Search

Perianal fistulizing diseases, namely perianal fistulas and/or abscesses, are well-known complications of Crohn's disease (CD). These are known to develop more frequently in Asian children with CD, especially in the early stages of the disease course. Approximately half of the pediatric CD cases in Korea present with perianal fistulizing diseases at diagnosis. We report a rare case of a 12-year-old boy with CD with an incidental discovery of a perianal abscess on pelvic magnetic resonance imaging during CD diagnosis. No symptoms or signs of perianal fistulizing disease were identified. The early diagnosis of the perianal abscess enabled timely and effective treatment. Considering the high incidence of concomitant perianal CD in Korean children at diagnosis, perianal imaging may be useful and should be considered during diagnostic evaluation, even in patients with no subjective or objective findings indicating perianal CD.

Background/Aims We evaluated whether anti-Saccharomyces cerevisiae antibody (ASCA) titers are associated with diagnostic findings, disease activity, Paris classification phenotypes, and persistence after infliximab (IFX) treatment in children with Crohn's disease (CD). We also investigated the role of ASCA as a predictor of mucosal healing (MH) and clinical remission (CR). Methods This study included 61 CD patients aged 19 years or younger who were diagnosed and treated between September 2010 and January 2019 and followed for at least 1 year. ASCA was regularly measured at the diagnosis of CD and at least 1 year after IFX therapy. Results The average follow-up period was 3.8±3.4 years (range, 1.0 to 7.2 years). Regression analysis showed that the ASCA titer was the only factor associated with Simple Endoscopic Score for Crohn's Disease (SES-CD) or CR among all the parameters. In patients who had achieved MH (SES-CD=0), ASCA immunoglobulin G (IgG) was not associated with MH, but in patients without MH, ASCA IgG was associated with SES-CD (p=0.005) and CR (p

Background/Aims Anti-drug antibodies (ADAs) can develop during treatment with anti-tumor necrosis factor (TNF) agents. We aimed to investigate the factors associated with immunogenicity of anti-TNF agents in pediatric patients with inflammatory bowel disease (IBD) and observe the clinical course of ADA-positive patients. Methods Pediatric IBD patients receiving maintenance treatment with anti-TNF agents who had been tested for ADAs against infliximab (IFX) or adalimumab (ADL) were included in this cross-sectional study. Factors associated with ADA positivity were investigated by analyzing clinicodemographic, laboratory, and treatment-related factors. Results A total of 76 patients (Crohn’s disease, 65; ulcerative colitis, 11) were included. Among these, 59 and 17 patients were receiving IFX and ADL, respectively. ADAs were found in 10 patients (13.2%), all of whom were receiving IFX. According to multivariable logistic regression analysis, the IFX trough level (TL) was associated with ADA positivity (odds ratio, 0.25; 95% confidence interval [CI], 0.08 to 0.51; p=0.002). According to the receiver operating characteristic analysis, the optimal cutoff of the IFX TLs for stratifying patients based on the presence of ADAs against IFX was 1.88 μg/mL (area under curve, 0.941; 95% CI, 0.873 to 1.000; sensitivity, 80.0%; specificity, 95.9%; p

Juvenile polyposis/hereditary hemorrhagic telangiectasia (JPS/HHT) syndrome is a rare, autosomal dominant disorder caused by mutations in the SMAD4 gene, presenting with features of both juvenile polyposis syndrome (JPS) and HHT. Reports and studies of JPS/HHT syndrome are mostly from Western countries, while there are scarce reports from East Asian countries. We report a case of a Korean boy who had been previously diagnosed with JPS at 7 years and had first visited to our center at 15 years of age. Genetic studies of the patient and parents revealed a novel variant in the SMAD4 gene, SMAD4 c.1146_1163del; p.His382_Val387del (NM_005359.5), which had developed de novo. Numerous pedunculated and sessile polyps were observed throughout the gastrointestinal (GI) tract. Mucocutaneous telangiectases were observed on the lips, tongue, and jejunum, and arteriovenous malformations (AVMs) were observed in both lungs. This is the first case report of JPS/HHT syndrome in Korea, with a novel deletion variant in the SMAD4 gene. Patients with JPS should undergo genetic evaluation of associated genes including SMAD4, and those with genetically confirmed SMAD4 variants should undergo further evaluation for coexisting asymptomatic AVMs in order to prevent life-threatening complications of thrombotic emboli and pulmonary hemorrhage.

Displacement of a mandibular third molar into a fascial space is a relatively rare event with potentially serious complications. The surgical procedure to remove a displaced tooth, or part thereof from these spaces may be difficult due to poor access and an abundance of vital structures within these spaces. Here, we present two cases of submandibular displacement, suggest an intra-oral approach and algorithm to help guide practitioners with management of displaced third molars in the submandibular space.

Objectives We investigated the therapeutic drug monitoring of adalimumab (ADL) on clinical remission (CR) and mucosal healing (MH) rates in paediatric patients with Crohn disease (CD). Furthermore, long-term treatment efficacy of ADL in paediatric CD was evaluated through 3-year follow-up. Methods We conducted a prospective study of 31 patients with CD who received ADL maintenance therapy and underwent endoscopic evaluation of MH and pharmacokinetic analysis. Patients in CR were identified based on Paediatric Crohn Disease Activity Index (PCDAI) scores less than 10. Patients with MH were identified based on Simple Endoscopic Scores for Crohn Disease (SES-CD) of less than 2. Results At 4 months and 1 year of ADL treatment, 28 and 26 patients, respectively, were under CR; 13 and 17 patients, respectively, achieved MH. The median trough levels (TLs) of ADL were higher in patients in CR (7.6 ± 3.5 μg/mL) than in patients with active disease (5.1 ± 2.2 μg/mL). ADL TLs were significantly higher in patients who achieved MH than in those who did not (14.2 ± 7.6 vs 7.8 ± 5.2 μg/mL). The optimal cut-point for predicting MH at 1 year of ADL treatment was 8.18 μg/mL. During long-term follow-up, ADL TLs were stably maintained over 10 μg/mL; not only CR and MH but also histologic remission was obtained at a high rate. ADL administration maintained a positive effect on growth during the maintenance period. Conclusions ADL TLs were significantly higher in paediatric patients with CD who achieved CR or MH. ADL treatment showed long-term stable efficacy and positive effects on growth indicators.

