Exercise-Induced Bronchoconstriction: The New Guidelines

Laura A. Stokowski, RN, MS; Jonathan P. Parsons, MD, MSc

February 03, 2014

Editor's Note:
Exercise-induced bronchoconstriction (EIB) is an acute narrowing of the airway that occurs as a result of exercise. In winter, cold-weather sports, such as skiing and ice-skating, can provoke EIB in professional or recreational athletes.^[1] To provide clinicians with practical guidance, a multidisciplinary panel of stakeholders was convened to review the pathogenesis of EIB and to develop evidence-based guidelines^[2] for the diagnosis and treatment of EIB. Medscape had the opportunity to speak with the Chair of the panel, Jonathan P. Parsons, MD, MSc, about what primary care clinicians should know about EIB and the new guidelines for the next time a patient comes into the office complaining of chest tightness, coughing, wheezing, dyspnea, or other vague respiratory symptoms with exercise.

Medscape: Can we start with why you have changed the terminology from "exercise-induced asthma" to "exercise-induced bronchoconstriction"?

Jonathan P. Parsons, MD, MSc: We have gotten away from saying "exercise-induced asthma" for a couple of reasons. One is that a substantial percentage of patients don't have the phenotype of chronic asthma, but do experience EIB. So saying that they have some form of asthma is actually giving them an inaccurate label that we are trying to avoid putting on them. That is 10%-15% of the general population, and the only time that they have any kind of breathing issues is during exercise, which is really not consistent with chronic asthma. Chronic asthmatics can have symptoms at many other times -- when they are exposed to allergens, during upper respiratory infections, and so forth.

The other reason that we have gotten away from the term "exercise-induced asthma" it is that it implies that exercise causes asthma, and that is not true. Asthma is a complicated inflammatory disease of the airway, and exercise is one potential trigger that could cause symptoms of asthma to develop, but it doesn't really cause the disease itself. So those are the reasons why we have switched from "exercise-induced asthma" to EIB.

Getting the Diagnosis Right

Medscape: In the new guidelines, you make a very clear, strong point that the diagnosis of EIB requires lung function testing provoked by exercise, and it should not be made on the basis of clinical symptoms. What is commonly happening in clinical practice?

Dr. Parsons: We have done a study, and data from multiple other studies show that the vast majority of clinicians, whether primary care doctors or specialists, are diagnosing EIB on the basis of symptoms alone. In some of our previous work, we have shown that in up to 70% of cases when a patient comes in with symptoms during exercise, they are attributed to EIB without any kind of form of diagnostic testing.

Now the problem with that is, as I just mentioned, many of the symptoms that can happen during exercise -- shortness of breath, chest tightness -- have nothing to do with asthma. So when we treat on the basis of symptoms alone, it's like tossing a coin in terms of whether or the patient is being treated for the proper diagnosis. So we really encourage clinicians, if they feel that the diagnosis of EIB is potentially present, to do an appropriate test to document it formally.

Medscape: What is the test, and where are patients sent to have it done?

Dr. Parsons: The tests are serial lung function measurements after specific exercise or a hypernea challenge. Most primary care clinicians will have access to, at least at their local hospital, a pulmonary function laboratory where they can refer their patients for formal testing. Very few people are going to have access to testing in their offices, so it would require them to order the test and have the patient go to their local hospital to have it done in the pulmonary function laboratory.

Medscape: According to the guideline, the testing grades the severity of EIB depending on the percent fall in FEV₁ compared with the pre-exercise level. How is this information used?

Dr. Parsons: Patients with bronchospasm tend to be poor receivers of how severely they are impaired. They are often not able to connect with how much they are dropping. It's hard for them to tease out the symptoms of intense exercise from the symptoms of bronchoconstriction.

This is another reason why it is so important to do the testing rather than just rely on symptoms, because many times, these patients won't make the connection that something is wrong here. It's for patient education; it gives the patient some idea of how severe their bronchospasm is if you can say, "Look, you dropped 30%." It may also be necessary to show them the severity of their EIB to convince some patients that they need treatment before they exercise.

Triggers and Risk Factors

Medscape: As we speak today, on the East Coast, it's 12°F outside. If I'm going to go outside and run today, what is it that might trigger EIB?

