Mannitol Challenge Research Articles

Stability of FeNO and airway hyperresponsiveness to mannitol in untreated asthmatics

ABSTRACTObjective: Airway hyperresponsiveness and airway inflammation are important hallmarks of asthma and are useful in asthma diagnosing, monitoring and treatment. The aim of the study was to assess whether two commonly used clinical tests, the mannitol challenge and Fraction of exhaled NO (FeNO), were stable clinical indicators over time in stable untreated asthmatics. Methods: 54 non-smoking, asthma patients not treated with steroids were enrolled in the study and assessed at baseline and a median of 6 months later. At baseline and follow-up, FeNO and airway hyperesponsiveness to mannitol were measured, and asthma control was assessed with the Asthma Control Questionnaire (ACQ). Results: A total of 41 subjects completed both visits. Mean (SD) FEV1% at baseline was 94.1% (17.7) and at re-examination 94.6% (19.7) (ns). The ACQ score was unchanged from baseline (Mean (SD): 0.90 (± 0.73)) to follow-up 0.90 (± 0.74) (ns), as was the FEV1% (94.1% (±17.1%) vs 94.6% (19.7%)(ns) indicating that patients were clinically stable during follow-up. The response to mannitol was unchanged at follow-up (Geometric mean (CI) of Response Dose Ratio (RDR) to mannitol: 0.026(0.013–0.046) vs 0.026(0.012–0.050) (ns). There was a slight decrease in FeNO at follow-up (25.5 ppb (19.7–32.9) to 21.9 ppb (17.1–28.2) (p < 0.001). Conclusions: In steroid-free non-smoking asthmatics with constant symptom scores and lung function, airway responsiveness to mannitol remained at the same level over a period of months, while a minor change in exhaled FeNO was reported. These results suggest that mannitol is a stable, reliable marker of clinical disease activity.

Mannitol challenge testing for asthma in a community cohort of young adults.

Mannitol challenge testing is an established tool for clinical asthma diagnosis, and can be performed outside of specialized respiratory laboratories. Despite applicability in both clinical and non-clinical populations, with different pre-test asthma probabilities, differences in diagnostic properties have not been well explored. This study aimed to quantify the diagnostic utility of mannitol challenge testing for asthma in a community cohort and a symptomatic wheezing subset of this cohort. During the 22-year follow-up of the Western Australian Pregnancy (Raine) Cohort, 772 participants (384 males) completed mannitol challenge and skin prick testing and respiratory health questionnaires, of whom 148 reporting wheeze in the past 12 months were included in a wheezing subset. Responsiveness to mannitol had low sensitivity (19%) and high specificity (97%) to identify current asthma in the complete cohort, with positive and negative predictive values (PPV and NPV) of 45% and 92%, respectively. Within the wheezing subset, sensitivity (19%) and specificity (94%) remained similar, but PPV increased to 79%, and NPV decreased to 52%. Our findings support previously reported high specificity and good PPV for mannitol challenge testing in symptomatic wheezing populations, and highlight the need for caution when interpreting mannitol test results in non-clinical populations.

Inhaled Mannitol as a Laryngeal and Bronchial Provocation Test

Timely diagnosis of vocal cord dysfunction (VCD), more recently termed "inducible laryngeal obstruction," is important because VCD is often misdiagnosed as asthma, resulting in delayed diagnosis and inappropriate treatment. Visualization of paradoxical vocal cord movement on laryngoscopy is the gold standard for diagnosis, but is limited by poor test sensitivity. Provocation tests may improve the diagnosis of VCD, but the diagnostic performance of current tests is less than ideal. Alternative provocation tests are required. This pilot study demonstrates the feasibility of using inhaled mannitol for concurrent investigation of laryngeal and bronchial hyperresponsiveness. Consecutive patients with suspected VCD seen at our institution's asthma clinic underwent flexible laryngoscopy at baseline and following mannitol challenge. VCD was diagnosed on laryngoscopy based on inspiratory adduction, or >50% expiratory adduction of the vocal cords. Bronchial hyperresponsiveness after mannitol challenge was also assessed. We evaluated the interrater agreement of postmannitol laryngoscopy between respiratory specialists and laryngologists. Fourteen patients with suspected VCD in the context of asthma evaluation were included in the study. Mannitol provocation demonstrated VCD in three of the seven patients with normal baseline laryngoscopy (42.9%). Only two patients had bronchial hyperresponsiveness. There was substantial interrater agreement between respiratory specialists and laryngologists, kappa = 0.696 (95% confidence interval: 0.324-1) (P = 0.006). Inhaled mannitol can be used to induce VCD. It is well tolerated and can evaluate laryngeal and bronchial hyperresponsiveness at the same setting.