Vedolizumab (VDZ) has been approved for the treatment of inflammatory bowel diseases (IBDs) in patients aged ≥18 years. We report a case of a pediatric patient with Crohn disease (CD) who was successfully treated with VDZ. A 16-year-old female developed severe active pulmonary tuberculosis (TB) during treatment with infliximab (IFX). IFX was stopped, and TB treatment was started. After a 6-month regimen of standard TB medication, her pulmonary TB was cured; however, gastrointestinal symptoms developed. Due to the concern of the patient and parents regarding TB reactivation on restarting treatment with IFX, VDZ was started off-label. After the second dose of VDZ, the patient was in clinical remission and her remission was continuously sustained. Ileocolonoscopy at 1-year after VDZ initiation revealed endoscopic healing. Therapeutic drug monitoring conducted during VDZ treatment showed negative antibodies to VDZ. No serious adverse events occurred during the VDZ treatment. This is the first case report in Korea demonstrating the safe and effective use of VDZ treatment in a pediatric CD patient. In cases that require recommencement of treatment with biologics after recovery of active pulmonary TB caused by anti-tumor necrosis factor agents, VDZ may be a good option even in pediatric IBD.

BACKGROUND/OBJECTIVES To evaluate the nutritional status and prevalence of malnutrition in hospitalized children at admission and during hospitalization in South Korea. SUBJECTS/METHODS This first cross-sectional nationwide "Pediatric Nutrition Day (pNday)" survey was conducted among 872 hospitalized children (504 boys, 368 girls; 686 medical, 186 surgical) from 23 hospitals in South Korea. Malnutrition risk was screened using the Pediatric Yorkhill Malnutrition Score (PYMS) and the Screening Tool Risk on Nutritional status and Growth. Nutritional status was assessed by z-scores of weight-for-age for underweight, weight-for-height for wasting, and height-for-age for stunting as well as laboratory tests. RESULTS At admission, of the 872 hospitalized children, 17.2% were underweight, and the prevalence of wasting and stunting was 20.2% and 17.3%, respectively. During hospitalization till pNday, 10.8% and 19.6% experienced weight loss and decreased oral intake, respectively. During the aforementioned period, fasting was more prevalent in surgical patients (7.5%) than in medical patients (1.6%) (P < 0.001). According to the PYMS, 34.3% and 30% of the children at admission and on pNday, respectively, had a high-risk of malnutrition, requiring consultation with the nutritional support team (NST). However, only 4% were actually referred to the NST during hospitalization. CONCLUSIONS Malnutrition was prevalent at admission and during hospitalization in pediatric patients, with many children experiencing weight loss and poor oral intake. To improve the nutritional status of hospitalized children, it is important to screen and identify all children at risk of malnutrition and refer malnourished patients to the multidisciplinary NST for proper nutritional interventions.

Oral cancer in children is rare. Diagnosis may be delayed as a result of confusion with reactive lesions. Furthermore, cancer staging, with or without bony invasion, can be complicated during tooth eruption. Literature on pediatric oral cancers is lacking, making determination of the possible etiopathology difficult. We describe an exceptional case of a 5-year-old male child who presented with anterior maxillary gingival pseudoepitheliomatous hyperplasia that progressed to carcinoma cuniculatum with invasive oral squamous cell carcinoma (OSCC). Because of the interesting timing of events, we hypothesize that human papillomavirus (HPV) inoculation through cutaneous squamous papilloma played a contributory role. A review of similar case reports in the literature is included. Biopsy of suspicious oral lesions should not be delayed because of the young age of the patient. Atypical hyperplasia should include squamous cell carcinoma (SCC) in the differential diagnoses. For surgical management of aggressive lesions during the mixed dentition, permanent successors should be included in the surgical margins to prevent recurrence.

BACKGROUND The association between NUDT15 polymorphisms and thiopurine-induced leucopenia is well known. AIM To investigate the association between NUDT15 polymorphisms and time-to-leucopenia in paediatric patients with inflammatory bowel disease (IBD) receiving azathioprine and to determine the relationship between NUDT15 polymorphisms and 6-thioguanine nucleotide (6-TGN) levels. METHODS This retrospective observational study included Korean paediatric patients with IBD who were treated with azathioprine and underwent NUDT15 and TPMT genotyping. Azathioprine doses were adjusted by regular thiopurine metabolite monitoring. Factors associated with time-to-leucopenia and the relationship between NUDT15 polymorphisms and 6-TGN levels were analysed. RESULTS Among the 167 patients included, leucopenia was observed in 16% (19/119), 44% (20/45) and 100% (3/3) of the NUDT15 normal, intermediate and poor metabolisers respectively (P

Introduction: Autoimmune pancreatitis (AIP) is a rare extraintestinal manifestation of inflammatory bowel disease (IBD) which is typically responsive to corticosteroid treatment.Case Presentation: We report a case of a 17-year-old male diagnosed with ulcerative colitis who subsequently developed acute pancreatitis. Blood tests demonstrated elevated pancreatic enzyme levels of amylase (1319 U/L) and lipase (809 U/L). Abdominal computed tomography revealed peripancreatic fat stranding and the presence of a perisplenic pseudocyst. Azathioprine and mesalazine were stopped as possible causes of drug-induced pancreatitis. However, pancreatic enzymes remained elevated and corticosteroid treatment was started. Despite corticosteroid therapy, amylase and lipase levels continued to increase. Infliximab was started due to a flare in gastrointestinal symptoms of ulcerative colitis. Follow-up abdominal ultrasonography revealed a pancreatic tail mass. Tumor markers, including CA 19-9, were elevated and atypical cells were seen on histological examination of an endoscopic ultrasonography-guided fine needle aspiration biopsy. Surgical pancreaticosplenectomy was performed for suspected pancreatic neoplasm. Surprisingly, histology revealed chronic pancreatitis with storiform fibrosis and infiltration of IgG4-positive cells, compatible with AIP type 1. Thereafter, pancreatic enzymes gradually decreased to normal levels and the patient has been in remission for 9 months on infliximab monotherapy.Conclusion: Pediatric gastroenterologists should keep in mind that AIP may develop during the natural course of pediatric IBD. Moreover, the development of pancreatic fibrosis may be non-responsive to corticosteroid treatment and mimic pancreatic neoplasia.

Collagenous gastritis (CG) is a rare disease diagnosed histologically by the subepithelial deposition of collagen bands thicker than 10 µm and the infiltration of inflammatory mononuclear cells in the lamina propria. The definite pathophysiology is yet to be elucidated. However, recent studies have suggested that the collagen deposition may be the result of a reparative process in response to an earlier inflammatory, autoimmune, infectious, or toxic insult. CG is divided into the pediatric- and adult-type. While the pediatric-type is limited to the stomach, the adult-type involves not only the stomach but also the intestine and/or colon. We report a rare case of adult-type CG in a 15-year-old boy who initially presented with abdominal pain and iron-deficiency anemia. Esophagogastroduodenoscopy (EGD) revealed findings suspicious for Helicobacter pylori (H. pylori) gastritis. Although histology did not reveal the organism, campylobacter-like organism (CLO) test was positive. Based on the diagnosis of suspicious H. pylori gastritis, eradication was conducted using the triple drug regimen. However, symptoms of intermittent abdominal pain persisted and diarrhea newly developed one year later. Histologic results from biopsies from the stomach, duodenum, and colon revealed findings compatible with CG, collagenous duodenitis (CD), and collagenous colitis (CC). This is the first pediatric case of collagenous gastroduodenocolitis (CGDC) reported in Asia. It is no longer assumed that adult-type and pediatric-type CG should be classified as an independent disease, but should be considered as similar diseases on a continuous spectrum. Therefore, children and adolescents diagnosed with CG should also consider undergoing a colonoscopy for the evaluation of possible coexisting CC when concurrent lower gastrointestinal symptoms are present. Moreover, considering the possibility of negative findings on the first endoscopy, repeat endoscopy should be considered when symptoms persist.

