Bronchial Responsiveness In Children Research Articles

Mycoplasma and Chlamydia infection related cough and bronchial responsiveness in children

Mycoplasma and Chlamydia infection related cough and bronchial responsiveness in children

Obesity and bronchial obstruction in impulse oscillometry at age 5-7 years in a prospective post-bronchiolitis cohort.

Obesity has been linked with asthma symptoms, need for asthma treatment and reduced lung function but not with increased bronchial reactivity in children. The aim of this study was to evaluate the association between previous or current weight status and current lung function and bronchial reactivity to exercise at early school age. Ninety-nine children hospitalized for bronchiolitis at the age of less than 6 months were studied with impulse oscillometry (IOS) at the mean age of 6.3 years. Data on birth weight and weight gain in infancy before hospitalization were collected during hospitalization. Current weight and height data were transformed into age- and sex-specific height-related body mass index z scores (zBMI) using the Finnish national population-based weight and height data as reference. Some significant though only low or modest correlations were found between current zBMI and baseline, post-exercise and post-bronchodilator IOS values in adjusted linear regression analysis. Seven obese children by zBMI had higher post-bronchodilator airway impedance (Zrs) and resistance (Rrs) at 5 Hz and lower post-bronchodilator frequency dependency of resistance (dRrs/df) than normal weight children. There were no significant differences in responses to exercise or to bronchodilators between currently obese or overweight children and normal weight children. Birth weight less than 3,000 g was associated with larger exercise-induced changes in Zrs and Rrs at 5 Hz, and in reactance (Xrs) at 5 Hz, than those with birth weight more than 3,000 g. Preliminary evidence was found that obesity may be associated with airway obstruction, but not with bronchial hyper-reactivity.

Relationship between bronchial hyperresponsiveness and lung function in children age 5 and 6 with and without asthma

It is unknown whether wheezy children have bronchial hyperresponsiveness (BHR) or which lung function parameters are correlated with BHR in children. We evaluated the relationship between BHR parameters and the lung functions by minimizing the effects of age and height in asthmatic, non-asthmatic wheezers and healthy children. The subjects comprised of 154 children aged 5 and 6 years (78 males, 76 females), who were divided into three groups: asthmatics, non-asthmatic wheezers and healthy controls. Spirometry and a methacholine inhalation challenge by the oscillation method were performed. The age of the study cohort was 5.9 ± 0.2 years (mean ± standard deviation), and the height was 114.4 ± 5.3 cm. No significant differences in height, weight, body mass index or lung function were observed in the three groups. The minimal dose of methacholine to start bronchoconstriction, a parameter of bronchial sensitivity, was lower in asthmatics and non-asthmatic wheezers than that in controls. The speed of bronchoconstriction in response to methacholine, a parameter of bronchial reactivity, was strongly correlated with baseline respiratory resistance (Rrs cont) in all three groups. Our data suggest that it not possible to distinguish preschool children with asthma from non-asthmatic wheezers based on their bronchial sensitivity and that the baseline Rrs has a strong effect on the bronchial reactivity in children.

International variations in bronchial responsiveness in children: Findings from ISAAC phase two

Bronchial responsiveness is an objectively measurable trait related to asthma. Its prevalence and association with asthma symptoms among children in many countries are unknown. To investigate international variations in bronchial responsiveness (BR) and their associations with asthma symptoms and atopic sensitization. Bronchial challenge tests were conducted in 6,826 schoolchildren (aged 8-12 years) in 16 countries using hypertonic (4.5%) saline. FEV(1) was measured at baseline and after inhalation for 0.5, 1, 2, 4, and 8 min. BR was analyzed both as a dichotomous (bronchial hyperreactivity, BHR, at least 15% decline in FEV(1)) and as a continuous variable (time-response slope, BR slope, individual decline in FEV(1) per log(min)). Prevalence of wheeze last year ranged from 4.4% in Tirana (Albania) to 21.9% in Hawkes Bay (New Zealand) and of BHR from 2.1% in Tirana to 48% in Mumbai (India). The geometric mean BR slope varied between 3.4%/log(min) in Tirana and 12.8%/log(min) in Mumbai and Rome (Italy). At the individual level, BHR was positively associated with wheeze during the past 12 months both in affluent countries (OR = 3.6; 95% CI: 2.7-5.0) and non-affluent countries (OR = 3.0; 1.6-5.5). This association was more pronounced in atopic children. There was a correlation (rho = 0.64, P = 0.002) between center-specific mean BR slope and wheeze prevalence in atopic, but not in non-atopic children. BR to saline in children varied considerably between countries. High rates of BR were not confined to affluent countries nor to centers with high prevalences of asthma symptoms. The association between wheeze and BHR at the individual level differed across centers and this heterogeneity can be largely explained by effect modification by atopy. Pediatr. Pulmonol. 2010; 45:796-806. (c) 2010 Wiley-Liss, Inc.

