Short- and Long-Term Renal Outcome of Hemolytic-Uremic Syndrome in Childhood

Outcome 10 years after Shiga toxin-producing E. coli (STEC)-associated hemolytic uremic syndrome: importance of long-term follow-up

BACKGROUND

Hemolytic uremic syndrome (HUS) is an important cause of acute kidney injury in children. HUS is known as an acute disease followed by complete recovery, but patients may present with kidney abnormalities after long periods of time. This study evaluates the long-term outcome of Shiga toxin-producing Escherichia coli-associated HUS (STEC-HUS) in pediatric patients, 10 years after the acute phase of disease to identify risk factors for long-term sequelae.

METHODS

Over a 6-year period, 619 patients under 18 years of age with HUS (490 STEC-positive, 79%) were registered in Austria and Germany. Long-term follow-up data of 138 STEC-HUS-patients were available after 10 years for analysis.

RESULTS

A total of 66% (n = 91, 95% CI 0.57-0.73) of patients fully recovered showing no sequelae after 10 years. An additional 34% (n = 47, 95% CI 0.27-0.43) presented either with decreased glomerular filtration rate (24%), proteinuria (23%), hypertension (17%), or neurological symptoms (3%). Thirty had sequelae 1 year after STEC-HUS, and the rest presented abnormalities unprecedented at the 2-year (n = 2), 3-year (n = 3), 5-year (n = 3), or 10-year (n = 9) follow-up. A total of 17 patients (36.2%) without kidney abnormalities at the 1-year follow-up presented with either proteinuria, hypertension, or decreased eGFR in subsequent follow-up visits. Patients needing extracorporeal treatments during the acute phase were at higher risk of presenting symptoms after 10 years (p < 0.05).

CONCLUSIONS

Patients with STEC-HUS should undergo regular follow-up, for a minimum of 10 years following their index presentation, due to the risk of long-term sequelae of their disease. An initial critical illness, marked by need of kidney replacement therapy or plasma treatment may help predict poor long-term outcome.

Kidney sequelae in 281 Shiga toxin-producing Escherichia coli-hemolytic uremic syndrome patients after a median follow-up of 12 years

BACKGROUND

A substantial proportion of patients with Escherichia coli-hemolytic uremic syndrome (STEC-HUS) evolve to chronic kidney disease (CKD). The objectives of this study were to evaluate long-term kidney outcomes and to identify CKD predictors.

METHODS

In this single-center retrospective study, long-term outcomes of patients were analyzed according to the presence of complete recovery (CR) or CKD at last visit. Then, they were grouped into favorable (CR + CKD1) or poor (CKD2-5) outcome to compare predictors at diagnosis (sex, age, leukocytes, creatinine, hemoglobin, HUS severity score), dialysis duration, and follow-up time between them.

RESULTS

Of 281 patients followed up for a median of 12 years, 139 (49%) had CR, 104 (37%) CKD1, 27 (10%) CKD2-4, and 11 (4%) CKD5. Thirty-eight patients progressed to CKD2-5 after a median of 4.8 years, 7% in the first 5 years, increasing to 8%, 10%, and 14% after 5-10 years, 10-15 years, and > 15 years, respectively. They were younger, had higher baseline hemoglobin and leukocytes, and required longer dialysis and follow-up than those with favorable outcome. By multivariate analysis, days of dialysis and follow-up time remained as independent predictors of poor outcome. The best cutoff for days of dialysis was 10 days. After 5 years, 20% of those dialyzed ≥ 10 days evolved to CKD2-5 versus 1% of those non-dialyzed or dialyzed < 10 days.

CONCLUSIONS

Fifty-one percent of patients evolved to CKD after 12 years of follow-up and 14% to CKD2-5. Ten days of dialysis was the best cutoff to recognize outcomes. In some cases, kidney damage was evident after 15 years of surveillance, highlighting the need for follow-up until adulthood in all STEC-HUS patients.

Kidney outcomes in Shiga toxin-associated hemolytic uremic syndrome in childhood: A retrospective single-center study from 1999 to 2017: Kidney outcomes in typical hemolytic uremic syndrome in childhood

BACKGROUND

Shiga toxin-associated hemolytic uremic syndrome (STECHUS) is the main cause of acute kidney injury in children and may be responsible for adverse outcomes despite an apparent quiescent period.

OBJECTIVE

To describe the medium- and long-term kidney outcomes of pediatric STECHUS in a French region.

METHODS

A single-center, descriptive, retrospective study of STECHUS cases that occurred at Besançon University Hospital between 1999 and 2017 in children up to 17 years of age was conducted. The primary study endpoint was the proportion of chronic kidney disease (CKD) cases at 5 years of follow-up.

