Microscopic Polyangiitis

• Clinically similar to GPA but not granulomatous and without upper airway involvement. The majority of the patients have renal involvement (rapidly progressive glomerulonephritis) and some pulmonary, neurologic or cutaneous manifestations.

• Diagnosis is based on similar laboratory findings, positive ANCA (commonly MPO) and biopsy shows necrotizing non-granulomatous vessel inflammation.

• Treatment approach for MPA is similar as GPA.