When an athlete can't catch his breath: a patient who's fine during practice but runs out of breath before the game's over may have exercise-induced bronchoconstriction. This practical guide can help.
* Don't rely on self-reported symptoms to diagnose exercise-induced bronchoconstriction (EIB) (A).
* Indirect testing is the best way to diagnose EIB in patients who do not have underlying asthma (A).
* Short-acting [beta]2-agonists should be first-line management in EIB (A).
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Luke, a 16-year-old basketball player, complains that he can't finish a game without running out of breath. He says things are at their worst when the game is close and when it's nearing the end. He doesn't have the problem during practice, or when he is playing other sports. The team physician suggested using an albuterol inhaler half an hour before game time and when he has symptoms, but he gets only minimal relief. Now he has come to you.
His vital signs, lung exam, and cardiac exam are normal. Results of pulmonary function tests with pre- and post-albuterol challenge done a year ago were also normal Does Luke have exercise-induced bronchoconstriction (EIB)? How can you be sure? And what can you do to help?
Symptoms like Luke's are common among athletes of all abilities. They may add up to EIB, a condition with an estimated prevalence of 6% to 12% in the general population--or they may not. (1) One study showed that only a third of athletes with symptoms or prior diagnosis of EIB had positive objective testing for the condition, and current studies show that reported symptoms are not an accurate guide in athletes like Luke who do not have underlying asthma. (2,3) To treat him correctly, you will need to nail down the diagnosis with additional tests. (3,4)
* Shortness of breath that's worse than expected
EIB can have many different presentations. The most common symptom is cough associated with exercise. (3) Other common signs and symptoms include wheezing, chest tightness, and more severe than expected or worsening shortness of breath. More unusual symptoms include a decrease in performance or fatigue out of proportion to workload. Often patients with EIB have other associated medical conditions, such as allergic rhinitis.
Bronchoconstriction usually occurs with maximal or near maximal exertion. Generally, it takes 5 to 8 minutes of exercising at 80% of maximal heart rate to trigger EIB. Classically, the symptoms peak 5 to 10 minutes after exercise begins. (5)
Rule out cardiac problems. If EIB is the correct diagnosis, the physical exam is usually normal. The importance of the physical exam is to evaluate for other diagnoses with similar presentations. Conditions to rule out include cardiac problems, exercise-induced hyperventilation, upper and lower respiratory infections or abnormalities, exercise-induced laryngeal dysfunction, exercise-induced anaphylaxis, and gastroesophageal reflux disease (GERD). The differential diagnosis for EIB is summarized in TABLE 1.
Test for asthma. Once you have gone through the differential diagnosis and are comfortable that the symptoms are respiratory, the next step should be pulmonary function tests (PFT), pre- and post-albuterol challenge. Findings of obstruction, such as reduced forced expiratory volume in 1 second (FEV1) or increased lung volume, are consistent with a diagnosis of asthma. In that case, no further workup is needed--unless the patient is unresponsive to asthma treatment. In athletes like Luke who do not have asthma and have a normal non-provocative spirometry, you can move on to either provocative spirometry or empiric treatment.
* Perform provocative spirometry
Direct spirometry is commonly done with a methacholine challenge. This test is less sensitive than indirect testing for EIB patients who do not have underlying asthma.
The gold standard for indirect testing is eucapnic voluntary hyperventilation (EVH). Because EVH requires special equipment, however, it may not be an option in your office. The more reasonable choice is exercise challenge testing, which can be done either in your office or in the milieu--the basketball court, for example--where the athlete's symptoms usually occur. In an exercise challenge, you get a baseline spirometry measurement, have the athlete exercise to 80% to 90% of maximal heart rate, and then repeat spirometry at short intervals after exercise ends. If you do an exercise challenge in the office, you can reduce false-negative results by maintaining an ambient temperature between 68[degrees] and 77[degrees]F (20[degrees]-25[degrees]C) with a relative humidity of less than 50%. (6,7)
Or try empiric treatment
Empiric treatment is a reasonable strategy for athletes with EIB symptoms, worth trying both for athletes who have underlying asthma and for those who do not. If the athlete with asthma responds to treatment, the problem is solved. For the athlete who does not have asthma, however, there are some exceptions to this approach--specifically, the elite athlete.
In the elite athlete, you will need to confirm the diagnosis because many of the substances used to treat EIB are restricted by governing bodies such as the International Olympic Committee (IOC) and require provocative testing to obtain a therapeutic use exemption. (8) There is some debate as to whether nonelite athletes also need bronchoprovocative testing. Some recommendations advise testing all elite and competitive athletes and restricting empiric treatment to recreational athletes. (1) For more information on banned or restricted medications, see "Is that drug banned from competition?" at left.
If you take the empiric approach and the athlete does not respond to treatment, consider further testing to rule out other, more serious problems. In Luke's case, where empiric treatment with albuterol has failed, indirect testing would be the next step.