The prevalence of cystic fibrosis (CF) is considerably lower in Asian populations compared with that of Caucasians. Cases of CF are typically due to mutations in the CF transmembrane conductance regulator gene with autosomal recessive inheritance. Here, we report two cases of newly diagnosed CF in Korea—a 13-year-old boy and his 5-year-old brother. The older brother was admitted to our hospital for evaluation and treatment of recurrent abdominal pain, frequent diarrhea, and failure to thrive. Fecal calprotectin (FC) was elevated, and when combining this with his clinical presentation, inflammatory bowel disease (IBD) or eosinophilic gastroenteritis (EoGE) was the first impression of his disease. Several ulcerative lesions were observed on ileocolonoscopy. However, incidental findings of suspicious bronchiectatic lesions were observed on plain radiography, which were confirmed by chest computed tomography. Moreover, diffuse bowel wall thickening with pancreatic atrophy was also incidentally detected by computed tomography of the abdomen. Comprehensively, these findings were highly suggestive of CF. Therefore, diagnostic exome sequencing was conducted, which revealed compound heterozygous variants of c.263T>G (p.Leu88*) and c.2977G>T (p.Asp993Tyr) in the CF transmembrane conductance regulator gene. Although symptoms in the younger brother were not as prominent as the older brother, genetic test was also conducted, which revealed the same mutation. We report the identification of a novel variant, p.Asp993Tyr, in siblings with Korean heritage. Although CF is rare in Koreans, it should be included in the differential diagnosis of IBD.

BACKGROUND: The occurrences of infection-related systematic diseases, such as Henoch-Schönlein Purpura (HSP), intussusception, and mucocutaneous lymph node syndrome (MCLS) may have decreased, similarly to the decreased occurrence of infectious diseases following the Coronavirus disease 2019 (COVID-19) pandemic. We aimed to investigate whether there was a change in the occurrence of these diseases in South Korea after the spread of the COVID-19 pandemic. METHODS: In this multicenter, retrospective study conducted in 16 medical centers in South Korea patients diagnosed with HSP, intussusception, and MCLS at the age of

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of mortality and morbidity in the world. It is characterized by different pathways of carcinogenesis and is a heterogeneous disease with diverse molecular landscapes that reflect histopathological and clinical information. Changes in the DNA methylation status of colon epithelial cells have been identified as critical components in CRC development and appear to be emerging biomarkers for the early detection and prognosis of CRC. OBJECTIVE: To explore the underlying disease mechanisms and identify more effective biomarkers of CRC. METHODS: We compared the levels and frequencies of DNA methylation in 11 genes (Alu, APC, DAPK, MGMT, MLH1, MINT1, MINT2, MINT31, p16, RGS6, and TFPI2) in colorectal cancer and its precursor adenomatous polyp with normal tissue of healthy subjects using pyrosequencing and then evaluated the clinical value of these genes. RESULTS: Aberrant methylation of Alu, MGMT, MINT2, and TFPI2 genes was progressively accumulated during the normal-adenoma-carcinoma progression. Additionally, CGI methylation occurred either as an adenoma-associated event for APC, MLH1, MINT1, MINT31, p16, and RGS6 or a tumor-associated event for DAPK. Moreover, relatively high levels and frequencies of DAPK, MGMT, and TFPI2 methylation were detected in the peritumoral nonmalignant mucosa of cancer patients in a field-cancerization manner, as compared to normal mucosa from healthy subjects. CONCLUSION: This study identified several biomarkers associated with the initiation and progression of CRC. As novel findings, they may have important clinical implications for CRC diagnostic and prognostic applications. Further large-scale studies are needed to confirm these findings.

Background It is uncertain whether non-alcoholic fatty liver disease (NAFLD) is associated with subclinical hypothyroidism (SH) in pediatric patients. The purpose of this study was to investigated the prevalence and related factors of SH in pediatric patients with NAFLD. We also evaluate the association between liver fibrosis and SH. Methods We retrospectively reviewed medical records for patients aged 4 to 18 years who were diagnosed with NAFLD and tested for thyroid function from January 2015 to December 2019 at 10 hospitals in Korea. Results The study included 428 patients with NAFLD. The prevalence of SH in pediatric NAFLD patients was 13.6%. In multivariate logistic regression, higher levels of steatosis on ultrasound and higher aspartate aminotransferase to platelet count ratio index (APRI) score were associated with increased risk of SH. Using receiver operating characteristic curves, the optimal cutoff value of the APRI score for predicting SH was 0.6012 (area under the curve, 0.67; P < 0.001; sensitivity 72.4%, specificity 61.9%, positive predictive value 23%, and negative predictive value 93.5%). Conclusion SH was often observed in patients with NAFLD, more frequently in patients with more severe liver damage. Thyroid function tests should be performed on pediatric NAFLD patients, especially those with higher grades of liver steatosis and fibrosis., Graphical Abstract

Background There are limited data regarding the extraintestinal manifestations (EIMs) associated with pediatric inflammatory bowel disease (IBD) in Korea. We aimed to investigate the clinical features and factors associated with the development of EIMs in Korean children and adolescents with IBD. Methods This multicenter, retrospective study was conducted from 2010 to 2017. Baseline clinicodemographic, laboratory findings, disease activity, disease phenotypes, and EIMs were investigated. Results A total of 172 patients were included. One-hundred thirty-seven (79.7%) had Crohn's disease (CD), and 35 (20.3%) had ulcerative colitis (UC). EIMs occurred in 42 patients (24.4%). EIMs developed in 34/137 diagnosed with CD (24.8%), and in 8/35 diagnosed with UC (22.9%), during a median follow-up duration of 3.2 (interquartile range, 1.9–5.4) years for CD and 3.0 (1.0–4.0) years for UC, respectively. Arthritis/arthralgia was most commonly observed (n = 15, 35.7%), followed by stomatitis/oral ulcer (n = 10, 23.8%), hepatitis (n = 5, 11.9%), nephritis (n = 4, 9.5%), pancreatitis (n = 2, 4.8%), erythema nodosum (n = 2, 4.8%), pyoderma gangrenosum (n = 1, 2.4%), primary sclerosing cholangitis (n = 1, 2.4%), uveitis (n = 1, 2.4%), and ankylosing spondylitis (n = 1, 2.4%). A significant difference in disease severity based on the Paris classification (P = 0.011) and ESR at diagnosis (P = 0.043) was observed between the EIM positive and negative group in patients with UC. According to logistic regression analyses, S1 disease severity based on the Paris classification was the only factor that was significantly associated with the development of EIMs (odds ratio, 16.57; 95% confidence interval, 2.18–287.39; P = 0.017). Conclusion Severe disease activity based on the Paris classification in pediatric patients with UC was significantly associated with EIM development. As disease severity in the Paris classification is a dynamic parameter, treatment should be focused on disease control to minimize the occurrence of EIMs in Korean children and adolescents with UC., Graphical Abstract

