They have described what you assume is a classic case of pneumonia. But, PNA isn’t an answer choice. What the next best thing? The cause! Old frail people (and alcoholics) love to get aspiration pneumonia. RLL is the most common site, which they have provided (thank you, big vertical bronchus). They even gave you the hint that the patient has “difficulty swallowing,” which is code for “aspirates when swallowing.”

To those wondering what alveolar proteinosis is, it is a rare lung disorder characterized by abnormal accumulation of surfactant-derived lipoproteins within the alveoli. Sometimes it can occur secondary to lung infections, although usually it is an autoimmune process.