Review Question - QID 214231

A 22-year-old man presents to the emergency department with a dry cough and shortness of breath. His symptoms started yesterday and have been gradually worsening. The patient takes no medications and is generally healthy. As a child, he had a ventricular septal defect that was repaired surgically. The patient states that he recently started college, drinks more alcohol than previously, and began using electronic cigarettes 5 weeks ago. He has also recently become sexually active and has not been using protection. There is a family history of heart disease. His temperature is 99.0°F (37.2°C), blood pressure is 122/88 mmHg, pulse is 124/min, respirations are 35/min, and oxygen saturation is 89% on room air. A chest CT is performed as seen in Figure A. The patient is started on bilevel positive airway pressure, and his saturation improves to 94%. Which of the following is the most likely diagnosis?