Long-term pulmonary function in esophageal atresia-A case-control study.

Esophageal atresia (EA) is a congenital anomaly associated with substantial pulmonary morbidity throughout childhood. The aim of this study was to evaluate pulmonary complications among 59 five to 15-year-old children and adolescents with surgically corrected congenital EA. Participants underwent a structured interview, spirometry, body plethysmography, mannitol challenge test, skin prick test, as well as measurements of the diffusion capacity, airway resistance, fraction of exhaled NO, and specific immunoglobulin E in serum. A control group consisted of 25 children being evaluated for gastroesophageal reflux disease. Among the EA patients 33 (55.9%) had respiratory symptoms, 31 (53.4%) had a history of at least three pneumonias, and 32 (54.2%) reported more frequent cough episodes than peers. The Forced Vital Capacity (FVC) was 84.9% ± 13.2% of predicted, forced expiratory volume 1 sec (FEV1) was 78.2% ± 12.4% of predicted, and forced expiratory fraction 25-75% (FEF25-75%) was 71.5 ± 17.8% of predicted in EA patients, lower than disease controls (P < 0.0001 for all). In addition, the total lung capacity (TLC) was lower in patients with EA than in the controls (P < 0.0001). Fifteen patients (28.8%) with EA had obstructive ventilatory impairment, compared to nine patients (17.3%) with restrictive ventilatory impairment, while one had a combination. The present study demonstrated significantly decreased pulmonary characteristics in EA patients. Restrictive ventilatory impairment occurring in EA is probably due to poor lung growth after thoracotomy. No single factor predicted ventilatory impairment in children and adolescents with EA. Pediatr Pulmonol. 2017;52:98-106. © 2016 Wiley Periodicals, Inc.

Asthma in ear, nose, and throat primary care patients with chronic rhinosinusitis with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a common inflammatory disorder associated with asthma. This association is well described in patients with CRSwNP undergoing endoscopic sinus surgery (ESS); however, some patients are never referred for surgery, and the frequency of asthma in this group is largely unknown. To determine the frequency of asthma in patients with CRSwNP treated in a primary care (PC) setting who have never been referred for surgery and to compare this with ESS patients. Fifty-seven patients with CRSwNP who had never undergone ESS were prospectively recruited from nine PC ear, nose, and throat clinics in the Copenhagen area. CRSwNP was diagnosed according to the European Position Paper on Chronic Rhinosinusitis and Nasal Polyps; severity was assessed by using a visual analog scale. Allergy, lung function, and asthma tests (reversibility to β2-agonist, peak expiratory flow variability, and mannitol challenge) were performed. Findings were compared with our previously published data from patients with CRSwNP referred for surgery. Asthma was diagnosed in 25 patients (44%) based on respiratory symptoms and a positive asthma test; of these, 12 (48%) had undiagnosed asthma prior to study onset. Furthermore, when using the same methods, we found a lower frequency of asthma in PC patients compared with ESS patients (44% versus 65%, p = 0.04). A high prevalence of asthma in PC patients with CRSwNP was found. Frequently, asthma was undiagnosed. However, asthma was significantly less prevalent in PC patients compared with patients referred for ESS. The frequent concomitance of asthma, i.e., united airways disease, in PC patients calls for closer collaboration between ear, nose, and throat specialists, and asthma specialists.

