Progress on identifying exercise-induced bronchoconstriction in children with asthma / 国际儿科学杂志

Asthma is one of the most common respiratory disease in children.Maintaining normal activity level(exercise ability) is the goal of treatment in children with asthma.However, when children with asthma do exercise, exercise-induced bronchoconstriction (EIB) may occur.EIB is a situation that needs urgent recognition and treatment, and its severity can be determined through exercise challenge testing.But exercise challenge testing needs the equipment that expensive and difficult to implement.And it has not been widely used in clinical practice.Therefore, we need to find a more convenient method to identify EIB in children with asthma and apply it to clinical practice.This article introduces the definition and pathogenesis of EIB in children with asthma, summarizes the diagnostic methods and the prevention and treatment of EIB, so as to help pediatricians understand EIB more deeply and instruct children with asthma to do exercise better.

Los efectos del entrenamiento físico en niños asmáticos / Effects of exercise training in children with asthma

Asthma is a chronic obstructive respiratory disease with high prevalence in children. Several factors may trigger asthma symptoms, including exercise, which can lead to exercise-induced bronchoconstriction (EIB). Although physical exercise may represent a risk factor for triggering bronchial obstruction in asthmatics, studies have also indicated several positive effects. Thus, this article aimed to summarize current evidence on the effects of exercise training in children with asthma. There is substantial available evidence on the topic. Most of the findings show that exercise induce positive effects, including the increase of aerobic fitness, decrease of EIB levels, as well as an increase in both disease control and quality of life levels in asthmatic children. As for possible influencing factors in order to obtain exercise-induced positive effects, an adequate prescription of exercise intensity highlights and should be personalized, as well as established close to the anaerobic threshold. Thus, considering the evidence showing beneficial effects and the fact that the practice of physical exercise consists of a low cost and safe non-pharmacological therapy, supervised, personalized and individual recommendation of exercise training by health professionals are indicated to asthmatic children.

El asma es una enfermedad respiratoria obstructiva crónica con alta prevalencia en niños. Varios factores pueden desencadenar síntomas de asma, incluido el ejercicio, que puede conducir a la broncoconstricción inducida por el ejercicio (BIE). Aunque el ejercicio físico puede representar un factor de riesgo para desencadenar la obstrucción bronquial en los asmáticos, estudios también han indicado varios efectos positivos. Este artículo tiene como objetivo resumir la evidencia actual sobre los efectos del entrenamiento físico en niños con asma. Hay evidencia sustancial disponible sobre el tema. La mayoría de los hallazgos muestran que el ejercicio induce efectos positivos, incluido el aumento de la aptitud aeróbica, la disminución de los niveles de la BEI, así como un aumento tanto en el control de la enfermedad como en los niveles de calidad de vida en niños asmáticos. Se destaca la importancia de una prescripción de la intensidad del ejercicio adecuada y personalizada, cerca del umbral anaeróbico, para obtener los efectos positivos inducidos por el ejercicio. Por lo tanto, considerando la evidencia que muestra efectos beneficiosos y el hecho de que la práctica del ejercicio físico consiste en una terapia no farmacológica, segura y de bajo costo, el entrenamiento físico supervisado, personalizado e individualizado por parte de profesionales de la salud es recomendado para niños asmáticos.

Plasma secreted phospholipase A2 in asthmatic children: correlation with leptin levels and exercise induced bronchoconstriction

PURPOSE: Dysregulated cysteinyl leukotriene (CysLT) synthesis is prominent in exercise-induced bronchoconstriction (EIB). Secreted phospholipase A2 (sPLA2) plays a key regulatory role in the biosynthesis of CysLTs. We previously found that serum leptin levels correlate with (EIB) in children with asthma. The aim of this study was to address the relationship between plasma sPLA2/leptin levels and EIB. METHODS: Sixty-seven prepubertal children between the ages of 6 and 10 years were included in the study. They were asthmatics with EIB (n=25), asthmatics without EIB (n=21), and healthy subjects (n=21). We measured the plasma sPLA2 and leptin levels. We also performed pulmonary function tests at baseline, after bronchodilator inhalation, and after exercise. RESULTS: The sPLA2 and leptin levels were significantly higher in asthmatics with EIB than in those without and control subjects. In addition, sPLA2 levels were significantly correlated with body mass index (Speraman correlation coefficient r=0.343, P=0.023) and leptin levels (partial correlation coefficient r=318, P=0.033). The maximum decrease in % forced expiratory volume in 1 second after exercise was significantly correlated with both PLA2 levels (r=0.301, P=0.041) and leptin levels (r=0.346, P=0.018). CONCLUSION: The sPLA2 and leptin levels were significantly higher in asthmatics with EIB than in asthmatics without EIB and control subjects. In addition, sPLA2 levels were significantly correlated with leptin levels and EIB in asthmatic children.

