Diffuse alveolar hemorrhage resulting from Pauci-immune pulmonary capillaritis

a 27 year-old female patient, cocaine user, presenting hemoptysis and progressive dyspnea with onset 48 hours prior to hospital admission, without any other signs or symptoms. serum tests for infectious diseases, collagen disorders and vasculitis were negative. urinalysis was normal. computed tomography of the chest showed diffuse alveolar infiltrate, affecting mainly the lower left lobe. a thoracoscopic lung biopsy was performed to clarify the diagnosis. the histopathological findings showed capillaritis and diffuse intra-alveolar hemorrhage. treated with steroid and cyclophosphamide pulse therapy, a good clinical and radiographical response was obtained. the recently described pauci-immune pulmonary capillaritis is characterized by the presence of isolated pulmonary capillaritis and negative serum testing for auto-immune diseases.