Bronchial hyperresponsiveness to 4.5% hypertonic saline indicates a past history of asthma-like symptoms in children

Predictive factors for airway hyperresponsiveness in children with respiratory symptoms

BACKGROUND

Asthma diagnosis is a challenging condition, particularly in patients without obstructive pattern and reversibility on spirometry. Determination of airway hyperresponsiveness (AHR) may be helpful, but the procedure is time-consuming and not always practical.

OBJECTIVE

To determine the potential factors that may predict the presence of AHR in children with asthmalike symptoms but without obstructive pattern and reversibility on spirometry.

METHODS

All patients with asthmalike symptoms but without obstructive pattern and reversibility on spirometry were analyzed retrospectively between January 9, 2007, and December 30, 2009. The features of clinical history and laboratory results were analyzed with univariate and multivariate regression analysis.

RESULTS

A total of 111 children between 6 and 18 years of age, with a median age of 10.2 years, were analyzed, and AHR was detected in 67 patients (60.3%). Multivariate logistic regression analysis revealed coexistence of nocturnal cough and exercise-induced cough (odds ratio [OR], 22.1; 95% confidence interval [CI], 3.1-159.2; P = .004), eosinophilia (OR, 18.7; 95% CI, 1.9-178.7; P = .01), and borderline bronchodilator response in forced expiratory volume in 1 second (between 7% and 11%) (OR, 10.1; 95% CI, 2.1-49.1; P = .004) as significant risk factors for the presence of AHR, whereas exercise-induced dyspnea was found to be related to the absence of AHR (OR, 0.2; 95% CI, 0.1-0.8; P = .02).

CONCLUSION

In children with asthmalike symptoms but with normal spirometry, certain features of clinical history and laboratory results can strongly predict the presence of AHR and may help less frequent use of challenge tests.

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

RATIONALE

Bronchial responsiveness is an objectively measurable trait related to asthma. Its prevalence and association with asthma symptoms among children in many countries are unknown.

OBJECTIVES

To investigate international variations in bronchial responsiveness (BR) and their associations with asthma symptoms and atopic sensitization.

METHODS

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)).

RESULTS

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.

CONCLUSIONS

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.

Assessing bronchial responsiveness to hypertonic saline using the stepwise protocol of Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC II)

Measurement of bronchial responsiveness to hypertonic saline was applied in 22 study centers worldwide as part of Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC Phase Two). Because the amount of inhaled saline was difficult to standardize during the stepwise protocol with inhalation periods of increasing duration, we evaluated different statistical procedures based on inhalation time in relation to wheeze and current asthma. Data on random samples on 9 to 11-year-old children (n = 1,418) from two German centers were analyzed. The following statistical approaches were evaluated: (1) bronchial hyperreactivity (BHR) defined dichotomously as a fall in FEV1 (forced expiratory volume in 1 s) >or=15%; (2) PT15: the provocation time causing BHR using survival-analyses methods; (3) time-response-slope (continuous) of the individual FEV1-courses calculated by a linear model after comparing different mathematical models. The sensitivity and specificity of BHR versus current asthma were 47% and 87%, respectively. Analyses of the provocation time indicated an increased risk (adjusted hazard-ratio: 4.3; 95% CI: 2.8-6.5) for a fall in FEV1 >or= 15% among children with current asthma in comparison to those without. The time-response-slope differed markedly between children with and without wheeze and current asthma (P < 0.0001). BHR is meaningful and relatively easy to use, but has low sensitivity. Time-response-slopes utilize the available information from the stepwise protocol better than BHR and survival-analysis based on PT15. Response parameters based on inhalation time discriminate well between children with and without asthma and will be compared in the analyses of ISAAC Phase Two data.