Bronchial hyperresponsiveness to mannitol, airway inflammation and Asthma Control Test in atopic asthmatic children.

IntroductionThe aim of this study was to evaluate the relationship between airway hyperresponsiveness (AHR) to mannitol and bronchial inflammation measured as exhaled nitric oxide (FeNO) and to assess whether asthma control correlates with AHR to mannitol and FeNO in atopic asthmatic children.Material and methodsAllergy evaluation, the mannitol challenge test, FeNO levels and the Asthma Control Test (ACT) questionnaire were assessed in 40 children with intermittent and mild persistent allergic asthma.ResultsAll the subjects showed positive AHR to mannitol. Pearson's correlation test revealed a significant inverse correlation between AHR (mannitol PD15) and FeNO (p = 0.020). There was also a significant positive correlation between ACT and PD15 (p = 0.020) and a significant negative correlation between ACT and FeNO levels (p = 0.003). The study population was divided into two groups according to FeNO levels (group A ≥ 16 ppb vs. group B < 16 ppb). In group A mannitol PD15 was significantly lower (p = 0.040) and ACT score values were significantly lower (p = 0.001) compared to group B. In group A, the ACT showed that 13.3% of subjects had well-controlled asthma, 80% had partially controlled asthma and 6.7% had uncontrolled asthma. In group B, the ACT showed that 72% of subjects had well-controlled asthma and 28% had partially controlled asthma.ConclusionsOur findings indicate that the degree of AHR to mannitol correlates with the degree of airway inflammation in asthmatic atopic children; moreover, better control of asthma correlates with a lower degree of AHR to both mannitol and FeNO.

Airway hyper-responsiveness to mannitol provides a good evaluation of atopy in childhood asthma.

The relationship between airway hyper-responsiveness (AHR) and atopy has been previously investigated, but there are still some issues to be clarified. The aim of this study was to assess the link between AHR and mannitol and atopy in asthmatic children. We evaluated 44 children with asthma, aged 6-16 years of age, using skin prick tests (SPTs), serum total and specific immunoglobulin E (IgE) levels and the mannitol challenge test (MCT). We found a good correlation between AHR to mannitol and specific IgE against Dermatophagoides pteronissinus (r = -0.66, p < 0.001) and a weak correlation with specific IgE against dog dander (r = -0.33, p = 0.01) and Aspergillus fumigatus (r = -0.23, p = 0.02). Furthermore, we found a weak correlation between AHR to mannitol and serum total IgE (r = -0.30; p = 0.03), the sum of specific IgE to aeroallergens (r = -0.37, p = 0.01) and the number of positive SPTs (r = -0.31, p = 0.02). Measuring AHR with MCT might provide an accurate evaluation of the degree of atopy in children. The patients with a higher degree of atopy were significantly more reactive to mannitol. In clinical practice, these results indicate that children with asthma who are more atopic may require more intensive treatment strategies to reduce AHR.

Airway responsiveness to mannitol 24 h after allergen challenge in atopic asthmatics.

Airway responsiveness to indirect stimuli correlates positively with airway inflammation. In atopic asthmatics, allergen inhalation is associated with an influx of inflammatory cells and increased responsiveness to the direct-acting stimuli methacholine at 3 and 24 h after exposure. We have shown mannitol responsiveness decreases 3 h after allergen inhalation. The current investigation assessed mannitol responsiveness 24 h after allergen challenge. Eleven mild atopic asthmatics completed allergen challenges on two separate occasions. In random order, methacholine or mannitol challenges were performed 24 h pre- and post-allergen challenge. Levels of fractional exhaled nitric oxide were also measured. Allergen challenge increased airway responsiveness to methacholine 24 h postchallenge; the geometric mean (95% CI) methacholine PC20 decreased from 5.9 mg/ml (1.8-19.4) to 2.2 mg/ml (0.81-5.89); P = 0.01. This coincided with a significant increase (P = 0.02) in FeNO levels. Conversely, allergen challenge decreased airway responsiveness to mannitol; geometric mean (95% CI) dose-response ratio was significantly higher after allergen exposure (57 mg/% FEV1 fall [27-121] to 147 mg/% FEV1 fall [57-379]; P = 0.03), and FeNO levels were not significantly increased (P = 0.054). Allergen-induced changes in airway responsiveness to direct and indirect stimuli are markedly different. The loss in responsiveness to mannitol is likely not explainable by a refractory state. The effect(s) of allergen exposure on airway responsiveness to indirect-acting stimuli require further investigation.

