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Radiology > VASCULAR/INTERVENTIONAL
Temporal Arteritis
Article Last Updated: Mar 22, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 11  
Author: Anthony W Allen, MD, Chief, Interventional Radiology, Department of Radiology, Division of Interventional Radiology, Brooke Army Medical Center
Anthony W Allen is a member of the following medical societies: American College of Radiology
Coauthor(s):
Timothy Biega, MD, Staff Physician, Department of Radiology, Tripler Regional Medical Center;
Manish K Varma, MD, Chief of Interventional Radiology, Department of Radiology, Tripler Army Medical Center
Editors: Anthony Watkinson, MD, Professor of Interventional Radiology, The Peninsula Medical School; Consultant and Senior Lecturer, Department of Radiology, The Royal Devon and Exeter Hospital, UK; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Douglas M Coldwell, MD, PhD, Professor of Interventional Radiology, Department of Radiology, Professor of Interventional Radiology, University of Texas Southwestern Medical Center; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Kyung J Cho, MD, FACR, William Martel Professor of Radiology, Fellowship Program Director, Department of Radiology, Division of Interventional Radiology, University of Michigan Medical School
Author and Editor Disclosure
Synonyms and related keywords:
giant cell arteritis, systemic vasculitis, temporal arteries
Background
Temporal arteritis, or giant cell arteritis, is a common systemic vasculitis of unknown etiology. In 1890, Hutchinson originally described the condition as inflamed and swollen temporal arteries. In 1932, Horton expanded the definition. In general, temporal arteritis can be thought of as a vasculitis involving medium-to-large arteries originating from the aorta. Although it was originally believed to be a rare entity, it is more commonly recognized today.
Pathophysiology
The exact cause of temporal arteritis is not well delineated. It is characterized by a granulomatous inflammatory process that is most pronounced along the internal elastic lamina of arterial walls. Temporal artery biopsy demonstrates a predominance of mononuclear cells or multinucleated giant cells with fragmentation of the intima. Inflammation may be followed by intimal proliferation and eventual stenosis or occlusion of the involved arterial segment.
The clinical findings are a result of decreased blood flow and include jaw or tongue claudication; extremity stiffness; scalp tenderness; and visual changes with anterior ischemic optic neuropathy (AION), amaurosis, or optic atrophy leading to blindness in as many as 60% of patients.
Frequency
United States
Temporal arteritis occurs in an estimated 15-30 individuals per 100,000. It almost exclusively affects individuals older than 50 years and is believed to have a prevalence as high as 1 case per 500 individuals in this age group.
Mortality/Morbidity
To the author's knowledge, no controlled studies have been performed to compare patients with untreated temporal arteritis with those with treated arteritis. However, definitive evidence suggests that mortality rates in treated patients and those in untreated patients do not differ.
Race
The incidence is lower in blacks than in whites.
Sex
The female-to-male ratio is 4-6:1.
Age
Although temporal arteritis almost exclusively occurs in patients older than 50 years, well-documented cases have been reported in patients as young as 40 years.
Anatomy
Temporal arteritis can affect any medium or large artery, but the clinical signs and symptoms are usually related to the inflammation that occurs in the branches of the external carotid artery. Temporal arteritis is caused by inflammation of the internal elastic lamina of the arterial wall. Intradural cranial arteries have no elastic lamina. For this reason, temporal arteritis seldom affects the cerebral circulation.
In the region of the parotid gland, the external carotid artery terminates by dividing into the superficial temporal and maxillary arteries. The superficial temporal artery crosses the zygomatic process of the temporal bone and divides into frontal and parietal branches that traverse the scalp. The superficial temporal artery typically does not develop atherosclerotic plaques, and the vessel is reportedly observed on 88% of cerebral angiograms. In addition, angiography can demonstrate areas of constriction, beading, and microaneurysm formation that are fairly specific for temporal arteritis. The most common sites for abnormalities to occur anatomically and on imaging studies are in the distal subclavian, proximal axillary, brachial, brachiocephalic, and femoral arteries.
