Abstract Introduction Diffuse alveolar hemorrhage (DAH) is a life-threatening condition characterized by bleeding into alveolar spaces due to disruption of the alveolar-capillary barrier. Although autoimmune vasculitides are the most common causes, “bland” pulmonary hemorrhage can occur with anticoagulant use. Recognition is critical, as delay in diagnosis may be fatal. Case Presentation An 82-year-old woman with hypertension, Hashimoto’s thyroiditis, and recent breast lumpectomy was admitted for MRSA sepsis secondary to parotid infection. After stabilization, she developed new-onset atrial fibrillation and was treated with apixaban. In anticipation of possible abdominal surgery for small bowel obstruction, anticoagulation was transitioned to enoxaparin. Within hours of the first dose, she developed hemoptysis and diffuse epistaxis, followed by hypoxemic respiratory failure requiring intubation. CT angiogram revealed new bilateral ground-glass opacities consistent with alveolar hemorrhage. Bronchoscopy confirmed DAH with progressively hemorrhagic lavage aliquots. Enoxaparin was discontinued, and reversal with protamine sulfate, prothrombin complex concentrate, tranexamic acid, and vitamin K was initiated, leading to cessation of bleeding. Despite hemostasis, her course was complicated by septic shock and multilobar pneumonia, and she expired on day 33 of hospitalization. Discussion DAH related to low molecular weight heparin (LMWH) is exceedingly rare but well-documented. The temporal relationship between enoxaparin initiation and hemorrhage, along with resolution after reversal, supports causality. Advanced age, infection, malignancy, and endothelial injury likely increased susceptibility. Anticoagulant-associated DAH carries a high mortality rate (50%) despite optimal management. Conclusion LMWH-induced DAH, though rare, should be suspected in any anticoagulated patient presenting with hemoptysis and new diffuse infiltrates. Prompt discontinuation, reversal of anticoagulation, and supportive care are essential to improve outcomes. References: Hayashi S et al. Respirol Case Rep. 2013;1(1):2-4. Cengiz D et al. Thorac Res Pract. 2019;20(1):324-324. Ioachimescu O, Stoller JK. Cleve Clin J Med. 2008;75:1-10. This abstract is funded by: None
Brestel et al. (Fri,) studied this question.