A 32-year-old man with hypoxemia and bilateral upper-lobe predominant ground-glass infiltrates on chest imaging.

Diffuse alveolar hemorrhage (DAH) is a rare, but potentially fatal, complication of antiphospholipid syndrome, and may present with acute and fulminant symptoms. We report a case of DAH presenting as sudden onset dyspnea in a gentleman with known antiphospholipid syndrome. Chest computed tomography angiography with pulmonary embolism protocol showed right lower lobe segmental filling defects, upper-lobe predominant diffuse ground-glass opacities, and centrilobular nodules bilaterally. The presence of DAH can be confirmed by bronchoalveolar lavage with serial aliquots, but this procedure typically does not elucidate the specific etiology for the hemorrhage. The treatment for patients with severe disease typically consists of a combination of immunosuppressive medications in the form of high-dose intravenous glucocorticoids plus rituximab, cyclophosphamide or mycophenolate; and/or plasma exchange. This case both provides an example of high-quality diagnostic imaging of diffuse alveolar hemorrhage as well as demonstrates the clinical and image-based improvement after treatment.