Methods for "indirect" challenge tests including exercise, eucapnic voluntary hyperpnea, and hypertonic aerosols

Airway dysfunction and inflammation in pool- and non-pool-based elite athletes

PURPOSE

This study sought to determine and compare the levels of airway dysfunction and inflammation in a large cohort of symptomatic international athletes from pool- and non-pool-based sporting backgrounds. In total, 118 athletes were recruited.

METHODS

All subjects had symptoms of exercise asthma and were steroid naïve. They completed baseline spirometry, a symptom score, exhaled nitric oxide, a eucapnic voluntary hyperventilation (EVH) test, and a postchallenge induced sputum and urine test.

RESULTS

Pool-based athletes had better lung function (FEV1 = 110% vs 102% predicted, mean difference = 8.200 ± 2.339, P = 0.0006 and FVC = 5.64 vs 4.75 L, mean difference = 0.8855 ± 0.1951, P < 0.0001) and more marked airways hyper-reactivity (AHR) (percent drop in FEV1 after EVH = 18.14 vs 11.47, mean difference = 6.67, 95% confidence interval = 2.89-10.53, P = 0.0009). More pool-based athletes had a positive EVH test (72% pool vs 39% nonpool), but there was no difference between groups with respect to eosinophilic inflammation (sputum eosinophil percentage: pool = 2.07, nonpool = 2.28, P = 0.77; exhaled nitric oxide: pool = 32.54, nonpool = 35.77, P = 0.60). Athletes with a positive EVH test had less neutrophilic inflammation (P = 0.01) and more epithelial cells (P = 0.03) in their sputum.

CONCLUSIONS

Pool-based endurance athletes have greater evidence of AHR than non-pool-based athletes but no evidence of greater eosinophilic airway inflammation. Athletes who test positive on EVH are more likely to be eosinophilic and have higher levels of epithelial cells in their sputum.

Bronchial hyperresponsiveness testing in athletes of the Swiss Paralympic team

BACKGROUND

The 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.

METHODS

Forty-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.

RESULTS

Fourteen (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.

CONCLUSION

EVH and MCT can be used to identify, but especially exclude asthma in Paralympic athletes.

Assessment of EIB: What you need to know to optimize test results

Respiratory symptoms and asthma control questionnaires are poor predictors of the presence or severity of exercise-induced bronchoconstriction (EIB), and objective measurement is recommended. To optimize the chance of a positive test result, there are several factors to consider when exercising patients for EIB, including the ventilation achieved and sustained during exercise, water content of the inspired air, and the natural variability of the response. The high rate of negative exercise test results has led to the development of surrogates to identify EIB in laboratory or office settings, including eucapnic voluntary hyperpnea of dry air and inhalation of hyperosmolar aerosols.

Assessment of exercise-induced bronchoconstriction in adolescents and young children

Recent research shows important differences in exercise-induced bronchoconstriction (EIB) between children and adults, suggesting a different pathophysiology of EIB in children. Although exercise can trigger classic symptoms of asthma, in children symptoms can be subtle and nonspecific; parents, children, and clinicians often do not recognize EIB. With an age-adjusted protocol, an exercise challenge test can be performed in children as young as 3 years of age. However, an alternative challenge test is sometimes necessary to assess potential for EIB in children. This review summarizes age-related features of EIB and recommendations for assessing EIB in young children and adolescents.

[Inhalation therapy: provocation tests, infectious risks, acute bronchiolitis and ENT diseases. GAT aerosolstorming, Paris 2011]

Communications from the 2011 meeting of the GAT are reported in this second article on the practical management of bronchial provocation tests and infectious risks associated with the use of nebulization. Recent advances on the role of nebulized hypertonic saline in the treatment of acute bronchiolitis in infants and of the nebulization in sinusal diseases are also reported.

Airway hyperresponsiveness in asthma: mechanisms, clinical significance, and treatment

Airway hyperresponsiveness (AHR) and airway inflammation are key pathophysiological features of asthma. Bronchial provocation tests (BPTs) are objective tests for AHR that are clinically useful to aid in the diagnosis of asthma in both adults and children. BPTs can be either “direct” or “indirect,” referring to the mechanism by which a stimulus mediates bronchoconstriction. Direct BPTs refer to the administration of pharmacological agonist (e.g., methacholine or histamine) that act on specific receptors on the airway smooth muscle. Airway inflammation and/or airway remodeling may be key determinants of the response to direct stimuli. Indirect BPTs are those in which the stimulus causes the release of mediators of bronchoconstriction from inflammatory cells (e.g., exercise, allergen, mannitol). Airway sensitivity to indirect stimuli is dependent upon the presence of inflammation (e.g., mast cells, eosinophils), which responds to treatment with inhaled corticosteroids (ICS). Thus, there is a stronger relationship between indices of steroid-sensitive inflammation (e.g., sputum eosinophils, fraction of exhaled nitric oxide) and airway sensitivity to indirect compared to direct stimuli. Regular treatment with ICS does not result in the complete inhibition of responsiveness to direct stimuli. AHR to indirect stimuli identifies individuals that are highly likely to have a clinical improvement with ICS therapy in association with an inhibition of airway sensitivity following weeks to months of treatment with ICS. To comprehend the clinical utility of direct or indirect stimuli in either diagnosis of asthma or monitoring of therapeutic intervention requires an understanding of the underlying pathophysiology of AHR and mechanisms of action of both stimuli.

Inhaled mannitol as a test for bronchial hyper-responsiveness

Bronchial provocation tests (BPTs) are useful for identifying one of the key features of asthma: bronchial hyper-responsiveness (BHR). The symptoms of asthma are not always reflective of the underlying pathophysiology of asthma and there is a need for objective tests to identify the presence and severity of BHR. A new BPT, involving the inhalation of dry powder mannitol, has recently been approved to identify BHR and is now in use as a diagnostic tool for currently active asthma. Airway sensitivity to mannitol identifies BHR that is dependent upon the presence of airway inflammation and would probably benefit from treatment with inhaled corticosteroids. The mannitol BPT is available commercially as a (single-use) test kit (Aridol/Osmohale), with the only additional requirement to perform the test being a spirometer. Accordingly, the mannitol BPT provides a point-of-need tool to identify BHR to assist in the diagnosis of asthma.

Challenge of exercise-induced asthma and exercise-induced bronchoconstriction

Exertional dyspnea is a common clinical problem seen with different etiologies in different clinical situations and may even be found in healthy individuals. Approximately 90% of asthmatic patients suffer from shortness of breath in the context of exercise. Dyspnea, occurring during or after exercise, can be the only clinical manifestation of asthma. On the other hand, bronchoconstriction may occur in the absence of asthma - so-called exercise-induced bronchoconstriction. In elite athletes and persons performing sports with high ventilatory demand, bronchospasm in the context of exercise may appear without the presence of asthma. In these circumstances, bronchoconstriction is characterized by neutrophilic inflammation in the bronchial epithelium. Exercise-induced bronchoconstriction in the absence of asthma is difficult to diagnose and to treat. Diagnostic tests are often complex to handle, infrequently performed and the majority miss well-defined cut-off points. Diagnosis is confirmed either by performing direct or indirect bronchial challenge tests for classical asthma or through indirect tests for exercise-induced bronchoconstriction. Therapy for both diseases is based on short-acting beta-agonists used 15 min before exercise. Daily basic therapy is different for asthmatics and nonasthmatics - where basic therapy consists of inhaled corticosteroids in asthmatics, leukotriene antagonists play a more important role in exercise-induced bronchoconstriction. In general, treatment of exercise-induced asthma follows the Global Initiative of Asthma guidelines.

