Rheum| Medium Vessel Vasculitis

4.02 Medium Vessel Vasculitis Rheumatology review for the USMLE Step 1 exam. Vasculitis: inflammation of blood vessels, classified by the size of the blood vessels affected Medium vessel vasculitis affects the main visceral arteries and veins, and their initial branches Three types of medium vessel vasculitis are discussed: polyarteritis nodosa, Kawasaki disease (mucocutaneous lymph node syndrome), and Buerger disease (thromboangiitis obliterans) Polyarteritis nodosa affects middle-aged to older men and is idiopathic, but can be secondary to other diseases, including hepatitis B Histology findings show transmural inflammation with fibrinoid necrosis in early lesions, and string-of-beads sign in angiogram Symptoms include constitutional symptoms, abdominal pain and melena, and hypertension caused by damage to the renal arteries Kawasaki disease most commonly affects young Asian children, and is triggered by upper airway infections Symptoms include conjunctival injection, desquamating rash, cervical lymphadenopathy, strawberry tongue, and prolonged fever Kawasaki disease has a predilection for the coronary vessels, which can lead to aneurysm rupture and thrombi development Treatment for Kawasaki disease includes IVIG and aspirin to prevent complications