Hypertonic saline challenge tests in the diagnosis of bronchial hyperresponsiveness and asthma in children

The hypertonic saline challenge test is the recommended method to assess bronchial hyperresponsiveness in the International Study of Asthma and Allergies in Childhood (ISAAC). The sensitivity of this procedure to assess asthma symptoms, however, has been reported to vary among study centers. The purpose of our study was to evaluate the value of this provocation test in an epidemiological survey in children, and to relate the degree of bronchial hyperresponsiveness to the severity of asthma symptoms. All 11–13‐year‐old children from 16 randomly selected schools in Linköping, Sweden received a questionnaire regarding respiratory symptoms and allergic disease. Skin prick tests with eight inhalant allergens were performed. In addition, all children with wheeze over the past 12 months (current wheeze) and a random sample of children without current wheeze were invited to perform hypertonic saline provocation tests. A complete data set was available for 170 children, including 50 with and 120 without current wheeze. Bronchial hyperresponsiveness (BHR) was defined as at least 15% decline in FEV₁. The degree of BHR was represented by the response/dose ratio, i.e. the fall in FEV₁ divided by total dose of inhaled saline. The severity of asthma symptoms was classified by the number of wheezing episodes over the past 12 months. ‘Asthma ever’ was defined by a combination of symptoms in the questionnaires. Children with ‘asthma ever’ and current wheeze were considered as having current asthma. Current atopic asthma was defined as current asthma with at least one positive skin prick test. The sensitivity of the procedure to detect ‘asthma ever’, current asthma and current atopic asthma was 62, 61 and 83%, and the specificity 83, 81 and 60%, respectively. The positive challenge rate was 52, 34, 13 and 7% among current wheezers, previous wheezers, non‐wheezers with a history of allergy and healthy children. The degree of bronchial hyperresponsiveness increased with the number of wheezing episodes. Thus, the median and range of the response/dose ratio were 4.8%/ml (2.1–14.8), 2.6%/ml (0.7–8.6) and 1.3%/ml (0.8–2.7), respectively, for children with ≥ 4 episodes, 1–3 episodes and no wheezing episodes over the past 12 months (p<0.001). In conclusion, hypertonic saline provocation test is useful as a tool to detect asthma in epidemiological studies in children. The degree of bronchial hyperresponsiveness, as represented by the response/dose ratio, reflects the severity of asthma symptoms.     

Lung function and bronchial hyper-responsiveness 11 years after hospitalization for bronchiolitis

AIM: Atopic infants hospitalized for wheezing not caused by respiratory syncytial virus (RSV) carry the highest risk for later asthma. In the present paper, early risk factors for later lung function abnormalities and for bronchial hyper-responsiveness (BHR) were evaluated in 81 children, hospitalized for bronchiolitis in infancy, at the median age of 12.3 years. METHODS: The basic data, including data on atopy in children and viral aetiology of bronchiolitis, had been collected on entry to the study at less than 2 years of age. Lung function was studied by flow-volume spirometry (FVS), and BHR by methacholine and exercise challenge tests 11.4 years after hospitalization during infancy. RESULTS: RSV aetiology of bronchiolitis was associated with reduced forced vital capacity (FVC; 93.65% of predicted +/- 11.05 vs. 99.57%+/- 12.59, p = 0.009). Early sensitization to inhalant allergens (OR 12.59, 95% CI 2.30-68.77) and maternal smoking during pregnancy (OR 4.58, 95% CI 1.28-16.39) were associated with BHR to exercise, and early atopic dermatitis (OR 3.48, 95% CI 1.09-11.10) was associated with BHR to methacholine. CONCLUSIONS: RSV bronchiolitis was associated with a restrictive pattern of lung function. Early atopy and maternal smoking during pregnancy may play a role in the development and persistence of BHR.     

