Polymyalgia rheumatica (musculoskeletal manifestations)

Musculoskeletal manifestations are the commonest presentation of polymyalgia rheumatica.

Epidemiology

Polymyalgia rheumatica is the most common inflammatory rheumatic condition in older adults ¹.

Associations

• giant cell arteritis

Clinical presentation

Patients typically present with ¹:

• shoulder or pelvic girdle aches lasting over 2 weeks

• morning shoulder or pelvic girdle stiffness

• raised inflammatory markers (e.g. ESR)

Radiographic features

Plain radiograph

Features of polymyalgia rheumatica are not typically visible on plain radiograph ⁵. Arthritis, if present, is non-erosive. Nevertheless, radiographs are useful to exclude other differential diagnoses of arthropathy.

Ultrasound

Although usually not required, ultrasound may commonly show ²:

• bilateral subacromial bursitis

• biceps long head tenosynovitis

• trochanteric bursitis

MRI

MRI typically shows synovitis and extra-articular manifestations such as enthesitis, bursitis, or tenosynovitis. Myofascial inflammation may also be seen. Gadolinium-enhanced sequences characteristically show peritendinous enhancement ⁵.

Nuclear medicine

FDG PET-CT

Several characteristic areas of hypermetabolic activity are seen on FDG PET-CT which likely reflect bursitis, synovitis, or tenosynovitis. Characteristic locations of hypermetabolic activity include the shoulder joints, sternoclavicular joints, interspinous regions, hip joints, prepubic regions, ischial tuberosities, and knee joints ^3,4. Smaller joints of the wrist and hand are less commonly affected ³.

Treatment and prognosis

Treatment is usually low dose corticosteroids which most patients respond well to ¹.