Polymyalgia Rheumatica | Musculoskeletal

Table of Contents

Overview – Polymyalgia Rheumatica

Polymyalgia Rheumatica (PMR) is a common inflammatory condition in older adults, particularly females, characterised by symmetrical proximal muscle pain and stiffness without weakness. It is closely associated with Giant Cell Arteritis and typically responds rapidly to corticosteroids. Timely recognition is critical to prevent misdiagnosis and to manage systemic symptoms effectively.

Definition

Polymyalgia Rheumatica is a systemic inflammatory disorder presenting with proximal myalgia and morning stiffness in individuals over 50 years of age. Unlike myositis, there is no true muscle weakness or elevated CK.

Aetiology

Exact cause unknown
Associated with:
- Giant Cell Arteritis (Temporal Arteritis)
- Genetic predisposition: HLA-DR4
- Possible viral triggers:
  - Parvovirus B19
  - Parainfluenza virus
  - Adenovirus

Pathogenesis

Autoimmune inflammation affecting periarticular structures and muscles
Does not directly involve muscle fibres (unlike myositis)

Clinical Features

Demographics:
- 50 years old
- Female predominance (2:1 ratio)
Symptoms:
- Symmetrical myalgia (especially shoulders and pelvic girdle)
- Morning stiffness lasting >45 minutes
- Muscle tenderness without true weakness or atrophy
- Constitutional symptoms:
  - Fatigue
  - Weight loss
  - Fever
  - Anaemia
  - Anorexia
  - General malaise

Investigations

Diagnosis is clinical, supported by:
- Age >50 years
- Pain in ≥2 proximal muscle groups
- Elevated ESR and CRP
- Normal CK levels
- Rapid improvement with corticosteroids

POLYMYALGIA RHEUMATICA — 1.Twisp, Public domain, via Wikimedia Commons
2.https://www.bmj.com/content/347/bmj.f6937

Management

First-line treatment:
- Corticosteroids (e.g. Prednisone)
Monitor closely for signs of associated Giant Cell Arteritis, which may require more aggressive therapy

Summary – Polymyalgia Rheumatica

Polymyalgia Rheumatica is a common autoimmune inflammatory syndrome of older adults, particularly females, presenting with symmetrical myalgia and stiffness of the shoulders and pelvic girdle. It is strongly associated with Giant Cell Arteritis and typically shows a dramatic response to corticosteroids. For a broader context, see our Musculoskeletal Overview page.