Report on the methacholine bronchial provocation test protocol: An updated statement of Korean Academy of Asthma, Allergy and Clinical Immunology

The Korean Academy of Asthma, Allergy, and Clinical Immunology task force report aims to provide new protocols for methacholine challenge test (MCT). Although new devices have different delivery system compared to old ones, previous protocols are still used, which cannot guarantee adequate diagnoses of asthma. Another important issue is the recent recommendation in European Respiratory Society (ERS) technical standard guideline to use a delivered methacholine dose that causes a 20% decrease in forced expiratory volume in 1 second (FEV1) (PD 20). Although the previous protocol based on the methacholine concentration causing a 20% decrease in FEV1 (PC 20) has been used globally, several studies have reported that PD 20 is more reliable and applicable for new protocols of MCT. Indeed, a tidal breathing inhalation protocol using a breath-actuated or continuous nebulizer is recommended. Herein, we recommend 3 protocols for the MCT using new devices and provide a brief summary of the change in strategy based on the updated ERS guideline.

Changes in the Clinical Characteristics of Kawasaki Disease After Coronavirus Disease (COVID-19) Pandemic: A Database Analysis

Background@#The impact of the coronavirus disease 2019 (COVID-19) pandemic on Kawasaki disease (KD) has not yet been established. We investigated changes in the observed number and severity of KD cases and accompanying coronary artery complications during the COVID-19 pandemic in Korea. @*Methods@#This retrospective observational study included patients aged < 18 years with acute-phase KD diagnosed between March 2018 and February 2021. Data were extracted from the Clinical Data Warehouse that houses data from five affiliated university hospitals in Korea. We analyzed changes in the number of patient admissions and clinical characteristics, including cardiac complications, before and after the onset of the COVID-19 pandemic. @*Results@#A total of 475 admissions were included in the analysis. After March 2020, we observed a significant decrease of 33% in the number of hospitalizations for KD compared with the average number of hospitalizations during the previous 2 years. The number of admissions per month significantly decreased by 7.9 persons/month (95% confidence interval, −13.8 to −2.0; P < 0.05) compared with that before COVID-19. By contrast, the proportion of patients aged < 1 year with KD increased. The proportion of patients with refractory KD and the rate of cardiac complications did not change significantly. @*Conclusion@#Since the onset of the COVID-19 pandemic, the total number of hospital admissions for KD has decreased in Korea. Although the proportion of admissions of infants aged < 1 year increased, no changes were observed in clinical courses and complications.

Effect of ethnicity on the prevalence of allergic disease

Differences in the prevalence and severity of allergic diseases exist among racial and ethnic groups. However, influence of population admixing on allergic disease has not been studied. This review aimed to review studies in the literature which examined the difference in the prevalence and severity of allergic disease among populations with different ancestry and to discuss the effect of population admixing on the occurrence and severity of allergic disease. Several studies have shown that the prevalence and severity of asthma, allergic rhinitis, and atopic dermatitis were different according to ethnicity. However, there have been only a few studies evaluating the effect of population admixing on allergic disease. Ethnicity and environmental effect should be considered in the diagnosis and treatment of allergic disease.

Anaphylaxis to honey

Honey is a food ingested worldwide. Allergic reaction to honey is rare and only a few cases have been reported in the literature. A 20-month-old boy developed angioedema 30 minutes after eating rice cake containing honey. After 2 weeks, we performed food challenge tests with honey which resulted in anaphylaxis. This is the first case report on anaphylaxis to honey in Korea.

Associated Factors for Asthma Severity in Korean Children: A Korean Childhood Asthma Study

PURPOSE: Childhood asthma has a considerable social impact and economic burden, especially in severe asthma. This study aimed to identify the proportion of childhood asthma severity and to evaluate associated factors for greater asthma severity. METHODS: This study was performed on 667 children aged 5–15 years with asthma from the nationwide 19 hospitals in the Korean childhood Asthma Study (KAS). Asthma was classified as mild intermittent, mild persistent, and moderate/severe persistent groups according to the National Asthma Education and Prevention Program recommendations. Multinomial logistic regression models were used to identify the associated factors for greater asthma severity. RESULTS: Mild persistent asthma was most prevalent (39.0%), followed by mild intermittent (37.6%), moderate persistent (22.8%), and severe persistent asthma (0.6%). Onset later than 6 years of age (adjusted odds ratio [aOR], 1.69 for mild persistent asthma; aOR, 1.92 for moderate/severe persistent asthma) tended to increase asthma severity. Exposure to environmental tobacco smoke (aOR, 1.53 for mild persistent asthma; aOR, 1.85 for moderate/severe persistent asthma), and current dog ownership with sensitization to dog dander (aOR, 5.86 for mild persistent asthma; aOR, 6.90 for moderate/severe persistent asthma) showed increasing trends with greater asthma severity. Lower maternal education levels (aOR, 2.32) and no usage of an air purifier in exposure to high levels of outdoor air pollution (aOR, 1.76) were associated with moderate/severe persistent asthma. CONCLUSIONS: Modification of identified environmental factors associated with greater asthma severity might help better control childhood asthma, thereby reducing the disease burden due to childhood asthma.

