41 yo M with shortness of breath


  • Practice reading CXRs
  • Differential of cystic lung disease


A 41 yo homeless M with no significant PMH who presented with acute onset chest pain and SOB 2 weeks ago. The pain and shortness of breath were intense initially but subsequently improved and he attempted to “wait it out.” However, over the past day, he’s had increasing shortness of breath and palpitations. He denies any fevers, chills, night sweats, URI symptoms and has had a chronic productive cough that he attributes to smoking. He noticed a change in his cough ~ 1 month ago and has been able to produce thick yellow sputum over this time. He additionally reports a 30 lb weight loss over the past 1-2 months.

He has no known PMH and takes no medications. He has a 20 pack year smoking history and is a heavy THC user. He is currently homeless and has been in jail multiple times in the past year. On exam, he is afebrile 36.8C, HR 126, RR 32, BP 159/91. Initially found to be 88% on RA. He was laced on 100% NRB with saturations down in the high 80s.

Before you examine the patient, what does his response to 100% NRB tell you about the cause of hypoxemia? 


BMP – Na 133, K 4.5, Cl 97, CO2 31, BUN 36, Cr 1.3
CBC – WBC 16k, Hb 14.9/hct 46, Plts 342
VBG: 7.31/59/42/34 (not ABG for reasons above)


What would you do now?


What disease processes cause cysts in the lung?

What is your differential for his lung findings?



  1. Raoof, S et al. “Cystic Lung Diseases: Algorithmic Approach.” 2016. CHEST. 150(4):945-965.