Management of Giant Cell Arteritis and Polymyalgia Rheumatica

Author: Sandra Meskimen, Robert L. Blake Jr.
Date: April 1, 2000

Giant cell arteritis and polymyalgia rheumatica are closely related disorders that affect persons more than 50 years of age and cause substantial morbidity. Patients with giant cell arteritis typically have a localized headache, nonspecific systemic symptoms, temporal artery tenderness and a high erythrocyte sedimentation rate (ESR). The diagnosis is confirmed by characteristic pathologic findings on temporal artery biopsy. Patients with polymyalgia rheumatica usually have similar nonspecific systemic symptoms, proximal muscle pain and stiffness, and an elevated ESR. The diagnosis is based on the clinical findings. Both disorders are treated with corticosteroids: high dosages for giant cell arteritis (prednisone in a dosage of 40 to 60 mg per day) and lower dosages for polymyalgia rheumatica (prednisone in a dosage of 10 to 20 mg per day). Symptom relief in response to treatment is rapid and reinforces the diagnosis. After normalization of the ESR, the corticosteroid is tapered, with the patient monitored closely for symptom recurrence. Most patients require corticosteroid therapy for two to three years and experience one or more treatment complications. (Am Fam Physician 2000;61:2061-8,2073.)

Giant cell arteritis and polymyalgia rheumatica are closely related clinical conditions that are sometimes considered to represent different manifestations of the same underlying disease process. Substantial impairment of function can occur with polymyalgia rheumatica, and blindness is a serious complication of giant cell arteritis. Because family physicians encounter both of these conditions in their practices, they should have a systematic approach to diagnosis and treatment.

Epidemiology

Giant cell arteritis and polymyalgia rheumatica are rare in persons less than 50 years of age. The incidence of each disorder increases with age, and both conditions are approximately two times more common in women than in men.(1)

Prevalences vary considerably in different ethnic and racial groups. Both disorders occur more often in whites than in blacks, Hispanics or Asians.(1) Geographically, prevalences increase as residence moves from southern to northern latitudes.(1)

In the United States, the reported annual incidence of giant cell arteritis ranges from 0.49 to 27.3 cases per 100,000 population more than 50 years of age.(1) The annual incidence of polymyalgia rheumatica is approximately three times higher.(2)

Clinically, considerable overlap exists between the two conditions. Approximately one half of patients with giant cell arteritis meet diagnostic criteria for polymyalgia rheumatica, and 15 to 25 percent of patients with polymyalgia rheumatica have concurrent giant cell arteritis or will develop manifestations of the disorder in the future.(3)

Little is known about causative factors for giant cell arteritis or polymyalgia rheumatica. The most prevalent speculation is that these disorders result from immunologic responses to infectious triggers in genetically susceptible persons.(4)

Pathology

Giant cell arteritis, also known as temporal arteritis or cranial arteritis, is a vasculitis of the large and medium arteries of the head and neck. Arteries below the aortic arch and veins are rarely involved. Microscopically, the inflammation of arterial walls is often patchy and segmental, and it is characterized by the infiltration of mononuclear cells and the presence of giant cells.(1)

In polymyalgia rheumatica, pathologic findings are variable and may be minimal or absent. There is no consistent pathology of muscle. Vasculitis may be present, and lymphocytic synovitis is sometimes found in large joints.(2)

Diagnosis

GIANT CELL ARTERITIS

The American College of Rheumatology (ACR) has developed diagnostic criteria for giant cell arteritis (Table 1).(5) Three of the five criteria must be met to support the diagnosis.

Symptoms. Approximately two thirds of patients with giant cell arteritis have new-onset headache. This headache is often present on a daily basis and is quite bothersome. The headache may be generalized, but it is more commonly unilateral and localized to the temporal area. When headache is absent or mild, the index of suspicion for the disorder is frequently low, and the diagnosis may be delayed for weeks or even months.

Patients with giant cell arteritis often have a variety of other symptoms, such as malaise, fatigue, low-grade fever, anorexia, weight loss, myalgias or arthralgias. They may also have various visual symptoms, including blurring and scotomas. The onset of these symptoms may be abrupt or insidious.

Jaw claudication in patients more than 50 years of age has fairly high specificity but only moderate sensitivity (45 to 50 percent) for giant cell arteritis.(1,2) Pain on chewing may be unilateral, but it is more often bilateral and frequently involves the masseter and temporalis muscles.

Physical Findings. In patients with giant cell arteritis, the physical findings are highly variable and frequently nonspecific. Nonetheless, the physical examination is important for detecting signs of neoplasm, infection, connective tissue disease and other conditions that can produce the nonspecific symptoms.

Fever and documented weight loss may be present but frequently are absent. Tenderness of one or both temporal arteries or of the adjacent scalp is often present. Temporal artery pulsations may be decreased or absent, but the classic finding of a nonpulsatile nodular temporal artery is uncommon. The funduscopic examination is usually normal but may show pallor or edema of the optic disc.

Patients with giant cell arteritis have few, if any, objective findings relating to muscles or joints. However, findings of coexisting osteoarthritis are often present. Muscle strength is normal.