Extent of central lymph node dissection for papillary thyroid carcinoma in the isthmus

PURPOSE: The incidence of papillary thyroid carcinoma (PTC) arising from the isthmus is low; however, these tumors have aggressive clinical and pathological features. Moreover, the existing guidelines regarding the extent of surgery for this type of tumor are unclear. METHODS: This study enrolled 282 patients who underwent total thyroidectomy with bilateral central lymph node dissection. The patients were divided into 2 groups based on the location of the median line of the PTC. Group I included patients in whom the median line was located between the lateral margins of the trachea; group II included all others. We compared the 2 groups and conducted a multivariate analysis to assess risk factors for contralateral node metastasis from a PTC arising from the isthmus. RESULTS: Patients in group I had significantly higher frequencies of extrathyroidal extension and central lymph node metastasis. Group I also had a higher frequency of contralateral node metastasis, and a tumor size >1.0 cm was identified as an independent risk factor for contralateral node metastasis among patients in this group. CONCLUSION: Bilateral central lymph node dissection could be considered for patients with isthmic PTCs >1.0 cm in size who have clinically suspicious node metastasis.

Diagnostic value of serum IgM enzyme-linked immunosorbent assays in polymerase chain reaction-positive Mycoplasma pneumonia in children

PURPOSE: Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia (CAP) in children. MP serum IgM and polymerase chain reaction (PCR) are the methods that enable early diagnosis in patients with MP pneumonia. The objective of this study was to investigate the clinical value of serum MP-specific IgM antibodies in PCR-positive MP pneumonia for the early diagnosis of MP pneumonia in children with CAP. METHODS: Out of 129 patients with lower respiratory tract infection aged over 3 years, 90 CAP children were enrolled in the study. Throat swab MP real-time PCR and serum enzyme-linked immunosorbent assays (ELISA) IgM antibodies were performed. A positive rate of MP PCR and serum IgM, the level of IgM index, clinical features, and laboratory findings were analyzed. RESULTS: PCR was positive in 57 cases. Longer fever duration before admission (P < 0.001), higher rates of lobar or segmental pneumonia (P=0.048), unilateral infiltration (P=0.038), and extrapulmonary symptoms (P=0.049) were associated with MP PCR-positive pneumonia. Serum IgM index was significantly higher in MP PCR-positive pneumonia them in MP PCR-negative pneumonia (3.9±3.0 vs. 0.8±1.3, P < 0.001). Using MP PCR as a gold standard, the sensitivity, specificity, positive predictive value and negative predictive value of serum IgM were 85.5%, 82.1%, 91.4%, and 71.9%, respectively. The area under the curves for serum IgM index was 0.892, and the ROC analysis indicated that an optimal cutoff value of 1.05 for serum IgM provided the highest sensitivity and specificity interestingly (83.9% vs. 85.7%, P < 0.001). CONCLUSION: Serum IgM ELISA has useful diagnostic value in PCR-positive MP pneumonia. Applying an IgM index cutoff of 1.05 improves diagnostic accuracy.

The association between nasal eosinophilia and aeroallergen sensitization in children and adolescents with rhinitis

