Despite being an essential specialty, pediatrics in South Korea faces the threat of collapse. While the declining birth rate is an important contributor to the decrease in the pediatric population, a more critical issue lies in the dysfunctional healthcare system. Primary care pediatricians are troubled by the lack of patients, whereas tertiary care specialists are concerned about the shortage of doctors. Although the absolute number of pediatric specialists is not small, there is a scarcity of doctors willing to specialize in pediatrics. Recently, pediatric abdominal ultrasonography has been conducted in tertiary hospitals. However, there is an argument that this responsibility should be shifted to primary care pediatricians. As someone who has been performing pediatric abdominal ultrasound examinations for years, I am committed to educating pediatric specialists in this field. My aim is to contribute, albeit modestly, to improving the South Korean healthcare system.

Purpose: Helicobacter pylori infections differ between children and adults. The Pediatric society practice guidelines recommend against a test-and-treat approach, characterized by the use of non-invasive tests for diagnosis (e.g. urea breath test [UBT] or stool antigen test). However, significant variations exist in clinical practice. This study examined the use of non-invasive testing for the screening and diagnosis of H. pylori infection in children at a tertiary pediatric hospital in Singapore, reviewing both management decisions and patient outcomes. Methods: A retrospective review was conducted on children between the ages of 0 and 18 years who were tested for H. pylori infection using either a stool antigen test or UBT between January 2018 and June 2020. Results: Among the 1,397 children tested, 117 (8.4%) had a positive stool H. pylori antigen result, and 5 out of 85 tested (5.9%) had a positive UBT. Abdominal pain was the predominant symptom (n=98; 80.3%). Only 7 treatment-naïve children had biopsy-proven disease. Tissue biopsies for H. pylori culture were sent to 2 children, with 1 negative result. A total of 111 children (91.0%) received treatment, wherein proton pump inhibitor, amoxicillin, and clarithromycin for 14 days was the most common therapeutic regimen. Symptom resolution was observed in 62 children (50.8%). Conclusion: A test-and-treat strategy was more widely utilized than endoscopy-based testing, showing a low compliance to existing guidelines for the management of H. pylori infections in children at our center and significant false-positive rates.

Purpose: The study aimed to investigate the recruiting of T lymphocytes including IL-7Rα^low CX3CR1⁺ effector memory (EM) CD8⁺ T cells and α4β7 integrin tagged T cells to inflamed intestinal mucosa. Methods: Whole blood and mucosal tissues of intestine were collected from 40 children with or without inflammatory bowel disease (IBD). T cell surface staining and immunohistochemistry were done with several antibodies in peripheral blood mononuclear cells (PBMCs) and intestinal mucosa, respectively. Serum levels of cytokines were measured by ELISA. Results: The frequency of IL-7Rα^lowCX3CR1⁺ EM CD8⁺ T cells in the PBMC was significantly higher in the ulcerative colitis group than in the control group (57.9±17.80% vs. 33.9±15.70%, p=0.021). The frequency of integrin α4β7⁺ CD4⁺ T cells in the PBMC was significantly lower in the ulcerative colitis group than in the control group (53.2±27.6% vs. 63.9±13.2%, p=0.022). Serum concentration of TNF-α was higher in the Crohn's disease group than in the control group (26.13±5.01 pg/mL vs. 19.65±6.07 pg/mL, p=0.008). Of the three groups, the ulcerative colitis group had the highest frequency of integrin α4β7⁺ T cells based on immunohistochemistry analyses for intestinal tissues, followed by the Crohn's disease group and the control group (4.63±1.29 cells vs. 2.0±0.57 cells vs. 0.84±0.52 cells, p<0.001). Conclusion: Trafficking immune cells with effector memory CD8⁺ T cells clarified by IL-7Rα^lowCX3CR1⁺ and integrin α4β7⁺ CD4⁺ T cells might be highly associated with the pathogenesis of ulcerative colitis.