Avaliação da hiperresponsividade brônquica à solução salina hipertônica em crianças e adolescentes

OBJETIVO: Avaliar a hiperresponsividade brônquica à solução salina hipertônica a 4,5% como método alternativo a outros agentes broncoconstritores e sua relação com a sensibilização alérgica do paciente. MÉTODOS: Estudo transversal, experimental, com 85 indivíduos assim distribuídos: 45 no grupo de asmáticos e 17 no grupo controle não asmáticos e não alérgicos, que completaram o teste. Para nebulizar a solução salina hipertônica foi utilizado um nebulizador ultra-sônico de grande volume, sucessivamente durante 0,5, 1, 2, 4 e 8 minutos até haver queda > 15% em relação ao volume expiratório forçado no primeiro segundo basal. A dosagem de imunoglobulina E específica ao Dermatophagoides pteronyssinus por ImmunoCap foi considerada positiva quando > 0,35 kU/L. RESULTADOS: No grupo de asmáticos, 36 apresentaram queda média do volume expiratório forçado no primeiro segundo de 27,4% após nebulização de solução salina hipertônica. Nenhum do grupo controle (imunoglobulina E < 0,35 kU/L) apresentou resposta à solução salina hipertônica e a queda média do volume expiratório forçado no primeiro segundo foi de 9%. Nove asmáticos tiveram provocação brônquica negativa. A freqüência de provocação brônquica positiva foi maior nos indivíduos com imunoglobulina E específica elevada, o que indica uma relação entre hiperresponsividade brônquica e o nível sérico de imunoglobulina E específica. A sensibilidade do teste foi de 80% e a especificidade de 92%. CONCLUSÃO: A inalação de solução salina hipertônica é um método de provocação útil para avaliar hiperresponsividade brônquica em crianças e adolescentes, com adequadas sensibilidade e especificidade, além do baixo custo e necessidade de poucos equipamentos.

Airway hyperresponsiveness and body mass index: the Child Health and Environment Cohort Study in Hesse, Germany

Increased body mass index has been linked to wheezing, a diagnosis of asthma, and morbidity. We investigated the association between body mass index (BMI), breastfeeding, and airway hyperresponsiveness (AHR) in 536 German schoolchildren. We analyzed consecutive surveys in 1994-1995 and 1997, conducted as part of the Child Health and Environment Cohort Study in Hesse, Germany. The questionnaire included questions adapted from the German version of the International Study of Asthma and Allergy in Childhood (ISAAC). A bronchial challenge test using 4.5% hypertonic saline was conducted during the 1997 survey. AHR was defined as a fall in forced expiratory volume in 1 sec (FEV(1)) of > or = 15%. Of 536 children who participated in the 1997 survey (median age, 10.3 years), 82 (15%) tested positive for AHR. In a multivariate analysis, there was no association between AHR determined at age 10 years and the highest quintile of BMI compared to the lowest quintile at age 4 years (odds ratio (OR), 1.4; 95% confidence interval (CI), 0.5-3.6), 7-8 years (OR, 0.6; 95% CI, 0.1-2.5), or 10 years (OR, 1.1; 95% CI, 0.2-4.3). Breastfeeding for 12 weeks or longer protected against AHR (OR, 0.4; 95% CI, 0.2-0.9). However, when children in the highest quintile of BMI at age 4 years had been breastfed for 8 weeks or less, the prevalence of AHR at age 10 years was significantly increased (27.7%, P = 0.01). In conclusion, our results demonstrate a protective effect of breastfeeding against AHR, and reinforce the need to encourage breastfeeding. Although there was no association between BMI and AHR, our finding of an interactive effect of high BMI and short breastfeeding on AHR suggests a complex etiological pathway that needs to be further explored.

Guidelines for evaluating chronic cough in pediatrics: ACCP evidence-based clinical practice guidelines

OBJECTIVES

To review relevant literature and present evidence-based guidelines to assist general and specialist medical practitioners in the evaluation and management of children who present with chronic cough.

METHODOLOGY

The Cochrane, MEDLINE, and EMBASE databases, review articles, and reference lists of relevant articles were searched and reviewed by a single author. The date of the last comprehensive search was December 5, 2003, and that of the Cochrane database was November 7, 2004. The authors' own databases and expertise identified additional articles.