Prostaglandin E2 prevents hyperosmolar-induced human mast cell activation through prostanoid receptors EP2 and EP4.

BackgroundMast cells play a critical role in allergic and inflammatory diseases, including exercise-induced bronchoconstriction (EIB) in asthma. The mechanism underlying EIB is probably related to increased airway fluid osmolarity that activates mast cells to the release inflammatory mediators. These mediators then act on bronchial smooth muscle to cause bronchoconstriction. In parallel, protective substances such as prostaglandin E2 (PGE2) are probably also released and could explain the refractory period observed in patients with EIB.ObjectiveThis study aimed to evaluate the protective effect of PGE2 on osmotically activated mast cells, as a model of exercise-induced bronchoconstriction.MethodsWe used LAD2, HMC-1, CD34-positive, and human lung mast cell lines. Cells underwent a mannitol challenge, and the effects of PGE2 and prostanoid receptor (EP) antagonists for EP1–4 were assayed on the activated mast cells. Beta-hexosaminidase release, protein phosphorylation, and calcium mobilization were assessed.ResultsMannitol both induced mast cell degranulation and activated phosphatidyl inositide 3-kinase and mitogen-activated protein kinase (MAPK) pathways, thereby causing de novo eicosanoid and cytokine synthesis. The addition of PGE2 significantly reduced mannitol-induced degranulation through EP2 and EP4 receptors, as measured by beta-hexosaminidase release, and consequently calcium influx. Extracellular-signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 phosphorylation were diminished when compared with mannitol activation alone.ConclusionsOur data show a protective role for the PGE2 receptors EP2 and EP4 following osmotic changes, through the reduction of human mast cell activity caused by calcium influx impairment and MAP kinase inhibition.

Mannitol vs Methacholine Challenge Testing in the Diagnosis of Exercise-Induced Bronchospasm

Mannitol vs Methacholine Challenge Testing in the Diagnosis of Exercise-Induced Bronchospasm

The potential role of direct and indirect bronchial challenge testing to identify overtreatment of community managed asthma.

Although airway hyperresponsiveness (AHR) is a defining feature of asthma pathophysiology, bronchial challenge testing is not routinely used in primary care asthma management. The aim of this study was to evaluate the potential role of direct (methacholine) and indirect (mannitol) challenge testing in community managed asthma. Patients currently treated for asthma from Tayside and Fife were identified by the Health Informatics Centre (HIC) and invited to take part in the study. At screening, the following tests were carried out: spirometry, methacholine and mannitol challenge, exhaled nitric oxide (FeNO); Asthma Control Questionnaire (ACQ) and Mini Asthma Quality of Life Questionnaire (AQLQ). A total of 3388 asthmatics were initially identified by HIC with 423 positive responses and 123 completing the study. Seventy percent had either a positive methacholine (PC20 <8mg/mL) or mannitol challenge (PD15 <635mg), and 30% were non-responsive to both challenges. Fourteen percent of methacholine responders (n=74) were negative to mannitol, and 16% of mannitol responders (n=76) were negative to methacholine. Spirometry, FeNO, ACQ and AQLQ were significantly better in the non-responder group who were exposed to high-dose inhaled corticosteroids and frequent long-acting beta-agonists. We found that 30% of unselected patients with community managed asthma were challenge negative and could be potentially misdiagnosed or overtreated, in turn suggesting the need for supervised step-down.

An open-label study examining the effect of pharmacological treatment on mannitol- and exercise-induced airway hyperresponsiveness in asthmatic children and adolescents with exercise-induced bronchoconstriction.

