Background: Mycoplasma pneumoniae is a major cause of community-acquired pneumonia (CAP) in children, with a rising incidence of macrolide resistance. Early diagnosis is crucial for reducing the disease burden; however, current diagnostic tools have limitations.We evaluated the diagnostic accuracy of serological assays and their performance based on symptom onset in children with CAP. Methods: From September 2023 to September 2024, we prospectively enrolled children with CAP, classified as M. pneumoniae pneumonia (MPP) or non-MPP, from 16 hospitals in Korea. Serological testing included chemiluminescence immunoassay (CLIA) and ELISA for detecting IgM and IgG, along with particle agglutination (PA) for total antibody measurements. Serological responses were analyzed at different times after symptom onset (0–4, 5–9, and 10–21 days). Results: Among 472 children with CAP (362 MPP, 110 non-MPP), 138 (29.2%) underwent PA testing, and 334 (70.8%) underwent IgM testing. PA at a 1:640 cutoff showed 48.0% sensitivity and 100% specificity. CLIA and ELISA showed comparable sensitivities (69.1% vs. 69.2%) and specificities (76.9% vs. 66.7%) for IgM testing. Seropositivity increased significantly with time since symptom onset (P for trend < 0.001), reaching 97.9% for IgM, 62.5% for IgG, and 94.7% for PA at 10–21 days. Conclusions The time post-symptom onset significantly influenced the diagnostic utility of serological tests for pediatric MPP, which showed limited value during the early stage of illness. These findings emphasize the importance of symptom onset-based interpretation of serological test results and their utility in complementing PCR when optimizing MPP diagnosis in children.

Purpose: This study aimed to identify the etiology and risk factors of community-acquired pneumonia (CAP) requiring hospitalization in Korean children during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Clinical information of children admitted with CAP to Seoul National University Children’s Hospital (SNUCH) between January 1, 2021, and February 28, 2022, was retrospectively collected and analyzed. In addition, the etiologic diagnosis and demographic data of children with CAP who were discharged at the other seven hospitals between January and February 2022 were collected. Pneumonia was diagnosed using strict criteria comprising clinical symptoms, physical examination findings, and chest radiographic findings. Results: Among 91 children hospitalized with CAP at SNUCH during the 14-month period, 68.4% were aged <5 years and 79.1% had underlying diseases. Among the 95 CAP cases, respiratory assistance was required in 70.5%, and the use of a ventilator was required in 20.0%.A total of five patients expired, all of whom were either immunocompromised or had underlying neurological diseases. Neurological diseases and immunosuppression were significantly correlated with respiratory assistance (P=0.003) and death (P=0.014). A total of 55% of the detected respiratory pathogens were viruses, the most common of which was rhinovirus at 35.9%. Among the 169 children hospitalized for CAP at the eight institutions, ≥1 respiratory virus was detected in 92.3%, among which respiratory syncytial virus (79.8%) was the most prevalent. Conclusions Even during the COVID-19 pandemic, Korean children were hospitalized with CAP caused by seasonal respiratory viral pathogens. Although atypical and pyogenic bacteria were not detected, continuous clinical monitoring and further prospective studies should be conducted.

There have been several reports on why the clinical course of coronavirus disease 2019 (COVID-19) in pediatric patients is milder than in adults. There are distinctive points in the immune system between children and adults, as well as in the angiotensin-converting enzyme 2 gene expression, the characteristics of the respiratory system, the effects of comorbidities and risk factors, and the effect of infection control. Even though children tend to have mild forms of COVID-19, this does not mean that we should not regard it as a matter of importance.

There have been several reports on why the clinical course of coronavirus disease 2019 (COVID-19) in pediatric patients is milder than in adults. There are distinctive points in the immune system between children and adults, as well as in the angiotensin-converting enzyme 2 gene expression, the characteristics of the respiratory system, the effects of comorbidities and risk factors, and the effect of infection control. Even though children tend to have mild forms of COVID-19, this does not mean that we should not regard it as a matter of importance.

Coronavirus disease 2019 (COVID-19) has resulted in an ongoing pandemic; however, the socioeconomic burden of COVID-19 treatment in the pediatric population remains unclear. Thus, the aim of this study was to determine the hospitalization periods and medical costs among children with COVID-19. In total, 145 billing statements for pediatric patients receiving healthcare services because of COVID-19 from February 1, 2020 to March 31, 2020 were used. The study showed that individual treatment costs for children with COVID-19 are approximately USD 2,192 under the Korean National Health Insurance Service System. This study revealed the differences in cost among age groups, determined by the type of hospital wherein admission occurred, as a trend of increasing age, increasing hospitalization time, and increasing cost was observed. Tailored COVID-19 treatment strategies by age group may lower costs and increase the effectiveness of resource allocation.

