Granulomatosis with Polyangitis

The Entity formerly known as Wegeners 

Epidemiology

-Auto-immune dz, Men ~1.5x> Women affected
-Most common in those of European descent, can occur at any age but usually age 35-55

Timing

-Sub-acute to chronic (weeks to months)

Clinical presentation

-Chronic sinusitis most common initial complaint (67 %), can see saddle nose deformity on exam

-Ophthalmic involvement (conjunctivitis, episcleritis, optic nerve vasculitis etc.)
-Pulmonary involvement (71 % pulmonary infiltrates, nodules often cavitary, cough hemoptysis, DAH, diffuse alveolar hemorrhage)
-Renal involvement: can see dysmorphic RBC, RBC casts, biopsy reveals Crescentic necrotizing GN
-Constitutional symptoms (night sweats, weight loss, lethargy)
-Also involves CNS (Mononeuritis multiplex, CN palsy), Cardiac involvement (Pericarditis, Vasculitis etc.), Skin involvement (from palpable purpura to necrotic plaques)

Diagnosis

-Patient with sinusitis + pulmonary nodules + active urinary sediment AND positive C-ANCA have ~98 % post-test probability of GPA but C-ANCA alone is NOT specific
-Lung or Kidney biopsy if diagnosis unclear

Treatment 

Induction therapy: Steroids +-Cyclophosphamide +-Rituximab
Maintenance therapy: multiple options-Azathioprine, MTX, Rituximab, Leflunomide

Comparison between the THREE small vessel Vasculitis that can cause Pauci-immune GN (minimal to no immune complex deposition on kidney biopsy)