Cardiorespiratory screening in elite endurance sports athletes: the Quebec study

BACKGROUND

Cardiorespiratory disorders are common in athletes. However, these conditions are often underdiagnosed, which potentially results in impaired performance and increased health risks. The aim of this study was to evaluate, in a research setting, the prevalence of cardiorespiratory disorders in athletes in order to determine the potential value of a screening program.

METHODS

One hundred thirty-three athletes were studied. Each subject underwent a physical examination. A eucapnic voluntary hyperventilation (EVH) test and a methacholine inhalation test were performed to confirm the diagnosis of asthma. A cardiovascular evaluation was also performed, including maximal exercise test with electrocardiogram, 24-hour ambulatory blood pressure monitoring, 24-hour Holter monitoring, and blood sampling.

RESULTS

Seventy-four (56%) athletes had airway hyperresponsiveness to EVH or the methacholine inhalation test. Among those with airway hyperresponsiveness, 45 (61%) athletes were only hyperresponsive to EVH, and 10 (14%) were only hyperresponsive to the methacholine inhalation test (using the criteria of a PC20 ≤ 4 mg/mL). Thirty-two (24%) athletes had a known diagnosis of asthma, while 34 (26%) athletes received a new asthma diagnosis. Ninety-seven (73%) athletes were sensitized to common airborne allergens. Forty-seven (35%) athletes completed the cardiovascular evaluation. Three (6%) and 7 (15%) athletes had a previous or new diagnosis of cardiovascular disease, respectively. Resting systemic hypertension was documented in 2 (4%) athletes and exaggerated blood pressure response to exercise was found in 12 (26%) athletes.

CONCLUSION

This cardiorespiratory screening data set in athletes showed a high prevalence of exercise-induced asthma and exercise hypertension, which in many cases were not previously diagnosed.

Distinctive bronchial inflammation status in athletes: basophils, a new player

The aim of the study was to establish bronchial inflammation status and to measure eicosanoids in sputum obtained from active elite athletes. A total of 68 subjects were enrolled. Twelve were non-athletes and non-asthmatic (NAtNAs), 21 non-athlete asthmatics (NAtAs), 11 athlete non-asthmatics (AtNAs), and 24 athletes with asthma (AtAs) with positive indirect or direct bronchial challenges. Induced sputum was used to measure cells and eicosanoids. Sputum differential cell counts in all the subject groups revealed eosinophilia with the exception of NAtNAs control subjects. Athletes with and without diagnosed asthma showed a significant increase in bronchial epithelial cells and lymphocytes present in their sputum. Also, flow cytometry revealed that a significantly higher number of basophils were present in sputum from athletes (without and with asthma) when compared with non-athletes (without and with asthma). Asthmatic athletes and non-athletes showed a higher increase in LTC(4) levels and PGE(2) metabolites in sputum when compared with healthy controls. The present study identifies basophils as a new player present in athletes bronchial inflammation defining athlete status and not necessarily associated with exercise-induced bronchoconstriction.

Determinants of asthma control and quality of life in stable asthma: evaluation of two new cough provocation tests

INTRODUCTION

Asthma control and quality of life are poorly associated with traditional asthma biomarkers.

OBJECTIVES

In the present study, we evaluated two new cough provocation tests in this respect.

METHODS

Asthma Control Questionnaire and Leicester Cough Questionnaire were completed by 36 stable asthmatics. Cough provocation tests with hypertonic saline and isocapnic hyperpnoea of dry air were performed, as well as spirometry, ambulatory peak expiratory flow (PEF) monitoring and exhaled nitric oxide (eNO) measurement.

RESULTS

Leicester Cough Questionnaire score correlated closely with cough responsiveness to hypertonic saline and isocapnic hyperpnoea (R = -0.66, P < 0.001 and R = -0.49, P = 0.002, respectively). Asthma Control Questionnaire score also correlated with the cough responsiveness to these tests (R = 0.52, P = 0.001 and R = 0.43, P = 0.008, respectively). Forced expiratory volume in 1 s (%predicted), diurnal PEF variation and eNO did not correlate with cough-related quality of life but showed some association with asthma control. There was a significant correlation between Leicester Cough Questionnaire and Asthma Control Questionnaire (R = -0.54, P = 0.001).

CONCLUSIONS

Asthma control and cough-related quality of life are more closely associated with cough responsiveness to the investigated cough provocation tests than to eNO and traditional indices of bronchial obstruction. Cough is a major contributor to poor asthma control.

Seasonal variations of cough reflex sensitivity in elite athletes training in cold air environment

BACKGROUND

Exercise-induced cough is common among athletes. Athletes training in cold air often report an increasingly troublesome cough during the winter season. Chronic airway irritation or inflammation may increase the sensory response of cough receptors. The aim of this study was to evaluate the seasonal variability of cough reflex sensitivity to capsaicin in elite athletes.

METHODS

Fifty-three elite winter athletes and 33 sedentary subjects completed a respiratory questionnaire and a capsaicin provocation test during the summer, fall, and winter. Allergy skin prick tests, spirometry, eucapnic voluntary hyperpnea test (EVH), methacholine inhalation test (MIT), and induced sputum analysis were also performed.

RESULTS

In athletes, the prevalence of cough immediately after exercise was high, particularly during winter. Athletes often showed a late occurrence of cough between 2-8 h after exercise. The cough reflex sensitivity to capsaicin was unchanged through the seasons in both athletes and non-athlete subjects. No significant correlations were found in groups between cough reflex sensitivity to capsaicin and the number of years in sport training, the number of hours of training per week, EVH response (% fall in FEV1), airway responsiveness to methacholine (PC20), airway inflammation or atopy.

CONCLUSION

The prevalence of cough immediately and a few hours after exercise is high in athletes and more frequently reported during winter. However, cough does not seem to be associated with cough reflex hypersensitivity to capsaicin, bronchoconstriction, or airway inflammation in the majority of athletes.

Seasonal factors influencing exercise-induced asthma

Purpose

Exercise-induced bronchoconstriction (EIB) in patients with asthma occurs more frequently in winter than in summer. The concentration of house dust mite (HDM) allergens in beds also shows seasonal variation. This study examined the relationship between seasonal differences in the prevalence of EIB and sensitization to HDMs in patients with asthma.

Methods

The medical records of 74 young adult male patients with asthma-like symptoms who underwent bronchial challenge with methacholine, 4.5% saline and exercise, and allergen skin prick tests, were reviewed. The subjects were divided into summer (n=27), spring/fall (n=26) and winter (n=21) groups according to the season during which they underwent testing.

Results

The positive responses to exercise differed according to season (48.1% in summer, 73.1% in spring/fall, and 90.5% in winter; P<0.01). In addition, the prevalence of positive responses to HDM (70.4%, 88.5%, and 95.2%, respectively; P<0.05) and pollen skin tests (37.0%, 19.2%, and 0%, respectively; P<0.01) also showed significant seasonal differences. Severe responses to 4.5% saline showed a similar trend, although it was not statistically significant (44.4%, 50.0%, and 71.4%, respectively; P=0.07). Skin test reactivity to HDMs was significantly related to maximal fall in forced expiratory volume in one second (FEV1) following exercise (r=0.302, P<0.01) and the index of airway hyperresponsiveness (AHR) to 4.5% saline (r=-0.232, P<0.05), but not methacholine (r=-0.125, P>0.05).

Conclusions

Positive skin test reactions to HDMs and EIB occurred in winter, spring/fall, and summer in decreasing order of frequency. Seasonal variation in the prevalence of EIB may be related to seasonal variation in sensitization to HDMs, accompanied by differences in indirect, but not direct, AHR.

