Polymyalgia rheumatica and temporal arteritis are inflammatory disorders that occur in persons older than 50 years. Elderly white women of European ancestry are most commonly affected. The disorders are considered to be closely related conditions in a spectrum of disease affecting the same patient population. The two entities may occur independently or concomitantly in the same patient.¹

First described in 1888 as “senile rheumatic gout,” polymyalgia rheumatica received its present name in 1957.² The disorder is a clinical syndrome characterized by pain and stiffness in the neck, shoulders and hips, fatigue, weight loss and low-grade fever. The erythrocyte sedimentation rate (ESR) is usually elevated, and the response to corticosteroid therapy is generally dramatic. Autoimmune responses are believed to play a prominent role in polymyalgia rheumatica, with bursitis, synovitis and tenosynovitis of the proximal shoulder and hip girdles being characteristic features.³

Temporal arteritis, or giant cell arteritis, involves humoral and cellular immune responses that are limited to vessels with an internal elastic component.¹ Compared with polymyalgia rheumatica, temporal arteritis is the more serious condition. It can lead to jaw claudication, visual disturbances and permanent blindness. The precise relationship between temporal arteritis and polymyalgia rheumatica remains unknown.

Illustrative Case

A 69-year-old white woman presented with a four-week history of severe pain in her neck, upper back and arms. The pain was worse at night and caused sleeplessness. Severe, incapacitating stiffness in her arms and shoulders was worse in the morning and decreased by the middle of the afternoon. She denied fever, trauma or past episodes of similar pain. However, she reported a general sense of malaise, fatigue and weakness, and she appeared to be moderately depressed. She said that her older brother had been treated with “steroids” for a similar affliction five years earlier.

On physical examination, the patient appeared distressed, but she was afebrile and had normal blood pressure and pulse. Marked tenderness to palpation was present over the paracervical and trapezius muscles and the glenohumeral joints. Muscle bulk, tone and strength were normal, but she displayed decreased range of motion in internal and external rotation, flexion and extension of both shoulders. Attempts to abduct either arm above 90 degrees produced marked pain. She had no tenderness, pain or obvious swelling over her temporal arteries. An incidental finding was mild pitting edema of her lower extremities.

Laboratory tests revealed elevation of the ESR to 105 mm per hour and the presence of a normochromic, normocytic anemia. All other studies were normal. Radiographs of the cervical spine and both shoulders revealed mild degenerative changes in her cervical spine, but no other abnormalities.

A presumptive diagnosis of polymyalgia rheumatica without temporal arteritis was made, and the patient was started on prednisone in a dosage of 20 mg taken orally each morning. She was instructed to begin range-of-motion exercises for her shoulders.

The patient demonstrated a stunning response to prednisone, with almost complete cessation of all neck, shoulder and arm pain. Her sleep improved, her mood lightened and her ESR fell to 39 mm per hour in two weeks. Within four weeks, she was able to resume golf and other activities.

Epidemiology

Polymyalgia rheumatica and temporal arteritis most commonly occur in men and women more than 50 years of age.⁴ The mean age at diagnosis is 70 years.⁴ The disorders are twice as common in women as in men, and the overall incidence varies geographically.^2,4 Polymyalgia rheumatica and temporal arteritis occur more frequently in white persons, predominantly those of northern European ancestry.^1,5 However, both conditions occur throughout the world and in all ethnic groups.

Temporal arteritis has an annual incidence of approximately 18 cases per 100,000 persons more than 50 years of age.¹ Polymyalgia rheumatica is relatively common in the United States, with an estimated prevalence of 0.5 percent in persons older than 50 years and an estimated annual incidence ranging from 12 to 68 cases per 100,000 persons older than 50 years.^2,5

The epidemiologies of the two disorders overlap. From 50 to 90 percent of patients with temporal arteritis initially have signs of polymyalgia rheumatica, and almost 33 percent of patients with polymyalgia rheumatica have evidence of temporal arteritis on temporal artery biopsy.⁶

Etiology

The causes of polymyalgia rheumatica and temporal arteritis are not completely understood. Infectious causes, including influenza, hepatitis B or Borrelia burgdorferi infection, have been postulated, but studies have not confirmed these relationships.^1,6

Current opinion is that temporal arteritis is caused by the deposition of immune complexes in the involved arteries, resulting in a local immune response. The eliciting cause of this immune system reaction is not known.^6,7

The etiology of polymyalgia rheumatica is even less well understood, but research has revealed many of the same immunologic responses as in temporal arteritis.⁷ In fact, polymyalgia rheumatica may be a milder, more widespread immune reaction, whereas temporal arteritis may be a more intense and focal form of the same process.