BACKGROUND Sedative upper endoscopy is similar in pediatrics and adults, but it is characteristically more likely to lead to respiratory failure. Although recommended guidelines for pediatric procedural sedation are available within South Korea and internationally, Korean pediatric endoscopists use different drugs, either alone or in combination, in practice. Efforts are being made to minimize the risk of sedation while avoiding procedural challenges. The purpose of this study was to collect and analyze data on the sedation methods used by Korean pediatric endoscopists to help physicians perform pediatric sedative upper endoscopy (PSUE). METHODS The PSUE procedures performed in 15 Korean pediatric gastrointestinal endoscopic units within a year were analyzed. Drugs used for sedation were grouped according to the method of use, and the depth of sedation was evaluated based on the Ramsay scores. The procedures and their complications were also assessed. RESULTS In total, 734 patients who underwent PSUE were included. Sedation and monitoring were performed by an anesthesiologist at one of the institutions. The sedative procedures were performed by a pediatric endoscopist at the other 14 institutions. Regarding the number of assistants present during the procedures, 36.6% of procedures had one assistant, 38.8% had 2 assistants, and 24.5% had 3 assistants. The average age of the patients was 11.6 years old. Of the patients, 19.8% had underlying diseases, 10.0% were taking medications such as epilepsy drugs, and 1.0% had snoring or sleep apnea history. The average duration of the procedures was 5.2 minutes. The subjects were divided into 5 groups as follows: 1) midazolam + propofol + ketamine (M + P + K): n = 18, average dose of 0.03 + 2.4 + 0.5 mg/kg; 2) M + P: n = 206, average dose of 0.06 + 2.1 mg/kg; 3) M + K: n = 267, average dose of 0.09 + 0.69 mg/kg; 4) continuous P infusion for 20 minutes: n = 15, average dose of 6.6 mg/kg; 5) M: n = 228, average dose of 0.11 mg/kg. The average Ramsay score for the five groups was 3.7, with significant differences between the groups (P < 0.001). Regarding the adverse effects, desaturation and increased oxygen supply were most prevalent in the M + K group. Decreases and increases in blood pressure were most prevalent in the M + P + K group, and bag-mask ventilation was most used in the M + K group. There were no reported incidents of intubation or cardiopulmonary resuscitation. A decrease in oxygen saturation was observed in 37 of 734 patients, and it significantly increased in young patients (P = 0.001) and when ketamine was used (P = 0.014). Oxygen saturation was also correlated with dosage (P = 0.037). The use of ketamine (P < 0.001) and propofol (P < 0.001) were identified as factors affecting the Ramsay score in the logistic regression analysis. CONCLUSION Although the drug use by Korean pediatric endoscopists followed the recommended guidelines to an extent, it was apparent that they combined the drugs or reduced the doses depending on the patient characteristics to reduce the likelihood of respiratory failure. Inducing deep sedation facilitates comfort during the procedure, but it also leads to a higher risk of complications.

Background Henoch–Schönlein purpura is a type of systemic vasculitis found in children. Its prognosis is usually good; however, recurrence is relatively common. If the intestines are affected, severe complications could arise. Here, we investigated the value of fecal calprotectin in the early screening of Henoch–Schönlein purpura and as a useful factor for predicting gastrointestinal manifestations. Methods We retrospectively reviewed the medical records of pediatric patients who were diagnosed with Henoch–Schönlein purpura and underwent fecal calprotectin testing during the acute phase. The patients were categorized into gastrointestinal involvement and non-gastrointestinal involvement groups based on their clinical symptoms. Moreover, gastrointestinal involvement was categorized as follows: upper gastrointestinal tract involvement (up to the duodenum) and lower gastrointestinal tract involvement (from the terminal ileum). Results A total of 69 patients were diagnosed with Henoch–Schönlein purpura and underwent fecal calprotectin testing. Among them, 40 patients (58.0%) showed signs of gastrointestinal involvement. The gastrointestinal involvement group had higher fecal calprotectin levels (379.9 ± 399.8 vs. 77.4 ± 97.6 mg/kg, P = 0.000). There were no significant differences in the recurrence of Henoch–Schönlein purpura symptoms or gastrointestinal symptoms. The cut-off value to identify gastrointestinal involvement was 69.10 mg/kg (P 50 mg/kg showed more frequent gastrointestinal involvement (77.8% vs. 20.8%, P = 0.000) and more severe gastrointestinal symptoms. Significant differences in abdominal pain duration, Henoch–Schönlein purpura clinical score, and abdominal pain severity were observed (P = 0.002, P = 0.000, and P = 0.000, respectively). Additionally, fecal calprotectin levels were significantly higher in patients with lower gastrointestinal tract involvement (214.67 ± 150.5 vs. 581.8 ± 510.1 mg/kg, P = 0.008), and the cut-off value was 277.5 mg/kg (P Conclusion Fecal calprotectin testing is useful for identifying gastrointestinal involvement in pediatric Henoch–Schönlein purpura patients.

The maternal vaginal microbiome is an important source for infant gut microbiome development. However, infants delivered by Cesarean section (CS) do not contact the maternal vaginal microbiome and this delivery method may perturb the early establishment and development of the gut microbiome. The aim of this study was to investigate the early gut microbiota of Korean newborns receiving the same postpartum care services for two weeks after birth by delivery mode using fecal samples collected at days 3, 7, and 14. Early gut microbiota development patterns were examined using 16S rRNA gene-based sequencing from 132 infants either born vaginally (VD, n = 64) or via Cesarean section (CS, n = 68). VD-born neonates showed increased alpha diversity in infant fecal samples collated at days 7 and 14 compared to those from day 3, while those of CS infants did not differ (p < 0.015). Bacterial structures of infants from both groups separated at day 7 (p < 0.001) and day 14 (p < 0.01). The bacterial structure of VD infants gradually changed over time (day 3 vs. day 7, p < 0.012; day 3 vs. day 14, p < 0.001). Day 14 samples of CS infants differed from day 3 and 7 samples (day 3 vs. day 14, p < 0.001). VD infant relative abundance of Bifidobacterium (days 7, 14), Bacteroides (days 7, 14), and Lachnospiraceae (day 7) significantly increased compared to CS infants, with a lower abundance of Enterobacteriaceae (found in all periods of the CS group) (LDA > 3.0). Relative abundances of Bifidobacterium, Lactobacillus, and Staphylococcus were significantly increased in both VD and CS groups at day 14 (LDA > 3.0). Predicted functional analysis showed that VD infants had overrepresented starch/sucrose, amino acid and nucleotide metabolism in gut microbiota with depleted lipopolysaccharide biosynthesis until day 14 compared to CS infants. This study confirmed that delivery mode is the major determinant of neonatal intestinal microbiome establishment and provides a profile of microbiota perturbations in CS infants. Our findings provide preliminary insight for establishing recovery methods to supply the specific microbes missing in CS infants.

