Pulmonary-renal syndrome: a life threatening but treatable condition.

Pulmonary renal syndrome (PRS) describes the occurrence of renal failure in association with respiratory failure, characterised by autoimmune-mediated rapidly progressive glomerulonephritis (RPGN) and diffuse alveolar haemorrhage (DAH), respectively. PRS is associated with significant morbidity and mortality, and prompt diagnosis and treatment significantly improve outcomes. Prompt diagnosis of PRS requires a high index of suspicion, as clinical features are non-specific, and immunological testing aids the diagnosis in many cases. The diagnostic evaluation of DAH and RPGN is outlined in the context of the important differential diagnoses. The commonest causes of PRS include antineutrophil cytoplasm antibody (ANCA)-associated vasculitis and antiglomerular basement membrane disease. As such, more emphasis has been placed on these two conditions in addition to an overview of the less common causes of PRS. We provide a practical review of the diagnostic evaluation, current treatment strategies and clinical outcomes of PRS for renal, respiratory and general physicians.