Clinical Presentation

Because polymyalgia rheumatica and temporal arteritis probably represent different manifestations of the same disease process, symptoms of the conditions often overlap. Thus, patients may have symptoms consistent with polymyalgia rheumatica, temporal arteritis, or both. The mixed clinical picture may be present at the initial visit or may develop over time.

Both conditions potentially include a variety of systemic symptoms. The most common is fever.⁸ Some patients have a temperature of 39°C (102.2°F), as well as night sweats. Additional symptoms include depressed affect, fatigue, malaise, anorexia and weight loss. These systemic complaints are nonspecific and also occur with other disease processes in the elderly.

The clinical hallmarks of polymyalgia rheumatica are pain and stiffness in the shoulder and pelvic girdle. Stiffness is greatest in the morning and lasts 30 to 60 minutes after patients arise. Patients complain of similar stiffness after prolonged sitting or reclining. The pain is most severe in the neck, shoulders and buttocks. Patients may report difficulty getting up in the morning and may need to “roll” themselves out of bed. They may also find it difficult to put on their clothes, groom their hair and brush their teeth. Although affected muscles are tender to palpation, weakness is rarely a feature of the disorder. Decreased strength is generally the result of “breakaway weakness” from pain or disuse atrophy.

The characteristic symptoms of temporal arteritis result from inflammation of affected arteries. The initial manifestations and clinical findings in 100 consecutive patients are shown in Table 1.⁹ Headache is the most frequent symptom and also the most common initial symptom. The pain is typically centered over the temporal or occipital regions, but pain in other locations cannot be discounted. The pain may be described as a burning or lancinating sensation.

Scalp tenderness is present in more than one fourth of patients with temporal arteritis. It occurs most often in patients with headaches but also can be an independent finding. Tenderness is usually localized over the temporal artery or sometimes around the occipital artery. The involved arteries may be nodular, erythematous or swollen. A decrease in the temporal artery pulse is frequently noted.

Another frequent complaint in temporal arteritis is jaw claudication resulting from inflammation of the maxillary artery. Chewing may produce pain bilaterally or predominantly on the affected side. Involvement of the lingual artery can result in pain and blanching of the tongue. Rarely, it can lead to gangrene of the tongue.

Inflammation of the arteries supplying the eyes can lead to anterior ischemic optic neuropathy, which can cause blindness, the most feared complication of temporal arteritis. Classically, the loss of vision is described as being painless. Other visual symptoms may include amaurosis fugax, diplopia and partial loss of vision. Ocular symptoms are initially unilateral, with the second eye becoming affected in one to 10 days.

Neurologic findings are present in approximately 30 percent of patients with biopsy-proven temporal arteritis.¹⁰ Neuropathies secondary to occlusion of the nutrient arteries are most common. Transient ischemic attacks and strokes resulting from carotid or vertebrobasilar disease are the next most frequent events. Compromise of the arteries supplying the otic region can lead to tinnitus, hearing loss and vertigo. Thoracic aortic aneurysms have also been related to systemic vascular diseases such as temporal arteritis.

Laboratory Studies

The ESR is the most useful serum laboratory test for diagnosing polymyalgia rheumatica and temporal arteritis. Although the Creactive protein level is typically elevated in patients with these conditions, it provides no better data than the simpler and less expensive ESR.

Elevation of the ESR is included in 89 percent of recommended criteria sets for the diagnosis of polymyalgia rheumatica.² The ESR value most often used to define this elevation is 40 mm per hour.² An ESR of greater than 100 mm per hour is common in temporal arteritis.