BackgroundMannitol- and exercise bronchial provocation tests are both used to diagnose exercise-induced bronchoconstriction. The study aim was to compare the short-term treatment response to budesonide and montelukast on airway hyperresponsiveness to mannitol challenge test and to exercise challenge test in children and adolescents with exercise-induced bronchoconstriction.MethodsPatients were recruited from a paediatric asthma rehabilitation clinic located in the Swiss Alps. Individuals with exercise-induced bronchoconstriction and a positive result in the exercise challenge test underwent mannitol challenge test on day 0. All subjects then received a treatment with 400 μg budesonide and bronchodilators as needed for 7 days, after which exercise- and mannitol-challenge tests were repeated (day 7). Montelukast was then added to the previous treatment and both tests were repeated again after 7 days (day 14).ResultsOf 26 children and adolescents with exercise-induced bronchoconstriction, 14 had a positive exercise challenge test at baseline and were included in the intervention study. Seven of 14 (50%) also had a positive mannitol challenge test. There was a strong correlation between airway responsiveness to exercise and to mannitol at baseline (r = 0.560, p = 0.037). Treatment with budesonide and montelukast decreased airway hyperresponsiveness to exercise challenge test and to a lesser degree to mannitol challenge test. The fall in forced expiratory volume in one second during exercise challenge test was 21.7% on day 0 compared to 6.7% on day 14 (p = 0.001) and the mannitol challenge test dose response ratio was 0.036%/mg on day 0 compared to 0.013%/mg on day 14 (p = 0.067).ConclusionShort-term treatment with an inhaled corticosteroid and an additional leukotriene receptor antagonist in children and adolescents with exercise-induced bronchoconstriction decreases airway hyperresponsiveness to exercise and to mannitol.

Assessing direct and indirect airway hyperresponsiveness in children using impulse oscillometry

BackgroundAirway hyperresponsiveness (AHR) is a hallmark of asthma but its assessment is usually restricted to older children who are capable of performing the maneuvers involved in spirometry. In younger children, a feasible option to perform the lung function measurement is impulse oscillometry (IOS), which requires less cooperation. ObjectiveTo evaluate whether assessment of AHR by IOS could differentiate children with various obstructive symptoms from one another. MethodsOne hundred twenty-one children (median age 6.0 years, range 3.7–8.1 years) were examined: 31 with probable asthma characterized by current troublesome lung symptoms, 61 with a history of early wheezing disorder (recurrent wheezing ≤24 months of age), 15 with a history of bronchopulmonary dysplasia, and 14 healthy controls. Indirect AHR was assessed by exercise and mannitol challenge tests, and direct AHR was assessed with methacholine using IOS. AHR to exercise was defined as an increase of at least 40% in respiratory resistance at 5 Hz. In the mannitol and methacholine challenges, the dose causing an increase of 40% in respiratory resistance at 5 Hz was calculated. ResultsAHR to exercise was good at differentiating children with current troublesome lung symptoms from those in the other groups (P < .001). AHR to methacholine separated children with current troublesome lung symptoms, early wheezing disorder, and bronchopulmonary dysplasia from the controls (P < .001), whereas the mannitol test did not distinguish among the study groups (P = .209). ConclusionThe methacholine and exercise challenge tests with IOS identify children with probable asthma characterized by troublesome lung symptoms and therefore may represent a practical aid in the evaluation of AHR in young children.

