Cardiac Manifestation among Children with Hemolytic Uremic Syndrome

Gastrointestinal involvement in STEC-associated hemolytic uremic syndrome: 10 years in a pediatric center

BACKGROUND

The gastrointestinal (GI) tract represents one of the main targets of typical hemolytic uremic syndrome (HUS) in children. In this observational study, we tried to establish (1) the main features of GI complications during STEC-HUS and (2) the relationship between Escherichia coli serotypes and Shiga toxin (Stx) variants with hepatopancreatic involvement.

METHODS

A total of 79 STEC-HUS patients were admitted to our pediatric nephrology department between January 2012 and June 2021. Evidence of intestinal, hepatobiliary, and pancreatic involvements was reported for each patient, alongside demographic, clinical, and laboratory features. Frequency of gastrointestinal complications across groups of patients infected by specific E. coli serotypes and Stx gene variants was evaluated.

RESULTS

Six patients developed a bowel complication: two developed rectal prolapse, and four developed bowel perforation which resulted in death for three of them and in bowel stenosis in one patient. Acute pancreatitis was diagnosed in 13 patients. An isolated increase in pancreatic enzymes and/or liver transaminases was observed in 41 and 15 patients, respectively. Biliary sludge was detected in three, cholelithiasis in one. Forty-seven patients developed direct hyperbilirubinemia. Neither E. coli serotypes nor Shiga toxin variants correlated with hepatic or pancreatic involvement.

CONCLUSIONS

During STEC-HUS, GI complications are common, ranging from self-limited elevation of laboratory markers to bowel perforation, a severe complication with a relevant impact on morbidity and mortality. Hepatopancreatic involvement is frequent, but usually short-lasting and self-limiting.

Autonomic activity and cardiovascular system risk assessment in pediatric patients with hemolytic uremic syndrome

In pediatric patients with hemolytic uremic syndrome (HUS), cardiac involvement and autonomic nervous system function can be evaluated by a non-invasive method called heart rate variability (HRV). This study aims to evaluate heart rate variability and electrocardiography findings in patients with HUS by comparing a healthy group. Patients who are diagnosed with HUS at a university hospital from December 2020 to June 2022 are screened by electrocardiography (ECG), echocardiography, and 24-h Holter ECG. A healthy control group, compatible in age and gender with the patient group, was selected from healthy subjects. HRV parameters, laboratory values, and ECG findings were analyzed and compared with the healthy group and each other. There were 25 patients with HUS and 51 participants in the healthy control group. Statistically significant differences were found in some HRV parameters: standard deviation of normal to normal intervals, the mean of the 5-min RR interval standard deviations, the standard deviation of 5-min RR interval means, the triangular interpolation of normal to normal interval, and very-low-frequency power. HUS patients had impaired and declined HRV values compared to the healthy group. There was a significant decrease in the PR distance, while a significant increase in the corrected QT and QT dispersion values was detected in the electrocardiographic findings of the patient group. HRV values impaired as renal failure parameters increased.  Conclusion: Patients with HUS may have autonomic nervous system dysfunction. HRV measurement is a non-invasive method that can evaluate this. It can be thought that there may be an increased risk of cardiovascular events and arrhythmias in some patients with HUS. ECG should be also considered to detect arrhythmia. What is Known: • Hemolytic uremic syndrome (HUS) primarily effects the hematologic parameters and kidney. • Secondary cardiomyopathy with hypertension and renal failure could be observed in these patients. • Rhythm problems are not expected primarily in these patients. • There is very limited data in evaluating autonomic function and arrhythmia risk for these patients. What is New: • Patients with HUS may have autonomic nervous system dysfunction. • HRV measurement is a non-invasive method that can evaluate this. • Cardiovascular events and arrhythmias due to the deterioration of the balance between the sympathetic and parasympathetic systems could manifest in patients with HUS. • An ECG and screening patients for cardiac events, and monitoring them closely should be considered.

Cardiac involvement in pediatric hemolytic uremic syndrome

BACKGROUND

Cardiac involvement is a known but rare complication of pediatric hemolytic uremic syndrome (HUS). We conducted a nationwide observational, retrospective case-control study describing factors associated with the occurrence of myocarditis among HUS patients.

METHODS

Cases were defined as hospitalized children affected by any form of HUS with co-existent myocarditis in 8 French Pediatric Intensive Care Units (PICU) between January 2007 and December 2018. Control subjects were children, consecutively admitted with any form of HUS without coexistent myocarditis, at a single PICU in Lyon, France, during the same time period.

RESULTS

A total of 20 cases of myocarditis were reported among 8 PICUs, with a mean age of 34.3 ± 31.9 months; 66 controls were identified. There were no differences between the two groups concerning the season and the typical, Shiga toxin-producing Escherichia coli (STEC-HUS), or atypical HUS (aHUS). Maximal leukocyte count was higher in the myocarditis group (29.1 ± 16.3G/L versus 21.0 ± 9.9G/L, p = 0.04). The median time between admission and first cardiac symptoms was of 3 days (range 0-19 days), and 4 patients displayed myocarditis at admission. The fatality rate in the myocarditis group was higher than in the control group (40.0% versus 1.5%, p < 0.001). Thirteen (65%) children from the myocarditis group received platelet transfusion compared to 19 (29%) in the control group (p = 0.03).

CONCLUSION

Our study confirms that myocarditis is potentially lethal and identifies higher leukocyte count and platelet transfusion as possible risk factors of myocarditis. A higher resolution version of the Graphical abstract is available as Supplementary information.