Charcot-Marie Tooth disease type 1A (CMT1A), the major type of CMT, is caused by duplication of peripheral myelin protein 22 (PMP22) gene whose overexpression causes structural and functional abnormalities in myelination. We investigated whether miRNA-mediated regulation of PMP22 expression could reduce the expression level of PMP22, thereby alleviating the demyelinating neuropathic phenotype of CMT1A. We found that several miRNAs were down-regulated in C22 mouse, a CMT1A mouse model. Among them, miR-381 could target 3′ untranslated region (3′UTR) of PMP22 in vitro based on Western botting and quantitative Real Time-PCR (qRT-PCR) results. In vivo efficacy of miR-381 was assessed by administration of LV-miR-381, an miR-381 expressing lentiviral vector, into the sciatic nerve of C22 mice by a single injection at postnatal day 6 (p6). Administration of LV-miR-381 reduced expression level of PMP22 along with elevated level of miR-381 in the sciatic nerve. Rotarod performance analysis revealed that locomotor coordination of LV-miR-381 administered C22 mice was significantly enhanced from 8 weeks post administration. Electrophysiologically, increased motor nerve conduction velocity was observed in treated mice. Histologically, toluidine blue staining and electron microscopy revealed that structural abnormalities of myelination were improved in sciatic nerves of LV-miR-381 treated mice. Therefore, delivery of miR-381 ameliorated the phenotype of peripheral neuropathy in CMT1A mouse model by down-regulating PMP22 expression. These data suggest that miRNA can be used as a potent therapeutic strategy to control diseases with copy number variations such as CMT1A.
Animals ; Demyelinating Diseases ; In Vitro Techniques ; Mice ; MicroRNAs ; Microscopy, Electron ; Myelin Sheath ; Neural Conduction ; Peripheral Nervous System Diseases ; Phenotype ; Sciatic Nerve ; Tolonium Chloride ; Tooth Diseases ; Untranslated Regions

BACKGROUND/AIMS: This study aimed to compare the clinical characteristics and management patterns of inflammatory bowel disease (IBD) patients in a secondary hospital (SH) with those in tertiary referral centers (TRC). METHODS: Data from IBD patients in SH and 2 TRCs were retrospectively reviewed. The cumulative thiopurine use rate was compared between hospitals after controlling for different baseline characteristics using propensity score matching. RESULTS: Among the total of 447 patients with IBD, 178 Crohn's disease (CD) and 269 ulcerative colitis (UC) patients were included. Regarding initial CD symptoms, patients from SH were more likely to show perianal symptoms, such as anal pain or discharge (56.6% vs. 34.3%, P=0.003), whereas those from TRCs more often had luminal symptoms, such as abdominal pain (54.9% vs. 17.1%, P < 0.001), diarrhea (44.1% vs. 18.4%, P < 0.001), and body weight loss (9.8% vs. 1.3%, P=0.025). Complicating behaviors, such as stricturing and penetrating, were significantly higher in TRCs, while perianal disease was more common in SH. Ileal location was more frequently observed in TRCs. For UC, SH had a more limited extent of disease (proctitis 58.8% vs. 21.2%, P < 0.001). The cumulative azathioprine use rate in SH was significantly lower than that in TRCs in both CD and UC patients after controlling for disease behavior, location, and perianal disease of CD and extent of UC. CONCLUSIONS: The clinical characteristics and management of the IBD patients in SH were substantially different from those in TRCs. Thiopurine treatment was less commonly used for SH patients.
Abdominal Pain ; Azathioprine ; Body Weight ; Colitis, Ulcerative ; Crohn Disease ; Diarrhea ; Humans ; Inflammatory Bowel Diseases* ; Phenobarbital ; Propensity Score* ; Retrospective Studies ; Secondary Care ; Tertiary Care Centers*

