Review Question - QID 212496

A patient is brought to the emergency department by his spouse. The patient is admitted, treated, and transferred to the floor. The patient has a past medical history of obesity, type II diabetes mellitus, asthma, depression, and multiple suicide attempts. His current medications include pantoprazole, insulin, metformin, albuterol, fluticasone, lithium, levothyroxine, and fluoxetine. The patient has a 20 pack-year smoking history. On the floor, his temperature is 99.5°F (37.5°C), blood pressure is 140/85 mmHg, pulse is 70/min, respirations are 13/min, and oxygen saturation is 98% on room air. The patient's initial radiograph is reviewed as seen in Figure A. Which of the following is the most likely etiology of this patient's initial presentation?