Low levels of fractional exhaled nitric oxide and deep inhalation bronchoprotection are associated with mannitol non-responsiveness in asthma

Airway hyperresponsiveness (AHR) to indirect agents like mannitol is thought to be dependent on concurrent airway inflammation as these stimuli exert their effects via the release of bronchoconstricting mediators from inflammatory cells. Airway inflammation correlates negatively with deep inhalation bronchoprotection against direct stimuli like methacholine. We hypothesised that deep inhalation bronchoprotection to methacholine would be absent and airway inflammation would be present in individuals with AHR to inhaled mannitol. Twenty asthmatic, otherwise healthy individuals, either gender, aged 18-65 years, with a Visit 1 (screening) methacholine two-minute tidal breathing PC20 of 16 mg/mL or less completed the study. Visits 2 and 3 consisted of either mannitol or deep inhalation methacholine challenge in random order, at least 24 h apart. All visits were completed within a period of two weeks. Eleven of the twenty participants had AHR to mannitol (PD15 ≤ 635 mg, the "responders") and nine did not (the "non-responders"). Responders did not bronchoprotect to methacholine via deep inhalation (doubling dose shift = 0.7; p = 0.13) and had high levels of exhaled nitric oxide (geometric mean 49 ppb; range 16-109 ppb). Conversely, significant deep inhalation bronchoprotection to methacholine occurred in the non-responder group (doubling dose shift = 1.6; p = 0.013). This group also had significantly lower levels of exhaled nitric oxide (geometric mean 23 ppb (range 16-45 ppb; p = 0.015). Deep inhalation bronchoprotection to methacholine and low levels of exhaled nitric oxide coincide with mannitol non-responsiveness in an asthmatic population. Clinical Trials Registration #NCT01642745 (clinicaltrials.gov).

PD08 ‐ Measuring direct and indirect airway hyperresponsiveness in young children with obstructive symptoms

Methods A total of 121 children (3.7-8.1 yr) were studied (31 with troublesome lung symptoms (TLS), 15 with bronchopulmonary dysplasia (BPD), 61 with history of early wheezing disorder and 14 healthy controls) to assess AHR by exercise test, mannitol and methacholine challenges with IOS. If the child used asthma control medication, it was stopped four weeks before the lung function tests. Tests were performed in separate days within two weeks period. AHR to exercise was defined as a ≥ 35% increase in Rrs5. For mannitol and methacholine challenges, the dose causing an increase of 40 % in Rrs5 (PD40Rrs5) was calculated.

Predictors of neutrophilic airway inflammation in young smokers with asthma

Introduction: Asthma is one of the most widespread chronic diseases worldwide. In spite of numerous detrimental effects on asthma, smoking is common among asthma patients. These smoking-induced aggravations of asthma may be attributed to changes in airway inflammation, which is characterized by a higher degree of neutrophilic inflammation than in non-smokers. A state of neutrophilic inflammation may lead to increased steroid resistance and an accelerated loss of lung function owing to tissue destruction. The aim of this study was to elucidate predictors of neutrophilic inflammation in young asthmatic smokers not on steroid treatment, including analysis of tobacco history and bacterial colonization. Methods: In a cross-sectional study, 52 steroid-free, current smokers with asthma were examined with induced sputum, fractional exhaled nitric oxide (FeNO), lung function, ACQ6 score, mannitol and methacholine challenge. A sample from the sputum induction was taken for bacterial analysis using 16S gene PCR technique and sequencing. Results: Using one-way analysis of variance and binary and linear regression models, only age and ACQ6 score were found to be significant predictors for airway neutrophilia. The investigation also included analysis for effect of pack years, current tobacco consumption, body mass index, lung function, FeNO; methacholine and mannitol responsiveness, atopy, gender, asthma history and presence of bacteria. The most common potentially pathogenic bacteria found were Streptococcus spp., Haemophilus spp. and Mycoplasma spp. Conclusion: In this study, no tobacco-related predictors of airway neutrophilia were found, indicating that in the younger years of asthma patients who smoke, the amount of tobacco smoked in life does not influence the degree of neutrophilia. Conversely, for asthmatic smokers, neutrophilia may be induced when a certain threshold of tobacco consumption is reached.