PURPOSE: To identify the correlation between nasal eosinophilia and aeroallergen sensitization in children and adolescents. METHODS: This is a retrospective study of patients below 18 years of age who had a history of rhinitis that lasted more than 2 weeks or had been repeated more than once a year, received nasal eosinophil examinations, and had serum specific IgE to aeroallergens measured at an Allergy Clinic in a single tertiary teaching hospital in Seoul, Korea. The percentage of nasal eosinophils was calculated by the number of eosinophils per total leukocytes in a high-power field of 1,000×. Data was analyzed to determine the association between nasal eosinophilia and 18 aeroallergens. RESULTS: Of the 245 patients included, 156 (63.7%) were male and the mean age (±standard deviation) was 7.9 years (±3.8). In total, 175 patients (71.4%) were sensitized to at least 1 of the 18 aeroallergens tested, and sensitization to house dust mite was most common. In addition, 118 (48.2%) and 69 patients (28.2%) had nasal eosinophilia of at least 1% and 5%, respectively. There were no significant correlations between serum total IgE or age and the percentage of nasal eosinophils. However, the percentage of nasal eosinophils in the group sensitized to any aeroallergens was significantly increased compared to the nonsensitized group (P=0.002). The percentage of nasal eosinophils was significantly higher in patients who were sensitized to Birch-Alder Mix, oak white, Bermuda grass, orchard grass, timothy grass, sweet vernal grass, rye, mugwort, short ragweed, Alternaria alternata, cats, dogs or Dermatophagoides farinae compared to those nonsensitized. CONCLUSION: Nasal eosinophilia was significantly associated with sensitization to aeroallergens.

Chest radiographs and computed tomography scans in children with airway foreign body

PURPOSE: This study aimed to evaluate the diagnostic value of radiologic findings in children with suspected foreign body aspiration. METHODS: A retrospective medical chart review was done on 32 children with suspected foreign bodies in terms of age, sex, symptoms, signs, bronchographic findings, and type and location of foreign bodies. The diagnostic value of radiography was analyzed: 29 with chest anteroposterior (AP) or posteroanterior (PA) view, 23 with chest lateral decubitus view, 27 with chest computed tomography (CT), 29 with chest AP, PA or chest lateral decubitus view, and 25 with bronchoscopy. RESULTS: As a measure for detecting foreign body aspiration, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of radiologic findings were: chest AP or PA view, 50%, 100%, 100%, 29.4%, and 58.6%, respectively; chest lateral decubitus view, 57.9%, 50.0%, 84.6%, 20.0%, and 56.5%, respectively; chest AP, PA or chest lateral decubitus view, 69.6%, 66.7%, 88.8%, 36.4%, and 69.0%, respectively; and chest CT, 100.0%, 85.7%, 95.2%, 100.0%, and 96.2%, respectively. CONCLUSION: There is clinical benefit to take chest radiographs to diagnose foreign body aspiration. However, based on the results of this study, it may be not necessary to take chest lateral decubitus to diagnose foreign body aspiration. If chest radiographs show unilateral hyperinflation, foreign body aspiration can be diagnosed. In cases of normal chest radiography and history of a witnessed choking episode combined with positive signs, the diagnosis of airway foreign body aspiration should be made by using chest CT.

Fulminant course in a case of malignant phyllodes tumor

We present the case of a 31-year-old woman with an inflammatory and ulcerative malignant phyllodes tumor in her right breast. A right modified radical mastectomy and transverse rectus abdominis myocutaneous (TRAM) flap were performed. A month after the initial operation, several masses recurred at the superior margin and deep margin of the TRAM flap. Wide excision was performed, but masses recurred at the inferior margin and in both lung fields 2 weeks after the second operation. Six weeks after the second operation, the patient died due to progression of dyspnea and respiratory failure.

Cervical Pedicle Screw Placement Using Medial Funnel Technique

OBJECTIVE: Cervical pedicle screw (CPS) placement is very challenging due to high risk of neurovascular complications. We devised a new technique (medial funnel technique) to improve the accuracy and feasibility of CPS placement. METHODS: We reviewed 28 consecutive patients undergoing CPS instrumentation using the medial funnel technique. Their mean age was 51.4 years (range, 30–81 years). Preoperative diagnosis included degenerative disease (n=5), trauma (n=22), and infection (n=1). Screw perforations were graded with the following criteria: grade 0 having no perforation, grade 1 having 50% of screw diameter. Grades 0 and 1 were considered as correct position. The degree of perforation was determined by 2 junior neurosurgeons and 1 senior neurosurgeon. RESULTS: A total of 88 CPSs were inserted. The rate of correct placement was 94.3%; grade 0, 54 screws; grade 1, 29 screws; grade 2, 4 screws; and grade 3, 1 screw. No neurovascular complications or failure of instrumentation occurred. In perforated screws (34 screws), lateral perforations were 4 and medial perforations were 30. CONCLUSION: We performed CPS insertion using medial funnel technique and achieved 94.3% (83 of 88) of correct placement. And it can decrease lateral perforation.

