Abstract Background Idiopathic pulmonary hemosiderosis (IPH) is an uncommon cause of diffuse alveolar hemorrhage (DAH) characterized by recurrent intra alveolar bleeding and hemosiderin laden macrophages. Although classically seen in children, it is rarely present in adults, creating diagnostic challenges due to nonspecific symptoms and variable radiologic patterns. It’s a diagnosis of exclusion requiring rule out for autoimmune, infectious, drug-related, and exposure related causes. Transbronchial lung cryobiopsy (TLBC) has recently emerged as a minimally invasive alternative to surgical lung biopsy, offering high quality tissue with preserved architecture. Case Presentation A 63-year-old woman with chronic kidney disease, atrial fibrillation, hypertension, type 2 diabetes, and prior tobacco use presented with progressive exertional dyspnea and bilateral infiltrates of waxing and waning pattern. Denied hemoptysis, vaping, recent illness, travel history or bird exposure. Lung exam revealed diminished sounds with fine right lower lobe crackles.CT chest two days before evaluation showed prominent right lower lobe infiltrates with resolving left lower lobe consolidation and new left upper lobe nodules, demonstrating a waxing and waning pattern of pulmonary involvement. Bronchoscopy with sequential bronchoalveolar lavage produced progressively hemorrhagic aliquots, and cytology revealed numerous hemosiderin-laden macrophages, consistent with chronic alveolar hemorrhage.Right lower lobe transbronchial and cryobiopsies showed benign lung parenchyma with abundant intra alveolar hemosiderin laden macrophages and edema but no granulomatous inflammation, vasculitis, fibrosis, or malignancy. Serologies for ANA, ANCA, and anti-GBM antibodies were negative. Kidney biopsy demonstrated diabetic glomerulosclerosis without immune complex deposition or vasculitis. These findings confirmed idiopathic pulmonary hemosiderosis. Discussion IPH is a diagnosis of exclusion in adults with unexplained alveolar hemorrhage. Radiologic waxing and waning nodules or infiltrates reflect recurrent alveolar bleeding episodes. BAL findings of siderophages support hemorrhage but are nonspecific; histopathology remains critical to rule out capillaritis or immune deposition. A hallmark of IPH is the absence of capillaritis, granulomas or immune complex deposition on biopsy. In this case, TLBC played a crucial role in providing high-quality, artifact-free tissue that enabled confident exclusion of alternative etiologies with reduced procedural morbidity compared to surgical lung biopsy. Recurrent alveolar bleeding in IPH leads to formation of free radicals through Fenton reaction which promotes pulmonary fibrosis. Conclusion This case highlights idiopathic pulmonary hemosiderosis as a rare but important cause of DAH in adults with waxing-waning pulmonary infiltrates. TLBC serves as an effective diagnostic tool providing high quality tissue sample distinguishing IPH from immune mediated and vasculitic disorders. Early recognition allows timely treatment to prevent progression to fibrosis and respiratory failure. This abstract is funded by: none
Biscuitwala et al. (Fri,) studied this question.