C62-20 The Hidden Hemorrhage: Delayed Detection of Idiopathic Pulmonary Hemosiderosis Behind Autoimmune Hemolytic Anemia

Introduction Diffuse alveolar hemorrhage (DAH) is a rare but potentially life-threatening condition in children resulting from autoimmune, infectious, or idiopathic causes. Autoimmune hemolytic anemia (AIHA) can coexist with immune-mediated lung disease, complicating and delaying both diagnosis and management. Early recognition of pulmonary involvement is critical to prevent irreversible damage. Case Report An 11-year-old girl with AIHA presented with recurrent episodes of fatigue, dyspnea, and anemia. Her symptoms were attributed to AIHA exacerbations and managed with rituximab and systemic steroids. Pulmonology evaluation was sought when she presented with hypoxemia requiring oxygen supplementation. Chest CT showed bilateral diffuse ground-glass opacities with interlobular septal thickening, more prominent in the lower lobes. These findings raised concern for pulmonary hemorrhage, infection, or inflammatory pneumonitis. A bronchoscopy was performed, and bronchoalveolar lavage (BAL) cytology showed numerous hemosiderin-laden macrophages, consistent with alveolar hemorrhage. BAL studies did not suggest an infectious process. An extensive autoimmune and rheumatologic work up was negative. Lung biopsy revealed pulmonary hemosiderosis with patchy fibrosis and mild chronic pneumonitis, without granulomas or evidence of infection. Given the possible association between pulmonary hemosiderosis and cow’s milk hypersensitivity (Heiner syndrome), milk-specific IgE and IgG antibodies were tested and came back negative.Based on clinical, radiologic, and pathologic findings, she was diagnosed with type 3 idiopathic pulmonary hemosiderosis (IPH)—recurrent alveolar hemorrhage without an identifiable autoimmune, infectious, or hypersensitivity cause.She was treated with pulse corticosteroids followed by a gradual taper. Rituximab infusions were resumed, with dosing intervals adjusted according to B-cell repopulation studies. She continues to show steady clinical and radiologic improvement. Follow-up pulmonary function testing revealed a mild restrictive defect with progressive improvement in total lung capacity, while spirometry, diffusion capacity, and six-minute walk test remained within normal limits. Discussion This case highlights recurrent DAH in a child with AIHA, ultimately diagnosed as type 3 IPH. Nonspecific respiratory symptoms and overlapping anemia contributed to diagnostic delay. BAL cytology for hemosiderin-laden macrophages remains crucial for detection, while lung biopsy confirms IPH when noninvasive testing is inconclusive.Early recognition and multidisciplinary management are essential to prevent fibrosis and preserve lung function. Clinicians should consider DAH in children with autoimmune cytopenias who present with unexplained hypoxemia or abnormal chest imaging.