Abstract Diffuse alveolar hemorrhage (DAH) is a serious pulmonary manifestation of ANCA-associated vasculitis. Although hemoptysis, anemia, and new bilateral infiltrates may strongly suggest the diagnosis, bronchoscopy with bronchoalveolar lavage (BAL) remains essential for confirmation and for excluding competing etiologies. We present an 84-year-old man with end-stage renal disease secondary to MPO-positive ANCA vasculitis who presented with new-onset hemoptysis and dyspnea. Chest imaging demonstrated diffuse bilateral alveolar infiltrates, and hemoglobin declined from 10 g/dL to 7 g/dL within 48 hours. Blood and respiratory cultures, viral testing, and MRSA screening were negative, and apixaban was held. Given his vasculitic history and rapid clinical decline, bronchoscopy with BAL was performed to confirm DAH. Sequential BAL aliquots from all lobes remained persistently bloody, establishing the diagnosis. No endobronchial lesions or mucus plugging were observed. Post-procedure imaging showed expected transient worsening of opacities without new effusions. The patient received pulse-dose intravenous methylprednisolone, nebulized tranexamic acid, and empiric cefepime for possible superimposed pneumonia. Hemodialysis continued with 2 L ultrafiltration. Over several days, oxygen requirements improved from high-flow nasal cannula (FiO2 35-40 %) to 4 L/min nasal cannula, accompanied by mild radiographic improvement of opacities. This case highlights the critical confirmatory role of bronchoscopy in vasculitic lung disease. Even when DAH is clinically suspected, direct visualization and sequentially hemorrhagic BAL aliquots provide the definitive evidence needed to justify immunosuppressive escalation while excluding infection. Here, bronchoscopy served not as a diagnostic exploration but as a confirmatory step that anchored management decisions and guided corticosteroid therapy. Objective confirmation of DAH enables clinicians to initiate high-dose corticosteroids with confidence, monitor therapeutic response, and establish a baseline for future relapses. This case underscores how timely bronchoscopy refines diagnostic certainty and directly influences outcomes in MPO-ANCA-related pulmonary disease. This abstract is funded by: None
Parikh et al. (Fri,) studied this question.