Erin M. Ney
Lan Chen
Susan Hoch
Vatinee Y. Bunya

BASICS

DESCRIPTION

• Polymyalgia rheumatica (PMR) is a disease characterized by pain and stiffness of the proximal muscles and joints, primarily the shoulders, hip girdles, neck, and torso.

• Occurs in people aged 50 years and older

– Characterized by bilateral aching and morning stiffness (lasting 30 min or more) persisting for at least 1 month

– Also can be associated with fever, malaise, anorexia, and weight loss. Erythrocyte sedimentation rate (Westergren) is increased to 40 mm/h or more.

• Thought to be on the same clinical spectrum with giant cell arteritis (GCA, also known as temporal arteritis)

EPIDEMIOLOGY

Incidence

• Varies geographically; annual incidence ranges from 13 to 113 per 100,000 between Italy and Norway, respectively.

• In Olmsted County, Minnesota, the annual incidence was 54.8 per 100,000 population aged 50 years and older.

• Higher incidence in women and Caucasians

Prevalence

Prevalence increases with increasing age

RISK FACTORS

See “Genetics” and “Commonly Associated Conditions”

Genetics

• No definitive inheritance pattern

• Associated with HLA-DR4 and HLA-DRB1, both of which have been implicated in GCA

GENERAL PREVENTION

Awareness of the overlap between PMR and GCA, with prompt diagnosis and treatment of GCA to prevent permanent visual loss (see “Commonly Associated Conditions”)

PATHOPHYSIOLOGY

• Idiopathic chronic inflammatory syndrome characterized by synovitis and bursitis

• Associated with IL-6 upregulation

ETIOLOGY

There have been no causative agents identified.

COMMONLY ASSOCIATED CONDITIONS

• GCA

– Vasculitis of large and medium-sized vessels characterized by headache, jaw claudication (pain with chewing), scalp tenderness particularly over temporal arteries, palpable cord-like temporal artery, and visual disturbances

– Visual phenomenon include amaurosis fugax, anterior ischemic optic neuropathy, diplopia, central retinal artery occlusion, optic chiasm, and retrochiasmal vascular damage.

– 15% of patients with PMR develop GCA

– 40–50% of patients with GCA have PMR

DIAGNOSIS

HISTORY

• Pain and stiffness of at least 4 weeks duration

– Joints involved include neck, shoulders, low back, hips, thighs, and trunk.

– Pain is usually symmetrical.

• Weight loss

• Anorexia

• Malaise

• Headache, scalp tenderness, acute visual loss

PHYSICAL EXAM

• Decreased range of motion in involved joints

• Muscle strength is normal, although testing may be limited by pain.

• Occasionally patients will have diffuse edema of hands and feet.

• If GCA is suspected, perform complete ophthalmic examination including visual acuity, pupils, color plates, visual fields, and dilated fundus examination.

– Optic nerve evaluation often reveals pale, edematous disc sometimes with flame hemorrhages.

– Fundus examination may reveal central retinal artery occlusion and evidence of arteritis (vascular sheathing).

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• ESR

– Greater than 40 mm/h; values can exceed 100 mm/h

• Elevated C-reactive protein (CRP)

• Normal values for both ESR and CRP are much less common, occurring in only 1.2% with PMR and/or GCA.

• Platelets: an acute phase reactant, can have thrombocytosis with GCA

Follow-up & special considerations

ESR and CRP levels should be monitored to gauge treatment efficacy and diagnose recurrence.

Diagnostic Procedures/Other

• Temporal artery biopsy

– Obtain if there are any visual disturbances or signs or symptoms consistent with GCA.

– If GCA is clinically suspected, do not defer treatment to attain biopsy specimen.

– Perform the biopsy within 1 week of initiating high-dose corticosteroid treatment (see “Inpatient Considerations”), although positive biopsy results can be seen up to 1 month after treatment.

DIFFERENTIAL DIAGNOSIS

• Rheumatoid arthritis

• Fibromyalgia

• Polymyositis

• Bursitis & tendinitis

• Malignancy

• Hypothyroidism

• Infection: endocarditis

TREATMENT

MEDICATION

First Line

• Prednisone

– No proven efficacious dose, initial goal of therapy is symptom control.

– Usually responds to oral prednisone 7.5–20 mg/day. The initial dose of prednisone needed to alleviate musculoskeletal symptoms associated with GCA is higher at 50–60 mg/day.

Second Line

• Methotrexate

– Can be used in patients with glucocorticoid-induced side effects

– Dosage of 10 mg with 1 mg of folinic acid supplementation (1)

IN-PATIENT CONSIDERATIONS

Admission Criteria

• Admit if the patient has vision loss or amaurosis fugax as could be GCA and may require IV methylprednisolone.

– While in hospital arrange for temporal artery biopsy.

IV Fluids

Typical methylprednisolone dose is 250 mg IV q6h × 12 doses then switch to oral prednisone 80–100 mg daily

Discharge Criteria

After completion of IV steroid course and temporal artery biopsy

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Primary care doctor

• Rheumatologist

• Ophthalmologist for evaluation and work-up of GCA

Patient Monitoring

• Prednisone should be tapered slowly once symptom control has been achieved.

– Once a daily dose of less than 5–10 mg is achieved, reduction should not exceed 1 mg/month.

• While on prednisone, blood pressure, glycemic control, and need for calcium and vitamin D supplementation and gastric acid suppression should be evaluated by primary care physician.

• ESR and CRP should be checked, if there is clinical evidence of recurrence.

PATIENT EDUCATION

• The Arthritis Foundation (http://www.arthritis.org)

• The American College of Rheumatology (www.Rheumatology.org)

PROGNOSIS

• Generally self-limited course over months to a year

– Most patients can be tapered off glucocorticoids

COMPLICATIONS

Developing GCA

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