Intestinal helminth infestation is associated with increased bronchial responsiveness in children

Non-atopic asthma is the predominant phenotype in non-affluent parts of Latin America. We recently reported that infestation with Ascaris lumbricoides increased the risk of non-atopic asthma in less affluent areas of Brazil but the mechanism is unclear. The present study was conducted to determine whether helminth infestation is associated with heightened bronchial responsiveness (BHR), a common finding in asthma. A random sample of 50 asthmatic and 50 non-asthmatic controls (mean age 10.1 years) were selected from a larger cohort (n = 1,011) without knowledge of their helminth infestation status. Three stool samples were collected from each child on different days and each sample was analyzed by the Kato-Katz method for quantitative determination of helminth eggs. Bronchial provocation tests were performed with inhaled 4.5% hypertonic saline using the ISAAC Phase II standardized protocol. There was no difference between the prevalence of positive BHR in the asthmatics (20.4%) compared with the controls (14.6%) (P = 1.0). Helminth infestation was detected in 24.0% of children, with A. lumbricoides being the most common. Children with high load infestation (>or=100 eggs/g) were five times more likely to have BHR than children with low load or no infestation. Despite the small sample size the results of the present study suggest that the link between high load helminth infestation and non-atopic asthma may be mediated via heightened bronchial responsiveness, possibly due to an inflammatory response to the pulmonary phase of the helminth life cycle.

Effect of Age on Bronchial Reactivity in Children with Asthma

In contrast to an abundance of data concerning age-related changes of bronchial sensitivity, the relationship between age and rapidity of bronchoconstriction (bronchial reactivity) remains unclear. We studied age and bronchial reactivity in children with asthma. Enrolled in this study were 511 asthmatic subjects and 115 age-matched control subjects 1 to 16 years of age. Bronchial reactivity was represented by the slope of the methacholine transcutaneous oxygen pressure dose-response curve (SPO2) in younger children and the slope of the respiratory resistance dose-response curve (SRrs) in older children. Overall, SPO2 and SRrs were higher in asthmatic than control subjects. SPO2 increased significantly from 1 to 6 years in asthmatic subjects, reaching a plateau after age 7. This age-related change in SPO2 also was seen in controls. SRrs in asthmatic subjects decreased after age 13, while SRrs in controls showed no significant change between age 7 and 16. Age-related change in bronchial reactivity occurs during childhood, possibly reflecting early changes in airway smooth muscle maturity and later changes in airway wall rigidity.

Effect of Inhaled Steroid Therapy on Exhaled Nitric Oxide and Bronchial Responsiveness in Children with Asthma

Inhaled steroid therapy is reported to reduce the level of exhaled nitric oxide (eNO), but the effects of inhaled corticosteroids (ICS) on bronchial hyperresponsiveness (BHR) have been controversial. The aim of this study was to determine the effects of ICS on the relationship between eNO and BHR. Twenty-six children with asthma were recruited, including 14 children who were receiving ICS (ICS group) and 12 who were not (ICS-naive group). The fractional exhaled nitric oxide concentration (FENO) was examined by the recommended online method. To evaluate BHR, an acetylcholine challenge test was performed. In the ICS-naive group, FENO was significantly correlated with PC20 (p < 0.05, r = −0.70), but not in the ICS group. In conclusion, FENO was significantly correlated with BHR in the ICS-naive group, but this relationship was not present in the ICS group. Our results suggest that the use of ICS should be taken into consideration when evaluating the relation between BHR and airway inflammation.

Bronchial Sensitivity and Bronchial Reactivity in Children With Cough Variant Asthma

