Medium-vessel vasculitis
- Lesion
Three diseases of medium arteries: one tears holes in visceral arteries, one hits the coronaries of small children, one closes the limb vessels of smokers.
What it is
Medium-vessel vasculitis targets the main visceral arteries and their branches. Polyarteritis nodosa (PAN) is a segmental necrotizing arteritis of kidneys, gut, nerves and skin that spares the lungs and is not ANCA-associated; some cases follow hepatitis B. Kawasaki disease is an acute febrile illness of infants and young children with arteritis of large to medium vessels; its danger is coronary artery aneurysms. Thromboangiitis obliterans (Buerger disease) is a segmental thrombosing inflammation of arteries and veins of the limbs in heavy smokers.
Structure
- PAN: segmental transmural inflammation with neutrophils, eosinophils and mononuclear cells; fibrinoid necrosis; thrombosis; healed lesions are fibrotic with nodular thickening.
- Kawasaki: dense transmural inflammation of coronary arteries, less fibrinoid necrosis than PAN; healing leaves intimal thickening or aneurysms.
- Buerger: sharply segmental acute and chronic inflammation of arteries, veins and nearby nerves; occlusive thrombus containing microabscesses with granulomatous rims.
Three medium-vessel vasculitides compared
| Disease | Who | Lesion | Main danger |
|---|---|---|---|
| Polyarteritis nodosa | Young to middle-aged adults; hepatitis B in some | Segmental fibrinoid necrosis, lesions of different ages, microaneurysms | Renal and mesenteric infarcts, hypertension, mononeuritis multiplex |
| Kawasaki disease | Children under 5 | Transmural arteritis of coronary arteries | Coronary aneurysm, thrombosis, myocardial infarction |
| Thromboangiitis obliterans | Young heavy smokers | Inflammatory thrombus with microabscesses in arteries and veins | Digital ischemia, ulcers and gangrene |
Clinical notes
- Untreated PAN is often fatal; immunosuppression (and antivirals when hepatitis B is the cause) changes the outcome.
- Early treatment of Kawasaki disease with intravenous immunoglobulin greatly lowers the rate of coronary aneurysms; a Kawasaki-like multisystem inflammatory syndrome was seen in children after SARS-CoV-2 infection.
Test yourself
Think of the answer, then tap the question to see it.
Which organ is spared in classic polyarteritis nodosa?
The lungs (pulmonary arteries are spared), and there is no glomerulonephritis.
What is the main cardiac complication of Kawasaki disease?
Coronary artery aneurysms, which can thrombose or rupture and cause myocardial infarction.
What is the single most important step in thromboangiitis obliterans?
Complete stopping of tobacco use; the disease is strongly tied to smoking.
Elsewhere in DurgiPedia
Connections
Microorganisms1
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Polyarteritis nodosa: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Kawasaki disease: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025); Thromboangiitis obliterans: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.