Pulmonary-renal syndromes (PRS) are characterized by the simultaneous presence of diffuse alveolar hemorrhage and acute glomerulonephritis. The most common causes of PRS are ANCA-associated vasculitides, Goodpasture's syndrome and systemic lupus erythematosus. The clinical picture of PRS includes hemoptysis (not always present), acute-onset anemia and renal abnormalities ranging from isolated urinary abnormalities to rapidly progressive glomerulonephritis. The severity of the pulmonary involvement determines the mortality risk as well as the need for mechanical ventilation in intensive care. The diagnosis of PRS is based upon clinical, serological, radiological and histological findings. Immunosuppressive therapy, along with an adequate support therapy (especially aimed at avoiding microbial infection), needs to be started promptly and effectively to reduce both the mortality risk and long-term complications such as end-stage renal disease