* Medicate before exercise: SABAs and LABAs
Prophylaxis for EIB usually starts with an inhaled short-acting [beta]2 agonist (SABA) such as albuterol or pirbuterol, taken 15 minutes before starting to exercise. (9,10) The effectiveness of both short- and long-acting [beta]2 agonists decreases with frequent use, which may be Luke's problem. For that reason, patients with mild HB may choose to use pretreatment medication only for more demanding exercise sessions. (11) Advise EIB patients who need daily pretreatment to try adjunctive maintenance therapy (discussed at greater length, below.)
Longer-acting [beta]2 agonists (LABAs) such as salmeterol or formoterol may be effective for prolonged or all-day exercise, but may lose their prophylactic effect with prolonged use. (12) Furthermore, the US Food and Drug Administration (FDA) has advised against using LABAs alone because of the possibility of severe asthma episodes or death. LABAs should be used only in conjunction with daily maintenance therapy with inhaled corticosteroids. The properties of these and other EIB medications are summarized in TABLE 2.
* Cromolyn, antileukotrienes are options, too
Mast cell stabilizers (cromolyn) can be used with [beta]2 agonists as prophylactic therapy. When these agents are used together, they have an additive effect. (13) The athlete may take them 10 minutes to an hour before exercise. Make sure your patient knows that mast cell stabilizers can not be used as a rescue inhaler or bronchodilator.
Inhaled corticosteroids (flunisolide, fluticasone, others) may be needed for athletes with poorly controlled chronic asthma; they can also be used as adjunct preventive treatment for athletes who have EIB with no underlying chronic asthma. (14-16) Often, inhaled corticosteroids are used as combination therapy with a LABA or an antileukotriene agent (montelukast, zafirlukast; see below). Recent research shows that montelukast in combination with inhaled corticosteroids is more efficacious than LABA with inhaled corticosteroids. (14,17)
Antileukotriene agents can be especially helpful for EIB in patients with mild, stable asthma. (18) Patients who do respond to antileukotriene agents usually respond very favorably. Antileukotrienes offer a reasonable alternative to inhaled corticosteroids and LABAs. They have a low side-effect profile and should be considered as daily prophylaxis. (19,20) The effects of montelukast are evident as early as 2 hours after administration, and bronchoprotective effects can last as long as 24 hours. (21,22) For that reason, montelukast is especially useful in children whose exercise patterns are not always predictable.
Be prepared for acute exacerbations. Prophylactic medication does not always prevent acute exacerbations. When that happens, your EIB patient will need to use a [beta]2 agonist as rescue therapy. Make sure your patient knows that none of the other medications are effective bronchodilators in acute exacerbations.
Remember, too, that EIB cannot be effectively treated if the athlete has poorly controlled chronic asthma. Underlying causes of asthma exacerbations like allergies or respiratory infections must be addressed and stabilized first, following guidelines of the National Asthma Education and Prevention Program (NAEPP). (9) You can access the guidelines at www.nhlbi.nih.gov/guidelines/asthma/ asthgdln.htm.
These tips can help the athlete
Encourage athletes with EIB to keep up their exercise routines, because cardiovascular fitness has a beneficial effect on this condition. Fit individuals breathe more slowly, which reduces the likelihood of exacerbations. Of note, though: Certain sports are easier on patients with EIB. Patients may want to keep this in mind when deciding which team they want to go out for. Specifically, indoor sports, where air temperature, humidity, and exposure to allergens are controlled, and sports like baseball, sprinting, or football, which require less prolonged aerobic endurance, are good options.
Tell athletes whose sports require cold, dry conditions--ice skating, or skiing, for instance--to try breathing through a scarf or mask to keep inspired air warm and less irritating.
And tell all athletes with EIB to warm up properly before they start to compete. (23) That means a 15-minute warm-up at moderate exertion, followed by a 15- to 30-minute rest period. The rest period is the time to take their medication.
When therapy fails
When an EIB patient fails to respond despite multiple drug therapy, it's time to reconsider other diagnoses, such as vocal cord dysfunction and severe GERD, which may mimic symptoms of EIB.
On the horizon. Other therapies for possible treatment of EIB are being studied. These include omega-3 fatty acid dietary supplementation and inhaled enoxaparin. (24,25) Data are currently insufficient to recommend use of these agents in clinical practice.
As for Luke, indirect testing via exercise challenge was positive for EIB. Adjunctive therapy with montelukast was added to his albuterol inhaler, and the combination has worked well for him. He's still playing basketball, and enjoying it.
Is that drug banned from competition?
Certain medications used in the treatment of asthma and exercise-induced bronchoconstriction (EIB) are considered performance-enhancing drugs and either banned or restricted in athletic competition. The regulatory bodies that make these designations in the United States are the National Collegiate Athletic Association (NCAA) and the International Olympic Committee World Anti-Doping Agency (IOC-WADA). These organizations update their list of banned substances yearly and make the current list available on the Web. You can find the NCAA list at www.pace.edu/emplibrary/NCAA%20LIST%20OF%20 BANNED%20SUBSTANCESb.doc and the IOC-WADA list at www.wada-ama.org/rtecontent/document/ 2009_Prohibited_List_ENG_Final_20_Sept_08.pdf.