Nonetheless, family physicians must be wary of placing all faith in laboratory data. One review² found that about 4 to 13 percent of patients with clinical polymyalgia rheumatica or temporal arteritis have a normal ESR. In like fashion, perhaps as many as 5 percent of patients initially have a normal ESR that later rises.¹¹ Furthermore, the ESR is a poor indicator of relapse of either disorder.

Liver function tests show mild abnormalities in patients with polymyalgia rheumatica or temporal arteritis. The most common finding is elevation of the alkaline phosphatase level. Elevation of the aspartate aminotransferase level is less often seen. A complete blood count may show a normocytic anemia with red blood cell indexes and iron studies consistent with an anemia of chronic disease (low serum iron level, normal or elevated ferritin level, reduced transferrin level and reduced total iron-binding capacity).

Laboratory testing may be most beneficial in excluding other possible causes of the symptoms. Screening for rheumatoid factor and antinuclear antibodies may identify rheumatoid arthritis or other connective tissue disorders. Measurement of the thyroid-stimulating hormone level can diagnose thyroid dysfunction. Blood cultures may provide evidence of occult endocarditis in the patient with unexplained fever. Serum protein electrophoresis can be used to assess the probability of myeloma. Lastly, prominent weakness may warrant muscle enzyme testing for polymyositis.

Diagnosis

The diagnosis of polymyalgia rheumatica is clinical and largely rests on the exclusion of other potential diagnoses. Similarly, the clinical presentation of temporal arteritis can be relatively nonspecific. The systemic features of both entities can mimic occult infection, malignancy, multiple myeloma and connective tissue disease. The cranial features of temporal arteritis can be mimicked by dental pathology, neuropathy or even sinus disease. Finally, visual disturbances are common in the elderly. The differential diagnosis of polymyalgia rheumatica and temporal arteritis is provided in Table 2.⁵

There have been numerous attempts to construct diagnostic criteria for polymyalgia rheumatica. The most frequently cited criteria sets^12,13 are presented in Table 3.² Prompt response to corticosteroid therapy and exclusion of other disease processes are key components of most recommended diagnostic criteria. Unfortunately, no single criteria set has been universally embraced, because most sets were established for research purposes. However, these attempts can provide family physicians with a framework for diagnosing polymyalgia rheumatica.

The diagnosis of temporal arteritis should be considered in patients more than 50 years of age with onset of a new type of headache, jaw claudication, symptoms of polymyalgia rheumatica, unexplained fever or unexplained weight loss. Suspicion is strengthened by the clinical findings of an elevated ESR, scalp tenderness, normocytic anemia or superficial artery abnormality.

Biopsy remains the standard approach to the diagnosis of temporal arteritis and is warranted whenever this disorder is suspected. The temporal artery is the most common site for biopsy, but segments of the facial or occipital arteries can also be examined.

If a specific area of tenderness or abnormal appearance is present, only a short arterial segment (less than 3 cm) needs be removed. If no localizing signs are present, a longer arterial segment (3 to 5 cm) should be obtained for histologic review. Segments should be sectioned serially because of the “skipping” nature of the lesions. If the biopsy findings are negative but temporal arteritis is still strongly suspected, biopsy of the opposite side is indicated.

The diagnostic yield of biopsy diminishes with the initiation of corticosteroid therapy. Hence, biopsy should be performed as quickly as practical (within seven days), but treatment should not be delayed to allow scheduling of the procedure.

The use of arterial biopsy in patients with symptoms of polymyalgia rheumatica alone is currently under debate. Biopsy studies indicate that 15 to 20 percent of these patients have histologic lesions consistent with temporal arteritis.¹⁴ However, their clinical risk of developing visual complications is low compared with the risks that are associated with high-dose corticosteroid therapy. It can be argued that these patients can be safely managed with close observation for development of signs of temporal arteritis.

