Idiopathic Pulmonary Hemosiderosis as a Mimic of Pulmonary Vasculitis: A Case Report and Review of the Literature

Purpose of Review Idiopathic pulmonary hemosiderosis (IPH) is one of the rarest and least understood causes of pulmonary hemorrhage in children. Illustrated by a complex case presentation, we discuss the clinical manifestations, diagnosis, pathology, proposed etiologies, and treatment of this rare disease. We also compare IPH with anti-glomerular basement membrane antibody syndrome (anti-GBM disease), another rare causes of pediatric pulmonary hemorrhage. Recent Findings Recent retrospective studies regarding IPH along with advanced immunotherapy have led to an improved understanding of how to best treat this condition, potential associations, and improved prognosis. Pathogenesis remains unknown, but several reports have suggested involvement of the alveolar capillary basement membrane. IPH is a poorly understood disease of unknown etiology that is a diagnosis of exclusion. Our patient was diagnosed with IPH after an exhaustive workup, including lung biopsy, into other immune-mediated causes of disease. While the pathogenesis of this rare disease remains elusive, our patient's immunofluorescent staining along the alveolar basement membrane without evidence of circulating antibody to type IV collagen raises the question of an immune-mediated pathogenesis of the disease with involvement of the alveolar basement membrane.