Airway remodeling and inflammation in competitive swimmers training in indoor chlorinated swimming pools

BACKGROUND

Airway disorders are common in regular chlorinated swimming pool attendees, particularly competitive athletes, but the impact of intense swimming training on airway function and structure remains unclear.

OBJECTIVE

This study aimed to evaluate airway inflammation and remodeling in elite swimmers.

METHODS

Twenty-three elite swimmers were tested during off-training season. All had exhaled nitric oxide measurement, methacholine test, eucapnic voluntary hyperpnea challenge, allergy skin prick tests, and bronchoscopy with bronchial biopsies. Clinical data and tissues from 10 age-matched mild-asthmatic and 10 healthy nonallergic subjects were used for comparison.

RESULTS

Swimmers had increased airway mucosa eosinophil and mast cell counts than did controls (P < .05). They had more goblet cell hyperplasia and higher mucin expression than did healthy or asthmatic subjects (P < .05). A greater submucosal type I and III collagen expression and tenascin deposition was also observed in swimmers than in controls (P < .05). Neither exhaled nitric oxide nor airway responsiveness to methacholine or eucapnic voluntary hyperpnea challenge correlated with these inflammatory and remodeling changes.

CONCLUSION

Intense, long-term swimming training in indoor chlorinated swimming pools is associated with airway changes similar to those seen in mild asthma, but with higher mucin expression. These changes were independent from airway hyperresponsiveness. The long-term physiological and clinical consequences of these changes remain to be clarified.

Extended diagnostic criteria used for indirect challenge testing in elite asthmatic swimmers

The aim of the study was to investigate the prevalence of asthma with or without exercise induced symptoms among elite and elite aspiring swimmers and to compare sport specific exercise provocation with mannitol provocation.

METHODS

101 adolescent swimmers were investigated with mannitol provocation and sport specific exercise challenge test. Mannitol positivity was defined as either direct FEV(1) PD15 (ordinary criteria) or as β(2)-reversibility ≥15% after challenge (extended criteria). A direct positive exercise test was defined as a drop in FEV(1) of 10% (ordinary criteria) or a difference in FEV of ≥15% either spontaneous, variability, or with β2-agonist, reversibility (extended criteria).

RESULTS

We found a high prevalence of mannitol and/or exercise positivity. Twenty-six swimmers were mannitol direct positive and 14 were direct exercise positive using ordinary criteria. Using extended criteria 43 were mannitol positive and 24 were exercise positive. When including reversibility and variability to define a positive test the sensitivity for current asthma with or without exercise induced symptoms increased while the specificity remained roughly unchanged. Direct positivity for mannitol and exercise poorly overlapped using ordinary criteria but improved using extended criteria.

CONCLUSION

We found a high prevalence of asthma among elite swimmers. The use of variability and reversibility (liability) as additional criteria to define a positive test provided to our mind relevant information and should be considered.

Mannitol dry powder challenge in comparison with exercise testing in children

RATIONALE

Mannitol dry powder (MDP) challenge is an indirect bronchial provocation test, which is well studied in adults but not established for children.

OBJECTIVE

We compared feasibility, validity, and clinical significance of MDP challenge with exercise testing in children in a clinical setting.

METHODS

Children aged 6-16 years, referred to two respiratory outpatient clinics for possible asthma diagnosis, underwent standardized exercise testing followed within a week by an MDP challenge (Aridol™, Pharmaxis, Australia). Agreement between the two challenge tests using Cohen's kappa and receiving operating characteristic (ROC) curves was compared.

RESULTS

One hundred eleven children performed both challenge tests. Twelve children were excluded due to exhaustion or insufficient cooperation (11 at the exercise test, 1 at the MDP challenge), leaving 99 children (mean ± SD age 11.5 ± 2.7 years) for analysis. MDP tests were well accepted, with minor side effects and a shorter duration than exercise tests. The MDP challenge was positive in 29 children (29%), the exercise test in 21 (21%). Both tests were concordant in 83 children (84%), with moderate agreement (κ = 0.58, 95% CI 0.39-0.76). Positive and negative predictive values of the MDP challenge for exercise-induced bronchoconstriction were 68% and 89%. The overall ability of MDP challenge to separate children with or without positive exercise tests was good (area under the ROC curve 0.83).

CONCLUSIONS

MDP challenge test is feasible in children and is a suitable alternative for bronchial challenge testing in childhood.

Asthma in elite athletes: pathogenesis, diagnosis, differential diagnoses, and treatment

Elite athletes have a high prevalence of asthma and exercise-induced bronchoconstriction. Although respiratory symptoms can be suggestive of asthma, the diagnosis of asthma in elite athletes cannot be based solely on the presence or absence of symptoms; diagnosis should be based on objective measurements, such as the eucapnic voluntary hyperpnea test or exercise test. When considering that not all respiratory symptoms are due to asthma, other diagnoses should be considered. Certain regulations apply to elite athletes who require asthma medication for asthma. Knowledge of these regulations is essential when treating elite athletes. This article is aimed at physicians who diagnose and treat athletes with respiratory symptoms. It focuses on the pathogenesis of asthma and exercise-induced bronchoconstriction in elite athletes and how the diagnosis can be made. Furthermore, treatment of elite athletes with asthma, anti-doping regulations, and differential diagnoses such as exercise-induced laryngomalacia are discussed.

Sputum zinc concentration and clinical outcome in older asthmatics

BACKGROUND AND OBJECTIVE

Mouse models of asthma show that zinc deficiency is associated with airway inflammation (AI), which is attenuated by zinc supplements. Whether zinc has a similar role in the human airway remains controversial, with studies demonstrating both high and low plasma zinc concentrations [Zn] in asthmatic patients compared with control subjects. This variability may reflect the inability of plasma measurements to accurately assess airway zinc levels. Examination of induced sputum is an established technique for measuring AI and mediators of inflammation. Recent advances allow measurement of the rapidly exchangeable (labile) and total zinc pools in sputum. The aims of this study were to measure labile and total [Zn] in sputum and plasma of subjects with or without asthma, and second to correlate [Zn] with symptoms, asthma severity, lung function (FEV(1)) and airway hyper-responsiveness.

METHODS

A total of 163 subjects (114 with asthma) completed a single visit for sputum induction and a blood test. Labile and total [Zn] were measured by Zinquin fluorescence and atomic absorption spectrophotometry.

RESULTS

The mean (SD) age of subjects with and without asthma was 55 (14) and 57 (14) years, respectively. Baseline FEV(1) was significantly lower in subjects with asthma (94.2 (16)%) than in those without asthma (103 (16.6)%). Sputum total and labile [Zn] were lower in subjects with asthma compared with control subjects, with median (interquartile range) values of 31.8 (117) versus 50 (188.5), P = 0.02 and 0 (48) versus 26 (84.5) µg/L, P = 0.05, respectively. Increased frequency of wheeze, as well as asthma severity and reduced FEV(1), was associated with significantly lower labile sputum [Zn].

CONCLUSIONS

These findings suggest that sputum [Zn] reflect clinical outcomes and underlying AI, suggesting a potential role for zinc as a biomarker in asthma.

Comparison of central and peripheral airway involvement before and during methacholine, mannitol and eucapnic hyperventilation challenges in mild asthmatics

INTRODUCTION

Testing for airway hyperresponsiveness with indirect stimuli as exercise or mannitol has been proposed to better reflect underlying airway inflammation, as compared with methacholine (MCh), believed to act directly on airway smooth muscle cells.

OBJECTIVE

To investigate whether different direct and indirect stimuli induces different patterns of obstruction, recorded as central and peripheral resistance, and to see whether baseline resistance could predict a positive response to direct or indirect provocation.

