Keeping Children With Exercise-induced Asthma Active Henry Milgrom, MD, and Lynn M. Taussig, MD ABSTRACT. Exercise-induced bronchospasm, exercise- prophylactically and do not require continuous therapy.13 induced bronchoconstriction, and exercise-induced Most asthma medications, even some unconventional asthma (EIA) are all terms used to describe the phenom- ones such as heparin, furosemide, calcium channel enon of transient airflow obstruction associated with blockers, and terfenadine, given before exercise, sup- physical exertion. It is a prominent finding in children press EIA.14,15 McFadden accounts for the efficacy of these and young adults because of their greater participation in disparate classes of drugs by their potential effect on the vigorous activities.1 The symptoms—shortness of breath, bronchial vasculature that modulates the cooling and/or cough, chest tightness, and wheezing—normally follow rewarming phases of the reaction.16 Short-acting b-ago- the brief period of bronchodilation present early in the nists provide protection in 80% to 95% of affected indi- course of exercise. Bronchospasm typically arises within viduals with insignificant side effects and have been 10 to 15 minutes of beginning exercise, peaks 8 to 15 regarded for many years as first-line therapy.17 Two long- minutes after the exertion is concluded, and resolves acting bronchodilators, salmeterol and formoterol, have 2 about 60 minutes later, but it also may appear during 18–21 3 been found effective in the prevention of EIA. A sustained exertion. EIA occurs in up to 90% of asthmat- single 50-mg dose of salmeterol protects against EIA for 9 ics and 40% of patients with allergic rhinitis; among hours; its duration appears to wane in the course of daily athletes and in the general population its prevalence is therapy.22–24 Cromolyn sodium is highly effective in 70% between 6% and 13%.4,5 to 87% of those diagnosed with EIA and has minimal EIA frequently goes undiagnosed. Approximately 9% side effects.17 Nedocromil sodium provides protection of individuals with EIA have no history of asthma or equal to that of cromolyn in children.25 allergy.1 Fifty percent of children with asthma who gave Children commonly engage in unplanned physical ac- a negative history for EIA had a positive response to exercise challenge.6 Among high school athletes, 12% of tivity and sometimes are not allowed to carry their own subjects not considered to be at risk by history or base- medication. Thus, a simple long-acting regimen given at line spirometry tested positive.5 Before the 1984 Olympic home is likely to be more effective than short-acting games, of 597 members of the US team, 67 (11%) were drugs that must be administered in a timely manner. found to have EIA. Remarkably, only 26 had been previ- Although the 12-hour protection by salmeterol reported 18 ously identified, emphasizing the importance of screen- by Bronsky et al may not persist with continued use, the 22–24 ing for EIA even in well-conditioned individuals who 9-hour duration of action is a dependable finding, appear to be in excellent health.1,7 and should be sufficient in most cases. The severity of bronchospasm in EIA is related to the Nonpharmacologic Approaches. At rest, inspired air is level of ventilation, to heat and water loss from the warmed and humidified primarily in the nose and tra- respiratory tree, and also to the rate of airway rewarming chea. As the rate of ventilation increases, the air is con- and rehydration after the challenge.8,9 Postexercise de- ditioned predominantly in the intrathoracic airways. crease in the peak expiratory flow rate of normal children Breathing through the nose rather than the mouth or may be as much as 15%; therefore, only a decrease in through a mask that reduces the loss of heat and moisture excess of 15% should be viewed as diagnostic. EIA is during physical exertion has been shown to minimize usually provoked by a workload sufficient to produce EIA.26,27 A gradual cooling off, rather than sudden cessa- 80% of maximum oxygen consumption; however, in se- tion of activity reduces the rate of rewarming of airways vere asthmatics even minimal exertion may be enough to and protects against bronchospasm.16 About 40% to 50% produce symptoms.1 Patients with normal lung function of patients with EIA experience a refractory period after at rest may have severe air flow limitation induced by an earlier exercise stimulus. This protection has a half- exercise,10 and as many as 50% of patients who are well- life of about 45 minutes and dissipates over 2 to 3 hours.28 controlled with inhaled corticosteroids still exhibit EIA.11 For this reason, a prolonged warm-up that includes brief A challenge of sufficient magnitude will provoke EIA in periods of