RESULTS

We included 98 consecutive patients. Among the 71 patients at the 5-year follow-up, we found 24 (34 %) patients with no adverse kidney outcome, 18 (25 %) with moderate adverse kidney outcome, and one (1.4 %) with severe adverse kidney outcome. Among the 96 patients at 1 year from the diagnosis, these figures were, respectively, 25 (26 %), 51 (53 %), and two (2 %); and among the 38 patients at 10 years, they were, respectively, nine (24 %), 12 (32 %), and one (3 %). The glomerular filtration rate level and oliguria-anuria beyond 8 days at baseline were significantly associated with more severe kidney outcomes at 10 years (p = 0.03 and 0.005, respectively). Two patients died during the acute phase. Overall, 33 patients (34 %) were lost to follow-up.

CONCLUSION

Adverse kidney outcomes may appear many years after an episode of STECHUS despite an apparent quiescent period. Regular long-term monitoring is required. The challenge is to reduce the proportion of patients lost to follow-up with potentially severe adverse kidney outcomes and no evaluation or treatment.

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.

Acute Kidney Injury and Hemolytic Uremic Syndrome in Severe Pneumococcal Pneumonia—A Retrospective Analysis in Pediatric Intensive Care Unit

Objectives: This study aimed to evaluate the prevalence of acute kidney injury (AKI) and hemolytic uremic syndrome (HUS) in severe pediatric pneumonia due to Streptococcus pneumoniae and to identify factors associated with AKI and HUS in these patients.

Methods: We retrospectively analyzed pediatric patients who were admitted to our pediatric intensive care unit due to severe pneumococcal pneumonia between 2013 and 2019.

Results: Forty-two patients with a median age of 4.3 years were included. Among these patients, 14 (33.3%) developed AKI, including seven (16.7%) stage 1, two (4.8%) stage 2, and five (11.9%) stage 3 AKI. Features of HUS were present in all of the patients with stage 3 AKI, and four required renal replacement therapy (RRT), with a median duration of 10.5 days (range 3 to 16 days). All patients with HUS required mechanical ventilation and inotropic supports. Patients with lower leukocyte and platelet counts, serum sodium and bicarbonate levels, positive urine dipstick (heme or protein ≥ 2 + ), and presence of bacteremia were associated with stage 2 and 3 AKI.

Conclusions: Pediatricians should be aware of the relatively high prevalence of kidney involvement in severe pneumococcal pneumonia, with one-third having AKI and 11.9% developing HUS. Majority (80%) of HUS patients required RRT. Positive urine dipstick, serum sodium, and bicarbonate at presentation, which can be measured in point-of-care tests, may potentially be useful as quick tests to stratify the risks of moderate-to-severe AKI.

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.

Shiga Toxin 2 Triggers C3a-Dependent Glomerular and Tubular Injury through Mitochondrial Dysfunction in Hemolytic Uremic Syndrome

Shiga toxin (Stx)-producing Escherichia coli is the predominant offending agent of post-diarrheal hemolytic uremic syndrome (HUS), a rare disorder of microvascular thrombosis and acute kidney injury possibly leading to long-term renal sequelae. We previously showed that C3a has a critical role in the development of glomerular damage in experimental HUS. Based on the evidence that activation of C3a/C3a receptor (C3aR) signaling induces mitochondrial dysregulation and cell injury, here we investigated whether C3a caused podocyte and tubular injury through induction of mitochondrial dysfunction in a mouse model of HUS. Mice coinjected with Stx2/LPS exhibited glomerular podocyte and tubular C3 deposits and C3aR overexpression associated with cell damage, which were limited by C3aR antagonist treatment. C3a promoted renal injury by affecting mitochondrial wellness as demonstrated by data showing that C3aR blockade reduced mitochondrial ultrastructural abnormalities and preserved mitochondrial mass and energy production. In cultured podocytes and tubular cells, C3a caused altered mitochondrial fragmentation and distribution, and reduced anti-oxidant SOD2 activity. Stx2 potentiated the responsiveness of renal cells to the detrimental effects of C3a through increased C3aR protein expression. These results indicate that C3aR may represent a novel target in Stx-associated HUS for the preservation of renal cell integrity through the maintenance of mitochondrial function.

Eculizumab exposure in children and young adults: indications, practice patterns, and outcomes-a Pediatric Nephrology Research Consortium study

BACKGROUND

Eculizumab is approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Its use off-label is frequently reported. The aim of this study was to describe the broader use and outcomes of a cohort of pediatric patients exposed to eculizumab.

