGE do not seek care when ill, thus, burden of disease estimates are limited by under-diagnosing and under-reporting. Further, little is known about the pathogens causing AGE as the majority of episodes are attributed to an “unidentified” etiology. Our team has two main objectives: 1) to improve health through enhanced enteric pathogen identification; 2) to develop economic models incorporating pathogen burden and societal preferences to inform enteric vaccine decision making.

Methods/Design

This project involves multiple stages: 1) Molecular microbiology experts will participate in a modified Delphi process designed to define criteria to aid in interpreting positive molecular enteric pathogen test results. 2) Clinical data and specimens will be collected from children aged 0–18 years, with vomiting and/or diarrhea who seek medical care in emergency departments, primary care clinics and from those who contact a provincial medical advice line but who do not seek care. Samples to be collected will include stool, rectal swabs (N = 2), and an oral swab. Specimens will be tested employing 1) stool culture; 2) in-house multiplex (N = 5) viral polymerase chain reaction (PCR) panel; and 3) multi-target (N = 15) PCR commercially available array. All participants will have follow-up data collected 14 days later to enable calculation of a Modified Vesikari Scale score and a Burden of Disease Index. Specimens will also be collected from asymptomatic children during their well child vaccination visits to a provincial public health clinic. Following the completion of the initial phases, discrete choice experiments will be conducted to enable a better understanding of societal preferences for diagnostic testing and vaccine policy. All of the results obtained will be integrated into economic models.

Discussion

This study is collecting novel samples (e.g., oral swabs) from previously untested groups of children (e.g., those not seeking medical care) which are then undergoing extensive molecular testing to shed a new perspective on the epidemiology of AGE. The knowledge gained will provide the broadest understanding of the epidemiology of vomiting and diarrhea of children to date.

Postdiarrheal hemolytic uremic syndrome in United States children: clinical spectrum and predictors of in-hospital death

OBJECTIVE

To assess the clinical spectrum of postdiarrheal hemolytic uremic syndrome (D(+)HUS) hospitalizations and sought predictors of in-hospital death to help identify children at risk of poor outcomes.

STUDY DESIGN

We assessed clinical variables collected through population-based surveillance of D(+)HUS in children <18 years old hospitalized in 10 states during 1997-2012 as predictors of in-hospital death by using tree modeling.

RESULTS

We identified 770 cases. Of children with information available, 56.5% (430 of 761) required dialysis, 92.6% (698 of 754) required a transfusion, and 2.9% (22 of 770) died; few had a persistent dialysis requirement (52 [7.3%] of 716) at discharge. The tree model partitioned children into 5 groups on the basis of 3 predictors (highest leukocyte count and lowest hematocrit value during the 7 days before to 3 days after the diagnosis of hemolytic uremic syndrome, and presence of respiratory tract infection [RTI] within 3 weeks before diagnosis). Patients with greater leukocyte or hematocrit values or a recent RTI had a greater probability of in-hospital death. The largest group identified (n = 533) had none of these factors and had the lowest odds of death. Many children with RTI had recent antibiotic treatment for nondiarrheal indications.

CONCLUSION

Most children with D(+)HUS have good hospitalization outcomes. Our findings support previous reports of increased leukocyte count and hematocrit as predictors of death. Recent RTI could be an additional predictor, or a marker of other factors such as antibiotic exposure, that may warrant further study.

[Microalbuminuria in pediatric patients diagnosed with hemolytic uremic syndrome]

INTRODUCTION

Hemolytic uremic syndrome (HUS) is characterized by the presence of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney failure. It is the leading cause of acute kidney failure in children under 3 years of age. A variable number of patients develop proteinuria, hypertension, and chronic renal failure.

OBJECTIVE

To evaluate the renal involvement in pediatric patients diagnosed with HUS using the microalbumin/creatinine ratio.

PATIENTS AND METHODS

Descriptive concurrent cohort study that analyzed the presence of microalbuminuria in patients diagnosed with HUS between January 2001 and March 2012, who evolved without hypertension and normal renal function (clearance greater than 90ml/min using Schwartz formula). Demographic factors (age, sex), clinical presentation at time of diagnosis, use of antibiotics prior to admission, and need for renal replacement therapy were evaluated.

RESULTS

Of the 24 patients studied, 54% were male. The mean age at diagnosis was two years. Peritoneal dialysis was required in 45%, and 33% developed persistent microalbuminuria. Antiproteinuric treatment was introduce in 4 patients, with good response. The mean follow-up was 6 years (range 6 months to 11 years). The serum creatinine returned to normal in all patients during follow up.

CONCLUSIONS

The percentage of persistent microalbuminuria found in patients with a previous diagnosis of HUS was similar in our group to that described in the literature. Antiproteinuric treatment could delay kidney damage, but further multicenter prospective studies are necessary.

