Asthma triggered by exercise , or E.I.A. , occurs when the airways are narrowed by exercise. The preferred term for this condition is bronchoconstriction induced by exercise ( EIB ); exercise does not cause asthma, but it is often a trigger for asthma.
Video Exercise-induced bronchoconstriction
Signs and symptoms
It might be expected that people with E.I.B. will present with shortness of breath, and/or increase in respiratory rate and wheezing, consistent with asthma attacks. However, many will be present with decreased stamina, or difficulty in recovering from exertion rather than team members, or paroxysmal coughing of the irritable airways. Similarly, the examination may reveal prolonged wheezing and expiratory phases, or may be quite normal. As a result, the diagnostic potential below exists. Airflow measurements, such as peak expiratory flow rates, which can be done inexpensively on the track or on the sideline, may be helpful.
Maps Exercise-induced bronchoconstriction
Cause
While potential trigger events for E.I.B. well recognized, the underlying pathogenesis is poorly understood. Usually occurs after at least a few minutes of strong aerobic activity, which increases the need for oxygen to the point where breathing through the nose (nasal breathing) should be equipped with mouth breathing. The result of inhalation of unheated air and moisturized by the nasal passages appears to result in increased blood flow to the bronchial tree lining, resulting in edema. This small airway constriction then follows, exacerbating the degree of obstruction to airflow. There is growing evidence that the smooth muscle lining the airways becomes increasingly more sensitive to changes that occur as a result of airway injuries due to dehydration. The chemical mediator that provokes muscle spasms arises from the mast cells.
Diagnosis
Bronchoconstriction induced by exercise can be difficult to diagnose clinically due to lack of specific symptoms and often misinterpretation as a manifestation of strenuous exercise. There are many imitations that come with the same symptoms, such as vocal cords dysfunction, cardiac arrhythmias, cardiomyopathy, and gastroesophageal reflux disease. It is also important to distinguish those with asthma with worsening exercise, and who will consequently experience abnormal tests at rest, from exercise-induced bronchoconstriction, where there will be a normal baseline outcome. Because of the wide differential diagnosis of occupational respiratory complaints, the exercise-induced bronchoconstriction diagnosis based on self-reported history and symptoms alone has proven to be inaccurate and will result in false diagnoses over 50% of the time. An important and often overlooked differential diagnosis is laryngeal obstruction caused by EILO exercise. The latter can co-exist with EIB and are best differentiated using objective testing and continuous laryngoscopy during exercise (CLE) testing.
Spirometry
Objective testing should begin with spirometry at rest. In bronchoconstriction induced by actual exercise, the results should be within normal limits. Should the resting value become abnormal, then asthma, or some other chronic lung condition, is present. There is, of course, no reason why exercise-induced asthma and bronchoconstriction should not coexist but this difference is important because without successful treatment of the underlying asthma, the maintenance of the exercise component is unlikely to succeed. If the initial test is normal, some form of exercise or pharmacologic stress will be required, either on the side or exercise site, or in the laboratory.
The practice test
A treadmill or ergometer test based on the lung function lab is an effective method for diagnosing exercise-induced bronchoconstriction, but can result in a negative error if the exercise stimulus is not strong enough.
Field-training challenge
Sports-field challenge challenges involving sports athletes where they are usually involved and assessing FEV 1 after exercise are helpful if not abnormal but have proven to be less sensitive than eukapnik voluntary hypervilations.
The voluntary voluntary challenge of Eucapnic
The International Olympic Committee recommended the challenge of eucapnic voluntary hyperventilation (EVH) as a test to document asthma triggered by exercise in Olympic athletes. In the EVH challenge, patients voluntarily, without exercise, rapidly breathe dry air enriched by 5% CO 2 for six minutes. The presence of CO enriched 2 compensates for CO 2 losses in air expired, not matched to metabolic production, which occurs during hyperventilation, and thus maintains CO 2 levels on normal.
Drug challenge
Drug challenge tests, such as the methacholine challenge test, have a lower sensitivity to detect exercise-induced bronchoconstriction in athletes and also not the first-line approach suggested in sport-triggered asthma evaluation.
