Mrs. P is a 62-year-old woman who arrives at the emergency department with shortness of breath and wheezing. She says that the symptoms have been present for 3 days. The symptoms are present both at rest and with exertion and have not improved with an albuterol inhaler.
She reports that she has had these symptoms intermittently for 6 years. When the symptoms occur, they generally last for hours to a few days. She had been diagnosed with asthma and took long- and short-acting beta-agonists and inhaled and systemic corticosteroids, before coming off all medications 1 year ago. She stopped her medications out of frustration with side effects and perceived lack of efficacy. She decided instead to treat herself with yoga and meditation. She reports no episodes since this decision.
Presently she denies cough, chest pain, fever, or rhinitis. She does report hoarseness that occurs when her breathing is bad.
At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?