Temporal (giant cell) arteritis is a chronic vasculitis that affects **medium- and large-sized arteries **with a proclivity for the cranial branches of the arteries that originate from the aortic arch.
It is characterized pathologically by the presence of subacute granulomatous inflammation.
The inflammation is segmental, with intervening segments of normal and inflamed vessel wall.
Temporal arteritis is more common in patients over the age of 50, and occurs more frequently in women.
Nearly half of the patients with temporal arteritis also have polymyalgia rheumatica.
Symptoms of temporal arteritis include:
Without treatment, the monocular blindness of temporal arteritis can become permanent.
The gold standard for diagnosing temporal arteritis is temporal artery biopsy, though this should never delay treatment. Biopsy will demonstrate granulomatous inflammation of the media and adventitia with a lymphocytic infiltrate. Since the lesions are segmental, a relatively long (minimum 2 cm) segment of temporal artery is required for diagnosis. Note that a negative biopsy does not rule out the disease.
Patients with temporal arteritis will usually have a markedly elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Suspicion for temporal arteritis is often considered one of the only (if not the only) true indication for ordering an ESR because the gold standard for diagnosis (i.e. biopsy) is time-consuming, and an appropriately elevated ESR in a patient with the defining symptomatology has a high positive predictive value for a positive biopsy.
Physical examination will reveal a prominent temporal artery with beading, tenderness to palpation, and diminished or absent pulse.
Doppler ultrasound may show stenosis or occlusion of the involved artery, but is highly operator-dependent and should never replace biopsy as a means of making the diagnosis.
Fundoscopic examination in patients presenting with acute visual loss secondary to temporal arteritis may reveal cotton wool spots; a swollen, pale disc with blurred margins; and a cherry-red macula.
Examination of patients presenting later with permanent visual loss may demonstrate optic atrophy; a flat, pale disc; and a Marcus-Gunn pupil with a positive swinging flashlight test consistent with an afferent pupillary defect.
Patient suspected of having temporal arteritis should receive high-dose corticosteroid therapy immediately, treatment should NOT be delayed to obtain or confirm the biopsy results. Patients with visual loss should be admitted and given IV steroids.
Low dose aspirin is used to reduce the risk of permanent vision loss or stroke from vessel occlusion.