last authored: March 2011, Natalia Gorelik
last reviewed: April 2011, Ken Flegel
Temporal arteritis, also known as giant cell arteritis or cranial arteritis, is a chronic vasculitis of large- and medium-sized vessels. It occurs almost exclusively in individuals over 50 years old, with a mean age of diagnosis of 72. Although it is a systemic disease, it most commonly involves cranial arteries originating from the aortic arch, particularly the temporal arteries. Involvement of these arteries causes anterior ischemic optic neuropathy which may lead to blindness. When giant cell arteritis affects the aorta, it results in aortitis and may lead to aneurysms formation as well as claudication in the extremities.
Theodora is a 66 year-old woman who developed recurrent headaches over the past two weeks accompanied by pain in the jaw when chewing and fatigue. She has also been suffering from pain in the hips and stiffness, which she blamed on osteoarthritis.
What should Theodora’s doctor ask and do?
The etiology and pathogenesis of giant cell arteritis remain unclear.
Amongst the possible causes is genetic susceptibility since the disease is more common in people with HLA-DR4 or HLA-DRB1. An infection with mycoplasma pneumoniae, parvovirus B19 and chlamydia pneumoniae may serve as the trigger for the onset of the disease.
Risk factors include:
Giant cell arteritis appears to be a maladaptive inflammatory response to arterial injury. This inflammatory reaction involves the cellular immunity, including macrophages, T cells, antigen-presenting cells, macrophage-derived inflammatory cytokines, and HLA molecules. It affects the arterial tunica media vasorum and tunica adventitia. Branches of the internal and external carotid arteries are the most commonly involved sites. Occlusion of these blood vessels leads to the clinical picture of ischemia (eg. claudication, loss of vision, headaches). Giant cell arteritis can also involve the mid-sized arteries of any other organ.
A complete history remains the best tool to diagnose giant cell arteritis. The most significant symptoms in making the diagnosis include neck pain and jaw claudication. Headache and myalgia are frequently seen, but they are not specific to temporal arteritis.
The manifestations of temporal arteritis are variable and often transient. They include:
Findings on physical exam can include:
The first three items of the laboratory work-up are the most important in establishing a diagnosis of giant cell arteritis. A concomitant increase in ESR and CRP has a sensitivity of 88% and a specificity of 98%. An increased platelet count is highly specific (91%), but has a lower sensitivity (57%).
It is also important to note that a negative temporal artery biopsy does not rule out giant cell arteritis, as the granulomatous inflammation is not continuous throughout the blood vessel. Bilateral biopsies increase the likelihood of positive findings.
Ultrasound of temporal artery may show stenoses, occlusions, and a halo sign (i.e. hypoechoicity around involved arteries)
Transthoracic echocardiography or chest CT may reveal thoracic aortic aneurysms which are 17 times more common in temporal arteritis patients than in matched controls
The differential diagnosis includes:
The management of temporal arteritis aims at reducing symptoms and preventing visual loss.
Giant cell arteritis responds extremely well to glucocorticoid treatment. For uncomplicated disease, the therapy consists of 40 to 60 mg/d of prednisone for about 1 month, followed by a gradual tapering. When visual symptoms are present, it is important to initiate therapy immediately without awaiting for the pathology results. The treatment then consists of 3 days of 1000mg of intravenous pulse methylprednisolone followed by the same treatment as for uncomplicated temporal arteritis. Monitoring ESR and CRP to assess inflammatory activity helps in adjusting the tapering plan. An increase in ESR may be normal with decreased steroids and is not necessarily an indication of arteritis exacerbation, especially in a symptom-free person.
Relapses are frequent, occurring in about 60 to 85% of patients, and are palliated with an increased dosage of corticosteroids. Some studies report that addition of methotrexate might reduce the relapse rate, as well as shorten the course of steroid therapy.
Low-dose aspirin reduces the incidence of cranial ischemic complications and should be added to the glucocorticoid therapy.
Often, temporal arteritis is self-limited and lasts several months or years. In most patients, glucocorticoid therapy can eventually be discontinued without complications. In a few patients, however, the disease is chronic and prednisone must be continued for years.
Overall, temporal arteritis does not seem to decrease longevity. Nevertheless, it may lead to serious complications such as visual loss, which occurs in about 15 to 20% of patients. Usually the visual loss is already present prior to the initiation of therapy. It rarely arises once treatment is started (1 per cent frequency). Amongst patients presenting with vision deficits, about 13% experience a progression in visual problems with treatment. Increased age is associated with a higher risk of developing bilateral blindness.
Another complication of giant cell arteritis is the development of aortic aneurysms, usually affecting the ascending aorta. Yearly chest x-rays may be useful to identify this problem.
Lastly, about half of the patients with giant cell arteritis will eventually develop polymyalgia rheumatica.
Polymyalgia Rheumatica & Giant Cell Arteritis [Internet]. Quick Answers to Medical Diagnosis and Therapy. [cited 2010 Mar 25].
Sabatine MS, editor. Pocket Medicine. 3rd ed. Philadelphia: Lippincott Williams & Wilkins; 2008. Chapter 8, Rheumatology; p. 15-8.
Porter JG, Unwin BK. Temporal Arteritis [Internet]. Essential Evidence; 2009 Sep 23 [cited 2010 Mar 25].
Hunder GG. Clinical Manifestation of Giant Cell (Temporal) Arteritis. UpToDate. 2010 July 19.
Hunder GG. Treatment of Giant Cell (Temporal) Arteritis. UpToDate. 2008 Sep 29.
Hunder GG. Diagnosis of Giant Cell (Temporal) Arteritis. UpToDate. 2009 Jun 15.
Belliveau MJ, ten Hove MW. Five Things to Know About...: Giant Cell Arteritis. Canadian Medical Association Journal. 2011 March 22;183(5):581.
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