The IOC-WADA allows competing athletes to use inhaled corticosteroids and 132 agonists, but requires athletes with asthma to provide documentation that the medication is for therapeutic use. Glucocorticosteroids and oral [beta]2 agonists remain prohibited by the IOC-WADA, but only oral [beta]2 agonists are banned by the NCAA. The NCAA warns that student athletes are responsible for knowing which substances are on the banned list and advises them to consult www.drugfreesport.com for more information. To avoid disqualifying a patient from sports participation, check medications you prescribe with the official lists and be sure your EIB patient has the documentation he or she needs to qualify for a therapeutic use exemption.
The authors thank Ken Rundell, PhD, for reviewing this article. Dr. Rundell is director of the Human Physiology Laboratory at the Keith J. O'Neill Center of Marywood University, Scranton, Pa.
The authors reported no potential conflict of interest relevant to this article.
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Michael A. Krafczyk, MD, and F. Dale Bautista, MD
St. Luke's Hospital, Bethlehem, Pa
Michael A. Krafczyk, MD, FAAFP, St. Luke's Sports Medicine, 153 Brodhead Rd, Bethlehem, PA 18017; email@example.com
TABLE 1 Is it EIB, or something else? ETIOLOGY POSSIBLE DIAGNOSES Pulmonary Exercise-induced hyperventilation (pseudo-asthma syndrome) Restrictive lung disease Cystic fibrosis Upper and lower respiratory infections Foreign body aspiration Cardiac Coronary artery disease Congenital and acquired heart defects Cardiomyopathy Congestive heart failure Laryngeal Exercise-induced laryngeal dysfunction Vocal cord dysfunction Laryngeal prolapse Laryngomalacia Gastroesophageal Gastroesophageal reflux disease Allergic Exercise-induced anaphylaxis Other Athlete is out of shape EIB, exercise-induced bronchoconstriction. Source: Weiler JM, et al. J Allergy Clin Immunol. 2007. (4) TABLE 2 EIB medications MEDICATION INDICATION DOSE Short-acting [beta]2 agonists (SABAs) Albuterol, pirbuterol Pre-exercise 2 puffs pre-exercise prophylaxis, or 2 puffs every acute treatment 4-6 h as needed Mast cell stabilizers Cromolyn Pre-exercise 2 puffs 30-45 min treatment before exercise Inhaled corticosteroids Flunisolide, Daily Variable fluticasone, maintenance budesonide, triamcinolone, beclomethasone, mometasone Leukotriene inhibitors Zafirlukast Daily 20 mg PO, bid maintenance Montelukast Daily 10 mg PO daily maintenance, or up to 2 h pre-exercise pre-exercise prophylaxis Zileuton Daily 1200 mg PO, bid maintenance Combinations Inhaled fluticasone Daily Variable doses and salmeterol maintenance (100/50, 250/50, 500/50 mcg/spray); 1 puff bid Inhaled budesonide Daily Variable doses and formoterol maintenance (80/4.5, 160/4.5 mcg/spray); 1 puff bid EIB medications MEDICATION CAUTIONS COMMENT Short-acting [beta]2 agonists (SABAs) Albuterol, pirbuterol May cause First-line treatment tachycardia, hypokalemia. Tachyphylaxis can develop with frequent use. Mast cell stabilizers Cromolyn None Best combined with SABA. Tell patients not to use for rescue. Inhaled corticosteroids Flunisolide, Can cause oral Tell patients this fluticasone, candidiasis, is not a rescue budesonide, hoarseness. inhaler. triamcinolone, beclomethasone, mometasone Leukotriene inhibitors Zafirlukast None Variable response. Works well with inhaled corticosteroids. Low side-effect profile. Montelukast None Variable response. Works well with inhaled corticosteroids. Low side-effect profile. Zileuton Risk of elevated Variable response. liver function Low side-effect tests. profile. Combinations Inhaled fluticasone Can cause oral Tell patients this and salmeterol candidiasis, is not a rescue hoarseness, inhaler. tachycardia, hypokalemia. Tachyphylaxis can develop with frequent use. Inhaled budesonide Can cause oral Tell patients this and formoterol candidiasis, is not a rescue hoarseness, inhaler. tachycardia, hypokalemia. Tachyphylaxis can develop with frequent use. EIB, exercise-induced bronchoconstriction. Adapted from the National Asthma Education and Prevention Program. Expert Panel Report 3: Guidelines for the diagnosis and management of asthma. (9)
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|Author:||Krafczyk, Michael A.; Bautista, F. Dale|
|Publication:||Journal of Family Practice|
|Date:||Sep 1, 2009|
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