Bronchopulmonary dysplasia (BPD) is a chronic lung disease of preterm infants with multiple factors affected from prenatal to postnatal periods. Despite significant advances in neonatal care over almost 50 years, BPD rates have not decreased; in fact, they may have even increased. Since more preterm infants, even at periviable gestational age, survive today, different stages of lung development affect the pathogenesis of BPD. Hence, the definition of BPD has changed from "old" to "new." In this review, we discuss the various definitions of BPD, risk factors from the prenatal to postnatal periods, management strategies by phase, and future directions for research.

Background: Attention deficit hyperactivity disorder (ADHD) symptoms have a major impact on individuals, families, and society. Therefore identification risk factors of ADHD are a public health priority. Purpose: This is meta-analysis evaluated the association between maternal prepregnancy body mass index and the risk of ADHD among the resulting offspring. Methods: The search identified studies published through December 2018 in the PubMed, Web of Science, and Scopus databases. The odds ratios (ORs) or hazard ratios (HRs) with 95% confidence intervals (CI) extracted from eligible studies were used as the common measure of association among studies. Results: A significant association was found between overweight women and the risk of ADHD among children with the pooled HR and OR estimates (HR, 1.27 and 95% CI, 1.17-1.37; OR, 1.28 and 95% CI, 1.15-1.40, respectively). This association was significant between obese women and the risk of ADHD among children and adolescents with the pooled estimates of HR and OR (HR, 1.65 and 95% CI, 1.55-1.76; OR, 1.42 and 95% CI, 1.23-1.61). Conclusion: The current epidemiological studies present sufficient evidence that prepregnancy overweight and obesity are significantly associated with an increased risk of ADHD among children and adolescents. These findings provide a new approach to preventing ADHD by controlling weight gain in the prenatal period, which should be considered by policymakers.

Background: Preterm infants have difficulty maintaining body temperature after birth. However, clinical guidelines advocate that neonatal body temperature should be maintained at 36.5℃-37.5℃. Purpose: We aimed to investigate the incidence of admission hypothermia in very low birth weight (VLBW) infants and to determine the association of admission temperature with in-hospital mortality and morbidities. Methods: A cohort study using prospectively collected data involving 70 neonatal intensive care units (NICUs) that participate in the Korean Neonatal Network. From registered infants born between January 2013 and December 2015, 5,343 VLBW infants born at less than 33 weeks of gestation were reviewed. Results: The mean admission temperature was 36.1℃±0.6℃, with a range of 31.9℃ to 38.4℃. Approximately 74.1% of infants had an admission hypothermia of <36.5℃. Lower birth weight, intubation in the delivery room and Apgar score <7 at 5 minutes were significantly related to admission hypothermia. The mortality was the lowest at 36.5℃-37.5℃ and adjusted odd ratios for all deaths increased to 1.38 (95% confidence interval [CI], 1.04-1.83), 1.44 (95% CI, 1.05-1.97) and 1.86 (95% CI, 1.22-2.82) for infants with admission temperatures of 36.0℃-36.4℃, 35.0℃-35.9℃, and <35.0℃, respectively. Admission hypothermia was also associated with high likelihoods of bronchopulmonary dysplasia, pulmonary hypertension, proven sepsis, pulmonary hemorrhage, air-leak, seizure, grade 3 or higher intraventricular hemorrhage and advanced retinopathy of prematurity requiring laser therapy. Conclusion: A large portion of preterm infants in Korea had hypothermia at NICU admission, which was associated with high mortality and several important morbidities. More aggressive interventions aimed at reducing hypothermia are required in this high-risk population.

Background: The esophagus is the most common part of gastrointestinal (GI) tract at the risk of stricture. Benign disorders are the leading causes of narrowing. Caustic ingestion is the most common cause of esophageal stricture in children, especially in developing countries. Clinical responses to the topical application of Mitomycin C in various medical procedures have been reported. Purpose: The study aimed to evaluate the methodology, efficacy, and side effects of Mitomycin C in the treatment of esophageal strictures. Methods: This study included 30 children with resistant esophageal strictures. Upper GI endoscopy was performed up to the area of stricture, esophageal dilatation was done, endoscopy was repeated, and Mitomycin C was applied topically under direct endoscopic vision. The effect of the procedure was followed over a period of 3-5 years. Results: The response to Mitomycin C was excellent (clinically and endoscopically) in 28 patients (93.3%) and good (endoscopically only) in 2 patients (6.7%). No side effects of topical Mitomycin C in children with esophageal strictures were reported in this study. Conclusion: Esophageal dilatation followed by local Mitomycin C application may be a useful strategy for treating resistant esophageal strictures.

Background: An increase in the numbers of patients with gastrointestinal symptoms has recently been observed. Purpose: To investigate the effects of proton pump inhibitor (PPI) therapy on intestinal inflammation in children and adolescents as confirmed by clinical manifestations and objectively assessed by fecal calprotectin (FC) level measurement. Methods: Consecutive children (aged 3-18 years) who presented with gastrointestinal symptoms and were treated with or without PPI for at least 1 month were enrolled. Patients were divided into PPI and non-PPI groups. The PPI group was further subdivided by treatment duration and type of PPI used. Stool samples were collected for FC evaluation at baseline and after treatment and clinical data and FC levels were compared between the groups. Results: Fifty-one patients (15 boys, 36 girls) were enrolled in the study. The PPI group included 37 patients, while the non-PPI group included 14 patients. Clinical symptoms were not significantly different. FC levels and laboratory results, including C-reactive protein levels, white blood cell count, and absolute neutrophil count, were not statistically different before versus after PPI treatment. After treatment, FC levels decreased to 8.1 mg/kg (-575.4 to 340.3 mg/kg) in the PPI group and increased to 5.6 mg/kg (-460.0 to 186.9 mg/kg) in the non-PPI group compared to those before treatment (P=0.841). The number of patients with increased FC levels was not significantly different between the 2 groups (48.6% vs. 64.3%, P=0.363), similar to that observed in patients with an FC level > 50 mg/kg (24.3% and 7.1%, P=0.250). PPI therapy type and duration did not affect the FC levels (P=0.811 and P=0.502, respectively). Conclusion: Although we aimed to confirm the evidence of intestinal inflammation due to PPI use in children and adolescents through clinical symptoms and FC measurement, no significant changes were observed.