Effect of Proparacaine in a Mouse Model of Allergic Rhinitis

OBJECTIVES: Lidocaine, a local anaesthetic is a treatment option in uncontrolled asthma due to its immunomodulatory effects. In the present study, proparacaine (PPC), a derivative of lidocaine was examined for its therapeutic application in a mouse model of allergic rhinitis. METHODS: The mice were grouped into 4 groups: control group, allergic rhinitis (AR) group, ciclesonide (CIC) group, and PPC group. Nasal symptom scores, eosinophil counts, goblet cell counts, and mast cells counts in the nasal mucosa were measured. Serum ovalbumin (OVA)-specific immunoglobulin (Ig) E, OVA-specific IgG1, OVA-specific IgG2a, interleukin (IL)-4, IL-5, and cortisol levels were measured. RESULTS: Intranasal administration of PPC significantly decreased nasal symptoms, number of eosinophils, goblet cells, and mast cells in the lamina propria of the nasal mucosa. Serum OVA-specific IgE, OVA-specific IgG1, OVA-specific IgG2a was significantly higher in the AR compared with the control group. Serum level of IL-4 was significantly lower in the CIC group and PPC group in comparison with AR group. Serum IL-5 showed no significant difference among all groups. No significant difference in serum cortisol levels was observed among the 4 groups. CONCLUSION: PPC appears to have a therapeutic potential in treatment of allergic rhinitis in a mouse model by reducing eosinophil, goblet cell, and mast cell infiltration in the nasal mucosa.

Significance of micrometastases in the calculation of the lymph node ratio for papillary thyroid cancer

PURPOSE: The lymph node ratio (LNR) is an important prognostic factor in papillary thyroid carcinoma (PTC), but micrometastases in cervical lymph nodes (LNs) are not of great clinical importance. In this study, we analyzed the accuracy of prediction of the prognosis depending on whether micrometastases were included in the number of metastatic LNs when calculating LNR. METHODS: The study included 353 PTC patients who underwent total thyroidectomy with neck LN dissection, and calculated LNR by 2 methods according to whether micrometastases were included in the number of metastatic LNs: Method 1 did not and method 2 did include. To compare the predictive values of LNR by the 2 methods, correlation coefficients and receiver operating characteristic (ROC) curves were analyzed. RESULTS: Positive correlations were found between LNR and preablation stimulated thyroglobulin (sTg) levels in both methods, but the correlation between method 1 LNR and preablation sTg level was significantly stronger than that for method 2 (Fisher z = 1.7, P = 0.045). The areas under these 2 independent ROC curves were analyzed; the prognostic efficacy of method 1 LNR was more accurate than that of method 2 LNR, and the difference was statistically significant (P = 0.0001). CONCLUSION: Regional recurrence of PTC can be predicted more accurately by not including micrometastases in the number of metastatic LNs when calculating LNR.

Delayed Epidural Mucin Collection after Surgery for Spinal Metastatic Pancreatic Adenocarcinoma

A rare case of delayed large epidural mucin collection causing neurologic deficit after surgery for metastatic pancreatic cancer is reported. A 65-year-old man presented with intractable upper-thoracic back pain radiating to the chest and gait disturbance. He had a history of subtotal pancreatectomy due to intraductal papillary mucinous neoplasm (IPMN) of the pancreas and concurrent chemotherapy. Eight months after pancreatectomy, multiple thoracic spinal metastasis was diagnosed with routine up positron emission tomography-computed tomography. Radiotherapy for spinal metastasis and subsequent chemotherapy was carried out. Sixteen months after pancreatectomy, gait disturbance occurred and follow-up thoracic magnetic resonance imaging (MRI) showed aggravation of metastasis at T2 and T4 compressing the spinal cord. We performed a decompressive laminectomy with subtotal resection of the tumor masses and pedicle screw fixation at C7–T6. Neurologic status improved after the operation. Histopathologic examinations revealed the tumor as metastatic mucin producing adenocarcinoma. Three months after surgery, motor weakness and pain was reappeared. MRI showed large amount of epidural fluid collection. We performed wound revision and there was large amount of gelatinous fluid at the epidural space. We suggest that postoperative mucin collection and wound problems should be considered after surgery for mucin producing metastatic pancreatic tumor.

