Pulmonary vasculitides and pulmonary haemorrhage

At a glance

• Small-vessel vasculitis is the lung's main vasculitis: GPA, MPA, EGPA (the ANCA-associated vasculitides) and anti-GBM disease.
• The respiratory emergency is diffuse alveolar haemorrhage (DAH). Think of it in anyone with new bilateral infiltrates and a falling haemoglobin, with or without haemoptysis.
• Pulmonary-renal syndrome (lung haemorrhage plus glomerulonephritis) is ANCA vasculitis or anti-GBM until proven otherwise. Send ANCA and anti-GBM the same day.