Laboratory Findings. The erythrocyte sedimentation rate (ESR) is the most important laboratory test in the evaluation of patients with suspected giant cell arteritis. The ESR is almost always elevated, frequently to greater than 100 mm per hour. Occasionally, the ESR may be as low as 40 or 50 mm per hour; rarely, it may be normal.(2)

A mild normocytic, normochromic anemia is frequently present. The white blood cell count is usually normal but may be mildly elevated. The serum alkaline phosphatase level may be mildly elevated. Less commonly, mild elevation of aminotransferase levels is present.

Temporal Artery Biopsy. If the clinical picture is confusing, a temporal artery biopsy is crucial to establish the diagnosis of giant cell arteritis. Because of the patchy distribution of the inflammation, an arterial segment at least 3 cm long (preferably 5 cm long) should be obtained for examination.(1) Occasionally, both temporal arteries need to be sampled to resolve the diagnostic dilemma. Biopsy of the temporal artery is a simple, low-risk procedure, and complications are rare.

The role of temporal artery biopsy is less clear when the findings of the history, physical examination and laboratory tests strongly indicate the diagnosis of giant cell arteritis. Some authorities recommend pathologic confirmation of the diagnosis in all patients because of the potentially serious side effects of long-term corticosteroid therapy.(1,2,4) Other authorities believe that biopsy is not necessary when patients have typical symptoms and physical findings with a high ESR.(5)

According to the ACR criteria, giant cell arteritis can be diagnosed without a biopsy. The issue is complicated by the fact that biopsies are not always positive, even when giant cell arteritis is present.(1)

Color Duplex Ultrasonography. The use of color duplex ultrasonography of the temporal arteries is under investigation as a diagnostic tool for giant cell arteritis. The sensitivity and specificity of this technique may prove to be sufficiently high to obviate the need for biopsy in some patients.(6)

POLYMYALGIA RHEUMATICA

One set of diagnostic criteria for polymyalgia rheumatica is presented in Table 2.4

Symptoms. In patients with polymyalgia rheumatica, symptoms may develop abruptly or insidiously. The most common symptom is aching pain involving large proximal muscle groups. Morning stiffness is often present. Initially, the pain may be unilateral or bilateral. As the condition progresses, pain is almost always bilateral, involves the neck, shoulders, back, hips and thighs, and increasingly interferes with physical function.

Muscle pain is frequently accompanied by malaise, fatigue and a low-grade fever. Some patients experience swelling of their hands and feet.

Physical Findings. On physical examination, patients may have a low-grade fever. Weight loss may be present. Proximal muscles may be tender, but muscle strength is good. The tender points characteristic of fibromyalgia are absent. Occasionally, patients have evidence of synovitis and peripheral edema.(7)

TABLE 1The American College of RheumatologyClassification Criteria for Giant Cell Arteritis[*]Patient age of 50 years or olderNew onset of localized headacheTemporal artery tenderness or decreased temporal artery pulseErythrocyte sedimentation rate of 50 mm per hour or greaterAbnormal temporal artery biopsy[*]--The diagnosis requires the presence of at least three criteria.Adapted with permission from Hunder GG, Bloch DA, Michel BA, Stevens MB,Arend WP, Calabrese LH, et al. The American College of Rheumatology 1990criteria for the classification of giant cell arteritis. Arthritis Rheum1990;33:1122-8.TABLE 2Diagnostic Criteriafor Polymyalgia RheumaticaPatient age of 50 years or olderAching and morning stiffness for at least one month and affecting atleast two of the following areas: Shoulders and upper arms Hips and thighs Neck and torsoErythrocyte sedimentation rate greater than 40 mm per hourExclusion of other diseasesRapid response to corticosteroid therapyAdapted with permission from Evans JM, Hunder GG. Polymyalgia rheumaticaand giant cell arteritis. Clin Geriatr Med 1998;14:455-73.TABLE 3Corticosteroid Therapy for Giant Cell ArteritisStarting dosage Prednisone in a dosage of 40 to 60 mg per day until the ESR is normal and the patient is asymptomaticDosage reduction Decrease the dosage by 2.5 to 5 mg per day every two weeks to a dosage of 20 mg per day; then decrease the dosage by 10 percent every 2 weeks to a dosage of 10 mg per day; then decrease the dosage by 1 mg per day every 4 weeks. or Decrease the dosage by 10 percent every 2 weeks to a dosage of 10 mg per day; then decrease the dosage by 1 mg per day every 4 weeks.Monitoring Monitor the patient for symptom recurrence throughout the steroid taper; monitor the ESR every 4 weeks for 2 to 3 months, then every 8 to 12 weeks until 12 to 18 months after the cessation of therapy.ESR = erythrocyte sedimentation rate.TABLE 4Corticosteroid Therapy for Polymyalgia RheumaticaStarting dosage Prednisone in a dosage of 10 to 20 mg per day until the ESR is normal and the patient is asymptomaticDosage reduction Decrease the dosage by 1 to 2.5 mg per day every 4 weeks to a dosage of 10 mg per day; then decrease the dosage by 1 mg per day every 4 weeks.Monitoring Monitor the patient for symptom recurrence throughout the steroid taper; monitor the ESR every 4 weeks for 2 to 3 months, then every 8 to 12 weeks until 12 months after the cessation of therapy.ESR = erythrocyte sedimentation rate.

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