Diffuse Alveolar Hemorrhage Mimicking Pneumonia in a Patient With Interstitial Lung Disease on Ticagrelor.

Diffuse alveolar hemorrhage (DAH) is a rare and potentially life-threatening cause of acute hypoxemic respiratory failure and may be difficult to diagnose in patients with underlying interstitial lung disease (ILD). Ticagrelor frequently causes dyspnea, but DAH related to its use is exceedingly uncommon. We report the case of a 74-year-old man with chronic ILD and recent percutaneous coronary intervention who presented with progressive dyspnea, hypoxemia, and diffuse bilateral ground-glass opacities while receiving dual antiplatelet therapy with ticagrelor. Initial evaluation favored infection or ILD progression. Bronchoscopy with bronchoalveolar lavage demonstrated progressively bloody aliquots, establishing the diagnosis of DAH. Infectious, autoimmune, and thromboembolic causes were excluded, and the temporal relationship to ticagrelor supported a drug-induced etiology. This case highlights the diagnostic challenge of DAH in ILD patients and emphasizes the need for early consideration of medication-related hemorrhage in patients receiving ticagrelor who develop unexplained hypoxemia or hemoptysis.