Cough variant asthma (CVA) is diagnosed in some children with chronic cough who do not have wheezing. However, the precise mechanism of CVA in children is unclear. To evaluate the physiologic differences in the airways of children with classic asthma and CVA, the methacholine dose-response curves of respiratory resistance (Rrs) were studied. CVA was diagnosed in 31 children with chronic cough (age range, 5 to 14 years; 19 boys and 12 girls; mean age, 8.5 years) on the basis of methacholine inhalation challenge using an oscillation method. For comparison, the study included 86 age-matched children with classic asthma (age range, 5 to 15 years; 42 boys and 44 girls; mean age, 9.5 years), 25 age-matched children with cough (age range, 5 to 15 years; 17 boys and 8 girls; mean age, 8.8 years), and 23 age-matched control subjects (8 boys and 15 girls; mean age, 9.2 years). Consecutive doses of methacholine were doubled until a 200% increase in Rrs from baseline was reached. The cumulative dose of methacholine at the inflection point of Rrs was considered to represent the bronchial sensitivity to inhaled methacholine (minimum dose of methacholine [Dmin]). The slope of the methacholine dose-response curve (SRrs), which was considered to represent bronchial reactivity, was measured from the increasing Rrs curve. The values of Dmin in classic asthma patients and in CVA patients were significantly lower than those for cough patients and control subjects. There was no significant difference in the values of Dmin between the classic asthma and CVA patients. The value of SRrs in CVA patients was significantly lower than that in classic asthma patients, cough patients, and control subjects (p < 0.05, p < 0.01, and p < 0.01, respectively). There was no significant difference in the value of SRrs between classic asthma patients, cough patients, and control subjects. These data show that bronchial reactivity in the children with CVA was significantly lower than that in the children with classic asthma, and this specificity has an effect on prolonged cough without wheezing in children with CVA.

Does Specific Immunotherapy Injection Cause an Increase in Bronchial Reactivity?

Background. Several well-controlled studies have proven the clinical benefit of specific immunotherapy (SIT) for seasonal allergic rhinitis (AR). However, whether subcutaneous SIT injection could cause a transient increase in bronchial reactivity (BR) remains unknown. Objective. To investigate whether subcutaneous SIT injection, either during or outside the pollen season, could cause an increase in BR in children with pollen allergy. Methods. Twenty-two children (mean age 13.6 ± 0.7 years) with AR who were receiving maintenance SIT for 15 months were included in the study. Pre-injection BR of the patients was evaluated with methacholine provocation test immediately before maintenance dose of SIT during the peak pollen season and outside the season. The post-injection test was administered 24 hours after SIT injection. Results. There was no difference in FEV1 measures recorded during [98(93–109)%] and outside [102(96–111)%] the pollen season. There was no significant difference between pre- [64(7–64)mg/mL] and post-allergen injection [32(7.5–64) mg/mL] BR outside the pollen season (p = 0.9). A trend towards improvement following allergen injection [64(5.4–64)] as compared to pre-allergen injection [14.6(3.5–64)] was shown during the pollen season (p = 0.053). Although PC20 measures in the pollen season were lower than outside the season, the difference was not significant. The percentage of the patients with bronchial hyperreactivity was 62% during and 43% outside the season. Conclusion. SIT injections both during and outside the pollen season cause no increase in BR in children with AR. This calls into question the necessity of empirical dose reduction during the pollen season.

Validation of a Single Concentration Methacholine Inhalation Provocation Test (SCIPT) in Children

A new method to assess bronchial hyperresponsiveness (BHR) using a single concentration methacholine has already been validated in adults with asthma. Because the geometrical dimensions of the airways in children are different, the results from studies in adults cannot be extrapolated to children. In this study, we validated the single concentration methacholine inhalation provocation test (SCIPT) in children. Twenty-two children performed three methacholine inhalation challenge tests in random order. Two challenges were performed according to the SCIPT: doubling doses (0.03–1.8 mg; maximal cumulated dose 3.6 mg) were administered with an Aerosol Provocation System (Masterscope, Jaeger). The third challenge was performed according to a standard dosimeter method (SDM): doubling doses (0.002–1.8 mg; maximal cumulative dose 3.5 mg) were administered with a DeVillbiss 646 nebulizer. The degree of BHR is expressed as a PD20. A difference of < 1.5 dose step was assumed to be due to intraindividual variation. We found an intraclass correlation of 0.91 between both tests according to the SCIPT and of 0.80 between the SCIPT and SDM. We found, according to the method of Bland and Altman, good agreement when comparing these two challenge tests. The single concentration inhalation provocation test is reproducible and shows good agreement with a standard dosimeter method to test bronchial responsiveness in children.

The effect of passive smoking on asthma symptoms,atopy,and airway hyperresponsiveness in schoolchildren.

Passive smoking is a major cause of respiratory morbidity, and is associated with increased bronchial responsiveness in children. To evaluate the effect of smoking by a parent on asthma symptoms, atopy, and airway hyperresponsiveness (AHR), we conducted a cross-sectional survey of 503 schoolchildren that involved questionnaires, spirometry, allergy testing, and a bronchial challenge test. If the PC20 methacholine was less than 16 mg/mL, the subject was considered to have AHR. The prevalence of a parent who smoked was 68.7%. The prevalence of AHR was 45.0%. The sensitization rate to common inhalant allergens was 32.6%. Nasal symptoms such as rhinorrhea, sneezing, nasal itching, and nasal obstruction were present in 42.7%. Asthma symptoms such as cough and wheezing were present in 55.4%. The asthma symptoms were significantly more prevalent in children who had a parent who smoked than in those whose parents did not. The nasal symptoms, atopy, and AHR did not differ according to whether a parent smoked. In a multiple logistic regression model, the asthma symptoms and atopy were independently associated with AHR, when adjusted for confounding variables. Passive smoking contributed to asthma symptoms in schoolchildren and was not an independent risk factor of airway hyperresponsiveness in an epidemiological survey.

