A 44-Year-Old Man Comes to the Office Due to Progressive

A 44-year-old man comes to the office due to progressive shorten of breath with mild exertion and cough.  He has had no chest pain, or leg swelling.  The patient smokes 1-pack-daily.  Temperature is 37.2 C (99 F) , blood pressure is 115/75 mm Hg, pulse is 92/min, and respirations are 18/min.  Oxygen saturation at rest is 88% on room air.  Lung auscultation shows scattered crackles.  other examination are normal.  Chest x-ray reveals bilateral midalveolar and lower alveolar opacities.  Transbronchial lung biopsy reveals lipoproteinaceous material that is positive on periodic acid-Schiff stain and fills up the terminal bronchioles and alveoli.  Electron microscopy of the substance shows lamellar bodies.  Impaired function of which of the following most likely caused excessive accumulation of the substance in this patient's alveoli?

A) Alveolar macrophages
B) Ciliated airway epithelium
C) Club cells
D) Fibroblasts
E) Type 1 pneumocytes

Correct Answer:

Verified

Show Answer