Polymyalgia Rheumatica & Giant Cell Arteritis

Essentials of Diagnosis

• Age over 50 years

• Elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CPR)

• Polymyalgia rheumatica: pain and stiffness in shoulders and hips

• Giant cell arteritis: headache, jaw claudication, polymyalgia rheumatica; without treatment, permanent blindness may occur

General Considerations

• Polymyalgia rheumatica and giant cell arteritis probably represent a spectrum of one disease and frequently coexist

• The important difference between the two conditions is that polymyalgia rheumatica alone does not cause blindness and responds to low-dose (10–20 mg/day) prednisone therapy, whereas giant cell arteritis can cause blindness and large artery complications and requires high-dose therapy (40–60 mg/day)

Demographics

• Both affect patients over age 50

• Giant cell arteritis is more common in northern Europeans and their descendants

• Incidence of the disease increases with each decade of life

Symptoms and Signs

POLYMYALGIA RHEUMATICA

• Pain and stiffness of the shoulder and pelvic girdle areas

• Fever, malaise, and weight loss

• Anemia and a markedly elevated sedimentation rate are almost always present

• Muscle pain much greater than muscle weakness

GIANT CELL ARTERITIS

• Headache, scalp tenderness, visual symptoms, jaw claudication, or throat pain

• The temporal artery is usually normal on physical examination but may be nodular, enlarged, tender, or pulseless

• Blindness

  • Results from occlusive arteritis of the posterior ciliary branch of the ophthalmic artery

  • Ischemic optic neuropathy may produce no funduscopic findings for the first 24–48 hours after the onset of blindness

• Asymmetry of pulses in the arms, a murmur of aortic regurgitation, or bruits heard near the clavicle resulting from subclavian artery stenoses identify an affected aorta or its major branches

• Forty percent of patients with giant cell arteritis have nonclassic symptoms at presentation, primarily respiratory tract problems (most frequently dry cough), mononeuritis multiplex (most frequently with painful paralysis of a shoulder), or fever of unknown origin

• The fever can be as high as 40°C and is frequently associated with rigors and sweats

• Unexplained head or neck pain in an older patient may signal the presence of giant cell arteritis

Differential Diagnosis

POLYMYALGIA RHEUMATICA

• Rheumatoid arthritis

• Polymyositis

• Chronic infection, eg, endocarditis

• Plasma cell myeloma

• Malignancy

• Fibromyalgia

• Polyarteritis nodosa

GIANT CELL (TEMPORAL) ARTERITIS

• Migraine

• Glaucoma

• Takayasu arteritis

• Uveitis

• Carotid plaque with embolic amaurosis fugax

• Trigeminal neuralgia

Laboratory Tests

POLYMYALGIA RHEUMATICA

• Anemia and elevated acute- phase reactants (generally ESR > 30 mm/h and CRP > 0.5 mg/dL) are present in most cases

GIANT CELL (TEMPORAL) ARTERITIS

• Nearly 90% of patients have ESRs > 50 mm/h

• Although the CRP is slightly more sensitive, patients with biopsy-proven giant cell arteritis with normal CRP have also been described

• Most patients also have a mild normochromic, normocytic anemia and thrombocytosis

• The alkaline phosphatase (liver source) is elevated in 20% of patients

Imaging Studies

• Magnetic resonance angiography or CT angiography establishes the diagnosis by demonstrating long stretches of narrowing of the subclavian and axillary arteries

• Imaging of the temporal artery with ultrasound, MRI, or CT angiography can sometimes obviate the need for biopsy

Diagnostic Procedures

• Temporal artery biopsy

• Diagnostic findings of giant cell arteritis may still be present 2 weeks (or even considerably longer) after starting corticosteroids

• An adequate biopsy specimen (2 cm in length) is essential, because the disease may be segmental

Medications

POLYMYALGIA RHEUMATICA

• Prednisone, 10–20 mg/day orally; if no dramatic improvement within 72 hours, the diagnosis should be revisited

• Weekly methotrexate may increase the chance of successfully tapering prednisone in some patients

GIANT CELL ARTERITIS

• The urgency of early diagnosis and treatment in giant cell arteritis relates to the prevention of blindness

• When a patient has symptoms and findings suggestive of cranial involvement from giant cell arteritis, therapy with prednisone, 1 mg/kg/daily or 60 mg daily orally, is initiated immediately

• Prednisone should be continued in a dosage of 60 mg/day for 1–2 months before tapering

• Intravenous pulse methylprednisolone (eg, 1 g/day for 3 days) may help patients with visual loss and may increase chance of remission; however, data supporting this recommendation are preliminary

• Low-dose aspirin (~81 mg/day orally) may reduce the risk of visual loss or stroke and should be added to prednisone

• Tocilizumab, an anti-interleukin-6 receptor monoclonal antibody

  • Phase 2 clinical trials have shown that patients initially treated with tocilizumab and prednisone were able to be tapered off prednisone faster than those who were treated with prednisone alone

  • After 1 year of treatment, tocilizumab achieves corticosteroid-free remission in approximately 50% of patients

Follow-Up

• Course is monitored by a composite of the patient's symptoms and laboratory markers of inflammation (ie, hematocrit, ESR, and C-reactive protein)

• In adjusting the dosage of corticosteroid, the ESR is a useful but not absolute guide to disease activity. A common error is treating the ESR rather than the patient

• Within 1–2 months after beginning treatment, the patient's symptoms and laboratory abnormalities will resolve

• Disease flares are common (50% or more) as prednisone is tapered

• The total duration of treatment varies considerably but ranges from 6 months to more than 2 years

Complications

• Blindness; once blindness develops, it is usually permanent

• Thoracic aortic aneurysms occur 17 times more frequently in patients with giant cell arteritis than in normal individuals

Prognosis

• Impact on survival appears small

When to Refer

• Refer to a rheumatologist to establish the diagnosis, plan therapy, and monitor treatment

• Consult an ophthalmologist for visual changes

When to Admit

• Admit for evaluation and high-dose intravenous methylprednisolone if the patient acutely develops visual loss