RESULTS/CONCLUSIONS

Pediatric chronic cough (ie, cough in children aged <15 years) is defined as a daily cough lasting for >4 weeks. This time frame was chosen based on the natural history of URTIs in children and differs from the definition of chronic cough in adults. In this guideline, only chronic cough will be discussed. Chronic cough is subdivided into specific cough (ie, cough associated with other symptoms and signs suggestive of an associated or underlying problem) and nonspecific cough (ie, dry cough in the absence of an identifiable respiratory disease of known etiology). The majority of this section focuses on nonspecific cough, as specific cough encompasses the entire spectrum of pediatric pulmonology. A review of the literature revealed few randomized controlled trials for treatment of nonspecific cough. Management guidelines are summarized in two pathways. Recommendations are derived from a systematic review of the literature and were integrated with expert opinion. They are a general guideline only, do not substitute for sound clinical judgment, and are not intended to be used as a protocol for the management of all children with a coughing illness. Children (aged <15 years) with cough should be managed according to child-specific guidelines, which differ from those for adults as the etiologic factors and treatments for children are sometimes different from those for adults. Cough in children should be treated based on etiology, and there is no evidence for using medications for the symptomatic relief of cough. If medications are used, it is imperative that the children are followed up and therapy with the medications stopped if there is no effect on the cough within an expected time frame. An evaluation of the time to response is important. Irrespective of diagnosis, environmental influences and parental expectations should be discussed and managed accordingly. Cough often impacts the quality of life of both children and parents, and the exploration of parental expectations and fears is often valuable in the management of cough in children.

Cough: are children really different to adults?

Worldwide paediatricians advocate that children should be managed differently from adults. In this article, similarities and differences between children and adults related to cough are presented. Physiologically, the cough pathway is closely linked to the control of breathing (the central respiratory pattern generator). As respiratory control and associated reflexes undergo a maturation process, it is expected that the cough would likewise undergo developmental stages as well. Clinically, the 'big three' causes of chronic cough in adults (asthma, post-nasal drip and gastroesophageal reflux) are far less common causes of chronic cough in children. This has been repeatedly shown by different groups in both clinical and epidemiological studies. Therapeutically, some medications used empirically for cough in adults have little role in paediatrics. For example, anti-histamines (in particular H1 antagonists) recommended as a front-line empirical treatment of chronic cough in adults have no effect in paediatric cough. Instead it is associated with adverse reactions and toxicity. Similarly, codeine and its derivatives used widely for cough in adults are not efficacious in children and are contraindicated in young children. Corticosteroids, the other front-line empirical therapy recommended for adults, are also minimally (if at all) efficacious for treating non-specific cough in children. In summary, current data support that management guidelines for paediatric cough should be different to those in adults as the aetiological factors and treatment in children significantly differ to those in adults.

A comparative study of bronchodilator reversibility with albuterol, between asthma symptomatic and asymptomatic children according to ISAAC questionnaire in Mexico City

BACKGROUND

Asthma is an important childhood disease. Recent surveys of the International Study of Asthma and Allergies in Childhood (ISAAC) suggest that the prevalence of asthma is increasing but these surveys do not include any pulmonary tests to confirm the possible diagnosis of asthma.

OBJECTIVE

To compare bronchodilator reversibility with the albuterol test in symptomatic and asymptomatic 6-7-year-old children with asthma participating in the ISAAC survey and living in Mexico City.

PATIENTS AND METHODS

We performed an observational, descriptive, comparative, cross sectional study in children participating in phase 3b of the ISAAC study. According to the ISAAC questionnaire children were classified as asthma symptomatic or asymptomatic. Both groups had bronchodilator reversibility with the albuterol test, using the guidelines of the American Thoracic Society to confirm or rule out the diagnosis of asthma.

RESULTS

The asymptomatic group had a baseline FEV1 of 1.70 +/- 0.34 l/sec (mean +/- SD) and an endpoint FEV1 of 1.76 +/- 0.42 l/sec; in the symptomatic group the respective values were 1.51 +/- 0.41 l/sec and 1.57 +/- 0.44 l/sec (p < 0.05). A positive reversibility test was found in 13/136 (9.6 %) children in the asymptomatic group and in 22/112 (19.6 %) children in the symptomatic group (p < 0.05).

CONCLUSION

Because of its low sensitivity, bronchodilator reversibility cannot be considered a diagnostic tool to confirm diagnosis of asthma.

Bronchial hyper-responsiveness to hypertonic saline and blood eosinophilic markers in 8-13-year-old schoolchildren

BACKGROUND

In adult asthma, bronchial hyper-responsiveness (BHR) to indirect stimuli reflects eosinophilic activation more closely than BHR to stimuli that directly cause smooth muscle contraction.

AIM

To assess the relationship between BHR to the indirect stimulus hypertonic saline (HS), blood eosinophil numbers, and serum eosinophilic cationic protein (ECP) in children with and without current wheeze.

