Granulomatosis with polyangiitis (GPA)

Wegener's granulomatosis

Wegener's granulomatosis is an autoimmune condition associated with a necrotizing granulomatous vasculitis, affecting both the upper and lower respiratory tract as well as the kidneys.

Features

• upper respiratory tract: epistaxis, sinusitis, nasal crusting, otitis media, mastoiditis, oral and gingival involvement
• lower respiratory tract: dyspnoea, haemoptysis
• rapidly progressive glomerulonephritis ('pauci-immune', 80% of patients)
• saddle-shape nose deformity
• also: vasculitic rash, eye involvement (e.g. proptosis), cranial nerve lesions

Investigations

• best initial test = **c-**ANCA positive in > 90%, pANCA positive in 25%
• chest x-ray: wide variety of presentations, including cavitating lesions
• biopsy is the most accurate test - (e.g. renal biopsy: epithelial crescents in Bowman's capsule)
• accuracy from higher to lower - Lung > renal > sinus

Management

• Steroids (Prednisone)
• Cyclophosphamide (90% response) - consider PCP prophylaxis with Bactrim
• Rituximab in relapsing case (RAVE trial shows it is superior to cyclophosphamide in relapse group)
• plasma exchange