intense activity is beneficial for many subjects all patients with asthma.12 with EIA.29 Pharmacologic Therapy. Exercise, unlike exposure to In individuals with EIA, aerobic conditioning lessens allergens, does not produce a long-term increase in air- the prospect of an asthma attack by reducing the venti- way reactivity. Accordingly, patients whose symptoms latory requirement for any activity. Although improved manifest only after strenuous activity may be treated fitness of children with asthma is highly desirable, we must emphatically discourage patients from adopting the From the Department of Pediatrics, National Jewish Medical and Research view that they can overcome their disease solely by being Center and the University of Colorado Health Sciences Center, Denver, in good physical shape. Colorado. Conclusions. EIA is a common clinical problem that Received for publication Apr 26, 1999; accepted Apr 26, 1999. is not limited to patients with asthma. It is as frequent in Reprint requests to (H.M.) Department of Pediatrics, National Jewish Med- ical and Research Center, 1400 Jackson St, Denver, CO 80206. E-mail: athletes as in the general population. With appropriate [email protected] therapy, 90% of individuals with EIA can control their PEDIATRICS (ISSN 0031 4005). Copyright © 1999 by the American Acad- symptoms and should be able to participate in any vig- emy of Pediatrics. orous activity.29 Those patients who are refractory may http://www.pediatrics.org/cgi/content/full/104/3/Downloaded from www.aappublications.org/newse38 PEDIATRICS by guest on September Vol. 104 24, No.2021 3 September 1999 1of5 not be taking their medication or may suffer from an- patients with allergic rhinitis; its prevalence in gen- other condition, most likely vocal cord dysfunction.30,31 eral population is between 6% and 13%; among ath- Exercise is a powerful trigger for asthma symptoms. letes estimates reach 12%.4,5 It is very likely that EIA For this reason, young patients may avoid vigorous ac- frequently goes undiagnosed. Approximately 9% of tivity with damaging consequences to their physical and individuals with EIA have no history of asthma or social well-being. Parents may be reluctant to allow their allergy.1 Fifty percent of children with asthma who youngsters with asthma to participate in athletics, and gave a negative history for EIA had a positive re- teachers may fear taking responsibility for a child’s se- 6 vere attack. All patients suspected of having asthma sponse to exercise challenge. When high school ath- should be questioned about how much exercise they letes were screened for EIA, 12% of subjects not perform, their exercise tolerance, and symptoms after considered to be at risk by history or baseline spi- exertion. Those with a concerning history should have an rometry tested positive.5 Before the 1984 Olympic exercise challenge. Early diagnosis coupled with practi- games, of 597 members of the US team 67 (11%) were cal, long-acting treatment regimes such as the one re- found to have EIA. Remarkably, only 26 of these ported by Bronsky et al18 should help these young people competitors who trained under close medical super- enjoy the benefits of an active lifestyle and fulfill their vision had been previously identified, emphasizing athletic potential. Pediatrics 1999;104(3). URL: http:// the importance of screening for EIA even in well- www.pediatrics.org/cgi/content/full/104/3/e38; exercise- conditioned individuals who appear to be in excel- induced asthma, exercise-induced bronchospasm, exercise- 1,7 induced bronchoconstriction. lent health. If EIA is underdiagnosed in the elite athlete then the problem must be even greater for the typical child. ABBREVIATIONS. EIA, exercise-induced asthma; FEV1, forced Although EIA can be diagnosed clinically, it is best expiratory volume in 1 second; PEFR, peak expiratory flow rate. to confirm the observation in the laboratory by a decrease in the peak expiratory flow rate (PEFR) or $ xercise-induced bronchospasm, exercise-in- FEV1 15% after exercise or hyperventilation. The duced bronchoconstriction, and exercise-in- occurrence of EIA generally requires a workload suf- Educed asthma (EIA) are all terms used to de- ficient to produce 80% of maximum oxygen con- scribe the phenomenon of transient airflow sumption; however, in severe asthmatics even mini- obstruction associated with physical exertion. EIA is mal exertion may be enough to produce symptoms.1 a problem for all age groups, but its effects are most Patients with normal lung function at rest may have prominent in children and young adults because of severe air flow limitation induced by exercise,10 and their greater participation in vigorous activities.1 In as many as 50% of patients who are well-controlled this issue