Problem
A 52-year-old man presents to your office for an acute visit because of coughing and shortness of breath. He is well known to you because of multiple office visits in the past few years for similar reasons. He has a chronic "smoker's cough," but reports that in the past 2 days his cough has increased, his sputum has changed from white to green in color, and he has had to increase the frequency with which he uses his albuterol inhaler. He denies having a fever, chest pain, peripheral edema, or other symptoms. His medical history is significant for hypertension, peripheral vascular disease, and two hospitalizations for pneumonia in the past 5 years. He has a 40 year history of smoking and continues to smoke two packs of cigarettes a day.
a) What is the probable diagnosis?
b) What are other possible diagnoses?
c) At this stage of the case study, what diagnostic studies and basic treatments are most appropriate to order and why?