Hemoconcentration: a major risk factor for neurological involvement in hemolytic uremic syndrome

BACKGROUND

Shigatoxin-associated hemolytic uremic syndrome (STEC-HUS) is a common thrombotic microangiopathy (TMA) in which central nervous system (CNS) involvement is responsible for the majority of deaths and for severe long-term sequelae. We have analyzed the role of hemoconcentration in disease severity.

METHODS

This was a retrospective review of the records and laboratory data at presentation of all patients with STEC-HUS cases (n = 61) over a 10-year period. The patients were grouped into three severity classes: group A, comprising patients who did not require dialysis; group B, patients who were dialyzed without CNS involvement; group C, patients with CNS involvement.

RESULTS

Patients with CNS involvement (group C) had a higher mean hemoglobin level (11.2 ± 2.3 g/dL) than those of group A or B ( 9.4 ± 2.1 and 7.5 ± 1.9 g/dL, respectively; p < 0.0001). We also observed that the higher the initial hemoglobin level, the more severe the long-term renal damage (p < 0.007).

CONCLUSIONS

In patients with STEC-HUS, hemoconcentration and hypovolemia may be responsible for more severe ischemic organ damage (both short and long term) at disease onset, and these signs should be regarded as risk factors for CNS damage and for more severe TMA. Therefore, we recommend that hydration status should be actively monitored in HUS patients and that dehydration, when diagnosed, should be promptly corrected.

Shiga Toxin/Verocytotoxin-Producing Escherichia coli Infections: Practical Clinical Perspectives

Escherichia coli strains that produce Shiga toxins/verotoxins are rare, but important, causes of human disease. They are responsible for a spectrum of illnesses that range from the asymptomatic to the life-threatening hemolytic-uremic syndrome; diseases caused by E. coli belonging to serotype O157:H7 are exceptionally severe. Each illness has a fairly predictable trajectory, and good clinical practice at one phase can be inappropriate at other phases. Early recognition, rapid and definitive microbiology, and strategic selection of tests increase the likelihood of good outcomes. The best management of these infections consists of avoiding antibiotics, antimotility agents, and narcotics and implementing aggressive intravenous volume expansion, especially in the early phases of illness.

Shiga toxin-producing Escherichia coli: a single-center, 11-year pediatric experience

The aim of this study was to identify the best practices for the detection of Shiga toxin-producing Escherichia coli (STEC) in children with diarrheal illness treated at a tertiary care center, i.e., sorbitol-MacConkey (SMAC) agar culture, enzyme immunoassay (EIA) for Shiga toxin, or the simultaneous use of both methods. STEC was detected in 100 of 14,997 stool specimens submitted for enteric culture (0.7%), with 65 cases of E. coli O157. Among E. coli O157 isolates, 57 (88%) were identified by both SMAC agar culture and EIA, 6 (9%) by SMAC agar culture alone, and 2 (3%) by EIA alone. Of the 62 individuals with diarrheal hemolytic uremic syndrome (HUS) seen at our institution during the study period, 16 (26%) had STEC isolated from cultures at our institution and 15 (24%) had STEC isolated at other institutions. No STEC was recovered in 31 cases (50%). Of the HUS cases in which STEC was isolated, 28 (90%) were attributable to E. coli O157 and 3 (10%) were attributable to non-O157 STEC. Consistent with previous studies, we have determined that a subset of E. coli O157 infections will not be detected if an agar-based method is excluded from the enteric culture workup; this has both clinical and public health implications. The best practice would be concomitant use of an agar-based method and a Shiga toxin EIA, but a Shiga toxin EIA should not be considered to be an adequate stand-alone test for detection of E. coli O157 in clinical samples.

Laboratory predictors of acute dialysis in hemolytic uremic syndrome

BACKGROUND

Strict guidelines on use of dialysis in children with post-diarrheal hemolytic uremic syndrome (D + HUS) are lacking. This study investigated laboratory predictors of acute dialysis because they are more objective than clinical features. Added to this, given that urine output is also an objective parameter, its ability to predict dialysis requirements was also investigated.

METHODS

Out of 153 D + HUS children reviewed, 88 received dialysis and 65 did not. Initial laboratory parameters and diuresis between both groups were analyzed.

RESULTS

Dialyzed patients had higher creatinine, urea, alanine aminotransferase, hematocrit and leukocyte count; and lower sodium, bicarbonate, and pH compared to non-dialyzed ones. Serum creatinine was the only independent predictor (P = 0.003) of dialysis; therefore, its ability to predict dialysis was estimated on receiver operating characteristic (ROC) curve analysis and using the Acute Kidney Injury Network (AKIN) staging system. Area under the ROC curve was 0.92 (95% confidence interval [95%CI]: 0.83-1) with a creatinine cut-off of 1.25 mg/dL (sensitivity, 100%; specificity, 76.5%) for children <1 year, and 0.93 (95%CI: 0.88-0.98) with a threshold of 2 mg/dL (sensitivity, 91%; specificity, 87.5%) for older children. AKIN stage 3 at admission predicted dialysis with a sensitivity of 92% and specificity of 84.2%. Urine output had the highest accuracy for dialysis prediction (sensitivity, 100%; specificity, 95.3%).

