Young Woman With Shortness of Breath

A 22-year-old woman presented to the emergency department with sudden onset of shortness of breath that began 12 hours before presentation, associated with positional chest pain. She denied any trauma or infectious symptoms. Her only significant past medical history included severe dysmenorrhea and vitamin D deficiency. There was no history of smoking or asthma. Physical exam was notable for tachypnea and tachycardia, and an absence of wheezing on auscultation. An urgent chest radiograph showed bilateral abnormalities in the lungs (Fig).