Validation of a single concentration inhalation provocation test (SCIPT) in children

Background:A new method to assess bronchial responsiveness (BR) using a single concentration methacholine has already been validated in adults with asthma1. Since the geometrical dimensions of the airways in children are different, and deposition of the inhaled aerosol also differs in children, results from studies in adults cannot simply be extrapolated to children.Aim of the study:validation of a single-concentration inhalation provocation method in children.Methods:Twenty-three subjects performed three methacholine inhalation challenge tests. The first two challenges according to method A: doubling doses, beginning with 0.03 mg to a maximum of 1.8 mg (maximal cumulated dose 3.6 mg), were administered with the Jeager Masterscope, Aerosol Provocation System (APS), medic aid sidestream nebulizer. The third challenge according method B: doubling doses, beginning with 0.002mg to a maximum of 1.8mg (maximal cumulated dose 3.5 mg), were administered with a Devillbiss 646 nebulizer. The degree of BR is expressed as a PD20. A difference of <1,5 dose step is assumed to be due to intra individual variation.Results:I.C.C. between method A and B is 0.80 and between both tests according method A 0.91. Comparing challenges 1 and 2, and 1 and 3 showed good agreement according to Bland and Altman.2Conclusion:This single concentration method is an accurate method of measuring BR in children.

Increased level of bronchial responsiveness in inactive children with asthma

We estimated the association between bronchial responsiveness and hours of exercise per week in children with and without asthma. A random sample of school children (n=2188), 6–16 years old, was enrolled in a cross-sectional study of asthma in Oslo using the ISAAC questionnaire. Lung function and bronchial responsiveness (BR) using methacholine was measured in a random sample of 80 children with asthma, wheeze and no asthma/no wheeze. The relation between hours of exercise per week and BR [log (DRS)] was estimated by linear regression. Sex and age were included as covariates. Hours of exercise were categorized in: none, 30 min, 1 h, 2–3 h, 4–6 h and 7 h or more. The mean values of log (DRS) were different in the low and high exercise groups for children with asthma (P=0·02), whereas there was no effect of exercise on BR for children without asthma. BR increased with decreasing hours of exercise per week in children with asthma. The bronchial responsiveness decreased with 0·11 (95% CI −0·20, −0·01) pr unit in scale. This pattern was not present in children without asthma. The results suggest that there is a relation between hours of exercise per week and bronchial responsiveness in children with asthma.

Viral croup.

Viral croup.

Influence of intranasal steroids during the grass pollen season on bronchial responsiveness in children and young adults with asthma and hay fever

BACKGROUNDIt has been reported that intranasal corticosteroids can influence bronchial hyperresponsiveness (BHR) in asthmatic subjects with seasonal rhinitis. The purpose of the present study was to evaluate the effect of...

Markers of inflammation and bronchial reactivity in children with asthma, exposed to animal dander in school dust.

Several studies have confirmed the presence of animal dander allergens in school dust but the effect of this indirect animal exposure on health has not been evaluated. In this study we investigated bronchial reactivity and markers of eosinophil activity and inflammation during two separate weeks of school in 10 children with mild asthma and a positive skin prick test to cat and dog. At the beginning and the end of the first week the children underwent bronchial challenges with methacholine, and at the beginning and the end of the second week they underwent nasal lavages (NAL) and induced sputum samplings. Blood and urine samples for analysis of inflammatory markers were obtained before and after both school weeks. Peak expiratory flow (PEF) and symptoms of asthma and allergy were recorded daily, and spirometry was performed on each visit. The exposure to animal dander allergens was estimated from dust samples obtained in the subjects' schools and homes. Bronchial sensitivity to methacholine increased in the week when this was measured. The proportion of eosinophils in peripheral blood, and urinary eosinophil protein X (EPX), decreased in both weeks. There was a trend towards an increase of eosinophil peroxidase (EPO) and myeloperoxidase (MPO) in sputum in the week when these proteins were measured. The concentrations of cat (Fel d1) and dog (Can f1) allergens were higher in dust collected in schools than in homes. Our results show that in children with mild asthma and animal dander allergy, there is a significantly increased bronchial sensitivity to methacholine after one school week. There is also a significant decrease in the number of circulating eosinophils and a trend towards an increase of sputum EPO, which could correlate with the early phase of eosinophil recruitment to the lungs. These effects may be related to the continuous exposure to animal allergens in school dust.