Usefulness of flexible bronchoscopy in children with suspected pulmonary tuberculosis who have difficulty in sputum expectoration

PURPOSE: To assess the usefulness of flexible bronchoscopy in patients with suspected pulmonary tuberculosis (PTB) who have difficulty in sputum expectoration. METHODS: The subjects of this study were patients who were suspected of PTB and visited the Division of Pediatric Pulmonology at a tertiary hospital from April 2006 to March 2016. PTB suspects were determined by clinical symptoms, radiologic findings, and immunologic studies. We aimed to examine the value and safety of bronchoscopy in diagnosis and differential diagnosis of PTB in PTB-suspected patients. The diagnostic criteria for PTB were defined when Mycobacterium tuberculosis was cultured in the sputum specimen or in the bronchial washing fluid. RESULTS: A total of 19 PTB suspects were included. One patient was diagnosed with PTB by using the sputum study. However, the remaining 18 patients could not expectorate sputum or showed no evidence of Mycobacterium tuberculosis infection from the sputum study. Of the 18 patients, 15 underwent bronchoscopy. After bronchoscopy, 6 patients were diagnosed with PTB and 9 patients were diagnosed with Mycoplasma, viral, or fungal pneumonia, and tumors. For antituberculous drug resistance, there were 1 case of isoniazid (INH) resistance and 1 case of concurrent resistance to INH and prothionamide. There was no multidrug-resistant tuberculosis. None of the patients had significant complications due to bronchoscopy. CONCLUSION: Flexible bronchoscopy appears to be a definitive and safe procedure for the differential diagnosis of patients suspecting PTB in children who have difficulty expectorating sputum.

Correlation between serum cytokines and clinical feature of children with mild lower respiratory infection

PURPOSE: Acute lower respiratory infection (ALRI), which is frequently encountered in pediatric patients, is the leading cause of hospitalization. We aimed to identify particular cytokines that correlated with ALRI clinical characteristics. We also aimed to identify any differences in cytokines between respiratory syncytial virus (RSV)-related ALRI and non-RSV-related ALRI. METHODS: Cytokine levels were measured in the sera sampled from 103 pediatric patients diagnosed with ALRI and admitted to Seoul St. Mary's Hospital between May 2012 and April 2013. The correlations between cytokine levels and the length of hospitalization, the number of days with fever, body temperature, pulse rate, respiration rate, oxygen saturation upon admission, and duration of oxygen supplementation were analyzed. RESULTS: In children with ALRI, the level of interleukin (IL)-6, granulocyte-colony stimulating factor (G-CSF), and IL-10 were correlated with a higher body temperature on admission. In addition, the IL-8 level was correlated with pulse rate and respiration rate, and IL-1β level was related with oxygen saturation on admission. In children with RSV-related ALRI, the IL-6 was correlated the with duration of fever, and the IL-1β, IL-2, and IL-8 levels were related to pulse rate and respiration rate. In addition, the increase in interferon-gamma-inducible protein-10 (IP-10) level was correlated with a higher body temperature on admission and a longer duration of hospitalization in children with RSV-related ALRI. CONCLUSION: In children with ALRI, the levels of IL-6, IL-8, IL-1β, G-CSF, and IP-10 were correlated with its clinical features. In children with RSV-related ALRI, the IL-1β, IL-2, IL-6, IL-8, and IP-10 level was correlated with the severity of the disease.

Clinical characteristics of interferon-gamma-inducible protein of 10 kDa in children with wheezing

PURPOSE: Recent studies have shown that interferon-gamma-inducible protein of 10 kDa (IP-10/CXCL10) levels is increased in acute bronchiolitis and asthma. The aim of this study was to examine the levels of IP-10 in children with wheezing and whether it correlates with other clinical variables. METHODS: A total of 62 subjects children were hospitalized for lower respiratory tract infection with wheezing and visited the Emergency Department due to an acute exacerbation of asthma. IP-10 levels were measured using enzyme-linked immunosorbent assay in the serum collected at admission. Serum IP-10 levels were evaluated for the relationships with age, sex, blood eosinophils counts, acute phase reactant, allergic sensitization, history of wheezing, and chest X-ray findings. RESULTS: Age showed a significant negative correlation with serum IP-10 levels (P=0.002). The serum levels of IP-10 were also significantly increased in patients with pneumonic infiltration on X-rays compared to those with normal or hyperinflation (P<0.009). There was no significant difference in the serum IP-10 level according to the other factors, including allergic sensitization. CONCLUSION: Serum IP-10 is significantly associated with inflammation of the lung and age, but not with allergic inflammation.

