Polymyalgia Rheumatica

Description

• An inflammatory clinical syndrome characterized by pain and morning stiffness of the shoulder, hip girdles, and neck; primarily impacts patients aged >50 years; associated with morning stiffness and elevated markers of inflammation
• Can be associated with giant cell arteritis (GCA)
• System(s) affected: musculoskeletal; hematologic/lymphatic/immunologic
• Synonym(s): senile rheumatic disease; polymyalgia rheumatica (PMR) syndrome; pseudo-polyarthrite rhizomélique

Geriatric Considerations
Incidence increases with age (age >50 years).

Pediatric Considerations
Rare in patients <50 years of age (1)

Epidemiology

Incidence

• Incidence increases after age 50 years. Incidence of PMR and GCA in the United States is 50 and 18 per 100,000 people, respectively.
• Predominant sex: female > male (2 to 3:1)
• Most common in Caucasians, especially those of Northern European ancestry and in Scandinavian countries
• Peak incidence occurs between ages 70 and 80 years.

Prevalence
Prevalence in those >50 years old: 700/100,000

Etiology and Pathophysiology

• Unknown; symptoms relate to enhanced immune system and periarticular inflammatory activity.
• Pathogenesis
  • Polygenic; involves multiple environmental and genetic factors
  • Significant association between histologic evidence of GCA and parvovirus B19 DNA in temporal artery specimen

Genetics
Associated with human leukocyte antigen determinants (HLA-DRB1*04 and DRB1*01 alleles)

Risk Factors

• Aged >50 years
• Presence of GCA

Commonly Associated Conditions

Concurrent GCA (temporal arteritis) in ~15–30% of patients; more commonly in females than males