BACKGROUND/AIMS: E-health technologies have been implemented for the management of Crohn’s disease (CD). We aimed to identify differences between patient activities at home and at routine clinic visits using a web-based self-reporting CD symptom diary (CDSD) and to determine the impact of this disparity on clinical outcomes. METHODS: Patients with CD from three tertiary hospitals were invited to assess their symptoms at least once a week using CDSD. We identified patients who showed disparities in disease activity (high activity at home but normal at the next hospital visit) and evaluated clinical outcomes of these patients such as unscheduled visits due to flares using Kaplan-Meier analyses. RESULTS: One hundred and forty-three patients recorded their symptoms weekly for at least 3 consecutive months and were included. Forty-eight patients (33.6%) showed disparate disease activities between at home and at the next outpatient clinic visit. The cumulative risk of unscheduled visits was significantly higher in this disparity group than in the concordant group (p = 0.001). Disparity in activity (p = 0.003), and anti-tumor necrosis factor use (p = 0.002) were independent risk factors of unscheduled visits due to disease flares. CONCLUSIONS: Disparity in disease activity is considerable in CD patients and is related to the risk of unscheduled hospital visit.
Ambulatory Care ; Ambulatory Care Facilities ; Crohn Disease ; Humans ; Necrosis ; Risk Factors ; Tertiary Care Centers

PURPOSE: Recent studies have shown that the cysteinyl leukotriene (cysLT) of exhaled breath condensate (EBC) could be predictive of inflammatory status and effectiveness of treatment in allergic disease. The aim of this study was to evaluate the inflammation and therapeutic effectiveness of cysLT in EBC in pediatric patients with allergic rhinitis (AR). METHODS: We enrolled 34 healthy children (median age, 4 years 10 months) and 67 AR children (median age, 5 years 1 month). All of the AR patients received intranasal steroid (fluticasone furoate) once daily for 2 weeks. After 2 week of fluticasone furoate treatment, they were classified into 2 groups: the fluticasone furoate (F) and montelukast (M) groups. We treated each group for another 8 weeks. To evaluate the therapeutic effectiveness, we used symptom score (SS) and EBC leukotriene E4 (LTE4). EBC samples were collected with RTube. Each parameter was checked at 0, 2, and 10 weeks of therapy. RESULTS: Most of the AR patients showed clinical improvement with 2- and 10-week fluticasone therapy (F group: 0-week SS, 5.6; 2-week SS, 3.6; 10-week SS, 2.1; P<0.01; M group: 0-week SS, 4.8; 2-week SS, 3.2; 10-week SS, 1.9: P<0.01). LTE4 levels were higher in AR patients than in control subjects (0 week: 87 pg/mL vs. 18 pg/mL) and were reduced after 2 weeks of fluticasone treatment (F group: 90→51.6 pg/mL, P<0.01; M group: 84→46.1 pg/mL, P<0.01). After 10 weeks of treatment, there was no significant difference in the LTE4 level between the F and M groups. CONCLUSION: LTE4 in EBC may be useful for evaluating inflammation and therapeutic effectiveness in patients with allergic rhinitis.
Child* ; Fluticasone ; Humans ; Inflammation* ; Leukotriene E4* ; Rhinitis, Allergic*

BACKGROUND/AIMS: A colon transit time test using radio-opaque markers (CTTRM) is considered the gold standard for evaluating colon transit function. A 24-hour delayed film of barium enema (BE) has been used as a supplementary method in structural evaluations. The aim of this study was to evaluate the utility of a 24-hour delayed BE film for assessing colon transit function in young children with constipation. METHODS: In total, 93 children with constipation who performed both single-contrast BE and CTTRM were enrolled in this study. Of these, the data from 70 children were analyzed (males 33, females 37; mean age [range], 5.63 ± 2.94 [2-14] years). The basic principle of the study is "velocity = distance/time". Time values were identified in both studies, and the colon length and distance of barium movement were measured on the 24-hour delayed BE film. Thus, colon transit velocity values could be calculated using both methods. The correlation between colon transit velocity using a 24-hour delayed BE film versus CTTRM was analyzed statistically. RESULTS: Median value (interquartile range) of colon transit velocity using CTTRM was 1.57 (1.07-2.89) cm/hr, and that using BE of that was 1.58 (0.94-2.07) cm/hr. The Spearman correlation coefficient was 0.438 (P < 0.001) for the overall group. The correlation was strongest in children younger than 4 years (r = 0.537, P = 0.032). CONCLUSIONS: Although the correlation between BE and CTTRM was not very strong, the 24-hour delayed BE film could provide broad information about colon transit function in young children, especially those under 4 years who usually cannot undergo CTTRM.
Barium* ; Child* ; Colon* ; Constipation* ; Enema* ; Female ; Humans ; Methods