METHODS

A retrospective, cohort analysis was performed on the clinical and biomarker characteristics of eculizumab-exposed patients < 25 years of age seen across 21 centers of the Pediatric Nephrology Research Consortium. Patients were included if they received at least one dose of eculizumab between 2008 and 2015. Traditional summary statistics were applied to demographic and clinical data.

RESULTS

A total of 152 patients were identified, mean age 9.1 (+/-6.8) years. Eculizumab was used "off-label" in 44% of cases. The most common diagnoses were aHUS (47.4%), Shiga toxin-producing Escherichia coli HUS (12%), unspecified thrombotic microangiopathies (9%), and glomerulonephritis (9%). Genetic testing was available for 60% of patients; 20% had gene variants. Dosing regimens were variable. Kidney outcomes tended to vary according to diagnosis. Infectious adverse events were the most common adverse event (33.5%). No cases of meningitis were reported. Nine patients died of noninfectious causes while on therapy.

CONCLUSIONS

This multi-center retrospective cohort analysis indicates that a significant number of children and young adults are being exposed to C5 blockade for off-label indications. Dosing schedules were highly variable, limiting outcome conclusions. Attributable adverse events appeared to be low. Cohort mortality (6.6%) was not insignificant. Prospective studies in homogenous disease cohorts are needed to support the role of C5 blockade in kidney outcomes.

Severely ill pediatric patients with Shiga toxin-associated hemolytic uremic syndrome (STEC-HUS) who suffered from multiple organ involvement in the early stage

BACKGROUND

Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is the main cause of pediatric acute kidney injury (AKI) in Argentina. Endothelial injury is the trigger event in the microangiopathic process. The host inflammatory response to toxin and E. coli lipopolysaccharide (LPS) is involved in disease pathophysiology.

METHODS

This retrospective study describes pediatric STEC-HUS patients with multiorgan involvement at the initial phase of disease. A retrospective study of critically ill HUS patients with evidence of E. coli infection was conducted through a period of 15 years.

RESULTS

Forty-four patients 35.4 ± 4.1 months were admitted to the intensive care unit for 21 ± 2 days. Mechanical ventilation was required in 41 patients, early inotropic support in 37, and 28 developed septic shock. Forty-one patients required kidney replacement therapy for 12 ± 1 days. Forty-one patients showed neurological dysfunction. Dilated cardiomyopathy was demonstrated in 3 patients, left ventricular systolic dysfunction in 4, and hypertension in 17. Four patients had pulmonary hemorrhage, and acute respiratory distress syndrome in 2. Colectomy for transmural colonic necrosis was performed in 3 patients. Thirty-seven patients were treated with therapeutic plasma exchange, and 28 patients received methylprednisolone (10 mg/kg for 3 days). Of the surviving 32 patients, neurological sequelae were seen in 11 and chronic kidney failure in 5.

CONCLUSIONS

Severe clinical outcome at onset suggests an amplified inflammatory response after exposure to Shiga toxin and/or E. coli LPS. STEC-HUS associated with severe neurological involvement, hemodynamic instability, and AKI requires intensive care and focused therapy.

Volume Resuscitation and Progression to Organ Failure in Shiga Toxin-Producing Escherichia coli Infection in Adults

OBJECTIVES:

Shiga toxin-producing Escherichia coli infection is associated with dysentery and the hemolytic uremic syndrome, marked by the triad of microangiopathic hemolytic anemia, acute kidney failure, and thrombocytopenia. Descriptions of Shiga toxin-producing Escherichia coli outbreaks causing hemolytic uremic syndrome in adults are sparse, and management strategies are largely adapted from pediatric literature where aggressive fluid administration is recommended. However, these may not be ideal for adults.

DESIGN:

We present a case series of an Shiga toxin-producing Escherichia coli outbreak in U.S. Marine Corps recruits.

SETTING:

We review the clinical course, laboratory data, and fluid resuscitation used in hospitalized patients during the 2017 Shiga toxin-producing Escherichia coli outbreak at Marine Corps Recruit Depot, San Diego.

PATIENTS:

Patients admitted to the hospital for complications from Shiga toxin-producing Escherichia coli infection. All were previously healthy men between the ages of 17 and 20 years.

INTERVENTIONS:

Isotonic crystalloid fluid resuscitation during the first 72 hours.