Dr. Parsons: It's not necessarily the temperature of the air; it's the humidity that really is a big deal. Typically, when it's really cold outside, the air is very dry. When you breathe relatively dry air compared with the air inside your lungs, sometimes it overwhelms the ability of your lung to humidify that air before it gets into the bottom of your lungs. It's the job of your lungs to get moisture into the air that you are breathing and to humidify it, because that's what your lungs need.

But if you're exercising outside in really dry air, the dry air overwhelms the ability of your lung to humidify it. Some of that relatively dry air gets down to the smaller airways of the lung and it irritates them, producing symptoms. If you went running out in the desert on a 90°F day when it was really dry out, you could have a similar phenomenon as if you were running in 12°F cold weather.

Medscape: Does it affect everybody?

Dr. Parsons: No, and if we knew why, we could probably prevent the disease itself from occurring. We don't know why it happens to certain people vs others, which is part of the big question with this diagnosis.

Moreover, sometimes the same person may be able to go out and run a half a dozen times in cold air and do fine, and then one time, for whatever reason, they have an episode provoked by cold air. Why it happened that time in that particular person is not clear.

Medscape: But EIB is more common in athletes, and so is that a risk factor that clinicians should be aware of? In particular, elite athletes or people who exercise every day -- should they be screened for EIB?

Dr. Parsons: That's a good question. There are 2 reasons that EIB may be more commonly found or more commonly diagnosed in athletes. One is that we have a higher index of suspicion in athletes. We are much more sensitive to it. By the nature of what competitive athletes are doing, we are more likely to look for EIB in a competitive athlete than in someone who is running on a treadmill recreationally.

The second reason is that simply by the laws of probability, competitive athletes are more likely to have an episode of EIB because they are exercising much more often than "normal" people. So the higher prevalence in athletes might be explained by the fact that they exercise more, and we look for EIB more.

We have looked at screening large populations of athletes and haven't found that it would be cost-effective, on the basis of the cost of testing, the risk for the disease, and the overall prevalence of the disease. Our studies to date don't support mass screening of athletes for EIB.

Treatment: Start With a Short-Acting Bronchodilator

Medscape: Let's talk about treatment. The guidelines list many different agents for the treatment of EIB. Do you suggest that clinicians use them in the order they are listed in the guidelines?

Dr. Parsons: Yes. The first step after you have made a formal diagnosis objectively of EIB, typically, is to start with a short-acting bronchodilator, such as albuterol -- usually 2 puffs 15-20 minutes before exercise. If a person really has EIB, that will be sufficient to control the symptoms of EIB in about 80% of the cases, so that in and of itself is an easy fix for this diagnosis in the vast majority of cases. Now, if an athlete continues to be symptomatic despite using the albuterol properly, that may indicate that he or she actually has underlying asthma that is inadequately controlled.

If that is the case, that patient may need an additional controller agent. There are multiple choices for that, as we outlined in the guidelines. You can go with an inhaled steroid or a leukotriene receptor antagonist. It depends on what the patient is comfortable with, what their insurance will cover, and the physician preference or caretaker preference as well. Typically, we start with the albuterol. If that's not doing the job, then we will go to a second-line agent of the patient's and prescriber's choice at that point.

I will also say that if you treated EIB with albuterol without making a formal diagnosis, on the basis of symptoms alone, and the patient continues to be symptomatic despite using the albuterol properly, that is the point in time when you need to start looking for an alternative diagnosis, because maybe this wasn't EIB after all.

Medscape: Does the severity of EIB enter into how you would treat the patient?

Dr. Parsons: I would still start with an albuterol inhaler and then go from there. Some patients who exercise every day, or multiple times a day or who are on a competitive sports team, and who have significant EIB might need a controller agent as well.

Typically, I would use an inhaled corticosteroid as a maintenance medicine, and then I would have the patient continue to use their albuterol before exercise. I don't think it would be wrong, if the patient had very severe EIB, to go ahead and give them an inhaled corticosteroid along with the albuterol. That's not necessarily in our guidelines, but in practice that would be a reasonable thing to do.

Medscape: Let's talk about the issue of performance-enhancing drugs and the treatment of EIB. Are any of the agents used to treat EIB banned, and whose responsibility is it to know?

