Microscopic polyangiitis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Ali Poyan Mehr, M.D. [2]Associate Editor(s)-in-Chief: Krzysztof Wierzbicki M.D. [3]

Overview

Microscopic polyangiitis must be differentiated from other diseases that cause purpura, alveolar hemorrhage, fever, arthralgia, myalgia, necrotizing extra-capillary glomerulonephritis, such as Granulomatosis with polyangiitis and Eosinophilic granulomatosis with polynagiitis.

Differentiating Microscopic polyangiitis for other diseases

Microscopic polyangiitis must be differentiated from other diseases that cause purpura, alveolar hemorrhage, necrotizing extra-capillary glomerulonephritis, such as Eosinophilic granulomatosis with polyangiitis and Granulomatosis with polyangiitis.

Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis serological findings
	Eosinophilic granulomatosis with polyangiitis	Granulomatosis with polyangiitis	Microscopic polyangiitis
Cytoplasmic ANCA (cANCA)		90% positive
Perinuclear ANCA (pANCA)	30 to 40% positive		60 to 80% positive
Myeloperoxidase antigen	40% sensitivity	10% sensitivity	30% sensitivity
Proteinase 3 antigen	<5% sensitivity	70-80% sensitivity	60% sensitivity

Differentiating Microscopic polyangiitis from other Diseases

Microscopic polyangiits must be differentiated form other diseases that cause purpura, alveolar hemorrhage, and arthralgia such as:

• Eosinophilic granulomatosis with polyangiitis
• Granulomatosis with polyangiitis
• Polyarteritis Nodosa
• Infective Endocardtitis
• Leukocytoclastic vasculitis
• Crescentic glomerulonephritis
• Acute mesenteric ischemia
• Cryoglobulinemia