TOC | Rheumatology
Temporal Arteritis SX | DX | RX
REF: JAMA. June 12, 2002;287:2996-3000
Temporal arteritis is the most common form of systemic vasculitis in adults. The disease is defined as a panarteritis that preferentially involves the extracranial branches of the carotid artery. Aging is the single greatest risk factor for the disease: TA virtually never occurs before the age of 50 years, and the annual incidence rises steadily thereafter, from 1.54 of 100 000 people in the sixth decade of life to 20.7 of 100 000 people in the eighth decade. The average age of onset of TA is 72 years.
Classic Symptoms & Findings in Temporal Arteritis
Atypical Manifestations of Temporal Arteritis
Establishing the Diagnosis
To be classified as having TA, a patient must meet 3 of the following 5 criteria established by the American College of Rheumatology:
However, these classification criteria were never meant to serve as diagnostic criteria. Others have demonstrated the limitations of these criteria, including having a positive predictive value of only 29%.
In clinical practice, establishing the diagnosis of TA usually requires a biopsy of the temporal artery. Because skip lesions are believed to occur in TA, diagnosis is facilitated by obtaining large biopsy specimens (>2 cm long) and by examining multiple pathologic sections. The administration of corticosteroids given for less than 2 weeks does not reduce the yield of temporal artery biopsy. Bilateral temporal artery biopsies are not usually needed because they are concordant in 95% to 99% of cases. Patients with large artery involvement are diagnosed by arteriography or magnetic resonance angiography, either of which may demonstrate long segments of smooth stenoses. Temporal artery biopsy is positive in only about half of patients who manifest large artery disease. Duplex ultrasonography has identified abnormalities in 93% of patients with TA but the technique is operator-dependent and the sensitivity and specificity of temporal artery ultrasound outside of a few research centers are unknown. It is also too early to tell whether the abnormalities seen on positron emission tomographic scanning will be useful diagnostically. Therefore, unless the patient has large artery disease, which is best diagnosed by angiography, all patients suspected of having TA should undergo temporal artery biopsy.
Approach to Treatment
Because the central goal in managing TA is to prevent blindness, treatment should be initiated immediately whenever the disease is strongly suspected. Most authorities believe that TA requires starting prednisone in the range of 60 mg/d. In contrast, isolated PMR, which is 3 times more common than TA, requires only 10 to 20 mg/d of prednisone at the start of therapy. The rate of tapering prednisone is chiefly determined by the patient's symptoms.
Although prednisone is the cornerstone of therapy, 60% of patients relapse during or after prednisone tapers. In addition, the long duration of prednisone therapy required to treat TA (often >2 years) and the high rate of prednisone adverse effects (weight gain, diabetes, hypertension, and compression fractures) have prompted searches for steroid-sparing agents.