Role of atopy in the natural history of wheeze and bronchial hyper-responsiveness in childhood

The role of atopy in the development of asthma has become increasingly recognised. We have been prospectively following a birth cohort of children of atopic parents to document the development of atopic disease. Our aim in this study was to document the natural history of BHR and wheeze at 10 years of age and to relate this to atopy. We reviewed 47 of our original cohort of 79 infants at 10 years of age and documented their clinical history of atopic disease and performed allergen skin prick tests and BHR to histamine. Thirty-three (70%) children wheezed at some time during their 10 years of life, with 13 commencing in infancy. Twenty-two children (47%) had current wheeze at 10 years of age. Wheeze in infancy was a poor predictor (RR 1.23, Cl₉₅ 0.66–2.23) of current wheeze while wheeze commencing after infancy was a good predictor (RR 2.89, Cl₉₅ 1.45–5.2). In contrast both atopy in infancy (RR 2.94, Cl₉₅ 1.92–4.53) and current atopy (RR 3.58, Cl₉₅ 1.43–9.03) were strong predictors of current wheeze. Analysis of BHR confirmed the importance of atopy in predicting its occurrence and severity. Sensitisation to D. pteronyssinus appeared to be the strongest predictor of both current wheeze and BHR. These observations confirm the importance of atopy in predicting outcome in children with asthma and suggest that wheezing in infancy and wheezing in later childhood may have different pathogenetic mechanisms.     

A different pattern of risk factors for atopic and non-atopic wheezing in 9–12-year-old children

Few epidemiological studies have compared the risk factors of asthma or wheezing between atopic and non-atopic children. The objective of this study was to determine if there are specific risk factors for current wheezing related to atopic status in schoolchildren. Schoolchildren 9-12 yr of age from three Spanish cities (n = 2720) were subject to a cross-sectional study of asthma risk factors (by questionnaire) and atopy (by skin prick test) according to the ISAAC phase-II protocol. Risk factors for current wheezing (in the last 12 months) as reported by parents were investigated among the atopic (positive prick test to at least one allergen) and the non-atopic (negative prick test) children. The prevalence of current wheezing was 13.1% in the whole group, 22.1% in the atopic group and 7.8% in the non-atopic group. However, only 62.4% of children with current wheezing were atopic. Male gender and asthma in the mother and/or the father were both significant and independent risk factors for current atopic wheezing, whereas maternal smoking in the first year of the child's life and mould stains on the household walls were for current non-atopic wheezing. In summary, this study shows that atopic and current non-atopic wheezing children in Spain do not share identical environmental and family risk factors.     

Exercise-induced bronchoconstriction in children with atopic eczema

Non-specific bronchial hyper-responsiveness has been reported in most of the eczematous children even in the absence of asthmatic symptoms. We therefore investigated the occurrence of exercise-induced bronchoconstriction (EIB) in children with atopic eczema (AE) and the predictors of EIB. Fifty-five children referred to the paediatric clinic for AE and a control group of 17 healthy children were recruited. They all carried out a physical examination and skin prick test (SPT) both to inhalant and food allergens, prior to the exercise challenge test. Their parents filled a questionnaire on atopic diseases. They underwent exercise challenge test that consisted in free running for 6 min. Spirometric measurements were carried out before running and till 11 min after. Exercise challenge test was positive in 13 (23%) children with AE. None of the children in the control group had a positive exercise challenge test [OR (95% CI) = 1.31 (1.13-1.51); p = 0.030]. Sixteen (29%) eczematous children had a history of EIB. Such history was not reliable for identifying children who had a positive exercise test. Twenty-nine (52%) children with AE had asthma. Allergic rhinitis affected 33 (60%) of eczematous children and allergic conjunctivitis 28 (50%). EIB was not related to any history of asthma, allergic rhinitis, allergic conjunctivitis, severity of eczema or SPT results. Our study shows that EIB is common in children with AE. Our data also indicate that screening by medical history and physical examination is not a sensitive marker of EIB. This may explain why EIB is often ignored in eczematous children.     

