Polymyalgia rheumatica

Polymyalgia rheumatica (PMR) is a common inflammatory rheumatic disease that mainly affects patients above the age of 50 years and occurs twice as often in women than in men. Patients typically present with new-onset pain in their shoulders, hips, or neck, morning stiffness, and systemic symptoms (e.g., fatigue, malaise, B symptoms, and depressed mood). In addition to clinical presentation, the diagnosis is made based on laboratory studies, which usually show a highly elevated erythrocyte sedimentation rate (ESR), while creatine kinase and autoantibodies are negative. Bursitis and serositis in the joints of the shoulder and pelvic girdle on ultrasound may also help to confirm the diagnosis. The most important step in the management of PMR is to administer a low dose of oral glucocorticoids and taper them slowly until full remission is achieved. Patients with polymyalgia rheumatica should be routinely monitored for symptoms of giant cell arteritis because this type of vasculitis commonly develops during the course of the disease.

• Sex: ♀ > ♂ (3:1) ^[1]
• Most common inflammatory rheumatic disease in the elderly (second most common overall)
• Age of onset: >70 years (rarely seen in patients < 50 years) ^[2]
• More common in individuals of Northern European descent ^[3]

Women of advanced age are particularly prone to the disease.

Epidemiological data refers to the US, unless otherwise specified.

• Unknown
• Possible contributing factors are:
  • Genetic predisposition (e.g., human leukocyte antigen HLA-DR4)
  • Association with giant cell arteritis (GCA): Approx. 10% of individuals with polymyalgia rheumatica also have GCA. ^[4]

• Systemic symptoms
  • Constitutional symptoms: fever, weight loss, night sweats
  • Fatigue and malaise
  • Depressed mood
  • Symptoms of anemia
• Musculoskeletal symptoms: primarily affects shoulders, neck, and pelvic girdle
  • New onset, symmetric pain that is worse at night
  • Morning stiffness (> 45 min)
  • Muscular atrophy and weakness: not directly caused by PMR but resulting from reduced activity due to pain and stiffness ^[5]
• Other: symptoms of giant cell arteritis (if both diseases are present)

• ↑ ESR, specifically > 50 mm/h
• ↑ CRP
• Leukocytosis
• Normochromic anemia
• Normal creatine kinase, negative rheumatoid factors, and no autoantibodies
• Bursitis on ultrasound of affected joints ^[6][7]

• Giant cell arteritis
  • Both diseases often coexist and share common findings (e.g., elevated ESR, B symptoms)
  • May develop during the course of PMR (patients should be routinely evaluated for symptoms of GCA)
• Rheumatoid arthritis: positive rheumatoid factor and/or anti-CCP antibodies
• Polymyositis and dermatomyositis: ↑ serum creatine kinase (normal in PMR)
• Fibromyalgia: normal laboratory values

The differential diagnoses listed here are not exhaustive.

• Low-dose oral glucocorticoids (alternatively IM glucocorticoids) ^[8]
  • Usually rapid symptomatic relief (2–4 weeks)
  • If symptoms improve: slowly taper and eventually stop glucocorticoids
  • No improvement after 2 weeks or relapse: increase dose