Polymyalgia Rheumatica

See Also

Temporal Arteritis

Epidemiology

Common over age 50 years (peaks between ages 70 to 80 years old)
1. Incidence: 50 per 100,000
2. Prevalence: One in 143 persons
Most common in white persons of Northern European descent
1. Rare in Asian and black patients
Women predominate by 2:1 ratio
Associated with HLA-DR4 and Cw3 haplotypes
1. Seasonal outbreaks suggest an infectious trigger
Associated with Temporal Arteritis
1. Temporal Arteritis is occurs in 18-26% of Polymyalgia Rheumatica cases
2. Polymyalgia Rheumatica is 2-3 times more common than Temporal Arteritis

Symptoms

Severe muscle ache and stiffness
1. Duration
  1. Minimum of 2 week duration for diagnosis
  2. Typically 1 month or longer at presentation
  3. Usually insidious onset
2. Location (symmetric, bilateral involvement)
  1. Shoulders (affected in 95% of cases)
  2. Neck
  3. Pelvic girdle and hips
3. Characteristics
  1. Ache worse at night and with movement
  2. Stiffness
4. Timing
  1. More prominent in morning or after inactivity
  2. Morning stiffness lasts >45 minutes for diagnosis
Associated systemic symptoms (30-50% of cases)
1. Malaise
2. Anorexia
3. Weight loss
4. Low grade fever
5. Depressed mood
6. Night Sweats

Signs

Unremarkable physical exam
1. Symptoms are usually well out-of-proportion to exam
2. No true motor weakness
  1. Strength limitation in PMR should be due to pain and disuse atrophy
  2. True Muscle Weakness suggests alternative diagnosis
Mild findings (variably present)
1. Limited range of motion in affected joints
  1. Limited by proximal myalgias
2. Shoulder or hip Bursitis
3. Localized tenderness over Shoulders and hips
Other findings which may be present (50% of cases)
1. Asymmetric knee or wrist Arthritis
2. Carpal Tunnel Syndrome
3. Distal extremity edema (wrists, hands, ankles, feet)

Precautions
Red Flags (suggestive of Temporal Arteritis)

See Temporal Arteritis
Abrupt Headache onset
Jaw Claudication (or tongue Claudication)
Limb Claudication
Temporal artery abnormalities (prominence, beading, decreased pulse, tenderness)
Visual disturbance
Upper Cranial Nerve deficit

Differential Diagnosis
PMR is a diagnosis of Exclusion (other disorders make PMR less likely)

Inflammatory Arthritis
1. See Shoulder Pain
2. See Rheumatologic Causes of Shoulder Pain
Myopathy
1. See Myopathy Causes
2. See Polymyositis Differential Diagnosis
3. See Medication Causes of Myositis
4. Thyroid Myopathy (Hypothyroidism, Hyperthyroidism)
5. Hyperparathyroidism
6. Polymyositis
7. Parkinsonism or other neurologic disorder
Prominent systemic symptoms (e.g. weight loss, night pain)
1. Malignancy
  1. Multiple Myeloma
  2. Lymphoma
  3. Prostate Cancer
  4. Stomach Cancer
  5. Ovarian Cancer
  6. Renal cell cancer
  7. Lung Cancer and paraneoplastic syndrome
2. Infection

Diagnosis
British Society for Rheumatology (BSR) and British Health Professionals in Rheumatology (BHPR) Criteria

Age over 50 years old
Bilateral ache in Shoulder and/or pelvic girdle
Morning stiffness >45 minutes in Shoulder and/or pelvic girdle
Duration of symptoms >2 weeks
Acute phase reactant increase (i.e. CRP or ESR)

Labs

Acute phase reactant increased (obtain both C-RP and ESR)
1. C-Reactive Protein (C-RP)
  1. Better Test Sensitivity for Polymyalgia Rheumatica than ESR
  2. ESR however is preferred for predicting relapse
2. Erythrocyte Sedimentation Rate (ESR)
  1. Normal upper limit ESR is typically age/2 for men and (age+10)/2 for women
  2. ESR >40 mm/h in >91% of Polymyalgia Rheumatica
    1. False Negative ESR in 6-20% of patients with Polymyalgia Rheumatica
    2. C-RP is typically positive in these False Negative cases
  3. ESR >50 mm/h in most cases (mean 65 mm/h)
  4. ESR 83 mm/h is average for Giant Cell Arteritis
    1. ESR >100 mm is associated with higher likelihood of Giant Cell Arteritis (or underlying malignancy)
Labs to evaluate differential diagnosis
1. Complete Blood Count
2. Thyroid Stimulating Hormone (TSH)
3. Comprehensive metabolic panel
  1. Includes electrolytes, Renal Function tests and Liver Function Tests
4. Creatine Phosphokinase (CPK) Normal
  1. Differentiate from Polymyositis
5. Rheumatoid Factor
6. Urinalysis
7. Serum Protein Electrophoresis or Urine Protein electrophoresis
Nonspecific Lab findings
1. Moderate Anemia
2. Decreased Serum Albumin
3. Mild hepatic dysfunction

