GIANT CELL ARTERITIS
GENERAL FEATURES
Giant cell arteritis (GCA) is an inflammatory disease that affects primarily the medium and large blood vessels of the head. Because the temporal artery is commonly involved, it is also referred to as temporal arteritis. A genetic predisposition is seen in patients with HLA-DR4 gene and others.
CLINICAL FEATURES
• Symptoms are headache, sensitivity of scalp to touch, jaw claudication, tongue or throat pain, and visual changes (eg, acute visual loss or decrease in visual acuity).
• Physical examination findings may include prominence of temporal arteries either with or without pulsation, tenderness in the temporal area, decreased pulses in the extremities, evidence of ischemia on funduscopic examination, carotid or subclavian artery bruits, and aortic regurgitation.
DIAGNOSIS
• The gold standard for diagnosis is temporal artery biopsy; but results may be negative in some patients.
• Other findings are ESR ≥50 mm/h, although ESR may be normal in some patients; elevated C-reactive protein level; elevated platelet count; and normochromic anemia.
• The usefulness of ultrasonography, MRI with contrast, CT with contrast, and positron emission tomography is debatable and subject to further study.
• The American College of Rheumatology classification of GCA notes that the presence of three of the following criteria is diagnostic for GCA with a 93.5% sensitivity and 91.2% specificity:
– Age 50 years and older at onset of symptoms
– Biopsy specimen demonstrating necrotizing arteritis with predominance of mononuclear cell infiltration or a granulomatous process, usually with multinucleated giant cells
– Decreased pulsation or tenderness of the temporal artery
– ESR ≥50 mm/h by the Westergren method
– New-onset localized head pain
TREATMENT
• The goal of treatment is to prevent irreversible blindness caused by ophthalmic artery occlusion.
• Treatment should be initiated immediately in patients whose symptoms and clinical findings suggest GCA. Temporal artery biopsy should be obtained to confirm the diagnosis after the initiation of corticosteroid therapy.
• High-dose corticosteroid therapy is the mainstay of treatment. Effective doses are usually 40 to 60 mg/d of prednisone in a single dose or divided doses.
• Prednisone dosages may be lowered at 2 to 4 weeks, followed by a slow taper over 9 to 12 months.
• Relapses are possible, and patients should be instructed to return emergently to the clinic if symptoms recur.