Exercise-Induced Respiratory Symptoms
At the Arizona Asthma and Allergy Institute our physicians commonly evaluate patients complaining of difficulty breathing with exercise. Causes to exercise-induced breathing difficulty include: Exercise-Induced Bronchoconstriction, Vocal Cord Dysfunction, gastroesophageal reflux, parenchymal pulmonary disease, coronary heart disease, heart failure, central airway obstruction and laryngotracheomalacia. We have the capability of offering several useful tools to aid in the accurate diagnosis of two of the most common causes of exercise-induced breathing difficulty: Exercise-Induced Bronchoconstriction and Vocal Cord Dysfunction .
These tests include:
Treadmill Exercise Challenge Testing
Fractional Exhaled Nitric Oxide (FENO) levels
As we perform an appropriate diagnostic work up for exercise induced symptoms we will collaborate with the primary care physician or other specialists to extend the work up and treatment when indicated.
Exercise-Induced Bronchoconstriction (EIB)
(Exercise-Induced Bronchoconstriction) – the estimated prevalence varies from 7 to 20 percent in the general population. Up to 80 percent of patients with symptomatic asthma have some degree of Exercise-Induced Bronchoconstriction. Typical symptoms are shortness of breath, chest tightness and cough. Patients with Exercise-Induced Bronchoconstriction typically have bronchoconstriction that begins a Treadmill Exercise Challenge Testing few minutes after exercise and generally peaks within 10-15 minutes. An exercise challenge test is the most direct way to establish a diagnosis of Exercise-Induced Bronchoconstriction and a drop in FEV1 of 15% is diagnostic. Evaluating for underlying asthma contributing is also helpful. For this a methacholine challenge to assess airway hyperreactivity and measurement of FENO levels as a marker of airway inflammation is useful.
Vocal Cord Dysfunction (VCD )
Vocal Cord Dysfunction is paradoxical motion of the vocal cords generally causing adduction of the vocal cords with inspiration but can also occur with expiration. Patients are often misdiagnosed as having asthma. Symptoms can include shortness of breath, stridor, hoarseness, choking sensation and cough. Blunting of the inspiratory loop on spiromety may be seen if the patient is having active symptoms. Exercise can be a common trigger to Vocal Cord Dysfunction . In fact, one study showed Vocal Cord Dysfunction can account for 15% of cases of exercise induced breathing difficulty. If symptoms are reproduced during exercise challenge then direct visualization of the vocal cords with laryngoscopy showing paradoxical motion is diagnostic. Not only do we have the expertise and tools to make this diagnosis, we also provide patients with education and training on breathing exercises that help manage this condition.