Review Article Towards a better understanding of childhood asthma

Objective: To explore the ways asthma may be defined in childhood and consider the current evidence to support these possible definitions.
Methodology The relationship of symptoms, atopy, bronchial hyperresponsiveness (BHR) and airway inflammation in defining childhood asthma is reviewed.
Results While none of the four proposed methods of defining asthma can stand alone as the 'gold standard], in childhood asthma, all four, namely clinical symptoms, atopy, BHR and airway inflammation, are intimately related. The degree of atopy and BHR, and the presence of airway inflammation, should be viewed as significant risk factors for persistent wheezing in childhood.
Conclusion At present the clinical diagnosis of asthma in childhood remains largely based on symptoms but it is likely that, with further research, the group of children who are now labelled as having asthma will be subdivided into different subgroups with implications for both treatment and outcome.     

Airway response to exercise and methacholine in children with respiratory symptoms.

Thirty atopic and 30 non-atopic subjects were identified from a population of 7-8 year old children with current respiratory symptoms. The response of the airways to exercise and provocation by methacholine were compared. In these children, who had symptoms but were not necessarily asthmatic, there was no significant correlation between the two stimuli. The atopic children were, however, significantly more responsive than the non-atopic children to both. For the whole group, odds ratios derived for atopy and for an increased response to methacholine (expressed as a PD20--the dose that caused the forced expiratory volume in one second (FEV1) to fall by 20%--of less than 6.4 mumol/l), a positive exercise test (greater than 15% fall in FEV1), and the presence of asthma were 13.5, 3.3, and 21.0, respectively; that for positive response to methacholine and positive exercise challenge was 1.5. Thus though increased bronchial responsiveness to methacholine and exercise challenge are both associated with a diagnosis of asthma, the association between the two stimuli is complex, and supports the view that they reflect entirely different components of airways dysfunction.     

Headache and asthma

The aim of this study was to investigate the association between headache and asthma, bronchodilators and atopy in school children. A cross-sectional survey of all primary school children was conducted in two towns near Newcastle, New South Wales, Australia; one in the vicinity of two coal-fired power stations, the other free of outdoor industrial air pollution. The main outcome measures were frequent headache, wheezing, bronchial reactivity, use of bronchodilators and atopy. Eight hundred and fifty-one primary school children aged 5-12 years participated (92% response rate). Twenty-three per cent of the children were reported to have had a history of frequent headache. Crude odds ratios indicated that the odds of frequent headache was significantly higher in children with asthma and atopy and where there was a smoker in the home, but that there was no association between frequent headache and use of bronchodilators or the sex of the child or socio-economic status measured as father's occupation. Stepwise logistic regression with frequent headache as the outcome of interest showed that, after adjusting for age and smoking in the home, the odds ratio for asthma (defined as current wheeze) was 3.24 (95% confidence interval [CI] 2.19-4.77). The similarly adjusted odds ratio for asthma defined as bronchial hyperreactivity (BHR).was 1.60 (95% Cl 1.09-2.37). Atopy was not statistically significantly associated with headache for either model. Asthma (defined as wheeze or BHR) is an independent risk factor for frequent headache. The relationship between headache and asthma is an association with bronchial hyperresponsiveness rather than atopy.     

Bronchial hyper-responsiveness and atopy in urban, peri-urban and rural South African children