Infectious Spondylodiscitis by Uncommon Pathogens: A Pitfall of Empirical Antibiotics

OBJECTIVE: The goal of this study is to evaluate the prevalence of spondylodiscitis (SD) caused by uncommon pathogens and review the efficacy of the treatment strategy including the coverage by usual empirical broad-spectrum antibiotic therapy. METHODS: Ninety-nine consecutive patients diagnosed and treated for infectious SD between January 2007 to May 2015 were reviewed retrospectively. The prevalence of uncommon SD, predisposing factors, antibiotics sensitivity, and clinical outcome were analyzed in comparison with that of common SD. RESULTS: Among 99 patients, 68 patients were culture positive. Out of 68 patients with positive culture results, 54 of them(79.4%) were common pathogen and 14 (20.6%) were uncommon pathogen. Postoperative SDs were significantly prevalent in uncommon SD(42.9%) than common SD(27.8%). Recurrence rate was higher in uncommon pathogen SD(14.3%) than common SD group (2.3%), and it showed statistically significant difference (p=0.025). Empirical antibiotics of vancomycin and 3rd or 4th generation cephalosporin covered 100% of nontuberculous common SD and 14.3% of uncommon SD. CONCLUSION: In our study, the prevalence of uncommon SD was relatively high uncommon (20.5% of culture positive SD and 14.1% of total cases) and the coverage rate of empirical antibiotics for them were only 14.3%. In particular, the possibility of SD with fun gal, polymicrobial, or multiple drug resistant organism should be considered in SD unresponsive to broad spectrum antibiotics therapy.

The Applicability of Intraoperative Neuromonitoring in Patients with Preoperative Motor Weakness during Spine Surgery

OBJECTIVE: The purpose of our study is to evaluate the success rate and feasibility of intraoperative neuromonitoring (IONM) focusing on transcranial motor evoked potential (TcMEP) monitoring for patients with preoperative motor weakness in spine surgery. METHODS: Between November 2011 and December 2013, TcMEP and somatosensory evoked potential (SSEP) monitoring were attempted in 130 consecutive patients undergoing spine surgeries for cervical or thoracic cord lesions. Patients ranged in age from 14 to 81 years (mean±standard deviation, 56.7±14.8 years), and 84 patients were male. The success rates of both SSEP and MEPs monitoring were assessed according to the preoperative Medical Research Council (MRC) and Nurick grades. RESULTS: TcMEP was recorded successfully in 0%, 28.6%, 72.3%, and 100% of patients with MRC grades 1, 2, 3, 4, and 5, respectively. SSEP was obtained from 0%, 37.5%, 21.5%, 61.4%, and 85.4% of patients with MRC grades 1, 2, 3, 4, and 5, respectively. TcMEP was recorded successfully in 84% of patients with Nurick grades 1-3 and 26% of patients with Nurick grades 4-5. SSEPs were recorded successfully in 76.3% of patients with Nurick grades 1-3 and 24% of patients with grades 4-5. CONCLUSION: IONM during spine surgery may be useless in patients with MRC grades 1-2, applicable MRC grade 3, and useful MRC grades 4-5. MRC grade 3 is a critical point of indication for application of MEPs. In unmonitorable cases with MRC grade 3, increasing stimulus intensity or facilitation techniques may be considered to improve the usefulness of TcMEP.

Flexible bronchoscopy in 76 children: Indications, yield, and complications

PURPOSE: This study was performed to investigate the indications, yield, and complications of flexible bronchoscopy for respiratory disease in children compared to earlier domestic studies and to examine if any differences existed in comparison to international studies. METHODS: The medical records of 100 cases of flexible bronchoscopy that were performed in 76 patients at the Department of Pediatrics of The Catholic University of Korea, Seoul St. Mary's Hospital from June 16, 2010 to August 6, 2013 were reviewed. RESULTS: A total of 76 patients (50 males and 26 females) were included in the study. The most common indication of flexible bronchoscopy was persistent pneumonia or pneumonia in immunocompromised patients (53 cases). The object of flexible bronchoscopy was accomplished in 65 of 100 cases, and, the treatment was changed in 24 of 65 cases. The most common abnormal finding was tracheomalacia that was found in 18 cases. In 67 cases where bronchoalveolar lavage was performed, bacteria were identified in 47 cases, fungi in 9 cases, and viruses in 22 cases. Complications occurred in 8 cases. CONCLUSION: Compared to earlier domestic studies, there was no significant change in diagnostic approaches and therapeutic improvement. However, this study showed that flexible bronchoscopy appears to be safe in patients with hemato-oncologic disease. Compared to international studies, the occurrence of complications due to flexible bronchoscopy was relatively low.