Background Limited data exist regarding mucosal healing (MH) and therapeutic drug monitoring (TDM) in pediatric Crohn's disease (CD) patients treated with adalimumab (ADL). We aimed to investigate the associations between ADL trough levels (TLs) and MH, and between ADL TLs and histologic remission (HR) at 16 weeks from ADL treatment in pediatric CD patients. Methods This was a prospective study on moderate-to-severe luminal pediatric CD patients receiving ADL. Ileocolonoscopies and biopsies, as well as clinical activity assessments, laboratory examinations, including tests for ADL TLs and antibody to ADL, were performed 16 weeks after ADL initiation. MH was defined as a Simple Endoscopic Score for CD of 0. HR was defined as the complete absence of microscopic inflammation. Results Seventeen subjects (13 males, 4 females) were included. At 16 weeks from ADL initiation, 14 (82.4%), 8 (47.1%), and 4 (23.5%) patients achieved clinical remission, MH, and HR, respectively. ADL TLs were significantly higher in patients who achieved MH compared to those who did not (13.0 ± 6.5 vs. 6.2 ± 2.6 μg/mL, respectively; P = 0.023) and also significantly higher in patients who achieved HR compared to those who did not (17.9 ± 5.3 vs. 6.8 ± 2.5 μg/mL, respectively; P = 0.02). The optimal TL for predicting MH was 8.76 μg/mL. Conclusion Serum ADL TLs at 16 weeks were significantly higher in pediatric patients with CD who achieved MH and HR, respectively. TDM may guide in optimizing treatment efficacy and better target MH in the era of treat-to-target., Graphical Abstract

Background/Aims: School nurses’ knowledge of inflammatory bowel disease (IBD) has not been evaluated. We aimed to investigate school nurses’ knowledge of IBD and determine whether education could improve this knowledge. Methods: School nurses were invited to complete self-reported questionnaires on IBD. Then, IBD specialists from tertiary referral hospitals provided a 60-minute lecture with educational brochures on two occasions, with a 3-month interval. Within 6 months after the educational interventions, school nurses were asked to complete the same IBD questionnaire via e-mail. Results: Among 101 school nurses who were invited to participate, 54 nurses (53.5%) who completed two consecutive questionnaires were included in this study (median age, 45 years; range, 25 to 59 years; 100% female); 11.1% and 7.4% of the study participants had no knowledge regarding ulcerative colitis and Crohn’s disease, respectively. They had heard of IBD most frequently from doctors (33.3%), followed by internet sources (25.9%). After 6 months, the number of nurses who could explain IBD to students with over 30% confidence increased from 24 (44.5%) to 42 (77.8%) (p

Purpose The incidence of inflammatory bowel disease (IBD) is rapidly increasing, and several reports have described the renal complications of IBD. We sought to evaluate the clinical manifestations of renal complications in children with IBD in order to enable early detection and prompt treatment of the complications. Methods We retrospectively reviewed the medical records of 456 children and adolescents aged

Glycogen storage disease (GSD) IV is a rare autosomal recessive inherited disorder caused by mutations in the gene coding for glycogen branching enzyme leading to progressive liver disease. GSD IV is associated with mutations in GBE1, which encodes the glycogen branching enzyme. We report a case of GSD IV with rare homozygous mutations in the GBE1 gene (c.791G>A (p.Gly264Glu), which was successfully treated by liver transplantation.

The incidence of inflammatory bowel disease (IBD) is rapidly increasing worldwide. Indigo naturalis is known to have an antiinflammatory effect. Indigo naturalis has been traditionally used in the treatment of IBD in China and Japan. Currently, it is used as a primary or adjunctive drug in patients with ulcerative colitis. There are some reports of the effects of indigo naturalis when used in patients with ulcerative colitis. However, its usage has been associated with adverse events, including liver dysfunction, headache, gastrointestinal disturbance, and pulmonary hypertension. Pancreatitis as an adverse event during treatment using indigo naturalis has not yet been reported. We report a case of recurrent events of pancreatitis that occurred briefly after starting medication with indigo naturalis in a child with severe Crohn’s disease. The pancreatitis improved after indigo naturalis was discontinued in 2 events. This is the first case to report the association between pancreatitis and indigo naturalis in the English literature.

Background/aims Information regarding the efficacy of early infliximab treatment in pediatric patients with Crohn's disease (CD) is limited. We aimed to evaluate the impact of early combined immunosuppression on linear growth in pediatric patients with CD by performing step-up comparisons. Methods This retrospective study included pediatric patients with moderate-to-severe CD, who received a combination therapy with infliximab and azathioprine for at least 3 years and sustained corticosteroid-free remission without loss of response. The z-scores of the growth indicators obtained at the time of diagnosis and annually for 3 years thereafter were compared between the two groups. Results The early combined immunosuppression group displayed significantly increased linear growth 3 years after diagnosis (p=0.026). A significant difference was also observed in the linear growth 3 years after diagnosis between subgroups of Tanner stages 1-2 (p=0.016). Conclusions The early introduction of biologics should be considered to improve linear growth in pediatric patients with CD.

Background Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS) is a common disease of urology, of which the pathogenesis and therapy remain to be further elucidated. Quercetin has been reported to improve the symptoms of CP/CPPS patients. We aimed to verify the therapeutic effect of quercetin on CP/CPPS and identify the mechanism responsible for it. Methods A novel CP/CPPS model induced with Complete Freund Adjuvant in Sprague Dawley rats was established and the prostates and blood specimens were harvested for further measurement after oral administration of quercetin for 4 weeks. Results Increased prostate index and infiltration of lymphocytes, up-regulated expression of IL-1β, IL-2, IL-6, IL-17A, MCP1, and TNFα, decreased T-SOD, CAT, GSH-PX, and increased MDA, enhanced phosphorylation of NF-κB, P38, ERK1/2, and SAPK/JNK were detected in CP/CPPS rat model. Quercetin was identified to ameliorate the histo-pathologic changes, decrease the expression of pro-inflammatory cytokines IL-1β, IL-2, IL-6, IL-17A, MCP1, and TNFα, improve anti-oxidant capacity, and suppress the phosphorylation of NF-κB and MAPKs. Conclusions Quercetin has specific protective effect on CP/CPPS, which is mediated by anti-inflammation, anti-oxidation, and at least partly through NF-κB and MAPK signaling pathways.