Dr. Parsons: It will always be the responsibility of the athlete to be aware of the rules and regulations of the governing body under which they exercise. Most of these athletes are going to clinicians who have good experience with what these rules are, but it's not going to be an acceptable excuse to a governing body to say, "I didn't know what the rules are" if they take something that is banned. That is pretty cut and dried. It's always the athlete's responsibility to know what they can and cannot put in their body, even if it's prescribed to them.

The good news is that the guidelines have changed quite a bit over the past 4-5 years. In the past, there was quite a bit of regulation with the inhaled asthma medications. Now, the vast majority of these medicines, if they are taken in therapeutic doses, do not need any kind of waiver or therapeutic use exemption.

Patients don't need to get a waiver anymore for inhaled steroids, leukotriene modifiers, or albuterol. All of those are okay now. The oral steroids, however, are not permitted. It is very uncommon to use oral bronchodilators, such as oral albuterol, anymore (although they are still available), and they are banned. The inhaled medications are fine, however.

Medscape: Just to summarize, are any of the agents that you might prescribe for the treatment of EIB banned?

Dr. Parsons: No. The long-acting bronchodilators, such as formoterol and salmeterol, which are the long-acting beta agonists, do have regulations based on dosing. They could potentially test the dose in the urine of an athlete to see if they are abusing it. But in therapeutic doses, if used as prescribed, those are totally fine. So there aren't any major regulations anymore for these medications except if for some other reason, the patient was taking oral prednisone, which can't be done without a waiver.

Exercising Safely

Medscape: How should clinicians advise patients about engaging in exercise if they are still having symptoms with EIB? Should they wear identification, or carry inhalers?

Dr. Parsons: Deaths have been associated with EIB, but they are rare. The goal of managing these patients is to get them to be able to exercise at whatever level they want to without symptoms. If the athlete is still having symptoms during exercise that by our criteria, by our goals of care, are inadequately controlled, then that regimen should be augmented.

I don't want any of my patients running around exercising with symptoms at all. They should be able to do whatever they want to, limit-free. That being said, when they are running competitive races, and they sign up for a half-marathon or a 10K, they are asked whether they have asthma, and it would be a good idea to indicate on their registration form that they do have asthma, so that if something were to happen the EMS personnel would know exactly what to do, to look for, or to attend to.

I don't recommend wearing identification because most of these patients can be controlled with their albuterol inhaler, even if they have an acute episode of symptoms during exercise.

I tell my patients who are athletes to always have immediate access to their albuterol inhalers. If they are cycling or swimming, that doesn't necessarily make it very convenient, but maybe on their bike they can have it available somewhere for a long cycling route or a long run.

An albuterol inhaler, if used properly before exercise, should provide 3-4 hours of protection. That is going to cover most competitive events that athletes will ever be competing in, unless they are doing one of these ultramarathons or triathlons.

We don't tolerate symptoms in patients who have documented EIB. They should be able to exercise without symptoms, and they need to have access to their albuterol inhalers -- if not immediate, then very easy access to it. There are forms of identification that can be worn, but I don't necessarily recommend that in most cases.

Medscape: What are your bottom-line messages about EIB to primary care providers?

Dr. Parsons: I would say a couple of things. Most important, the symptoms of EIB are very nonspecific. Making a diagnosis on the basis of symptoms alone is setting a clinician up to make the wrong diagnosis in a significant percentage of cases. For that reason, it is clinically important to objectively document that you are making the proper diagnosis, and once you make the proper diagnosis, that you are documenting the severity of EIB in this particular patient.

The next point I would make is that albuterol is very effective in controlling EIB in the vast majority of patients. If you have an athlete or a patient who is still symptomatic despite adequate treatment with albuterol, then I would start to look for alternative diagnoses or start to consider augmenting pharmacologic therapy at that point.

Medscape: What is the most common alternative diagnosis?

Dr. Parsons: In our practice, the most common alternative diagnosis is vocal cord dysfunction, which is something that is not commonly considered by a primary care doctor but is a very common diagnosis in patients with exercise-induced respiratory symptoms. These patients have an irritable larynx syndrome where the upper airway becomes irritated in a similar fashion to EIB, but they don't respond to inhalers, and they continue to have symptoms despite a significant regimen of asthma medicines because they don't have asthma or EIB.

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Cite this: Exercise-Induced Bronchoconstriction: The New Guidelines - Medscape - Feb 03, 2014.