polymyalgia rheumatica (PMR)

Etiology

• unknown
• frequently associated with osteoarthritis
• may be associated with temporal arteritis
• may be paraneoplastic syndrome

Epidemiology

• more frequent in women
• more frequent in northern Europeans, rare in Asians

Pathology

• large vessel vasculitis

Clinical manifestations

• onset of symptoms after 50 years of age
• onset of symptoms may be insidious or abrupt
• bilateral shoulder pain, neck pain & hip pain
  • prolonged morning stiffness
  • pain on range of motion in shoulders
  • pain may be in associated muscles rather than in joints
  • no crepitus with movement of shoulders
• myalgias with disuse atrophy
• no muscle tenderness; + muscle tenderness
• true weakness is not present
• joint effusions in knees (frequent)
• proximal symptoms predominate but distal joints may also be involved
• generalized symptoms
  • mild weight loss
  • depression
  • malaise
  • fatigue
  • anorexia
  • low-grade fever
• often attributed to 'getting old' by patients

Laboratory

• complete blood count (CBC):
  • anemia of chronic inflammation may be present
  • MCV marginally low or low normal
• erythrocyte sedimentation rate (ESR) may be elevated
  • do not use ESR to adjust glucocorticoid dosage
• serum creatine kinase must be normal
• rheumatoid factor (RF) is negative
• antinuclear antibody (ANA) is negative
• complement levels are normal
• serum iron may be very low (10 ug/dL) out of proportion to moderately low TIBC (200 ug/dL)
• serum ferritin may be high
• increased serum AST, serum ALT (example of 54 & 58 U/L respectively)
• muscle biopsies & joint aspirations are normal & should be avoided

Diagnostic procedures

• temporal artery biopsy to rule out giant cell arteritis (see giant cell arteritis)

Radiology

• bone scans may be abnormal, but are not helpful
• MRI to detect subacromial bursitis & subdeltoid bursitis if diagnosis is uncertain
• CT angiography of neck & thorax if
  • giant cell arteritis suspected, but bilateral temporal artery biopsy negative
  • unexplained fever without symptoms of temporal arteritis

Complications

• excess risk for cardiovascular disease (HR=2.6)
  • excess risk similar for cardiac, cerebral & peripheral vascular events

Differential diagnosis

• giant cell arteritis*
  • presence of generalized symptoms
  • temporal tenderness, jaw claudication, low grade fever
  • failure to respond to low-dose (15 mg) of prednisone
• fibromyalgia
• myalgia of viral infection
• rheumatoid arthritis
• osteoarthritis - crepitus on movement of shoulders
• bursitis
• tendonitis
• polymyositis/dermatomyositis:
  • proximal muscle weakness not due to pain
  • morning stiffness not a feature
• malignancy
  • may be paraneoplastic syndrome
  • increased serum AST & serum ALT suggest polymyalgia rheumatica or giant cell arteritis
• depression
• amyloidosis

* constitutional symptoms (intermittent fever, weight loss) increases likelihood of giant cell arteritis, even in the absence of increased ESR, serum CRP, or classic giant cell arteritis symptoms, such as headache & jaw claudication

Management

• glucocorticoids (treatment of choice)
  • prednisone 40-80 mg QD or 1 mg/kg/day divided BID-QID for suspected giant cell arteritis (headache, temporal tenderness, jaw claudication, failure to respond to low-dose (15 mg) of prednisone)
  • prednisone 15 mg QD for 3-5 days, 10 mg QD for 1-2 weeks, 5 mg QD for 12 months, then taper 1 mg/month
  • prednisone 10-20 mg QD for 4-6 weeks
    • taper by 1 mg each month
  • for recurrences, resume previous dose or 5 mg/day, whichever is greater
    • restart at 12.5-25 mg
  • clinical improvement generally within a few days
  • do not use ESR to adjust glucocorticoid dosage
  • treatment failures usually secondary to:
    • incorrect diagnosis
    • underlying or co-existing condition
      • consider giant cell arteritis if failure to respond to 1st week of therapy
• methotrexate 10 mg QD plus folinic acid 7.5 mg QD may facilitate reduction in prednisone dose
• tocilizumab (8 mg/kg) every 4 weeks may facilitate reduction in prednisone dose
• sarilumab sustains remission & reduces total glucocorticoid use in relapsing polymyalgia rheumatica during glucocorticoid taper
• non-steroidal anti-inflammatory agents (NSAIDs)
  • rarely effective
  • may facilitate reduction in prednisone dose
• follow-up after 4-6 weeks then every 4-6 months. Visits every 1-2 months as prednisone is tapered from 5 mg.
• watch for symptoms of temporal arteritis
  • in the absence of symptoms, temporal artery biopsy is not indicated
• relapses common, duration of treatment typically 1-3 years

More general terms

• autoimmune disease
• vasculitis

Additional terms

• temporal arteritis; cranial arteritis; giant cell arteritis; Horton's disease

Patient information

polymyalgia rheumatica patient information