Background/Aims: Tens of trillions of microorganisms constitute the gut microbiota of the human body. The microbiota plays a critical role in maintaining host immunity and metabolism. Analyses of the gut microbial composition in Korea are lim ited to a few studies consisting of small sample sizes. To investigate the gut microbial community in a large sample of healthy Koreans, we analyzed the 16S ribosomal RNA of 4 representative bacterial genera Lactobacillus, Bifidobacterium, Bacteroi des, and Clostridium. Methods: A total of 378 DNA samples extracted from 164 infants and 214 adults were analyzed using quantitative real-time polymerase chain reaction. Results: Analysis of 16S ribosomal RNA of 4 representative bacterial genera Lactobacillus, Bifidobacterium, Bacteroides, and Clostridium showed that the gut microbiota in infants had higher relative abundances of Bifidobacterium and Lactobacillus than that in adults, which was dominated by Bacteroides and Clostridium. Conclusions: To the best of our knowledge, this was the first study evaluating the distinct characteristics of the microbial com munity of Korean infants and adults. The differences between the 2 populations suggest that external factors such as age, diet, and the environment are important contributing factors to the change in gut microbial composition during development. (In test Res 2018;16:246-254)

Background and aims We aimed to investigate the outcome in paediatric-onset Crohn's disease patients who had discontinued infliximab after maintaining clinical remission with combined immunosuppression, and to determine factors associated with clinical relapse. Methods We conducted a retrospective observational study of 63 paediatric-onset Crohn's disease patients who had stopped scheduled infliximab during sustained corticosteroid-free clinical remission for at least 1 year with infliximab and azathioprine, and were followed up for at least 1 year thereafter. Cumulative relapse rates and the median time to relapse were estimated statistically. Factors at cessation were also evaluated for their association with clinical relapse. Results After a median follow-up period of 4.3 years [range, 1-7.5 years], 60.3% [38/63] of patients had experienced clinical relapse. According to Kaplan-Meier survival analysis, the estimated cumulative relapse rates at 1, 4, and 6 years were 19.0%, 62.2%, and 75.2%, respectively, and the median relapse time was 3.3 years from infliximab cessation. According to multivariate Cox proportional hazard regression analysis, infliximab trough levels of ≥2.5 μg/mL and incomplete mucosal healing were associated with clinical relapse (hazard ratio [HR] = 7.199, 95% confidence interval [CI] = 1.641-31.571, p = 0.009 and HR = 3.628, 95% CI = 1.608-8.185, p = 0.002, respectively). Although re-treatment with infliximab was effective in 90.9% [30/33] of patients, 7.9% [3/38] eventually underwent surgery within 1 year of relapse. Conclusions Considering the high cumulative relapse rates in the long term and cases of severe relapse requiring surgery, discontinuing infliximab in paediatric-onset Crohn's disease patients is currently inadvisable. However, there may be a subgroup of patients who are good candidates for infliximab withdrawal.

Purpose The prevalence of reflux esophagitis (RE) has increased recently in Korea. Little is known concerning the prevalence and characteristics of RE in pediatric patients. This study investigated the prevalence and influence of risk factors in endoscopically proven RE in Korea in pediatric patients over a period of 14 years. Methods A retrospective chart review of all patients between the ages of 1 month and 20 years who underwent esophagogastroduodenoscopy at Samsung Medical Center between 2001 and 2014 was carried out. Univariate and multivariate analyses were conducted to identify independent risk factors for RE. Results The prevalence rate of endoscopically proven RE in this study was 28.7% (978/3,413). The prevalence of RE increased from 11.8% from 2001 to 2007 to 37.7% from 2008 to 2014. Multivariate logistic regression analysis revealed that residency in the Greater Gangnam area (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.02-1.44) and age (OR, 1.13; 95% CI, 1.11-1.15) were significant predictive factors for the presence of RE. Conclusion The prevalence rate of endoscopically proven pediatric RE has increased over the past 14 years. Residency and older age are more important independent risk factors for pediatric RE in Korea.

Mycoplasma pneumoniae infections mainly involve respiratory tract; however, also can manifestate other symptoms by site involved. Extrapulmonary manifestations of M. pneumoniae infection are rarely known to occur without pneumonia. Herein we report a case of a 9-year-old boy who presented with acute cholestatic hepatitis in the absence of pneumonia. Rhabdomyolysis, skin rash, and initial laboratory results suspicious of disseminated intravascular coagulopathy were also observed in this patient. M. pneumoniae infection was identified by a 4-fold increase in immunoglobulin G antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. This is the first pediatric case in Korea of M. pneumoniae infection presenting with acute cholestatic hepatitis in the absence of pneumonia.

OBJECTIVES We aimed to quantitatively investigate the therapeutic response to combined immunosuppression treatment by magnetic resonance enterography (MRE) in active luminal Crohn disease (CD) in the pediatric population. METHODS Pediatric patients with moderate-to-severe luminal CD, who received scheduled infliximab and azathioprine, were included in this preliminary study. Ileocolonoscopy and MRE were performed at baseline and at 1 year, and Simple Endoscopic Score for Crohn's Disease (SES-CD) and Magnetic Resonance Index of Activity (MaRIA) scores were calculated. The correlation between SES-CD and MaRIA scores were investigated with analysis per person and per segment. RESULTS A total of 167 segments from 17 patients were evaluated by both Ileocolonoscopy and MRE. SES-CD and MaRIA scores showed significant correlations on both per-person analysis (ρ = 0.699, P

Background/Aims The clinical use of measuring infliximab (IFX) trough levels (TLs) and antibodies against IFX (ATIs) in patients with pediatric inflammatory bowel disease (IBD) remains unclear. We propose measuring these variables to create individual IFX treatment strategies for patients with pediatric IBD. Methods This retrospective study was conducted in pediatric patients with IBD who received IFX from July 2009 to June 2014. Results Samples were available from 39 patients with pediatric IBD. A significant difference was observed in IFX TLs in 16 patients who were in clinical remission (group A) after IFX therapy (median, 3.99 μg/ mL; interquartile range [IQR], 0.30 to 21.96) compared to 23 patients who had a poor response to treatment (group B) (median, 0.88 μg/mL; IQR, 0.00 to 6.80, p=0.002). In group B, 21 patients underwent empiric intensification of IFX treatment. After dose intensification, 17 patients had an improved response to treatment. Four patients still had no response to dose intensification. Therefore, these patients were switched to other biologics. Conclusions Patients who had poor responses and subtherapeutic IFX TLs had an improved response to dose intensification. Patients who had ATIs were likely to continue to have no response after dose intensification. Therefore, tailoring individual IFX treatments based on IFX TLs, ATIs, and the clinical response should be considered.