Asthma control in patients on fixed dose combination evaluated with mannitol challenge test

Asthma is often difficult to control and it is likely that not all patients are optimally treated. This study aimed to explore asthma control in adults receiving fixed dose combination (FDC) therapy. Control of asthma was assessed using the mannitol challenge test as a monitoring tool to see if this would give additional information compared to the asthma control test (ACT). The study was an open-label, prospective study on 98 adults prescribed with FDC therapies for at least three months. 74 patients considered that their asthma was well controlled. However, 60 patients had a positive mannitol challenge test (PD15<635mg), and when those with a positive response to the short-acting β2-agonist (≥15%) after the mannitol challenge test were included, this increased to 64 patients (65%). Exploratory analysis determined that the spirometry parameters; FEV1/FVC and FEV1% of predicted, were statistically significant predictors of a positive mannitol challenge test. Co-morbid conditions such as concomitant upper airway involvement or eczema did not predict mannitol reactivity. Although most patients rated their asthma as well controlled, many provided a positive mannitol challenge test, suggesting the presence of underlying inflammation, despite treatment with fixed dose combination therapy.

The safety and feasibility of the inhaled mannitol challenge test in young children

To the Editor : The mannitol challenge is an indirect challenge that increases airway surface liquid osmolality resulting in bronchoconstriction [1, 2]. Mannitol challenge tests are used clinically to diagnose asthma and, in particular, exercise-induced broncoconstriction (EIB) in adults and children above 6 years of age [3]. To date, mannitol has not been used as a challenge agent in children under 6 years of age and the feasibility and safety of its use in this age group is unknown. The assessment of bronchial responsiveness in young children is difficult and limited by the cooperation of the child. The standardisation of lung function tests suitable for use in young children, such as the interrupter technique or the forced oscillation technique (FOT), provide an opportunity to assist in the assessment of bronchial responsiveness in young children and a variety of challenge tests using FOT have been reported in young children [4]. The aim of this preliminary study was to assess the feasibility and safety of the mannitol challenge test in young children using the FOT as the objective outcome measure. 20 children aged 3–7 years were recruited; 10 of these children were healthy and 10 children had a history of parentally reported exercise-induced symptoms (EIS) in the past year. The mannitol challenge test (Aridol; Pharmaxis, Frenchs Forest, Australia) was performed as previously published [2], with the exceptions that the respiratory resistance at 8 Hz ( R rs8) from the FOT was used as the primary outcome and the definition of a positive response was altered, as detailed below. Prior to …

Bronchial hyperresponsiveness testing in athletes of the Swiss Paralympic team

BackgroundThe aim of this study was to assess airway hyperresponsiveness to eucapnic voluntary hyperventilation and dry powder mannitol challenge in athletes aiming to participate at the Paralympic Games 2008 in Beijing, especially in athletes with spinal cord injury.MethodsForty-four athletes with a disability (27 with paraplegia (group 1), 3 with tetraplegia (group 2) and 14 with other disabilities such as blindness or single limb amputations (group 3) performed spirometry, skin prick testing, measurement of exhaled nitric oxide, eucapnic voluntary hyperventilation challenge test (EVH) and mannitol challenge test (MCT). A fall in FEV1 of ≥10% in either challenge test was deemed positive for exercise-induced bronchoconstriction.ResultsFourteen (32%) athletes were atopic and 7 (16%) had a history of physician-diagnosed asthma. Absolute lung function values were significantly lower in patients of group 1 and 2 compared to group 3. Nine (20%) athletes were positive to EVH (8 paraplegics, 1 tetraplegic), and 8 (18%) athletes were positive to MCT (7 paraplegics, 1 tetraplegic). Fourteen (22.7%) subjects were positive to at least one challenge; only three athletes were positive to both tests. None of the athletes in group 3 had a positive test. Both challenge tests showed a significant association with physician-diagnosed asthma status (p = 0.0001). The positive and negative predictive value to diagnose physician-diagnosed asthma was 89% and 91% for EHV, and 75% and 86% for MCT, respectively.ConclusionEVH and MCT can be used to identify, but especially exclude asthma in Paralympic athletes.

Mannitol Challenge Test, Sputum Eosinophils and Exhaled Nitric Oxide (FENO) for Diagnosis of Asthma

Mannitol Challenge Test, Sputum Eosinophils and Exhaled Nitric Oxide (FENO) for Diagnosis of Asthma