Etiology of Diffuse Alveolar Hemorrhage Many disorders can cause alveolar hemorrhage; they include Autoimmune disorders (eg, systemic vasculitides, Goodpasture syndrome, antiphospholipid antibody syndrome, connective tissue disorders) Cardiac disorders (eg, mitral stenosis) Coagulation disorders caused by diseases or anticoagulant drugs Drug reactions (eg, propylthiouracil, diphenylhydantoin, amiodarone, methotrexate, nitrofurantoin, bleomycin, montelukast, infliximab) Hematopoietic stem cell transplantation or solid organ transplantation Idiopathic pulmonary hemosiderosis Isolated pauci-immune pulmonary capillaritis Pulmonary infections (eg, hantavirus infection) Toxic exposures (eg, trimellitic anhydride, isocyanates, crack cocaine, certain pesticides) Symptoms and Signs of Diffuse Alveolar Hemorrhage Symptoms and signs of milder diffuse alveolar hemorrhage are dyspnea, cough, and fever; however, many patients present with acute respiratory failure, sometimes leading to death.