Propionic acidemia (PA) is a rare organic acidemia resulting from a deficiency of the mitochondrial enzyme propionyl-coenzyme A carboxylase. Most cases are diagnosed after the detection of metabolic abnormalities—such as hyperammonemia, metabolic acidosis, and ketosis—associated with complaints of vomiting, feeding difficulties, and hypotonia during the neonatal period. However, in rare late-onset cases, mild or vague symptoms make the diagnosis more challenging. Even though acute pancreatitis is relatively uncommon in children, it can occur in association with PA. We present the case of a 4-year-old child who was admitted owing to the complaint of recurrent pancreatitis and had not previously been diagnosed with having metabolic disease. During inpatient treatment for acute pancreatitis, convulsions occurred with concomitant hyperammonemia, metabolic acidosis, coagulopathy, and shock 1 week after the administration of total parenteral nutrition. He was diagnosed to have PA after a metabolic work-up and confirmed to have novel mutation by molecular genetic analysis. Because children with PA may have acute pancreatitis, although rare, vomiting and abdominal pain should raise a suspicion of acute pancreatitis. On the contrary, even among children who have never been diagnosed with a metabolic disease, if a child has recurrent pancreatitis, metabolic pancreatitis caused by organic acidemia should be considered., Graphical Abstract

Extraintestinal manifestations (EIMs) are frequently observed in adult and pediatric patients with inflammatory bowel disease (IBD). The most common EIMs involve the joints, skin, and eyes, but they can affect various organs and result in significant morbidity. Since EIMs can appear years before the diagnosis of IBD is made, clinicians should be aware of their various manifestations to help decrease diagnostic delay of IBD and establish appropriate treatment plans.

Purpose We aimed to investigate clinical outcomes between top-down (TD) and conventional step-up (SU) therapies in pediatric patients with moderate to severe ulcerative colitis (UC). Materials and methods All patients underwent clinical and endoscopic evaluation at diagnosis and 4 months and 1 year after treatment. Patients who started treatment with corticosteroid were grouped in the SU group, while those that initiated early infliximab (IFX) were grouped in the TD group. Among the SU group, patients who eventually changed to IFX treatment due to steroid resistance or dependency were included in the SU(R) group. Results In total, 44 children with moderate to severe UC were included for analysis. Twenty-one patients were included in the SU group, 23 were included in the TD group, and 10 were enrolled in the SU(R) group. Relapse rates were 47.6% (10/21) in the SU group and 17.4% (4/23) in the TD group (p=0.033). Among relapsed patients, the durations from remission to relapse were 17.3 months (0.9-46.9) in the SU group and 24.3 months (1.8-44.9) in the TD group. There was no statistically significant difference in the sustained durations of remission after IFX administration between the SU(R) and TD groups [3.9 (1.4-6.3) and 2.3 (0.3-5.2) years, respectively (p>0.05)]. Conclusion According to our study, early use of IFX without corticosteroid treatment for children with moderate to severe UC helps to lower relapse rates. We also found that IFX was a very effective treatment for pediatric UC, with a sustained duration of remission similar between TD and SU(R) groups.

Purpose We aimed to investigate the efficacy and safety of adalimumab in pediatric-onset Crohn's disease patients who had failed treatment with infliximab. Methods In this retrospective study, patients included were those who had been diagnosed with Crohn's disease before 18 years old, and had received treatment with adalimumab after infliximab failure. The efficacy of adalimumab treatment was investigated at 1 month and 1 year, and adverse events that had occurred during treatment with adalimumab were explored. Results Ten patients were included in this study. The median duration from diagnosis to adalimumab treatment was 5.5 years (range: 2.4-7.9 years). At 1 month after adalimumab initiation, 80% (8/10) of patients showed clinical response, and 40% (4/10) achieved clinical remission. At 1 year, 71% (5/7) of patients showed clinical response, and 43% (3/7) were under clinical remission. Among the total included patients, 5 patients (50%) showed clinical response at 1 year. Primary non-response to adalimumab was observed in 2 patients (20%), and secondary failure to adalimumab was observed in 3 patients (30%) during 1 year treatment with adalimumab. No serious adverse event had occurred during adalimumab treatment. Conclusion Adalimumab was effective for 1 year without serious adverse events in half of pediatric-onset Crohn's disease patients who had failed treatment with infliximab.

Background and Aims: We aimed to compare the efficacy of combined immunosuppression in terms of mucosal healing in paediatric patients with moderate-to-severe luminal Crohn’s disease receiving infliximab according to either an ‘escalated combined immunosuppression’ or an ‘early combined immunosuppression’ strategy. Methods: In this prospective observational study, the efficacy of combined immunosuppression was evaluated in terms of mucosal healing at weeks 14 and 54 from baseline infliximab infusion. Comparison was performed between the escalated combined immunosuppression group [group A] and the early combined immunosuppression group [group B]. Factors associated with mucosal healing at weeks 14 and 54 from baseline infliximab infusion were also investigated. Results: Seventy-six patients initiated infliximab with concomitant azathioprine [group A = 28; group B = 48]. Comparison of baseline characteristics revealed a significantly longer duration from initial diagnosis to infliximab infusion in group A [median 8.1 vs. 0.7 months; p < 0.001]. Mucosal healing was achieved in 32% of patients in group A and 51% in group B at week 14 [ p = 0.121], and in 42% in group A and 74% in group B at week 54 [ p = 0.007]. Group B was also positively associated with mucosal healing at week 54 on multivariate logistic regression [odds ratio = 6.216, 95% confidence interval = 1.782–21.686, p = 0.004]. Conclusions: Mucosal healing during combined immunosuppression is more effectively achieved by treatment with an early combined immunosuppression strategy without corticosteroid induction administered within 1 month rather than escalating to receive combination therapy later during the course. The therapeutic window of opportunity in early Crohn’s disease may be shorter than generally thought, especially in children.

Highlights • A 2-month-old male infant presenting with only peripheral facial palsy was diagnosed with a primitive neuroectodermal tumor of the skull base. • Primitive neuroectodermal tumors located in the skull base are rarely detected in infants. • After subtotal resection of the tumor, asymmetrical facial expression showed mild improvement., Introduction Peripheral facial palsy is rarely caused by primary neoplasms, which are mostly constituted of tumors of the central nervous system, head and neck, and leukemia. Presentation of case A 2-month-old male infant presented with asymmetric facial expression for 3 weeks. Physical examination revealed suspicious findings of right peripheral facial palsy. Computed tomography of the temporal bone revealed a suspicious bone tumor centered in the right petrous bone involving surrounding bones with extension into the middle ear cavity and inner ear. Subtotal resection of the tumor was performed due to crucial structures adjacent the mass. Histopathology and immunohistochemistry of the resected tumor was consistent with primitive neuroectodermal tumor. Conclusion We report a rare case of a primitive neuroectodermal tumor located at the skull base presenting with only peripheral facial palsy.