Twenty years ago, the prevalence of atopic sensitization and bronchial hyper‐responsiveness (BHR) in Xhosa children in a rural location in South Africa was very low. The aim of this study was to document the current prevalence of these two indices by comparing traditional rural Xhosa children, recently urbanized Xhosa children and established city white children, and to consider factors that may account for the observed increase in all of these groups. One thousand four hundred and fifty‐seven school children aged 10–14 years from the rural Transkei, from a recently urbanized peri‐urban area and from urban Cape Town areas were studied using a questionnaire. Four hundred and eighteen children had histamine challenges, and 492 tests for atopy were also conducted. As determined by bronchial challenge with histamine, 17% of rural and 34.4% of recently urbanized Xhosa children had increased BHR, a marked increase from the 0.03% and 3.17% prevalence of increased BHR previously found using the exercise challenge. The prevalence of increased BHR in white urban children was 33%. Sensitization to one or more aero‐allergens, as indicated by CAP RAST tests, was present in 36.6% of the rural Xhosa children with normal BHR and in 62.5% of those with increased BHR, a striking increase from that of previous studies. Atopic sensitization to one or more aero‐allergens, as indicated by a skin prick test (SPT), was found in 42.3% of the recently urbanized Xhosa children and 45% of urbanized white children. We have also documented sensitization to house dust mites in the rural Xhosa children for the first time. Passive cigarette smoking was not identified as a risk factor for increased BHR or atopy. Wood smoke in the indoor environment did not play a role in the rural Xhosa children's BHR. Ascaris infection does not appear to play any modifying role in the development of increased BHR in the rural or urban children. We have found that increases in BHR in the rural and recently urbanized Xhosa children develop independently of increases in atopy. Our results challenge the ‘hygiene’ hypothesis as a complete explanation for the recent dramatic worldwide increases in allergic diseases.     

Wheezing bronchitis reinvestigated at the age of 10 years

We have reinvestigated 92/101 children aged 10, who before the age of 2 years were admitted to a paediatric ward due to wheezing bronchitis. At the present time, 70% are symptom-free without medication, 20% have mild asthma, 8% moderate and 2% severe asthma. Persistent asthma correlated significantly to the presence of some other atopic disease in recent years, to early start of wheezing during infancy and to intense obstructive disease as a young child, while initial respiratory syncytial virus infection did not. A clear-cut relationship between smoking in the home in infancy and persistent asthma emerged (not visible at a preschool follow-up). The histamine challenge results correlated to the clinical picture. A normal histamine challenge was seen in 63%, mild hyperresponsiveness in 19%, moderate in 12% and pronounced hyper-responsiveness in 6%. The figures for persistent asthma and bronchial hyperresponsiveness are high compared with the prevalence of asthma in the overall population of schoolchildren.     

Atopy, bronchial responsiveness, and symptoms in wheezy 3 year olds.

Fifty children with at least one hospital admission for acute lower airway obstruction in the first 2.5 years of life were assessed at 3 years of age to determine the relationship between atopy, bronchial responsiveness, and the pattern of their symptoms. Bronchial responsiveness was measured by assessing the effect of inhaled metacholine, using the change in transcutaneous oxygen tension (PtCO2) as an indirect measure of response. Symptom patterns were defined by the number of wheezing episodes associated with colds and the presence or absence of cough or wheeze unrelated to viral infections. Forty per cent of the children were found to be atopic by skin prick test or history. In contrast to the situation found in older children and adults, the non-atopic children had significantly greater bronchial responsiveness (lower mean concentration of methacholine causing a 20% fall in PtCO2, the PC20) than the atopic children and significantly more of them had an onset of respiratory symptoms in the first year of life. Cough and wheeze in the absence of colds was more frequently found in the atopic children as was the use of continuous medication. However, the number of reported acute episodes of wheeze associated with colds was the same in the two groups. The findings of the study suggest that in this hospital based group of children, acute wheeze associated with colds in the first three years of life is independent of the finding of atopy and that bronchial responsiveness in this age group may have a different pathogenesis from that in older subjects.     

