Giant Cell Arteritis

Vasculitis may be localized, multifocal, or widespread. The disorder tends to affect arteries containing elastic tissue, most often the temporal, cranial, or other carotid system arteries. The aortic arch branches, coronary arteries, and peripheral arteries can also be affected. Mononuclear cell infiltrates in the adventitia form granulomas containing activated T cells and macrophages. Multinucleated giant cells, when present, cluster near the disrupted elastic lamina. The intimal layer is markedly thickened, with concentric narrowing and occlusion of the lumen.

Symptoms of giant cell arteritis may begin gradually over several weeks or abruptly.

Patients may present with systemic symptoms such as fever (usually low-grade), fatigue, malaise, unexplained weight loss, and sweats. Some patients are initially diagnosed as having fever of unknown origin. Eventually, most patients develop symptoms related to the affected arteries.

Severe, sometimes throbbing headache (temporal, occipital, frontal, or diffuse) is the most common symptom. It may be accompanied by scalp pain elicited by touching the scalp or combing the hair.

Visual disturbances include diplopia, scotomas, ptosis, blurred vision, and loss of vision (which is an ominous sign). Brief periods of partial or complete vision loss (amaurosis fugax) in one eye may be rapidly followed by permanent irreversible loss of vision. If untreated, the other eye may also be affected. However, complete bilateral blindness is uncommon. Vision loss is caused by arteritis of branches of the ophthalmic artery or posterior ciliary arteries, which leads to ischemia of the optic nerve. Funduscopic findings may include ischemic optic neuritis with pallor and edema of the optic disk, scattered cotton-wool patches, and small hemorrhages. Later, the optic nerve atrophies. Rarely, central blindness results from infarction in the occipital cortex caused by arterial lesions in the distal cervical region or base of the brain. The incidence of visual disturbances has declined over the past 5 decades, likely because giant cell arteritis is recognized and treated before visual disturbances develop.

Intermittent claudication (ischemic muscle pain) may occur in jaw muscles and muscles of the tongue or extremities. Jaw claudication is noted especially when firm foods are chewed. Jaw claudication and diplopia are associated with a higher risk of blindness.

Neurologic manifestations, such as strokes and transient ischemic attacks, can result when the carotid or vertebrobasilar arteries or branches are narrowed or occluded.

Thoracic aortic aneurysms and dissection of the aorta are serious, often late complications of aortitis and may progress in the absence of other symptoms.

• Erythrocyte sedimentation rate (ESR), C-reactive protein, and complete blood count (CBC)

• Biopsy, usually of the temporal artery

• Sometimes, temporal artery ultrasound

Giant cell arteritis is suspected in patients > 55 if any of the following develops, especially if they also have symptoms and laboratory evidence of systemic inflammation:

• A new type of headache

• Any new symptom or sign compatible with ischemia of an artery above the neck

• Jaw muscle pain during chewing

• Temporal artery or scalp tenderness

• Unexplained subacute fever or anemia

The diagnosis of giant cell arteritis is more likely if patients also have symptoms of polymyalgia rheumatica.

Physical examination may detect swelling and tenderness, with or without nodularity or erythema, over the temporal arteries, sometimes with loss of a palpable pulse. Temporal arteries can become prominent. A temporal artery that rolls under the examiner’s fingers, rather than collapses, is abnormal. The large arteries of the neck and branches of the aorta should be evaluated for bruits.

If the diagnosis of giant cell arteritis is suspected, biopsy of an artery is recommended. Because inflamed segments often alternate with normal segments, a segment that appears abnormal should be sampled if possible. Usually, the temporal artery is biopsied from the side that is symptomatic, but the occipital artery can also be biopsied if it appears abnormal. The optimal length of temporal artery to remove is unclear, but longer samples, up to 5 cm, increase the yield. The added diagnostic value of contralateral biopsy is small. Treatment should not be delayed to do the biopsy. Because inflammation resolves slowly, the temporal artery biopsy can be done up to 2 weeks after corticosteroid treatment is started.

Color Doppler ultrasonography of the temporal artery may detect vessel wall edema, seen as a halo, when performed by experts, and may come to substitute for temporal artery biopsy in the diagnosis of giant cell arteritis (1). Ultrasound of the temporal artery should be done before treatment is started or within 5 days, because corticosteroids decrease the test sensitivity. Among many advantages, the test is noninvasive, involves no exposure to radiation, and can image other cranial vessels. However, the diagnostic usefulness of temporal artery ultrasound is heavily dependent on the ultrasound operator skills and equipment.

Imaging of the aorta and its branches should be done at the time of diagnosis and then periodically after, even in the absence of suggestive symptoms or signs (see table Imaging Tests Used in Takayasu Arteritis).

• Corticosteroids

Treatment should be started as soon as giant cell arteritis is suspected. Even if biopsy is delayed for up to 2 weeks, the pathology should still be evident.

Tocilizumab is an effective option that may reduce exposure to corticosteroids (1). When combined with corticosteroids, tocilizumab has shown efficacy superior to corticosteroids alone (1-3

4).