METHODS

Thirty-four mild asthmatics and 15 controls underwent MCh, mannitol and eucapnic voluntary hyperventilation (EVH) challenge tests. The response was evaluated with spirometry and impulse oscillometry (IOS).

RESULTS

Twenty-three out of 34 asthmatics were positive to either EVH (22) or mannitol (13). Those positive to mannitol had a significant increased baseline value of IOS parameters such as ΔR5-R20 and AX. Twelve of the asthmatics had a 10% fall or more in forced expiratory volume in 1 s (FEV(1)) in all three challenge tests. However, the response pattern measured by IOS did not differ between the tests. When the limit for a positive mannitol provocation was set to 10% fall in FEV(1), 16 out of 19 mannitol-positive patients were also positive to EVH.

CONCLUSION

Even in mild asthmatics, a substantial number had a positive indirect test. Mannitol FEV(1) provocative dose to decrease FEV(1) by 10% from baseline (PD10) was closely associated to EVH10%. No difference in bronchoconstrictive pattern could be seen between the different provocation tests, but those positive to mannitol had more peripheral airway involvement at baseline. This supports the idea that peripheral airway involvement is an important predictor of asthma airway reactivity.

The environment, the airway, and the athlete

OBJECTIVE

To review the interaction of environmental factors with host conditions, including atopy, the potential resulting impaired upper and lower airway function, and diagnostic and therapeutic considerations in the athlete.

DATA SOURCES

OVID, MEDLINE, and PubMed searches were performed cross-referencing the keywords asthma, athlete, atopy, bronchospasm, exercise, pollution, and rhinitis.

STUDY SELECTION

Articles were selected based on relevance to the subject matter.

RESULTS

Recent studies have yielded significant advances in our understanding of how intrinsic and extrinsic factors can potentially result in impaired function of the airways of athletes. Extrinsic factors include environmental exposure to temperature, humidity, aeroallergens, irritants, and pollution. Intrinsic factors include atopy, allergic rhinitis, asthma, and anatomical variants. These intrinsic and extrinsic factors can affect both the athlete's quality of life and athletic performance. However, uncertainty remains regarding relative contributions of these factors in explaining the high degree of bronchospasm seen in various populations of athletes with and without asthma, and no consensus exists regarding the most appropriate diagnostic and therapeutic modalities.

CONCLUSIONS

Great variability exists in the presentation, laboratory findings, diagnostic maneuvers, and response to therapeutic measures among populations of athletes in different sports and among individuals. An improved understanding of the unique exposures faced by athletes in different disciplines, of the available tests for pursuing the appropriate diagnosis, and of the available therapies will allow the allergist to provide clinical improvement and allow the athlete to find relief and achieve his/her full potential.

Bronchial provocation tests in clinical practice

Bronchial hyperresponsiveness, which consists of an exaggerated response of the airways to bronchoconstrictor stimuli, is one of the main characteristics of asthma, presented in nearly all asthmatic patients. Bronchial hyperresponsiveness may also be present in other diseases, such as allergic rhinitis, chronic obstructive pulmonary disease, cystic fibrosis, heart failure and respiratory infection, and with some medications, such as β-blockers. Bronchial provocation tests (also known as bronchial challenges) are used to evaluate bronchial responsiveness. These tests have become increasingly used over the last 20 years, with the development and validation of accurate, safe and reproducible tests, and with the publication of well-detailed protocols. Several stimuli can be used in a bronchial challenge, and they are classified as direct and indirect stimuli. There are many indications for a bronchial challenge. In this review, we discuss the main differences between direct and indirect stimuli, and the use of bronchial challenges in clinical practice, especially for confirming diagnoses of asthma, exercise-induced bronchoconstriction and cough-variant asthma, and for use among elite-level athletes.

Airway response to exercise by forced oscillations in asthmatic children

Forced expiratory volume in 1 s (FEV1) detection of exercise-induced bronchoconstriction (EIB) to identify asthma has good specificity but rather low sensitivity. The aim was to test whether sensitivity may be improved by measuring respiratory resistance (Rrs) by the forced oscillation technique (FOT). Forty-seven asthmatic and 50 control children (5-12 y) were studied before and after running 6 min on a treadmill. Rrs in inspiration (Rrsi) and expiration (Rrse), FEV1 and Rrsi response to a deep inhalation (DI) were measured before and after exercise. In asthmatics versus controls, exercise induced significantly larger increases in Rrsi (p < 0.001) and larger decreases in FEV1 (p = 0.004). Asthmatics but not controls showed more bronchodilation by DI after exercise (p = 0.02). At specificity >0.90, sensitivity was 0.53 with 25% increase Rrsi and 0.45 with 27% increase Rrse or 5% decrease FEV1. It is concluded that the FOT improves sensitivity of exercise challenge, and the Rrsi response to DI may prove useful in identifying the mechanism of airway obstruction.

The inflammatory basis of exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) is common in individuals with asthma, and may be observed even in the absence of a clinical diagnosis of asthma. Exercise-induced bronchoconstriction can be diagnosed via standardized exercise protocols, and anti-inflammatory therapy with inhaled corticosteroids (ICS) is often warranted. Exercise-related symptoms are commonly reported in primary care; however, access to standardized exercise protocols to assess EIB are often restricted because of the need for specialized equipment, as well as time constraints. Symptoms and lung function remain the most accessible indicators of EIB, yet these are poor predictors of its presence and severity. Evidence suggests that exercise causes the airways to narrow as a result of the osmotic and thermal consequences of respiratory water loss. The increase in airway osmolarity leads to the release of bronchoconstricting mediators (eg, histamine, prostaglandins, leukotrienes) from inflammatory cells (eg, mast cells and eosinophils). The objective assessment of EIB suggests the presence of airway inflammation, which is sensitive to ICS in association with a responsive airway smooth muscle. Surrogate tests for EIB, such as eucapnic voluntary hyperpnea or the osmotic challenge tests, cause airway narrowing via a similar mechanism, and a response indicates likely benefit from ICS therapy. The complete inhibition of EIB with ICS therapy in individuals with asthma may be a useful marker of control of airway pathology. Furthermore, inhibition of EIB provides additional, useful information regarding the identification of clinical control based on symptoms and lung function. This article explores the inflammatory basis of EIB in asthma as well as the effect of ICS on the pathophysiology of EIB.

Indirect challenge tests: Airway hyperresponsiveness in asthma: its measurement and clinical significance

Indirect challenges cause the release of endogenous mediators that cause the airway smooth muscle to contract and the airways to narrow. Airway sensitivity to indirect challenges is reduced or even totally inhibited by treatment with inhaled corticosteroids (ICS), so a positive response to an indirect stimulus is believed to reflect active airway inflammation. The indirect challenges commonly used in pulmonary function laboratories include exercise, eucapnic voluntary hyperpnea, hypertonic (4.5%) saline, and mannitol. Exercise was the first test to be standardized and was used to identify exercise-induced bronchoconstriction (EIB). The inhibition of EIB in young children by sodium cromoglycate led to the concept that mast cells were important very early in the onset of asthma. All of these indirect challenges are associated with the release of mast cell mediators (eg, prostaglandins, leukotrienes, and histamine). The hypertonic saline and mannitol challenges arose from the concept that EIB was caused by an increased osmolarity of the airway surface with release of mediators. These osmotic aerosols simplified testing with indirect challenges in the laboratory, improving the potential to identify currently active asthma. Although hyperresponsiveness to indirect challenges is frequently associated with a sputum eosinophilia, it is not a prerequisite because the mast cell is the most important source of mediators. The mechanism for ICS reducing hyperresponsiveness to indirect challenges likely involves both mast cells and eosinophils. Indirect challenges are appropriate to inform further on both the pathogenesis of asthma and the role of antiinflammatory agents in its treatment.