中国三城市儿童个人过敏原与喘息及气道高反应性的相关性研究

目的 了解个人过敏原阳性与喘息及气道高反应性的关系。方法 在北京、广州及香港三城市中采用整群抽样的方法,在9～11岁在校学龄儿童中,应用国际间儿童哮喘与过敏性疾病研究的第二阶段研究方案进行研究,内容包括(1)家长书面问卷(共收集问卷10902份),(2)儿童皮肤过敏原点刺试验(3478例),(3)乙酰甲胆碱支气管激发试验(608例)。结果 近期喘息(在12个月内有发作)发生率：北京3．8％、广州3．4％、香港5．8％。特应性(即≥1种过敏原阳性)阳性率北京23．9％、广州30．8％、香港41．2％。乙酰甲胆碱支气管激发试验阳性率：北京33．2％、广州45．8％、香港30．7％。多因素logistic回归分析显示,屋尘螨P[相对危险度(OR)=4．48;95％可信限(CI)：3．02—6．66]、猫毛(OR=2．59;95％CI：1．67～4．02)、粉尘螨F(OR=2．41;95％CI：1．65～3．51)及混合草花粉过敏(OR=2．85;95％CI：1．24～6．50)是近期喘息显著相关的危险因素;特应性(OR=1．29;95％CI：0．74～2．24)与近期喘息无显著相关性。特应性(OR=2．53;95％CI：1．07～5．97)、猫毛(OR：3．01;95％CI：1．39～6．52)及粉尘螨F(OR=3．67;95％CI：1．93～6．97)是气道高反应性显著相关的危险因素。结论 屋尘螨P、粉尘螨F、猫毛、混合草花粉是9-ll岁组儿童近期喘息的危险因素,而特应性不是近期喘息的独立危险因素。特应性、猫毛、粉尘螨F是气道高反应性的危险因素。     

乌鲁木齐地区喘息患儿发生支气管哮喘的危险因素

目的 探讨乌鲁木齐地区喘息患儿发生支气管哮喘(哮喘)的危险因素.方法 对2008年1 -12月在新疆医科大学第五附属医院门诊及住院的300例喘息患儿的临床资料进行统计.用统一的调查表调查其年龄、性别、湿疹、变应性鼻炎、食物过敏、家族过敏史/哮喘史、运动相关性喘息等.出院后通过门诊或电话进行随访.采用 Logistic回归分析方法对各因素与哮喘发生的关系及相关程度进行分析.结果 随访2a,275例获得随访;25例失访.275例喘息患儿在随访期内86例(31.2％)发生哮喘.Logistic回归分析发现湿疹、变应性鼻炎、家族过敏史/哮喘史、运动相关性喘息、反复下呼吸道感染( LRTI)、外周血嗜酸性粒细胞(EOS)增高与喘息患儿发生哮喘有关(湿疹:OR=2.376,95％ CI0.098～0.935,P=0.039;变应性鼻炎:OR=1.052,95％ CI2.267 ～14.283,P =0.024;家族过敏史/哮喘史:OR=1.886,95％CI1.004～3.542,P =0.048;运动相关性喘息:OR=1.881,95％ CI2.267 ～18.983,P =0.001;LRTI:OR=5.341,95％ CI1.676～ 10.983,P =0.016;外周血EOS增高:OR=3.915,95％ CI1.459～ 10.501,P=0.002).结论 个人过敏史(湿疹和变应性鼻炎)、家族过敏史/哮喘史、运动相关性喘息、LRTI、外周血EOS增高是乌鲁木齐地区喘息患儿发生哮喘的危险因素.     

Wheezy babies—wheezy adults? Review on long-term outcome until adulthood after early childhood wheezing

Population-based birth cohort studies have documented that about 30% of children suffer from wheezing during respiratory infection before their third birthday. Recurrent wheezing is common in early childhood, but most patients outgrow their symptoms by school age. However, recent long-term postbronchiolitis follow-up studies from Sweden and Finland have revealed that asthma is present in about 40% of young adults and over half of the cases are relapses after many symptom-free years.
In population studies, the principal predictors for later asthma have been parental asthma, recurrent wheezing, atopy and eosinophilia. In the Swedish postbronchiolitis study, atopic diathesis through the development of clinical atopy, and early passive smoking through bronchial hyper-reactivity or later active smoking led to adult asthma. The Finnish postbronchiolitis follow-up stressed early recurrence of wheezing, wheezing induced by less invasive viruses than respiratory syncytial virus (RSV), early-life atopy and eosinophilia and parental asthma as predictors for adult asthma.
Conclusion: The majority of wheezing infants and children outgrow their symptoms by school age, but based on recent long-term follow-up studies, asthma relapses are common in young adults. These studies have highlighted parental asthma, maternal smoking and wheezing induced by other viruses than RSV as predictive factors for later asthma.     

