ALGORITHM FOR THE DIAGNOSIS AND TREATMENT OF EXERCISE-INDUCED BRONCHOSPASM

Abstract

Introduction Exercise-induced bronchospasm (EIB) is the acute onset of transient bronchoconstriction of the lower airways during or immediately following exercise. The prevalence of EIB in the general population is only 5-20% compared to up to 90% in asthmatic patients. In EIB, the initial bronchodilation from exercise is then followed by bronchoconstriction resulting in subsequent symptoms. Case Description A 15-year-old boy with severe asthma on high-dose combination therapy and significant recurrent episodes of shortness of breath, chest tightness, and difficulty breathing with activities presented to our Day Program for evaluation and treatment. During his exercise challenge, his FEV1 decreased from a baseline of 125% predicted to 48% predicted (>77%). He was diagnosed with EIB. His eNO and leukotriene E4 (LTE4) levels were unremarkable, and urinary prostaglandin E2 was present. Bronchoscopy was essentially normal. Two different pre-treatment regiments involving pre-exercise warm-up, tiotropium, montelukast, albuterol, and ipratropium bromide followed by a standardized free run were all insufficient to fully block the drop in FEV1, and nebulized cromolyn was ultimately required. Since cromolyn in the United States is only available in nebulized form, we were unable to transition him to an MDI. Discussion Severe EIB can still occur in patients with normal baseline spirometry and can lead to a reduction in quality of life. Repeated exercise challenges are critical in assessing response to EIB interventions. Cromolyn is an effective therapy and the lack of metered dose inhalers limits it use. Exercise-induced bronchospasm (EIB) is the acute onset of transient bronchoconstriction of the lower airways during or immediately following exercise. The prevalence of EIB in the general population is only 5-20% compared to up to 90% in asthmatic patients. In EIB, the initial bronchodilation from exercise is then followed by bronchoconstriction resulting in subsequent symptoms. A 15-year-old boy with severe asthma on high-dose combination therapy and significant recurrent episodes of shortness of breath, chest tightness, and difficulty breathing with activities presented to our Day Program for evaluation and treatment. During his exercise challenge, his FEV1 decreased from a baseline of 125% predicted to 48% predicted (>77%). He was diagnosed with EIB. His eNO and leukotriene E4 (LTE4) levels were unremarkable, and urinary prostaglandin E2 was present. Bronchoscopy was essentially normal. Two different pre-treatment regiments involving pre-exercise warm-up, tiotropium, montelukast, albuterol, and ipratropium bromide followed by a standardized free run were all insufficient to fully block the drop in FEV1, and nebulized cromolyn was ultimately required. Since cromolyn in the United States is only available in nebulized form, we were unable to transition him to an MDI. Severe EIB can still occur in patients with normal baseline spirometry and can lead to a reduction in quality of life. Repeated exercise challenges are critical in assessing response to EIB interventions. Cromolyn is an effective therapy and the lack of metered dose inhalers limits it use.