Bronchial hyperresponsiveness in the assessment of asthma control: Airway hyperresponsiveness in asthma: its measurement and clinical significance

The two key pathophysiologic features of asthma are bronchial hyperresponsiveness (BHR) and airway inflammation. Symptoms and lung function are the most accessible clinical markers for the diagnosis of asthma as well as for assessing asthma control using the most effective treatment of asthma, inhaled corticosteroids (ICS). However, BHR and inflammation usually take longer to resolve using ICS compared with symptoms and lung function. BHR can be assessed using "direct" stimuli that act on the airway smooth muscle (eg, methacholine) or "indirect" stimuli that require the presence of airway inflammation (eg, exercise, osmotic stimuli). Although there are practical limitations in using BHR to assess asthma control, efforts have been made to make BHR more accessible and standardized. Some studies have demonstrated that treatment aimed to decrease BHR with direct stimuli can lead to improved asthma control; however, it often results in the use of higher doses of ICS. Furthermore, BHR to direct stimuli does not usually resolve using ICS because of a fixed component. By contrast, BHR with an indirect stimulus indicates a responsive smooth muscle that occurs only in the presence of inflammation sensitive to ICS (eg, mast cells, eosinophils). BHR to indirect stimuli does resolve using ICS. Because ICS target both key pathophysiologic features of asthma, assessing indirect BHR in the presence of ICS will identify resolution or persistence of BHR and airway inflammation. This may provide a more clinically relevant marker for asthma control that may also lead to improving the clinical usefulness of ICS.

[Exercise-induced bronchoconstriction in non-asthmatic athletes]

INTRODUCTION

A new clinical entity, exercise-induced bronchoconstriction (EIB), has been recently defined which describes bronchoconstriction occurring in association with exercise in susceptible non-asthmatic persons.

STATE OF ART

There is considerable evidence that the pathogenesis of this condition is related to airway injury, due to prolonged hyperventilation and aggressive environmental factors. If the objective diagnostic tests are identical for the diagnosis of exercise induced asthma and EIB, the diagnoses are established differently, according to the high sensitivity of provocation by exercise "in the field" or the eucapnic voluntary hyperventilation provocation test.

PERSPECTIVES

Current pharmacological treatment is based upon the inhalation of ß2-agonists prior to exercise, but to be granted permission to use them, athletes are required to provide documentation of objective evidence of EIB. Therefore, the diagnostic pathway in athletes is essential and respiratory physicians need to know the specific features of this new clinical entity.

CONCLUSIONS

EIB distinct from the presence of asthma is prevalent in elite athletes and its determinants should be well known by their health care providers to assure an optimal management of this peculiar disease, in respect to drug doping regulations.

Exercise but not mannitol provocation increases urinary Clara cell protein (CC16) in elite swimmers

Elite swimmers have an increased risk of developing asthma, and exposure to chloramine is believed to be an important trigger factor. The aim of the present study was to explore pathophysiological mechanisms behind induced bronchoconstriction in swimmers exposed to chloramine, before and after swim exercise provocation as well as mannitol provocation. Urinary Clara cell protein (CC16) was used as a possible marker for epithelial stress. 101 elite aspiring swim athletes were investigated and urinary samples were collected before and 1 h after completed exercise and mannitol challenge. CC16, 11β-prostaglandin (PG)F(2α) and leukotriene E(4) (LTE(4)) were measured. Urinary levels of CC16 were clearly increased after exercise challenge, while no reaction was seen after mannitol challenge. Similar to CC16, the level of 11β-PGF(2α) was increased after exercise challenge, but not after mannitol challenge, while LTE(4) was reduced after exercise. There was no significant difference in urinary response between those with a negative compared to positive challenge, but a tendency of increased baseline levels of 11β-PGF(2α) and LTE(4) in individuals with a positive mannitol challenge. The uniform increase of CC16 after swim exercise indicates that CC16 is of importance in epithelial stress, and may as such be an important pathogenic factor behind asthma development in swimmers. The changes seen in urinary levels of 11β-PGF(2α) and LTE(4) indicate a pathophysiological role in both mannitol and exercise challenge.

Monitoring asthma therapy using indirect bronchial provocation tests

OBJECTIVES

Bronchial provocation tests that assess airway hyperresponsiveness (AHR) are known to be useful in assisting the diagnosis of asthma and in monitoring inhaled corticosteroid therapy. We reviewed the use of bronchial provocation tests that use stimuli that act indirectly for monitoring the benefits of inhaled corticosteroids.

DATA SOURCE

Published clinical trials investigating the effect of inhaled corticosteroids on bronchial hyperresponsiveness in persons with asthma were used for this review.

STUDY SELECTION

Studies using indirect stimuli to provoke airway narrowing such as exercise, eucapnic voluntary hyperventilation, cold air hyperventilation, hypertonic saline, mannitol, or adenosine monophosphate (AMP) to assess the effect of inhaled corticosteroids were selected.

RESULTS

Stimuli acting indirectly result in the release of a variety of bronchoconstricting mediators such as leukotrienes, prostaglandins, and histamine, from cells such as mast cells and eosinophils. A positive response to indirect stimuli is suggestive of active inflammation and AHR that is consistent with a diagnosis of asthma. Persons with a positive response to indirect stimuli benefit from daily treatment with inhaled corticosteroids. Symptoms and lung function are not useful to predict the long-term success of inhaled corticosteroid dose as they usually resolve rapidly, and well before inflammation and AHR has resolved. Following treatment, AHR to indirect stimuli is attenuated. Further, during long-term treatment, asthmatics can become as non-responsive as non-asthmatic healthy persons, suggesting that asthma is not active.

CONCLUSIONS

Non-responsiveness to indirect bronchial provocation tests following inhaled corticosteroids occurs weeks to months following the resolution of symptoms and lung function. Non-responsiveness to indirect stimuli may provide a goal for adequate therapy with inhaled corticosteroids.

Current and future use of the mannitol bronchial challenge in everyday clinical practice

OBJECTIVES

Asthma is a disease associated with inflammation, airway hyperresponsiveness (AHR) and airflow limitation. Clinical diagnosis and management of asthma often relies on assessment of lung function and symptom control, but these factors do not always correlate well with underlying inflammation. Bronchial challenge tests (BCTs) assess AHR, and can be used to assist in the diagnosis and management of asthma.

DATA SOURCE

Data presented at the symposium 'Use of inhaled mannitol for assessing airways disease' organised by the Allied Respiratory Professionals Assembly (9) of the European Respiratory Society (ERS) at the ERS Congress, Berlin 2008.

RESULTS

Indirect challenge tests such as exercise testing, hypertonic saline or adenosine 5'-monophosphate (AMP) are more specific though less sensitive than direct challenge tests (such as methacholine) for identifying patients with active asthma. Indirect BCTs may be used to diagnose exercise-induced bronchoconstriction or AHR consistent with active asthma, to evaluate AHR that will respond to treatment with anti-inflammatory drugs and to determine the effectiveness and optimal dosing of such therapy. An ideal indirect challenge test should be standardised and reproducible, and the test result should correlate with the degree of airway inflammation. The mannitol BCT provides a standardised and rapid point-of-need test to identify currently active asthma, and is clinically useful in the identification of patients with asthma who are likely to benefit from inhaled corticosteroid therapy.

CONCLUSION

In the future, mannitol BCT may be added to lung function and symptom assessment to aid in the everyday management of asthma.