Wheezy babies--wheezy adults? Review on long-term outcome until adulthood after early childhood wheezing.

Population-based birth cohort studies have documented that about 30% of children suffer from wheezing during respiratory infection before their third birthday. Recurrent wheezing is common in early childhood, but most patients outgrow their symptoms by school age. However, recent long-term postbronchiolitis follow-up studies from Sweden and Finland have revealed that asthma is present in about 40% of young adults and over half of the cases are relapses after many symptom-free years. In population studies, the principal predictors for later asthma have been parental asthma, recurrent wheezing, atopy and eosinophilia. In the Swedish postbronchiolitis study, atopic diathesis through the development of clinical atopy, and early passive smoking through bronchial hyper-reactivity or later active smoking led to adult asthma. The Finnish postbronchiolitis follow-up stressed early recurrence of wheezing, wheezing induced by less invasive viruses than respiratory syncytial virus (RSV), early-life atopy and eosinophilia and parental asthma as predictors for adult asthma. CONCLUSION: The majority of wheezing infants and children outgrow their symptoms by school age, but based on recent long-term follow-up studies, asthma relapses are common in young adults. These studies have highlighted parental asthma, maternal smoking and wheezing induced by other viruses than RSV as predictive factors for later asthma.     

Bronchial hyper-responsiveness in selective IgA deficiency

Secretory IgA in mucosal secretions has a broad protective function. The insufficient protection provided by the respiratory mucosa in children with selective IgA deficiency (sIgAD) might facilitate the development of bronchial hyper-responsiveness (BHR) and consequently asthma symptoms. This study was conducted to clarify the prevalence of BHR in sIgAD children and the relationship with atopic status. A cohort of 20 children (group A) aged 6.4-20.1 yr (median: 12.6) with sIgAD (serum IgA <6 mg/dl) were evaluated for BHR using inhaled hypertonic saline test as well as for atopy by skin prick testing (SPT) to eight common aero-allergens. Seventy other children with normal levels of serum IgA, but sensitized to aero-allergens (group B) and 102 with normal IgA and negative SPTs (group C) were also evaluated. Baseline spirometry demonstrated that forced vital capacity (FVC) values in group A were significantly lower than in C. Forced expiratory volume in 1 s values were similar in all groups, but impairment of the forced expiratory flow over the middle half of the FVC was detected in group B. The prevalence of BHR was similar among group A (30.0%) and group B (35.7%) (p = 0.79) but they differed from group C (5.9%) (p = 0.005). An association between BHR and reported current (p = 0.001) but not lifetime asthma symptoms among group A was also observed. There was no association between atopy and BHR in group A but only to mites' sensitization (p = 0.03). In conclusion, these results indicate that sIgAD constitutes a risk factor for development of BHR but it appears to be related to sensitization to mites.     

Asthma attributable to atopy: does it depend on the allergen supply?