Mannitol inhalation was recently approved for use in the United States.
It should be noted, however, that a relatively recent literature review has concluded that currently there is insufficient evidence available to conclude that neither inhaled mannitol or voluntary hypnotized eucapnic is an appropriate alternative to perform a challenge test to detect exercise-induced bronchoconstriction and that additional research is needed.
Treatment
Lifestyle
The best treatment is to avoid conditions that predispose the attack, if possible. In athletes who wish to continue their exercise or do so under adverse conditions, preventive measures include altering training techniques and medications.
Some take advantage of the refractory period by accelerating the attack by "warming up," and then the time of such competition occurs during the refractory period. Gradual exercise works in the same way. Warming occurs in several stages of intensity improvement, using the refractory period generated by each stage to achieve full workload.
Medication
EIB treatment has been extensively studied in asthma subjects over the last 30 years, but not so in EIB. Thus, it is unknown whether athletes with EIB or 'exercise asthma' respond equally to subjects with classic allergic or nonallergic asthma. However, there is no evidence to support different treatments for EIB in asthma and non-athlete athletes.
The most common drug used is a beta agonist taken about 20 minutes before exercise. Some doctors prescribe inhaled antiinflammatory fogs such as corticosteroids or leukotriene antagonists, and mast cell stabilizers have also proven to be effective. A randomized crossover study compared oral montelukast with inhaled salmeterol, both given two hours before exercise. Both drugs have similar benefits but montelukast lasts 24 hours.
Three randomized double-blind cross-over trials have examined the effects of vitamin C on EIB. Pooling results from three vitamin C tests showed a mean decrease of 48% in decreased FEV1 caused by exericise (Fig. The systematic review concludes that "given the safety and low cost of vitamin C, and positive findings for vitamin C administration in three EIB studies, it seems reasonable for physically active people to test for vitamin C when they have respiratory symptoms like cough associated with exercise. "It should be admitted that the total number of subjects involved in all three trials is only 40.
Figure: This plot of forest shows the effects of vitamin C (0.5-2 g/day) on post-exercise reduction in FEV1 in three studies with asthma participants. Built from the data in Fig. 4 from HemilÃÆ'¤ (2013). Three horizontal lines show three studies, and the diamond shape at the bottom shows a combined effect of vitamin C: a decrease in post-exercise posture in FEV1 by 48% (95% CI: 33 to 64%).
In May 2013, the American Thoracic Society issued its first treatment guidelines for EIB.
Prognosis
As evidenced by many professional athletes who have overcome the EIB using some combination of treatments received, the prognosis is usually very good. Olympic swimmer Tom Dolan, Amy Van Dyken and Nancy Hogshead, Jackie Joyner-Kersee Olympic track stars, Catfish Hunter Baseball Hall of Famer and American soccer player Jerome Bettis are among the many who have done so. Tour de France winner Chris Froome admits suffering from a condition after being seen using a nasal inhaler during the race. Other athletes with EIB include cyclist Simon Yates, Paula Radcliffe long-distance runner and cross-country skier Marit BjÃÆ'¸rgen. Research by sports scientist John Dickinson found that 70 percent of British swimming team members based in the UK have some form of asthma, as do a third of Sky Team cyclists, compared with national asthma rates of eight to ten percent, while a study by the American Olympic Committee The Society in 2000 found that half of the cross country skiers had EIB.
Schoolchildren are also one of the major groups affected by the EIB because exercise programs and sports activities are a big part of most schools. Proactive schools usually set EIB-friendly guidelines exclusively for students with EIB so they can be included in the main student training program.
References
External links
- "Tips to Remember: Asthma triggered by exercise". American Academy of Allergy, Asthma, and Immunology . Retrieved 2007-04-12 .
- "Triggered Asthma Exercise". National Jewish Medical and Research Center. July 2002 . Retrieved 2010-04-11 .
- Reynolds, Gretchen (January 13, 2010). "Why So Many Winter Olympians Have Asthma?". The New York Times . Retrieved 2009-02-13 .
- What Is Asthma Triggered by Exercise?
- Fact sheets: Asthma triggered by exercise
Source of the article : Wikipedia
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