Clinical Details
Multiple symptoms may be present in the patient with temporal arteritis and are usually attributable to decreased blood flow in the affected anatomic area. These symptoms include headache, which may be unilateral; scalp tenderness; jaw and/or tongue claudication; and changes in vision, including blindness. Constitutional symptoms may be present as well, and these are likely the result of the inflammatory nature of the disease. Fever; anorexia; and stiffness of the neck, trunk, and extremities may be present.
In 1990, the American College of Rheumatology established criteria for the classification of temporal arteritis. In one study, investigators compared 214 patients with temporal arteritis with 593 control subjects and determined that if patients had 3 of the 5 criteria, temporal arteritis could be diagnosed with a sensitivity of 93.5% and a specificity of 91.2%. The 5 criteria are as follows: (1) age older than 50 years, (2) new onset of localized headache, (3) temporal artery tenderness or decreased temporal arterial pulse, (4) increased erythrocyte sedimentation rate (>50 mm/h), and (5) arterial biopsy showing necrotizing arteritis characterized by a predominance of mononuclear cell infiltrates or a granulomatous process.
Preferred Examination
Currently, temporal artery biopsy is the criterion standard for the diagnosis of temporal arteritis. A negative biopsy finding does not exclude the diagnosis. Angiography can be used when biopsy results are negative, or it can be used to help guide biopsy by demonstrating areas of abnormality. When performed, angiography is typically directed at the large branch vessels of the proximal aorta and extracranial carotid branch vessels. The temporal arteries are depicted well in almost 90% of patients. In patients with proximal artery stenoses, angioplasty can be used in addition to corticosteroid therapy for symptomatic relief.
Although angiography is one of the best-studied techniques, it is invasive and inconvenient. As a result, less-invasive procedures for evaluating the arterial anatomy have been sought. Magnetic resonance angiography (MRA) has results comparable to those of angiography in evaluating medium-to-large vessels. In some reported cases, MRA has successfully depicted disease in the temporal arteries. As the sensitivity of MRA continues to improve, it will likely become a more realistic method for evaluating stenotic lesions attributed to temporal arteritis.
Recent studies have revealed the benefit of ultrasonography in the diagnosis of temporal arteritis. Studies have demonstrated that characteristic changes, including stenoses and occlusions of temporal artery segments and a dark halo around the vessel, are reliably observed in patients with temporal arteritis. Doppler flow studies have also been performed, with promising results.
In February of 2000, a study of positron emission tomography (PET) scanning was undertaken to evaluate 18F-glucose uptake. This study demonstrated a sensitivity of 56%, a specificity of 98%, and a positive predictive value of 93% for the diagnosis of giant cell arteritis or polymyalgia rheumatica when thoracic vascular uptake was demonstrated.
Limitations of Techniques
Angiography is an excellent study; however, it is limited by the invasive nature of the examination and by the risks associated with the administration of contrast material.
MRA is a noninvasive examination, but it has limited use in evaluating smaller vessels, and imaging artifacts may result in false-positive results. In addition, larger vessels with mildly thickened walls can be missed.
Ultrasonography may not depict minor vascular changes or diseased vessels, such as intrathoracic vessels, that are not amenable to ultrasonography.
Arteritis, Giant Cell
Arteritis, Takayasu
Fibrous Dysplasia
Other Problems to be Considered
Atherosclerotic disease affects the temporal arteries in rare cases, and its changes may resemble those associated with temporal arteritis.
Findings
Radiographs are of no use in diagnosing temporal arteritis
Findings
Thickening of the arterial walls, stenosis, or occlusion may be demonstrated on contrast-enhanced CT scans.
Degree of Confidence
The findings can be observed in a variety of other disease processes.
False Positives/Negatives
CT commonly fails to depict mild inflammatory changes in the vessels. CT is not useful for the evaluation of small-vessel disease. In older persons, disease processes such as atherosclerotic disease are far more common than temporal arteritis and may result in similar CT findings.
