A 6-year-old girl is brought to your pediatric pulmonology clinic due to a persistent wet cough for the past two years. She is otherwise well and meets her developmental milestones. The cough is productive of yellow sputum, present daily, and worsens during exacerbations, which occur 3-4 times per year. These episodes have been diagnosed as “pneumonia” and treated with various courses of oral antibiotics with temporary improvement. She was diagnosed with asthma at age four but has not responded to inhaled corticosteroids or albuterol. Her past medical history is significant for three hospitalizations for severe pneumonia. There is no history of recurrent sinus infections, choking episodes, or failure to thrive. All her immunizations are up to date.