Vasculitis: an overview
Vasculitis is inflammation and necrosis of blood vessel walls, classified by the Chapel Hill scheme into large, medium, small (ANCA-associated versus immune-complex), and variable-vessel disease, each with a vessel-size-predicted clinical syndrome. Diagnosis requires excluding mimics such as infective endocarditis and cholesterol embolization before confirming with serology and biopsy, and treatment is glucocorticoid induction plus cyclophosphamide or rituximab for organ-threatening disease.
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What this article covers
- Overview
Definition: vasculitis is inflammation and necrosis of blood vessel walls producing ischemia in the territory supplied; it is a family of conditions grouped by vessel caliber, not one disease.
- Epidemiology
GCA: the most common vasculitis in adults older than 50, incidence about 10 to 20 per 100,000 in White persons of European ancestry, women affected 2 to 3 times more than men.
- Risk factors
Ancestry: Takayasu arteritis and Behcet disease cluster in young women of Asian, Middle Eastern, or Mediterranean ancestry, unlike GCA's North European predominance.
- Pathophysiology
Large-vessel disease: granulomatous inflammation with T-lymphocytes, macrophages, and often giant cells spans the arterial wall, and intimal proliferation narrows the lumen.
- Clinical features
Large-vessel syndrome: new headache, temporal artery tenderness, jaw claudication, and amaurosis fugax in a patient older than 50 suggest GCA; asymmetric limb pressures, absent pulses, and bruits in a young woman suggest Takayasu arteritis.
- Differential diagnosis
Infective endocarditis: fever, embolic lesions, glomerulonephritis, and a positive ANCA can occur, but persistent bacteremia and an echocardiographic vegetation confirm infection; immunosuppressing…
- Diagnosis
What establishes the diagnosis: each vasculitis has its own classification criteria (the ACR 1990 criteria for GCA require 3 of 5: age 50 or older, new headache, temporal artery abnormality, ESR 50…
- Management
First, confirm the diagnosis and exclude infection, except when vision, an organ, or life is threatened, when treatment starts before biopsy.
- Complications
Vision loss: irreversible ischemic optic neuropathy from GCA is the reason treatment is never delayed for biopsy.
- Prognosis
GCA and AAV: GCA life expectancy with treatment approaches the general population's; AAV remission occurs in more than 90% of GPA (complete remission about 75%), but relapse is common.
- Prevention
Pneumocystis prophylaxis and bone protection: trimethoprim-sulfamethoxazole for anyone on prednisone 20 mg/day or more for 4 or more weeks, or receiving cyclophosphamide; bone densitometry…
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- Microscopic polyangiitis
Microscopic polyangiitis (MPA) is a pauci-immune small-vessel vasculitis, almost always with perinuclear antineutrophil cytoplasmic antibody (p-ANCA) targeting myeloperoxidase (MPO), that causes rapidly progressive crescentic glomerulonephritis and pulmonary alveolar hemorrhage without the granulomas, eosinophilia, or upper-airway disease of its ANCA-associated siblings. Diagnosis combines urine microscopy, ANCA serology, and biopsy, and treatment is glucocorticoids plus rituximab or cyclophosphamide induction followed by rituximab or azathioprine maintenance.
- Giant cell arteritis
Giant cell arteritis is a granulomatous large- and medium-vessel vasculitis of patients over 50 that threatens irreversible blindness through ischemic optic neuropathy. Diagnosis is clinical and must not delay treatment: start high-dose glucocorticoids immediately on suspicion, intravenous methylprednisolone pulse for visual loss, then confirm with temporal artery biopsy within 1 to 2 weeks and add tocilizumab as glucocorticoid-sparing therapy.
- Polyarteritis nodosa
Polyarteritis nodosa is a rare, antineutrophil cytoplasmic antibody (ANCA)-negative necrotizing vasculitis of medium and small arteries that spares the lungs and spares glomeruli, presenting with constitutional illness, mononeuritis multiplex, livedo reticularis, mesenteric ischemia, and renovascular hypertension. Diagnosis rests on biopsy or mesenteric/renal angiography, and treatment is glucocorticoids plus cyclophosphamide for severe idiopathic disease, or a short glucocorticoid course with antiviral therapy and plasma exchange when hepatitis B-associated.
- Cryoglobulinemia
Cryoglobulinemia is the presence of immunoglobulins that precipitate below 37 degrees Celsius, classified as type I (monoclonal, driven by a lymphoproliferative disorder, causing hyperviscosity) or mixed types II/III (immune-complex, driven mainly by hepatitis C virus infection, causing small-vessel vasculitis). Type I is treated by targeting the underlying clonal disorder; mixed disease is treated with direct-acting antiviral therapy for hepatitis C, escalating to glucocorticoids plus rituximab for organ-threatening vasculitis.