Even though biopsy is the diagnostic “gold standard” for temporal arteritis, its sensitivity has been assessed at 60 to 80 percent.^14,15 This less than ideal sensitivity, combined with the possibility of permanent blindness, has led to the development of diagnostic criteria for temporal arteritis. The American College of Rheumatology has adopted the criteria set presented in Table 4.¹⁶ A diagnosis of temporal arteritis can be made if three of the five criteria are met. This diagnostic scheme has a sensitivity of 93 percent and a specificity of 91 percent.¹⁶

Color duplex ultrasonography of the temporal artery is a promising new diagnostic technique. This modality is used to look for areas of stenosis and occlusion, as well as arterial segments with “halos.” In one study,¹⁷ these findings were present in 73 percent of patients with a diagnosis of temporal arteritis and were absent in all control subjects. The halos may represent arterial edema and have been shown to resolve with corticosteroid therapy.

Some investigators have suggested that patients with clinical symptoms of temporal arteritis and “halos” on ultrasonography may proceed directly to treatment without undergoing biopsy, whereas patients with clinical symptoms and no evidence of “halos” on ultrasound examination should undergo biopsy as usual.¹⁷ Although more experience with color duplex ultrasonography is necessary, this technique may prove to be the diagnostic method of the future.

Treatment

Corticosteroids are the mainstay of therapy for temporal arteritis and polymyalgia rheumatica. Typically, the response is dramatic, with symptoms improving within 48 to 72 hours after treatment is initiated.

Patients suspected of having temporal arteritis should begin therapy at once. Although dosage recommendations vary, most investigators recommend the use of prednisone administered orally in a dosage of 40 to 60 mg per day. Patients with visual symptoms should begin treatment with a higher dosage, such as 250 mg of methylprednisolone sodium succinate (Solu-Medrol) administered intravenously every six hours for three to five days; the patients are then switched to oral corticosteroid therapy.¹⁸

In most patients with temporal arteritis, clinical symptoms resolve and the ESR returns to normal within two to four weeks. At this point, the corticosteroid dosage is tapered slowly, with a reduction of no more than 10 percent of the total daily dose every two weeks.¹⁹ During the taper, patients should be monitored for clinical relapse or an increase in the ESR. If either occurs, the taper is discontinued and the current dosage is maintained. Once symptoms resolve and the ESR is no longer increasing, the taper is restarted with smaller dosage reductions at longer intervals. This weaning process may “plateau” at a dosage of 10 to 20 mg per day, which is maintained for several months before further dosage reductions can be made.

A trial of nonsteroidal anti-inflammatory drugs may be attempted in patients with polymyalgia rheumatica. If no response occurs in two to four weeks, corticosteroid therapy is initiated. The starting dosage of prednisone ranges from 5 to 20 mg per day. After symptoms resolve, the corticosteroid is tapered by 2.5 mg every two to four weeks until a dosage of 10 mg per day is reached. Then the prednisone is tapered by 1 mg every two to four weeks until a dosage of 5 mg per day is attained.

In both polymyalgia rheumatica and temporal arteritis, once a dosage of 5 mg per day of prednisone is reached, the taper lengthens considerably and may last 18 to 24 months. The weaning process must balance the prevention of relapse against the complications of chronic corticosteroid use.

The most common complications of corticosteroid therapy are osteoporosis, fractures and infection. Studies indicate that intermittent etidronate therapy prevents bone loss in patients receiving chronic corticosteroid therapy.^20,21 In addition, the American College of Rheumatology has recommended alendronate for the prevention of glucocorticoid-induced osteoporosis.²² Several steroid-sparing medications, including dapsone, methotrexate (Rheumatrex) and azathioprine (Imuran), have been studied in patients in whom corticosteroid reduction has proved difficult. Insufficient supporting evidence is available to consider any of these drugs for primary therapy.

Both polymyalgia rheumatica and temporal arteritis tend to run a self-limited course of several months to as long as five years. Relapses are most likely to occur in the first 18 months of therapy or within 12 months after the cessation of corticosteroid treatment. Relapse rates may be as high as 25 percent.¹ There is currently no way to predict which patients are at risk for a return of symptoms. Patients should be advised to see their physician immediately if symptoms recur, especially cranial or visual symptoms.