The use of the population attributable fraction (PAF) of asthma owing to atopy has not been widely used in epidemiological studies on childhood asthma, especially to compare regions of the same country. The present study includes 1039 children from Cartagena, Spain (Mediterranean coast) and 663 from Madrid (centre of Spanish plateau) using the ISAAC phase II methodology (questionnaire and prick test to the most common allergens). While there were no differences in asthma symptoms between school children (aged 10-11 yr) from Madrid and Cartagena, atopy to any allergen was significantly higher in those from Madrid (40.9% vs. 29.3%, respectively, p < 0.0001). However, children from Madrid were mainly positive to pollen allergy whereas those from Cartagena were positive for mite allergy. PAF of all the different asthma symptoms owing to atopy (any positive skin test) and PAF of current wheezing owing to a more severe atopy (three positive wheals) were higher in children from Cartagena than those from Madrid (45.5% vs. 28.6% and 14.2% vs. 6.2%, respectively). Per cent of previous year wheezing attributable to atopy to specific allergens varied among those cities and was higher for D. pteronissinus, D. farinae, cat, and olive tree in children from Cartagena, and--conversely--higher for mixed grasses, mixed trees and Alternaria in those from Madrid. All of these differences remained significant even after adjusting for risk factors. PAF for asthma owing to atopy could be very different within the same country, probably depending on the allergen supply which may depend on environmental factors such as the climate.     

支气管激发试验在儿童哮喘诊断和治疗中的应用

目的探讨支气管激发试验在儿童哮喘诊断和治疗中的价值及安全性。方法采用组胺支气管激发试验对103例疑诊为哮喘或哮喘缓解期患儿进行气道反应性的测定,阳性者计算其FEV1下降20%预计值时的累积吸入组胺量(PD20FEV1),并以此判定其气道高反应性(BHR)的程度。结果观察组支气管激发试验阳性62例(60.2%),其中极轻度BHR10例(16.2%),轻度34例(54.8%),中度18例(29.0%),重度0例(0%)。在试验过程中,有1例患儿出现气喘、咳嗽,2例患儿出现胸闷,4例出现刺激性咳嗽,对症处理后迅速消失。对照组30例中有2例为支气管激发试验阳性(阳性率6.7%),均为极轻度BHR,无一例出现气喘、咳嗽、胸闷、声嘶等症状。结论支气管激发试验提高了临床医生对儿童哮喘的诊断水平,并且对病情评估以及疗效的判断均具有重要价值。     

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate (AMP) in young children with post-infectious bronchiolitis obliterans

Aim: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently demonstrated by children and adults with chronic obstructive lung diseases. BHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in young children with post-infectious bronchiolitis obliterans (BO). Methods: Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on preschool children with post-infectious BO (n=18), those with asthma (n=23) and in controls (n=20), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation. Results: A positive response to methacholine (an endpoint concentration ≤8 mg/ml) was observed in 88.9% (16/18) of the patients with post-infectious BO, but a positive response to AMP (an endpoint concentration ≤200 mg/ml) was observed in only 22.2% (4/18). All patients with asthma responded positively to methacholine, and most (21/23, 91.3%) of them also responded positively to AMP. The majority of the controls were insensitive to both challenges.

Conclusion: BHR to methacholine is a frequent, but by no means universal, finding in young children with post-infectious BO, but is usually not accompanied by BHR to AMP.     

Evaluation of allergic sensitization and gastroesophageal reflux disease in children with recurrent croup

Background:  Croup, which is seen commonly in childhood, is a disorder that can be recurrent and progress to bronchial asthma. In the present study the prevalence of gastroesophageal reflux (GER) and atopy and the response to therapy were investigated in children with recurrent croup.
Methods:  Between October 2003 and June 2004, 57 patients with acute stridor were admitted to the emergency room. The patients who had at least three croup episodes and patients with first croup episode were compared.
Results:  Thirty-two children had recurrent croup history, GER was found in of 62.5%, and atopy in 17.2%. Atopy was not found in any children with first croup episode. The difference was significant. In addition it was found that atopic dermatitis, previous history of wheezing and established atopy increased the risk of croup recurrence. Alone or combined inhaled corticosteroids and GER therapy were administered, and 77.7% of the patients responded very well.
Conclusion:  GER and atopy should be investigated in patients with recurrent spasmodic croup. Recurrent croup is a non-specific manifestation of atopy. Patients with atopy should be followed closely for developing bronchial asthma.