Challenges in the management of exercise-induced asthma

Exercise and physical activity are common triggers of symptoms in patients with asthma, although some individuals - especially athletes - may have symptoms with exercise alone. Exercise-induced bronchospasm (EIB) describes airway hyper-reactivity that is observed following exercise in a patient who is not otherwise diagnosed with asthma; exercise-induced asthma (EIA) describes airway hyper-reactivity associated with exercise in a patient who has persistent asthma. Specific challenges affecting both the diagnosis and treatment of these conditions are discussed in this review. The past decade has seen substantial advances in our understanding of EIA and EIB, including new guidelines on their management. With appropriate therapy, all patients with exercise-related symptoms should be able to reach their desired level of performance.

Bronchial challenges and respiratory symptoms in elite swimmers and winter sport athletes: Airway hyperresponsiveness in asthma: its measurement and clinical significance

This study was aimed at the following: (1) the prevalence of airway hyperresponsiveness (AHR) and exercise-induced bronchoconstriction (EIB) in swimmers and winter sport athletes according to the previously recommended regulatory sport agencies criteria, (2) the relationship between respiratory symptoms and AHR/EIB, (3) the impact of the chosen cutoff value for AHR on its prevalence, and (4) the effect on the prevalence of the positive eucapnic voluntary hyperpnea (EVH) test of using the highest vs the lowest spirometric post-EVH values to calculate the magnitude of the airway response. We compared the prevalence of respiratory symptoms with responses to methacholine challenge and EVH in 45 swimmers, 45 winter sport athletes, and 30 controls. Two methacholine challenge cutoffs for AHR were analyzed: <or= 4 mg/mL (the sport agencies' criteria for AHR) and <or= 16 mg/mL. Sixty percent of swimmers, 29% of winter sport athletes, and 17% of controls had evidence of EIB or AHR (with the <or= 4 mg/mL criteria). Among athletes with a methacholine provocative concentration inducing a 20% decrease in the FEV(1) between 4 and 16 mg/mL, 43% of swimmers and 100% of winter sport athletes were symptomatic (P < .05). Prevalence of positive EVH tests were 39% in swimmers, 24% in winter sport athletes, and 13% in controls when the highest FEV(1) value measured at each time point post-EVH was used to identify maximal response for calculation of airway response, although these prevalences were higher if we used the lowest value. This study suggests that AHR/EIB is frequent in swimmers, whereas the frequently reported respiratory symptoms in winter sport athletes are often not related to AHR/EIB. Furthermore, the choice of methods for assessing methacholine challenge and EVH responses influences the prevalences of AHR and EIB.

TRIAL REGISTRATION

clinicaltrials.gov; Identifier NCT 00686491 and NCT 00686452.

Exercise-induced wheeze: Fraction of exhaled nitric oxide-directed management

BACKGROUND AND OBJECTIVE

Exercise-induced wheeze (EIW) is common. Several treatment options exist. Patients with low fraction of exhaled nitric oxide (F(E)NO) are unlikely to be steroid-responsive and might benefit from non-steroidal therapies. We assessed: the efficacy of cromoglycate, formoterol and montelukast in patients with EIW and low F(E)NO (<35 ppb) in a randomized cross-over trial, and the efficacy of inhaled corticosteroid in a high F(E)NO (>35 ppb) group.

METHODS

Patients had EIW and airway hyperresponsiveness (AHR) to mannitol and/or exercise. Those with low F(E)NO (n = 19) received cromoglycate (20 mg inh. bd + before challenge tests), formoterol (12 microg inh. bd + before challenge tests) and montelukast (10 mg p.o. od), each for 2 weeks. Those with high F(E)NO (n = 20) took inhaled fluticasone (500 microg) daily for 4 weeks. Primary end-points were: 50% reduction in maximum FEV(1) %fall (clinical protection) and decrease in AHR to mannitol.

RESULTS

In patients with low F(E)NO, cromoglycate, formoterol and montelukast significantly decreased AHR to mannitol in 63%, 61% and 47% of patients, respectively. In this group, the magnitude of exercise-induced bronchoconstriction (EIB) was significantly reduced with montelukast and formoterol; between-treatment differences were not significant. Of 6/19 with low F(E)NO and EIB, protection occurred in 67% (cromoglycate), 83% (formoterol) and 50% (montelukast), respectively. In the high F(E)NO group, AHR to mannitol and EIB decreased significantly with fluticasone (P < 0.001, P = 0.005, respectively), and protection occurred in 7/8 (88%) with EIB.

CONCLUSIONS

In patients with EIW and low F(E)NO, the number of 'responders' to cromoglycate, formoterol and montelukast was similar. In a high F(E)NO population the response to inhaled corticosteroid was highly significant and comparable to previous studies.

Exhaled nitric oxide in the diagnosis and management of childhood asthma

The management of asthma in children and adolescents is currently guided by assessment of clinical symptoms, exacerbation risk and spirometric measure of lung function. The use of biomarkers, an objective measure which indicates normal or pathophysiologic processes and/or the response to a treatment intervention, could greatly enhance the efficacy and safety of current algorithms. Measurement of the fraction of expired nitric oxide in exhaled air (FeNO) has been suggested as a readily determined biomarker that can aid in the diagnosis and management of asthma. FeNO has been used to identify steroid responsive patients, adjust the dose of controller medications, most notably inhaled corticosteroids, and predict relapse during medication taper. In spite of early enthusiasm for the utility of this measure, more recent data suggest a more limited role for FeNO. This review will focus on the use of FeNO in the diagnosis and management of asthma in children and adolescents.

Use of mannitol inhalation challenge in assessment of cough

Bronchial provocation testing uses a variety of direct and indirect inhalational challenges to evaluate airway hyperreactivity. Mannitol, a simple, easy-to-administer hypertonic stimulus available in many countries, is currently under review by the FDA in the US. Healthy subjects show no airway response to inhaled mannitol; asthmatic patients respond with airway narrowing similar to challenges with hypertonic saline and exercise. Mannitol challenge also has a tussive effect that is independent of bronchoconstriction, suggesting different physiologic pathways. Patients with chronic cough show increased sensitivity to mannitol, and mannitol testing may be useful for evaluating heterogeneity in the cough response.

Provoked models of asthma: what have we learnt?

Asthma is a chronic inflammatory disease of the airways characterized by physiological abnormalities of variable airflow obstruction and airway hyperresponsiveness (AHR) to a wide variety of physical and inhaled chemical stimuli and the presence of symptoms. AHR is measured by challenging the airways with a variety of agonists and naturally occurring stimuli, which results in constriction of the airway smooth muscle, leading to airway narrowing and airflow limitation. There are two distinct mechanisms by which the airways can narrow to a constrictor stimulus and these are defined by the pathways they take to induce AHR. Direct stimuli are pharmacological agents administered exogenously (such as histamine or methacholine) that act 'directly' on specific receptors on the bronchial smooth muscle to cause constriction. The other mechanism by which the airway can narrow is via the inhalation of indirect stimuli, which include natural stimuli, such as allergen or exercise, and pharmacological agents such as adenosine monophosphate and hyper-osmotic agents (e.g. hypertonic saline or dry powder mannitol). These stimuli induce airway narrowing 'indirectly' by causing the endogenous release of mediators of bronchoconstriction from airway inflammatory cells. Provoked models of asthma have been extremely valuable in understanding the pathobiology of asthma, in aiding diagnosis, in helping to clarify the mechanisms of actions of effective drugs and in the development of new entities to treat asthma. Some provoked models are valuable clinically, particularly those that measure direct AHR, while others, particularly allergen challenge, have been used in animal models and in humans to study the mechanisms of allergen-induced airway inflammation and the associated physiological changes, as well in the development of new drugs for asthma. An emerging role for measurements of AHR is in the evaluation of the optimal treatment for patients with asthma.