Background & Aims Mucosal healing (MH) has become a goal of therapy for Crohn’s disease (CD), but frequent endoscopies are not feasible. We aimed to develop and validate a non-invasive index to assess mucosal inflammation in children with CD. Methods We collected data from the multi-center prospective ImageKids study, in which children with CD underwent ileocolonoscopy with magnetic resonance enterography. We investigated the association of pediatric CD activity index (PCDAI) items and laboratory test results with the simple endoscopic score for CD (SESCD). We used these data in a blended mathematical judgmental clinimetric approach to develop a weighted categorized index to identify children with CD who have MH, which we called the MINI index. We validated the index using data from 3 independent patient cohorts. The derivation and validation cohorts included 154 and 168 children, respectively (age 14.1 ± 2.5 years and 14.2 ± 3.9 years), of whom 16% and 36% had MH (defined as SESCD Results In multivariable models, the stooling item of the PCDAI, erythrocyte sedimentation rate, and level of fecal calprotectin were associated with SESCD (all P Conclusions We developed an index to non-invasively assess mucosal inflammation in children with CD. This index, identifies children with MH with high sensitivity and specificity. The added benefit of MINI over measurement of fecal calprotectin was small but significant, especially for patients with concentrations of fecal calprotectin from 100 to 599 μg/g. ClinicalTrials.gov no: NCT01881490 .

Purpose We aimed to investigate the disease phenotype of Korean pediatric Crohn's disease (CD) patients at diagnosis according to the Paris classification by comparison with patients from the European multicenter 5-years recruitment of children with newly developed IBD (EUROKIDS registry). Methods Korean children and adolescents who had been newly diagnosed with CD at the age of

The Committee on Pediatric Obesity of the Korean Society of Pediatric Gastroenterology, Hepatology and Nutrition newly developed the first Korean Guideline on the Diagnosis and Treatment of Obesity in Children and Adolescents to deliver an evidence-based systematic approach to childhood obesity in South Korea. The following areas were systematically reviewed, especially on the basis of all available references published in South Korea and worldwide, and new guidelines were established in each area with the strength of recommendations based on the levels of evidence: (1) definition and diagnosis of overweight and obesity in children and adolescents; (2) principles of treatment of pediatric obesity; (3) behavioral interventions for children and adolescents with obesity, including diet, exercise, lifestyle, and mental health; (4) pharmacotherapy; and (5) bariatric surgery.

Background and Aims Mucosal healing is an important treatment goal in Crohn's disease. We investigated the association between serum infliximab trough levels and mucosal healing, and the infliximab cut-off levels required for mucosal healing in paediatric patients. Methods In this multicentre, retrospective, cross-sectional study, medical records and electronic data of paediatric patients with luminal Crohn's disease, who had received infliximab for ≥1 year, were examined. Ileocolonoscopy was performed on the same day as the infliximab infusion, and serum samples for trough levels were collected immediately before infusion. Mucosal healing was defined as a Simple Endoscopic Score for Crohn's Disease of 0. Univariate, multivariate logistic regression, and receiver operating characteristic curve analyses were performed. Results Overall, 105 patients [median age 14.8 years] were included, with mucosal healing observed in 48.6%. Median serum infliximab trough levels were higher in patients with mucosal healing [4.5 µg/mL] than without [3.3 µg/mL, p = 0.002]. In the final multivariate model, infliximab trough level ≥4.2 µg/mL [p = 0.002] and ≥1-year duration from diagnosis to infliximab treatment [p = 0.003] were positively and negatively associated with mucosal healing, respectively. The infliximab trough level for achieving mucosal healing with a specificity of 80% was ≥5 µg/mL. Conclusions Associations between serum infliximab trough concentrations and mucosal healing were observed in paediatric patients. Identification of the infliximab trough level that positively associates with mucosal healing in most paediatric patients with Crohn's disease [≥5 µg/mL] may guide treatment decisions to optimise therapeutic response in the era of treat-to-target.

Objectives Inflammatory bowel disease (IBD) is a chronic lifelong condition and is related to poor quality of life (QoL). The aim of this study was to evaluate the QoL of Asian pediatric patients with IBD and to determine the clinical factors that can influence QoL. Methods Children and adolescents aged 9 to 18 years diagnosed with IBD were enrolled from 7 hospitals. The patients completed the IMPACT-III questionnaire, and clinical data were collected. The results of the questionnaire and the correlation with clinical data were analyzed. Results A total of 208 patients (Crohn disease: n = 166; ulcerative colitis: n = 42) were enrolled. There was no definite QoL difference according to the Paris classification. Female sex (-5.92 ± 2.97, P = 0.0347) and active disease status (-10.79 ± 3.11, P = 0.0006) were significantly associated with poor QoL. Extreme body weight z score and older age at diagnosis were also associated with worse QoL. Conclusions Various clinical factors may affect the QoL in patients with IBD, but determining the overall QoL of patients using only these clinical factors is difficult. Therefore, regular direct measurements of QoL are necessary to better understand patients with IBD.

Thyroid-like follicular carcinoma (TLFC) of the kidney is an extremely rare type of renal tumor, which has not been classified under a known subtype of renal cell carcinoma. It is histologically similar to the primary thyroid follicular carcinoma; however, the characteristics lack thyroid immunohistochemical markers. The aim of the present study was to illustrate the clinical characteristics of 3 new cases along with a review of the literature. The patients were compared with regards to gender, age, location and size of the tumor, imageology, morphology, immunohistochemistry and prognosis. According to the limited data, TLFC occurs mainly in young women and its clinical manifestations have no difference with other renal tumors. Its imageological features resemble a large spectrum of benign and malignant renal and extra-renal conditions, which should be eliminated in the diagnostic process. Confirmed diagnosis depends on the examination of pathology and immunohistochemistry. Surgical ablation is the preferred therapeutic method. Currently, TLFC has a relatively good prognosis; however, this conclusion requires further cases and long-term follow-ups. Improving the understanding of TLFC can help avoid misdiagnosis and prevent inappropriate treatment.

Mycoplasma pneumoniae is responsible for approximately 20% to 30% of community-acquired pneumonia, and is well known for its diverse extrapulmonary manifestations. However, acute necrotizing pancreatits is an extremely rare extrapulmonary manifestation of M. pneumoniae infection. A 6-year-old girl was admitted due to abdominal pain, vomiting, fever, and confused mentality. Acute necrotizing pancreatitis was diagnosed according to symptoms, laboratory test results, and abdominal computed tomography scans. M. pneumoniae infection was diagnosed by a 4-fold increase in antibodies to M. pneumoniae between acute and convalescent sera by particle agglutination antibody assay. No other etiologic factors or pathogens were detected. Despite the occurrence of a large infected pseudocyst during the course, the patient was able to discharge without morbidity by early aggressive supportive care. This is the first case in Korea of a child with acute necrotizing pancreatitis associated with M. pneumoniae infection.