CONCLUSIONS

Initial serum creatinine concentration was the best laboratory predictor of dialysis, but the first 24 h diuresis was even better for this purpose. But, given that serum creatinine is an immediate available parameter, the cut-offs identified may label D + HUS children who will probably need dialysis, prompting early referral to centers able to provide dialysis.

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).

Treatment of Shiga toxin-producing Escherichia coli infections

The management of Shiga toxin-producing Escherichia coli (STEC) infections is reviewed. Certain management practices optimize the likelihood of good outcomes, such as avoidance of antibiotics during the pre-hemolytic uremic syndrome phase, admission to hospital, and vigorous intravenous volume expansion using isotonic fluids. The successful management of STEC infections is based on recognition that a patient might have an STEC infection, and appropriate use of the microbiology laboratory. The timeliness of STEC identification cannot be overemphasized, because it avoids therapies prompted by inappropriate additional testing and directs the clinician to focus on effective management strategies. The opportunities during STEC infections to avert the worst outcomes are brief, and this article emphasizes practical matters relevant to making a diagnosis, anticipating the trajectory of illness, and optimizing care.

Impact of platelet transfusions in children with post-diarrheal hemolytic uremic syndrome

BACKGROUND

Platelet transfusions should be avoided in children with post-diarrheal hemolytic uremic syndrome (D + HUS) because they might increase microthrombi formation, thereby aggravating the disease. As this possibility has not yet been explored, we investigated whether platelet transfusion in patients with D + HUS would lead to a worse disease course compared to that in patients who did not receive platelet transfusion.

METHODS

This was a case-control study in which data from D + HUS children who received platelet transfusions (cases, n  =  23) and those who did not (controls, n  =  54) were retrospectively reviewed and compared.

RESULTS

Both patient groups were similar in age (p = 0.3), gender (p  =  0.53), weight (p  =  0.86), height (p  =  0.45), prior use of non-steroidal anti-inflammatory drugs (p  =  0.59) or antibiotics (p  =  0.45) and presence of dehydration at admission (p  =  0.79). The two groups also did not differ in initial leukocyte count (p  =  0.98), hematocrit (p  =  0.44) and sodium (p  =  0.11) and alanine aminotransferase levels (p  =  0.11). During hospitalization, dialysis duration (p  =  0.08), number of erythrocyte transfusions (p  =  0.2), serum creatinine peak (p  =  0.22), presence of severe bowel (p  =  0.43) or neurologic (p  =  0.97) injury, arterial hypertension (p  =  0.71), need for intensive care (p  =  0.33) and death (p  =  1.00) were also comparable.

CONCLUSION

Our findings suggest that platelet transfusion does not aggravate the course of the disease. Conversely, no hemorrhagic complications were observed in the group of patients who did not receive a platelet transfusion. Until these observations are confirmed by further studies, the benefits and risk of platelet transfusion should be thoughtfully balanced on an individual case basis.

Risk factors for development of hemolytic uremic syndrome in a cohort of adult patients with STEC 0104:H4 infection

The outbreak of Shiga toxin producing E.coli O104:H4 in northern Germany in 2011 was one of the largest worldwide and involved mainly adults. Post-diarrheal hemolytic uremic syndrome (HUS) occurred in 22% of STEC positive patients. This study’s aim was to assess risk factors for HUS in STEC-infected patients and to develop a score from routine hospital parameters to estimate patient risks for developing HUS. In a cohort analysis, adult patients with STEC infection were included in five participating hospitals in northern Germany between May and July 2011. Clinical data were obtained from questionnaires and medical records, laboratory data were extracted from hospitals’ electronic data systems. HUS was defined as thrombocytopenia, hemolytic anemia and acute renal dysfunction. Random forests and multivariate logistic regression were used to identify risk factors for HUS and develop a score using the estimated coefficients as weights. Among 259 adults with STEC infection, vomiting (OR 3.48,95%CI 1.88–6.53), visible blood in stools (OR 3.91,95%CI1.20–16.01), age above 75 years (OR 3.27, 95%CI 1.12–9.70) and elevated leukocyte counts (OR 1.20, 95%CI 1.10–1.31, per 1000 cells/mm³) were identified as independent risk factors for HUS. A score using these variables has an area under the ROC curve of 0.74 (95%CI 0.68–0.80). Vomiting, visible blood in stools, higher leukocyte counts, and higher age indicate increased risk for developing HUS. A score using these variables might help to identify high risk patients who potentially benefit from aggressive pre-emptive treatment to prevent or mitigate the devastating consequences of HUS.