Findings
MRI findings include loss of the normal flow void in affected vessels from occlusion or slow flow associated with disease. Enhancement of the arterial wall may be observed after the administration of gadolinium-based contrast material. MRA may also demonstrate stenoses, irregularity of the vessel wall, and beading or thickening of the vessel wall. Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans. As of late December 2006, the FDA had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble movingor straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.
Degree of Confidence
The findings can be observed in a variety of other disease processes.
False Positives/Negatives
MRI commonly will miss mild inflammatory changes of vessels. MRI is not useful for the evaluation of small-vessel disease. In the elderly, disease processes such as atherosclerotic disease are far more common than temporal arteritis and may result in similar MRI findings.
Findings
Ultrasonography can be used to evaluate small vessels such as the temporal arteries. Findings include stenoses and occlusion of the vessels. A characteristic hypoechoic halo has been described as surrounding the affected vessel that disappears after corticosteroid therapy. Ultrasonography is also useful in guiding biopsy.
Degree of Confidence
These findings can be observed with a variety of other disease processes. Findings may be negative in patients with minimal involvement of the temporal arteries. Ultrasonography cannot be used to evaluate vessels such as intrathoracic arteries that are more amenable to angiography or MRI.
False Positives/Negatives
Though unusual, atherosclerotic disease involving the temporal arteries may have an appearance similar to that of temporal arteritis. Minimally involved vessels may appear normal.
Findings
PET scanning has been used to evaluate unusual involvement that cannot be evaluated by means of surgical biopsy or ultrasonography.
Degree of Confidence
PET cannot be used to distinguish between the increased uptake observed with temporal arteritis and that observed in polymyalgia rheumatica.
Findings
Angiography is an invasive test with inherent risks associated with the procedure and with the administration of contrast material. Findings consist of the involvement of small-to-moderate vessels. Angiography can demonstrate areas of constriction, beading, and microaneurysm formation that are fairly specific for temporal arteritis. The occlusion of vessels and stenoses that are amenable to treatment may also be observed.
The most common sites for abnormalities to occur anatomically and on imaging studies are in the distal subclavian, proximal axillary, brachial, brachiocephalic, and femoral arteries. Atherosclerotic disease is a common finding in the older population; however, narrowings observed with atherosclerotic disease are typically short, segmental, and irregular, whereas stenoses in temporal arteritis are smooth, long, segmental, and tapered.
Degree of Confidence
Similar findings may be observed in patients with Takayasu arteritis and in those with atherosclerotic disease. Temporal artery biopsy is more definitive than angiography, and it can be guided by the arteriographic findings.
False Positives/Negatives
False-negative results may occur in a few patients in whom the temporal arteries are not well visualized.
Angioplasty and stent placement have been used in patients with ischemic symptoms who were not adequately treated with corticosteroid therapy. (As many as 58% of patients receiving long-term steroid therapy will have a major adverse effect. These include avascular necrosis of the hip, diabetes, congestive heart failure, peptic ulcers, hypertension, fractures, and depressive psychosis.)
Medical/Legal Pitfalls
- The failure to consider the diagnosis in an older patient with systemic complaints is the most likely medical pitfall.
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- The failure to diagnose this condition with the prompt initiation of corticosteroid therapy may lead to ischemia and blindness.
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- Ruling out temporal arteritis on the basis of a negative radiologic imaging study alone is a pitfall.
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Special Concerns
- No radiologic finding is specific for the diagnosis of temporal arteritis alone. Imaging studies are helpful in determining the extent of involvement and in identifying unsuspected areas of involvement.
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- Special care must be taken when invasive procedures such as arteriography are performed, because complications may occur.
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- Patients with temporal arteritis are older than other patients, and they may have concomitant illnesses that increase the risk of a procedure.
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- Patients with atherosclerotic disease or renal insufficiency have an increased risk of procedural complications.
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- The risk of a potentially serious reaction to the contrast material also must be taken into consideration.
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Temporal Arteritis excerpt Article Last Updated: Mar 22, 2007
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