Exercise-induced bronchospasm among athletes in Lower Silesia Province

A few studies have reported data on the prevalence of exercise-induced bronchospasm in high school and university athletes. Recently published data suggest that exercise-induced bronchospasm may affect up to 39% of American university athletes. To date, no data describing this pathology in athletes from Central Europe have been published. The aim of the present study was to establish the prevalence of exercise-induced bronchospasm in pupils attending sports mastership classes in secondary school as well as students of the University of Physical Education in Wroclaw. The participants were 77 athletes (30 women and 47 men) aged 16-27 years (mean 17.3 years). Only one athlete (1.29%) diagnosed with atopic asthma before testing experienced a fall in forced expiratory volume in one second (12.9% FEV(1)) compared with baseline, which showed that the exercise test result was positive. From a clinical point of view, the ventilation disturbance was asymptomatic. In the other participants, there were slight but statistically significant rises in FEV(1) (P < 0.02). The results of our study indicate a very low prevalence of exercise-induced bronchospasm in the population of athletes examined.

Comparison of mannitol and methacholine to predict exercise-induced bronchoconstriction and a clinical diagnosis of asthma

BACKGROUND

Asthma can be difficult to diagnose, but bronchial provocation with methacholine, exercise or mannitol is helpful when used to identify bronchial hyperresponsiveness (BHR), a key feature of the disease. The utility of these tests in subjects with signs and symptoms of asthma but without a clear diagnosis has not been investigated. We investigated the sensitivity and specificity of mannitol to identify exercise-induced bronchoconstriction (EIB) as a manifestation of BHR; compared this with methacholine; and compared the sensitivity and specificity of mannitol and methacholine for a clinician diagnosis of asthma.

METHODS

509 people (6-50 yr) were enrolled, 78% were atopic, median FEV1 92.5% predicted, and a low NAEPPII asthma score of 1.2. Subjects with symptoms of seasonal allergy were excluded. BHR to exercise was defined as a > or = 10% fall in FEV1 on at least one of two tests, to methacholine a PC20 < or = 16 mg/ml and to mannitol a 15% fall in FEV1 at < or = 635 mg or a 10% fall between doses. The clinician diagnosis of asthma was made on examination, history, skin tests, questionnaire and response to exercise but they were blind to the mannitol and methacholine results.

RESULTS

Mannitol and methacholine were therapeutically equivalent to identify EIB, a clinician diagnosis of asthma, and prevalence of BHR. The sensitivity/specificity of mannitol to identify EIB was 59%/65% and for methacholine it was 56%/69%. The BHR was mild. Mean EIB % fall in FEV1 in subjects positive to exercise was 19%, (SD 9.2), mannitol PD15 158 (CI:129,193) mg, and methacholine PC20 2.1(CI:1.7, 2.6) mg/ml. The prevalence of BHR was the same: for exercise (43.5%), mannitol (44.8%), and methacholine (41.6%) with a test agreement between 62 & 69%. The sensitivity and specificity for a clinician diagnosis of asthma was 56%/73% for mannitol and 51%/75% for methacholine. The sensitivity increased to 73% and 72% for mannitol and methacholine when two exercise tests were positive.

CONCLUSION

In this group with normal FEV1, mild symptoms, and mild BHR, the sensitivity and specificity for both mannitol and methacholine to identify EIB and a clinician diagnosis of asthma were equivalent, but lower than previously documented in well-defined populations.

TRIAL REGISTRATION

This was a multi-center trial comprising 25 sites across the United States of America.

Exercise-induced bronchoconstriction: The effects of montelukast, a leukotriene receptor antagonist

Exercise-induced bronchoconstriction (EIB) is very common in both patients with asthma and those who are otherwise thought to be normal. The intensity of exercise as well as the type of exercise is important in producing symptoms. This may make some types of exercise such as swimming more suitable and extended running more difficult for patients with this condition. A better understanding of EIB will allow the physician to direct the patient towards a type of exercise and medications that can result in a more active lifestyle without the same concern for resulting symptoms. This is especially important for schoolchildren who are usually enrolled in physical education classes and elite athletes who may desire to participate in competitive sports. Fortunately several medications (short- and long-acting beta(2)-agonists, cromolyn, nedocromil, inhaled corticosteroids, and more recently leukotriene modifiers) have been shown to be effective in preventing or attenuating the effects of exercise in many patients. In addition, inhaled beta(2)-agonists have been shown to quickly reverse the airway obstruction that develops in patients and continue to be the reliever medications of choice. Inhaled corticosteroids are increasingly being recommended as regular therapy now that the role of inflammation and airway injury has been identified in EIB. With the discovery that there is a release of mediators such as histamine and leukotrienes from cells in the airway following exercise with resulting airway obstruction in susceptible individuals, interest has turned to attenuating their effects with mediator antagonists especially those that block the effects of leukotrienes. Studies with an oral leukotriene antagonist, montelukast, have shown beneficial effects in adults and children aged as young as 6 years with EIB. These effects can be demonstrated as soon as two hours and as long as 24 hours after administration without a demonstrated loss of a protective effect after months of treatment. The studies leading up to and resulting in an approval of montelukast for EIB for patients aged 15 years and older are reviewed in this paper.

Protective effect of bronchial challenge with hypertonic saline on nocturnal asthma

Inhalation of hypertonic saline (HS) causes bronchoconstriction in asthmatic subjects. Repeated inhalation of HS leads to substantially reduced bronchoconstriction, known as the refractory period. Refractoriness due to different stimuli has also been described (cross-refractoriness). Nocturnal asthma is defined as an increase in symptoms, need for medication, airway responsiveness, and/or worsening of lung function that usually occurs from 4 to 6 am. Our objective was to determine the effect of refractoriness on nocturnal asthma. The challenge test consisted of inhalations of 4.5% saline with increasing durations until a reduction of 20% in forced expiratory volume in 1 s (FEV1) (PD20HS) or total time of 15.5 min. Twelve subjects with nocturnal asthma were challenged with HS at 16:00 and 18:00 h and FEV1 was measured at 4:00 h. One to 2 weeks later, FEV1 was determined at 16:00 and 4:00 h. LogPD20HS at 18:00 h was significantly greater than logPD20HS at 16:00 h, 0.51 +/- 0.50 and 0.69 +/- 0.60 mg, respectively (P = 0.0033). When subjects underwent two HS challenges in the afternoon, mean (+/- SD) FEV1 reduction was 206 +/- 414 mL or 9.81 +/- 17.42%. On the control day (without challenge in the afternoon) FEV1 reduction was 523 +/- 308 mL or 22.75 +/- 15.40% (P = 0.021). Baseline FEV1 values did not differ significantly between the control and study days, 2.48 +/- 0.62 and 2.36 +/- 0.46 L, respectively. The refractory period following HS challenges reduces the nocturnal worsening of asthma. This new concept may provide beneficial applications to asthmatic patients.

Exercise and other indirect challenges to demonstrate asthma or exercise-induced bronchoconstriction in athletes

The prevalence of exercise-induced bronchoconstriction is reported to be high among recreational and elite athletes, yet diagnosis is often symptom-based. Indirect challenges such as the laboratory exercise challenge provide objective criteria for proper diagnosis and treatment. However, a standardized protocol using appropriate exercise intensity, duration, and dry air inhalation is often not implemented, and thus a false-negative test may result. This article reviews and describes the symptom-based diagnosis, the exercise challenge, and other indirect challenges such as eucapnic voluntary hyperpnea, hypertonic saline inhalation, and inhaled powdered mannitol as methods to diagnose and evaluate exercise-induced bronchoconstriction. Advantages and disadvantages of each diagnostic procedure are presented.

