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

These results indicate that the stimulus applied and the bronchoconstrictor mechanism activated, and not the challenge protocol, determine the outcome of a cold air challenge. In clinical practice, a brief single step cold air challenge can substitute for a more time-consuming multiple step cold air challenge. As nonpharmacological challenges seem to measure a different type of bronchial responsiveness, neither a single step nor a multiple step cold air challenge can substitute for a pharmacological provocation.

Section: Discussionsupporting

confidence: 92%

Section: Subjectsmentioning

confidence: 99%

mentioning

confidence: 97%

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Comparing methods for assessing bronchial responsiveness in children: single step cold air challenge, multiple step cold air challenge, and histamine provocation

Modl

Eber²,

Steinbrugger³

et al. 1995

“…Of special interest is that "former wheeze" showed no significant association with a positive response to HS, since this is in contrast to challenges using pharmacological agents such as histamine or methacholine [17,18]. Unlike pharmacological challenges, nonpharmacological challenges such as HS or cold air challenge involve inflammatory cells in the airways, a key pathophysiological feature of current asthma, but most likely not of former asthma [19].…”

Section: Discussionmentioning

confidence: 99%

Prevalence of bronchial hyperresponsiveness to 4.5% saline and its relation to asthma and allergy symptoms in Austrian children

Riedler

Gamper²,

Eder³

et al. 1998

The prevalence of asthma in school children has been reported to have increased, with wide variations between countries. To allow comparison of prevalence data, objective markers of asthma should be measured. Therefore, we assessed the prevalence of bronchial hyperresponsiveness (BHR) to hypertonic saline and its relation to asthma and allergy symptoms in 507 Austrian school children, aged 12-15 yrs in a cross-sectional, community based survey. These children were selected from 3,371 children who had answered a self-administered written questionnaire on asthma, hay fever, eczema and environmental factors. The prevalence of BHR to hypertonic saline was 14% and the majority (70%) of the children had mild BHR. The prevalence of wheeze in the last 12 months was 12% and of a diagnostic label of asthma was 6%. Fifty three per cent of the children with symptoms in the last 12 months and a diagnostic label of asthma had BHR, and 33% of those with symptoms in the last 12 months regardless of a diagnostic label of asthma showed a positive response to hypertonic saline. Atopic dermatitis, a diagnostic label of asthma, night cough apart from colds, wheeze in the past 12 months (but not "former wheeze") and male gender were significantly associated with increased response to 4.5% saline in the final logistic regression model. These results show that the prevalence of asthma symptoms in the last 12 months and the prevalence of bronchial hyperresponsiveness to hypertonic saline are twice that of a diagnosis of asthma and that asthma might be underdiagnosed in the present population. The response to hypertonic saline is most strongly associated with current asthma and allergy symptoms. A combination of a "diagnostic label of asthma" and "asthma symptoms in the last 12 months" might best reflect "current asthma" in epidemiological studies in this population.

“…Although there are fewer studies available, the results are consistent with the findings for exercise challenge. Eucapnic hyperpnoea with dry air is more specific and less sensitive than histamine or methacholine challenges [147,[156][157][158]. Dry air challenge is clearly more able to separate asthmatics from subjects with chronic airflow limitation than is histamine challenge [139,140].…”

Section: Diagnostic Value Of Indirect Challengesmentioning

confidence: 99%

Indirect airway challenges

Joos

O’Connor²,

Anderson³

et al. 2003

325

274

Indirect challenges act by causing the release of endogenous mediators that cause the airway smooth muscle to contract. This is in contrast to the direct challenges where agonists such as methacholine or histamine cause airflow limitation predominantly via a direct effect on airway smooth muscle.Direct airway challenges have been used widely and are well standardised. They are highly sensitive, but not specific to asthma and can be used to exclude current asthma in a clinic population. Indirect bronchial stimuli, in particular exercise, hyperventilation, hypertonic aerosols, as well as adenosine, may reflect more directly the ongoing airway inflammation and are therefore more specific to identify active asthma. They are increasingly used to evaluate the prevalence of bronchial hyperresponsiveness and to assess specific problems in patients with known asthma, e.g. exercise-induced bronchoconstriction, evaluation before scuba diving.Direct bronchial responsiveness is only slowly and to a modest extent, influenced by repeated administration of inhaled steroids. Indirect challenges may reflect more closely acute changes in airway inflammation and a change in responsiveness to an indirect stimulus may be a clinically relevant marker to assess the clinical course of asthma. Moreover, some of the indirect challenges, e.g. hypertonic saline and mannitol, can be combined with the assessment of inflammatory cells by induction of sputum.