Diagnostic and prognostic value of the investigation of external respiration function and bronchial reactivity in children with respiratory allergoses

The state of bronchial patency and hyperactivity in children with preasthma and bronchial asthma is studied. The combined examination with compulsory functional pulmonary tests allows to select a bronchospasmolytic drug individually for a patient and to define the efficiency of prescribed specific and nonspecific therapy in the disease dynamics.

Use of tracheal auscultation for the assessment of bronchial responsiveness in asthmatic children.

It can be difficult to assess bronchial responsiveness in children because of their inability to perform spirometric tests reliably. In bronchial challenges lung sounds could be used to detect the required 20% fall in the forced expiratory volume in one second (FEV1). A study was undertaken to determine whether a change in lung sounds corresponded with a 20% fall in FEV1 after methacholine challenge, and whether the occurrence of wheeze was the most important change. Fifteen children with asthma (eight boys) of mean age 10.8 years (range 8-15) were studied. All had normal chest auscultation before the methacholine challenge test. Lung sounds were recorded over the trachea for one minute and stored on tape. They were analysed directly and also scored blindly from the tape recording by a second investigator. Wheeze, cough, increase in respiratory rate, and prolonged expiration were assessed. The total cumulative methacholine dose causing a fall in FEV1 of 20% or more (PD20) was detected in 12 children by a change in lung sounds - in four by wheeze and in eight by cough, increased respiratory rate, and/or prolonged expiration. In two subjects altered lung sounds were detectable one dose step before PD20 was reached. In three cases in whom no fall in FEV1 occurred, no change in lung sounds could be detected at the highest methacholine dose. Changes in lung sounds correspond well with a 20% fall in FEV1 after methacholine challenge. Wheeze is an insensitive indicator for assessing bronchial responsiveness. Cough, increase in respiratory rate, and prolonged expiration occurs more frequently.

A Comparison of a Single-Step Cold-Dry Air Challenge and a Routine Histamine Provocation for the Assessment of Bronchial Responsiveness in Children and Adolescents

It has remained unclear whether bronchial responsiveness as measured by a single-step cold-dry air challenge (CACh) correlates closely to the responsiveness that is assessed by a routine pharmacologic challenge. On 2 consecutive days, we performed a CACh and a histamine challenge in 128 symptom- and medication-free pediatric and adolescent asthma patients. The CACh consisted of 4 min of isocapnic hyperventilation of -10 degrees C, absolutely dry air; responsiveness was expressed by the induced change in FEV1 (delta FEV1). The histamine challenge consisted of sequential inhalations of incremental increases in concentrations of histamine; responsiveness was expressed by the concentration which caused a 20% fall of FEV1 (PC20). Five children did not bronchoconstrict sufficiently in the histamine challenge for measuring a PC20 and were excluded from analysis. In the remaining 123, delta FEV1 (CACh) ranged from +5 to -73%, PC20 (histamine) from 0.05 to 7.2 mg/mL. There was a statistically significant correlation between delta FEV1 and PC20 (r = 0.54, p < 0.001), but also a considerable scatter of individual data points around the regression line. Fifty-two subjects were hyperresponsive by CACh and 114 by histamine criteria. There is a relatively weak correlation between the results of these two challenges; thus, one cannot be substituted one for the other. Histamine appears as more sensitive in detecting airway hyperresponsiveness than CACh. The poor correlation between the responses to these two challenges can be explained by differences between the challenge protocols, or, alternatively, by differences between applied stimuli and activated mechanisms.

Passive smoking in childhood.

There is increasing interest in the effects of adult smoking on the health of infants and children. Although passive smoking is important in many childhood disorders, most attention has been paid to its effects on the respiratory tract and on infant mortality. Several studies have reported an increased risk of sudden infant death syndrome and respiratory illness in infants of mothers who had smoked during pregnancy. Post-natal exposure to passive smoking has been found responsible for an increased risk of acute respiratory illness morbidity and an increased occurrence of chronic respiratory symptoms. Maternal cigarette smoking aggravates asthma symptoms and bronchial responsiveness in children with an established diagnosis of the disease, and the possibility that passive smoking has a causal role in the aetiology of asthma is currently a matter of growing interest. In addition, several studies have shown small but significant reductions in lung function values of children exposed to passive smoking.