METHODS

A cross-sectional survey among 8-13-year-old schoolchildren, using the International Study of Asthma and Allergic disease in Childhood questionnaire, bronchial challenge with HS, skin prick tests, serum IgE, blood eosinophil counts and ECP (in a subset). Based upon the presence of current wheeze (WHE) and BHR, we defined three case groups (WHE+BHR+, WHE-BHR+, WHE+BHR-) and the reference group (WHE-BHR-). By regression analyses, each case group was compared with the reference group for differences in atopic sensitization, blood eosinophil counts and serum ECP.

RESULTS

Complete data were obtained for 470 children. BHR was present in 103 children (22%), 66 being asymptomatic and 37 symptomatic. Children of all three case groups were more often atopic. Sensitization to indoor allergens particularly occurred in children with BHR, irrespective of symptoms (P < 0.05). Children with WHE+BHR+ had highest values for blood eosinophils and serum ECP (P < 0.05). Children with WHE-BHR+ had less severe responsiveness. In atopic children with WHE-BHR+, serum ECP was higher than in children with WHE-BHR-(P < 0.05).

CONCLUSIONS

BHR to HS is associated with blood markers of eosinophilic activation, particularly in atopic children.

Are oral contraceptive use and pregnancy complications risk factors for atopic disorders among offspring?

In utero programming of atopic manifestations has been suggested. We investigated the association between oral contraceptive (OC) use before, and complications during pregnancy (CDP) and asthma, along with other atopic manifestations. The study is based on neonates from Kingston and St Andrew, a geographic subcohort from the Jamaican Perinatal Morbidity, Mortality Survey conducted in 1986-1987. Information on OC use and CDP was extracted from maternal interviews and medical records. In a follow up in 1997-1998, via interviews with mothers, trained nurses collected information on asthma/wheezing, coughing, eczema, and hay fever. Data, specific to this paper, from birth and 11-12 yr of age was available for a total of 1040 of the 1720 members of the geographic subcohort. Using logistic regression, controlling for confounders, we estimated adjusted odds ratio (aOR) and corresponding 95% confidence intervals (CI). For asthma or wheezing, and coughing, aOR for OC use were 1.81 (95% CI: 1.25-2.61), and 2.72 (95% CI: 1.41-5.24), respectively. CDP was only shown to be a significant risk factor for hay fever. Additionally, a higher number of older siblings were protective for hay fever. The results suggest that asthma in childhood may be programmed in utero.

Atopic manifestations, breast-feeding protection and the adverse effect of DDE

Despite the numerous studies on the possible protective effect of breast feeding against the onset of atopic manifestations during childhood, this issue remains controversial. As part of an environmental epidemiological study, we investigated whether different blood concentrations of dichlorodiphenyl-dichloroethylene (DDE) modified the protective effect of breast feeding against atopic manifestations in 338 children. DDE concentration, duration of breast feeding and manifestation of atopic disorders were measured in 1994-95 at age 7-8 years. Information gathered on asthma, atopic eczema and hay fever was based on questionnaire data. We measured the total serum concentration of immunoglobulin E (IgE) and specific IgE levels against inhalant allergens. In 1997, we also determined bronchial hyper-reactivity with a hypertonic saline challenge test. To estimate odds ratios from our cross-sectional analysis, we applied logistic regressions, controlling for confounders. Breast feeding had a protective effect on the two asthma variables (e.g.> 12 weeks breast feeding for doctor-diagnosed asthma, OR = 0.32 [95% CI 0.11, 0.87]; for 'ever' asthma, OR = 0.13 [95% CI 0.02, 0.68]), but not on bronchial hyper-reactivity, hay fever, atopic eczema or the two IgE variables. The protective effect became stronger in children with DDE blood levels below the median of 0.29 micro g/L (e.g. doctor-diagnosed asthma,> 12 weeks breast feeding, OR = 0.24 [95% CI 0.06, 0.95]). Also, for specific IgE against inhalant allergens, the association gained statistical significance. For children with a DDE concentration of 0.29 micro g/L and higher, breast feeding did not show a significant protective effect. Our results suggest that contaminants such as DDE may modify the protective effect and may have contributed to inconsistent findings on the protective effect of breast feeding in previous studies. We recommend determining levels of breast milk contaminants in children when assessing the impact of breast feeding on atopic manifestations.