Ratio of Leukotriene E4 to Exhaled Nitric Oxide and the Therapeutic Response in Children With Exercise-Induced Bronchoconstriction

PURPOSE: This study assessed the association between the ratio of leukotriene E4 (LTE4) to fractional exhaled nitric oxide (FENO) in the response of children with exercise-induced bronchoconstriction (EIB) enrolled in a therapeutic trial with montelukast or inhaled corticosteroid (fluticasone propionate [FP]). METHODS: Children aged 6 to 18 years with EIB were randomized in a 4-week, placebo-controlled, double-blinded trial with montelukast or FP. Before and after treatment, treadmill exercise challenges were performed. The LTE4 levels in the induced sputum and urine and the FENO levels were measured in subjects before and 30 minutes after the exercise challenges. The same tests were conducted after treatment. RESULTS: A total of 24 patients completed the study: 12 in the montelukast group and 12 in FP group. Both study groups displayed a similar postexercise maximum decrease in forced expiratory volume in one second (FEV1) before treatment as well as after treatment. However, there were significant differences in the magnitude of change between the two (Delta; -18.38+/-14.53% vs. -4.67+/-8.12% for the montelukast and FP groups, respectively; P=0.021). The Delta logarithmic sputum baseline and postexercise LTE4/FENO ratio were significantly lower in the montelukast group than in the FP group (baseline; -0.09+/-0.21 vs. -0.024+/-0.03, P=0.045; postexercise, -0.61+/-0.33 vs. -0.11+/-0.28, P=0.023). CONCLUSIONS: These data indicate that the efficacy of montelukast for preventing a maximum decrease in FEV1 after exercise is significantly higher than that of FP, and the high LTE4/FENO ratio is associated with a greater response to montelukast than to FP for EIB therapy. These results suggest that LTE4 may play an important role in EIB.

Nitric Oxide Correlates with Exercise-Induced Bronchoconstriction in Asthmatic Children / 소아알레르기및호흡기학회지

PURPOSE: Exercise-induced bronchoconstriction (EIB) affects daily activities as well as school performance in children. Exhaled nitric oxide (eNO) is a noninvasive test that measures airway inflammation in asthmatics. The aim of this study was to address the relationship between eNO and childhood EIB. METHODS: Our study consisted of 101 children aged 6 to 18 years belonging to one of three groups, asthmatic children with EIB (n=31), asthmatic children without EIB (n=28), or healthy controls (n=42). After children were taken off drugs that treated their asthma, baseline (pre-exercise) eNO and biomarkers of inflammation were measured. All subjects underwent spirometry and the bronchial challenge by methacholine inhalation and outdoor free running. RESULTS: eNO levels in asthmatic children with EIB were significantly greater than those in both asthmatic children without EIB (P=0.012) and controls (P<0.001). The median eNO (interquartile range) levels were 26.0 (15.0 to 46.0) parts per billion (ppb) in asthmatic children with EIB, 16.0 (12.5 to 28.0) ppb in asthmatic children without EIB, and 12.0 (10.0 to 15.3) ppb in controls. Post-exercise decrease of forced expiratory volume in 1 second correlated positively with eNO (r=0.637, P<0.001; r, partial correlation coefficient adjusted for age and height). The cutoff value for prediction of significant EIB was 20 ppb, and the overall sensitivity, specificity, positive predictive value, and negative predictive values were 61.3%, 80.0%, 57.6%, and 82.4%, respectively. The area under the receiver operating characteristic curve was 0.767 (95% confidence interval, 0.661 to 0.874). CONCLUSION: Baseline eNO levels correlate with the post-exercise decrease of forced expiratory volume in 1 second, suggesting that eNO may be a tool in the prediction of EIB.

Correlation of Exercise-Induced Bronchoconstriction to PC20 and Maximal AirwayNarrowing on the Dose-Response Curve to Methacholine / 결핵

BACKGROUND: Exercise is one of the most common precipitants of acute asthma encountered in clinical practice. The development of airflow limitation that occurs several minutes after vigorous exercise, i. g. exercise-induced bronchoconstriction(EIB), has been shown to be closely correlated with the nonspecific bronchial hyperresponsiveness, which is the hallmark of bronchial asthma. All previous reports that assessed the correlation of EIB to nonspecific bronchial hyperresponsiveness have focused on airway sensitivity(PC20) to inhaled bronchoconstrictor such as methacholine or histamine. However, maximal airway narrowing(MAN), reflecting the extent to which the airways can narrow, when being exposed to high dose of inhaled stimuli, has not been studied in relation to the degree of EIB. METHODS: Fifty-six children with mild asthma(41 boys and 15 girls), aged 6 to 15 years(mean +/- SD, 9.9 +/- 2.5 years) completed this study. Subjects attended the laboratory on two consecutive days. Each subject performed the high-dose methacholine inhalation test at 4 p.m. on the first day. The dose-response curves were characterized by their position(PC20) and MAN, which was defined as maximal response plateau(MRP: when two or three data points of the highest concentrations fell within a 5% response range) or the last of the data points(when a plateau could not be measured). On the next day, exercise challenge, free running outdoors for ten minutes, was performed at 9 a.m.. FEV1 was measured at graduated intervals, 3 to 10 minutes apart, until 60 minutes after exercise. Response(the maximal DeltaFEV1 from the pre-exercise value) was classified arbitrarily into three groups; no response ((-) EIB: DeltaFEV1 20%). RESULTS: 1) When geometric mean PC20 of the three groups were compared, PC20 of (+) EIB group was significantly lower than that of (-)EIB group. 2) There was a close correlation between PC20 and the severity of EIB in the whole group(r= -0.568, p<0.01). 3) Of the total 56 subjects, MRP could be measured in 36 subjects, and the MRP of these subjects correlated fairly with the severity of EIB(r= 0.355, p<0.05) 4) The MAN of (+) EIB group was significantly higher than that of (-)EIB group(p<0.01). 5) The MAN correlated well with the severity of EIB in the whole group(r=0.546, p<0.01). CONCLUSION: The degree of MAN as well as bronchial sensitivity (PC2o) to methacholine is correlated well with the severity of EIB. The results suggest that the two main components of airway hyperresponsiveness may be equally important determinants of exercise reactivity, although the mechanism may be different from each other. The present study also provides further evidence that EIB is a manifestation of the increased airway reactivity characteristic of bronchial asthma.