Exercise-induced hypersensitivity syndromes in recreational and competitive athletes: a PRACTALL consensus report (what the general practitioner should know about sports and allergy)

Exercise-induced (EI) hypersensitivity disorders are significant problems for both recreational and competitive athletes. These include EI-asthma, EI-bronchoconstriction, EI-rhinitis, EI-anaphylaxis and EI-urticaria. A group of experts from the European Academy of Allergology and Clinical Immunology and the American Academy of Allergy Asthma and Immunology met to discuss the pathogenesis of these disorders and how to diagnose and treat them, and then to develop a consensus report. Key words (exercise with asthma, bronchoconstriction, rhinitis, urticaria or anaphylaxis) were used to search Medline, the Cochrane database and related websites through February 2008 to obtain pertinent information which, along with personal reference databases and institutional experience with these disorders, were used to develop this report. The goal is to provide physicians with guidance in the diagnosis, understanding and management of EI-hypersensitivity disorders to enable their patients to safely return to exercise-related activities.

Inflammatory and functional effects of increasing asthma treatment with formoterol or double dose budesonide

Adding a long-acting beta(2)-agonist to inhaled corticosteroids (ICS) for asthma treatment is better than increasing ICS dose in improving clinical status, although there is no consensus about the impact of this regimen on inflammation. In this double-blind, randomized, parallel group study, asthmatics with moderate to severe disease used budesonide (400 mcg/day) for 5 weeks (run-in period); then they were randomized to use budesonide (800 mcg/day--BUD group) or budesonide plus formoterol (400 mcg and 24 mcg/day, respectively--FORMO group) for 9 weeks (treatment period). Home PEF measurements, symptom daily reporting, spirometry, sputum induction (for differential cell counts and sputum cell cultures), and hypertonic saline bronchial challenge test were performed before and after treatments. TNF-alpha, IL-4 and eotaxin-2 levels in the sputum and cell culture supernatants were determined. Morning and night PEF values increased in the FORMO group during the treatment period (p<0.01), from 435+/-162 to 489+/-169 and 428+/-160 to 496+/-173 L/min, respectively. The rate of exacerbations in the FORMO group was lower than in the BUD group (p<0.05). Neutrophil counts in sputum increased in both groups (p<0.05) and leukocyte viability after 48 h-culture increased in the FORMO group (p<0.05). No other parameter changed significantly in either group. This study showed that adding formoterol to budesonide improved home PEF and provided protection from exacerbations, although increase of leukocyte viability in cell culture may be a matter of concern and needs further investigation.

Post-exercise airway narrowing in healthy primary school children

Changes in lung function after exercise in healthy primary school children have mostly been described in field studies. More complete description and insight into relevant mechanisms may be provided in lung function laboratory. The aim was to describe airway caliber and response to deep inhalation (DI) after exercise in healthy primary school children. Respiratory resistance (Rrs) by the forced oscillation technique and spirometry were measured before and after exercise in 50 healthy primary school children. The Rrs response to DI was assessed in 31 subjects, assuming a significantly larger decrease in Rrs after exercise would attest relief of exercise-induced airway smooth muscle contraction. Measurements were taken before, 5 min (E5) and 15 min (E15) after exercise. Significantly larger Rrs and lower forced expiratory volume in 0.5 s were observed at E5 versus baseline or E15 (p < 0.05). DI induced significant decrease in Rrs (p = 0.01) that was not different between E5 and baseline. Healthy primary school children exhibit changes in Rrs and spirometry after exercise indicating small but significant airway narrowing. The response to DI similar at baseline and E5 suggests airway narrowing from hyperemia in the bronchial wall rather than airway smooth muscle constriction.

Relationship between airway responsiveness to mannitol and to methacholine and markers of airway inflammation, peak flow variability and quality of life in asthma patients

BACKGROUND

Airway hyperresponsiveness (AHR) to stimuli that cause bronchial smooth muscle (BSM) contraction indirectly through the release of endogenous mediators is thought to reflect airway inflammation more closely compared with AHR measured by stimuli that act directly on BSM.

METHODS

Fifty-three adult non-smoking asthmatics (28 females, 18-56 years) who were not taking inhaled steroids were challenged with mannitol (up to 635 mg) and methacholine (up to 8 mumol). Induced sputum eosinophils, exhaled nitric oxide (eNO), peak flow variation and clinical severity of asthma according to the Global Initiative for Asthma guidelines were measured in addition to the health-related quality-of-life score using the Juniper asthma quality-of-life questionnaire.

FINDINGS

Both AHR to mannitol as well as to methacholine was associated with elevated markers of airway inflammation: in 83% of asthma patients with AHR to mannitol, and in 88% of asthma patients with AHR to methacholine, the eNO level was >20 p.p.b. Sputum% eosinophils >1% was measured in 70% of asthma patients with AHR to mannitol and in 77% of asthma patients with AHR to methacholine. In asthma patients without AHR, 15% had an eNO level >20 p.p.b., but none had sputum% eosinophils >1%. AHR to mannitol was more closely associated with the percentage of sputum eosinophils (PD(15) to mannitol vs. sputum% eosinophils: r: -0.52, P<0.05), compared with AHR to methacholine (PD(20) to methacholine vs. sputum% eosinophils: r: -0.28, NS). Furthermore, there was a stronger correlation between AHR to mannitol and the level of eNO [PD(15) to mannitol vs. eNO (p.p.b.): r: -0.63, P<0.001], compared with AHR to methacholine [PD(20) to methacholine vs. eNO (p.p.b.): r: -0.43, P<0.05].

INTERPRETATION

In asthma patients not being treated with steroids, AHR to mannitol and to methacholine indicated the presence of airway inflammation. AHR to mannitol reflected the degree of airway inflammation more closely when compared with methacholine.

Comparison of 4 AM and 4 PM bronchial responsiveness to hypertonic saline in asthma

Bronchial responsiveness to methacholine or histamine increases at night and may contribute to the mechanisms of nocturnal asthma. Hypertonic saline (HS) is a more clinically relevant stimulus for the diagnosis and assessment of the severity of asthma, but the circadian variation in bronchial responsiveness to hypertonic challenges has not been addressed. The aim of this study was to compare the responsiveness to hypertonic saline at 4:00 AM and at 4:00 PM. Eighteen diurnally active patients (11 women) with asthma, 31 +/- 9 years of age (mean +/- SD) and with a forced expiratory volume in 1 s (FEV(1)) of 79.11% +/- 12.85%, underwent two challenge tests (4:00 AM and 4:00 PM) in random sequence separated by an interval of 7 days. The challenge test consisted of inhalations of 4.5% saline with increasing doses by doubling the duration of nebulization (0.5, 1, 2, 4, and 8 min). The inhalation continued until a drop of 20% in FEV(1) was achieved or total time of 15.5 min. The provocative dose that caused the 20% drop in FEV(1) (PD(20)) was calculated. Differences were found between 4:00 PM and 4:00 AM values for inhalation times [3.80 +/- 3.57 min and 2.19 +/- 2.42 min (p = 0.001), respectively] and for PD(20) [4.94 +/- 6.77 ml and 2.93 +/- 4.74 ml (p = 0.002), respectively]. Eight patients with a home-assessed nocturnal peak expiratory flow (PEF) drop of more than 15% formed the nocturnal asthma group. The behavior of these patients was similar to that of the non-nocturnal asthma group. We conclude that the bronchial responsiveness to HS increases at night.