MEASUREMENTS AND MAIN RESULTS:

Of 244 identified cases of Shiga toxin-producing Escherichia coli infection, 30 required hospitalization, 15 progressed to hemolytic uremic syndrome, and five required hemodialysis. Patients were admitted and given aggressive IV fluid hydration. Those who progressed to hemolytic uremic syndrome received on average 8.4 L of isotonic crystalloid over the initial 72 hours, with up to 18% of body weight delivered. The six critically ill patients received a mean 12.2 L in the first 72 hours. Those who did not progress to hemolytic uremic syndrome received a mean 3.0 L of crystalloid. If oligoanuria developed, a net-even fluid balance was maintained. The amount of volume infused was not associated with improved outcomes. The patients with the highest fluid balance totals more often required dialysis than those who received less fluid. One hemolytic uremic syndrome patient developed flash pulmonary edema.

CONCLUSIONS:

The aggressive IV hydration protocols (as a percentage of body weight) in the pediatric literature may not be applicable to adults diagnosed with hemolytic uremic syndrome. A more conservative fluid strategy in adults with hemolytic uremic syndrome merits further investigation.

Shiga Toxin-Associated Hemolytic Uremic Syndrome: Specificities of Adult Patients and Implications for Critical Care Management

Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (STEC-HUS) is a form of thrombotic microangiopathy secondary to an infection by an enterohemorrhagic E. coli. Historically considered a pediatric disease, its presentation has been described as typical, with bloody diarrhea at the forefront. However, in adults, the clinical presentation is more diverse and makes the early diagnosis hazardous. In this review, we review the epidemiology, most important outbreaks, physiopathology, clinical presentation and prognosis of STEC-HUS, focusing on the differential features between pediatric and adult disease. We show that the clinical presentation of STEC-HUS in adults is far from typical and marked by the prevalence of neurological symptoms and a poorer prognosis. Of note, we highlight knowledge gaps and the need for studies dedicated to adult patients. The differences between pediatric and adult patients have implications for the treatment of this disease, which remains a public health threat and lack a specific treatment.

Complement activation in children with Streptococcus pneumoniae associated hemolytic uremic syndrome

BACKGROUND

Hemolytic uremic syndrome caused by invasive pneumococcal disease (P-HUS) is rare in children and adolescents, but accompanied by high mortality in the acute phase and complicated by long-term renal sequelae. Abnormalities in the alternative complement pathway may additionally be contributing to the course of the disease but also to putative treatment options.

METHODS

Retrospective study to assess clinical course and laboratory data of the acute phase and outcome of children with P-HUS.

RESULTS

We report on seven children (median age 12 months, range 3-28 months) diagnosed with P-HUS. Primary organ manifestation was meningitis in four and pneumonia in three patients. All patients required dialysis which could be discontinued in five of them after a median of 25 days. In two patients, broad functional and genetic complement analysis was performed and revealed alternative pathway activation and risk haplotypes in both. Three patients were treated with the complement C5 inhibitor eculizumab. During a median follow-up time of 11.3 years, one patient died due to infectious complications after transplantation. Two patients showed no signs of renal sequelae.

CONCLUSIONS

Although pathophysiology in P-HUS remains as yet incompletely understood, disordered complement regulation seems to provide a clue to additional insights for pathology, diagnosis, and even targeted treatment.

Rasburicase improves the outcome of acute kidney injury from typical hemolytic uremic syndrome

BACKGROUND

Typical hemolytic uremic syndrome (HUS) causes acute kidney injury (AKI) and serious sequelae of chronic kidney disease (CKD) in some. Hyperuricemia is a common finding in typical HUS that may contribute to kidney damage. We explored whether aggressive management of hyperuricemia with rasburicase could improve outcomes in AKI patients with typical HUS.

METHODS

We retrospectively analyzed medical records of children with typical HUS admitted to a tertiary center between 2005 and 2017. We compared clinical outcomes of hospitalization and 1-year post-discharge between those with rasburicase treatment (n = 13) and those without (controls, n = 29).

RESULTS

With rasburicase treatment, hyperuricemia corrected more rapidly (median 36 vs. 120 h, p < 0.001), and hospital stays were shorter (median 9 vs. 12 days, p = 0.003) than in the controls. There was no difference in dialysis requirement. At 1-year post-discharge, the proportion of patients with impaired kidney function (estimated glomerular filtration rate < 90 mL/min/1.73 m²) was lower in the rasburicase group (7.7% vs. 41.4%, p = 0.036) than in the controls. Hypertension and proteinuria tended to be more common in the controls than in the rasburicase group. Collectively, long-term renal sequelae of impaired kidney function, proteinuria, or hypertension at a 1-year follow-up was less common in the rasburicase group than in the controls (7.7% vs. 62.1%; p = 0.001).

CONCLUSIONS

Children with typical HUS treated with rasburicase had shorter hospital stays and less long-term sequelae at 1-year post-discharge than those who were not treated with rasburicase. These results support the use of rasburicase to prevent CKD in pediatric patients with typical HUS-associated AKI. Graphical Abstract.