Imaging

Chest XRay
1. Consider if paraneoplastic syndrome associated with Lung Cancer is suspected

Associated Conditions
Temporal Arteritis

Occurs in 18-26% of PMR patients
Risk of blindness
Consider Temporal Arteritis in all PMR patients
Factors suggesting concurrent Temporal Arteritis
1. Age over 70 years
2. New onset Headache
3. Jaw Claudication
4. Raised liver enzymes
5. Abnormal temporal arteries on exam
References
1. Rodriguez-Valverde (1997) Am J Med 102:331-6 [PubMed]

Management

General measures
1. Consider concurrent Temporal Arteritis (See above)
2. NSAIDs
Prednisone (key to management)
1. See Corticosteroid Associated Osteoporosis
2. Efficacy: 90% response
  1. Dramatic improvement within first week (especially in first 48 hours)
  2. Acute phase reactants (C-RP and ESR) normalize within first 4 weeks
  3. If no response to steroids
    1. Reconsider diagnosis
    2. Consider Methotrexate (see below)
3. Polymyalgia alone
  1. Dose: 15-20 mg orally daily
    1. Prednisone 15 mg is sufficient for most patients and no added benefits to higher dose
    2. Prednisone 10 mg is associated with increased relapse rate
  2. Example Prednisone course
    1. Prednisone 15 mg daily for 3 weeks, then
    2. Prednisone 12.5 mg daily for 3 weeks, then
    3. Prednisone 10 mg daily for 4-6 weeks, then
    4. Prednisone taper by 1 mg/day every 4-8 weeks over 1-2 years
  3. Alternative: Example Methylprednisolone IM course
    1. Methylprednisolone (Depo Medrol) 120 mg IM every 3-4 weeks
    2. Taper by 20 mg/dose every 2-3 months
4. Polymyalgia with Temporal Arteritis
  1. Dose: 40-60 mg orally daily
  2. Symptoms and signs remit within 1 month
  3. Decrease dose by 10% each week after improvement
5. Course (mean total length of treatment 1.8 years)
  1. Initial: Maintain starting dose for 1 month
  2. First steroid taper (depends on clinical response)
    1. Taper by 2.5 mg per month down to 10 mg/day then
    2. Taper 1 mg per 4-6 weeks down to 5 to 7.5 mg/day
  3. Final steroid taper
    1. Indicated when symptom free for 6-12 months
    2. Do not taper until sedimentation rate normalizes
    3. Taper by 1 mg every 6-8 weeks until done
  4. Anticipate 2-6 year course of steroids
    1. Relapse common in first 18 months of steroid use
    2. Patients off steroids at 2 years: 25%
  5. Monitoring
    1. Follow C-RP and anticipate decreased levels after initiating therapy
6. Prevention of Corticosteroid related Osteoporosis
  1. See Corticosteroid Associated Osteoporosis
  2. Vitamin D Supplementation
  3. Calcium Supplementation
  4. Consider DEXA Scan while starting Corticosteroids
  5. Consider bisphosphonate on starting Prednisone
    1. Strongly consider for high risk of Fracture (over 65 years old or prior Fracture)
    2. Also consider if DEXA Scan T-Score -1.5 or less
Adjunctive medications
1. Methotrexate 10 mg weekly
  1. Associated with lower steroid doses and lower relapse rates
2. Etanercept (Enbrel)

Management
Follow-up

Rheumatology referral indications (most cases referred in U.S.)
1. Age <60 years old at onset
2. Chronic presentation >2 years
3. Other Rheumatologic Disease
4. Poor response to Corticosteroids
5. Significant systemic symptoms (e.g. weight loss, neurologic symptoms)
6. Significant increases in acute phase reactants (e.g. ESR >100 mm/h)
7. Absent key PMR features
  1. Minimal morning stifffness
  2. No Shoulder involvement
Clinic Visits
1. Timing
  1. One week after starting steroids, then
  2. Three weeks after starting steroids, and then
  3. Every 3 months
2. Labs (each visit)
  1. Complete Blood Count
  2. Erythrocyte Sedimentation Rate (ESR)
  3. C-Reactive Protein (C-RP)
  4. Basic chemistry panel (Electrolytes, Renal Function tests, and Serum Glucose)
3. Evaluation
  1. Relapse symptoms
    1. Proximal muscle pain (Shoulder or pelvic girdle)
    2. Morning stiffness
    3. Fatigue
  2. Giant Cell Arteritis symptoms
    1. Temporal Headache
    2. Jaw Claudication (or tongue Claudication)
    3. Vision changes
  3. Adverse effects to treatment (Corticosteroid adverse effects)
    1. Gastritis or peptic ulcer
    2. Bone density
    3. Hyperglycemia

Prognosis

Self limited course over years (usually 3-6 years)

References