Purpose: This study aimed to establish and characterize patient-derived intestinal organoids (PDOs) from children with Crohn's disease (CD). Methods: To generate PDOs, endoscopic biopsy specimens were obtained from non-inflamed duodenal bulbs of normal controls and CD patients. To verify the presence of PDOs, histological staining and quantitative reverse transcription polymerase chain reaction (RT-qPCR) analyses were performed. Results: PDOs were successfully established in normal controls (n=2) and CD patients (n=2). Hematoxylin and eosin staining of formalin-fixed, paraffin-embedded PDO sections revealed crypt and villus structures, whereas immunofluorescence staining with EpCAM and DAPI confirmed the epithelial-specific architecture of the PDOs. RT-qPCR results revealed a significant increase in Lgr5, Si, and Chga gene expression and a decrease in Olfm4 and Muc2 expression in CD patients compared to normal controls, suggesting altered stem cell activity and mucosal barrier function (p<0.05). Conclusion: We successfully established and characterized PDOs in children with CD, providing a valuable tool for understanding the pathophysiology of the disease and evaluating potential therapeutic approaches. The differential gene expression of PDOs in CD patients might be caused by the complex interplay between epithelial adaptation and inflammation in the intestinal epithelium.

Purpose: The practice of withholding oral nutrition for children hospitalized for critical asthma receiving continuous albuterol is not evidence based. We sought to characterize oral nutrition practices in this population and estimate the frequency of aspiration-related respiratory failure. Methods: We performed a single-center retrospective, matched cohort study of children 3-17 years of age admitted to a pediatric intensive care unit from Oct 2020 to May 2023 for critical asthma receiving continuous albuterol. Cases provided oral nutrition were matched 1:2 to controls withheld nutrition by age and National Heart Lung and Blood Institute asthma severity classification. The primary outcome was aspiration-related respiratory failure defined as any respiratory support escalation following observed aspiration. Descriptive data included demographics, anthropometrics, pediatric asthma severity scores, adjunct asthma interventions, continuous albuterol duration, mortality, and length of stay. Results: Of 36 cases and 72 matched controls, the mean age was 9.1±3.9 years and 66.7% had moderate-severe persistent asthma. Cases and controls had comparable anthropometrics and admission pediatric asthma severity scores. No aspiration-related respiratory failure events were observed even among those receiving nutrition concurrent to noninvasive ventilation. Compared to controls, cases experienced a longer continuous albuterol duration (median: 1.1 [interquartile range: 0.7-1.8] versus 0.7 [interquartile range: 0.3-1.3] days, p<0.001). No differences in length of stay, adjunct interventions, endotracheal intubation rates, and mortality were observed between cases and controls. Conclusion: For children hospitalized for critical asthma, oral nutrition during continuous nebulized albuterol appeared well tolerated. While prospective validation is required, the practice of withholding oral nutrition for continuous albuterol administration may be unwarranted.

Purpose: This study investigated the prevalence of bowel dysfunction and associated factors after pull-through surgery. Methods: The medical records of children under 18 years old diagnosed with Hirschsprung disease (HD) based on histopathology between 2004 and 2022 were reviewed. Bowel dysfunction after pull-through surgery was categorized into Hirschsprung-associated enterocolitis (HAEC), constipation, and fecal incontinence. Results: Among 97 children diagnosed with HD, the median age at presentation was 3 (2-15) days (84.54% male). The clinical manifestations included abdominal distension (58.76%), constipation (17.52%), bilious vomiting (17.52%), nonbilious vomiting (14.43%), and enterocolitis (12.37%). HDs were classified by the location of aganglionosis: short segments (74.23%), long segments (8.25%), total colonic (12.37%), and small intestinal (5.15%). Excluding surgical complications, the prevalence of bowel dysfunction was 64.95% during an average follow-up of 8.33 years. HAEC was the most common issue (46.39%), followed by nonretentive incontinence (22.68%), constipation (20.62%), and retentive incontinence (15.46%). Preoperative HAEC was significantly associated with post-surgery HAEC (adjusted odds ratio [aOR] 18.31; 95% confidence interval [CI], 1.30-257.73; p=0.031). The Duhamel operation was associated with constipation and retentive incontinence (aOR 62.15; 95% CI, 1.64-2,349.13; p=0.026). Age under 6 months at pull-through surgery was associated with nonretentive fecal incontinence after 4 years (aOR 8.83; 95% CI, 1.11-70.39; p=0.040). Conclusion: The prevalence of bowel dysfunction in children with HD remains high despite successful surgical correction. Preoperative HAEC, Duhamel operation, and pull-through surgery before the age of 6 months were found to be independent factors associated with bowel dysfunction after pull-through surgery.