Systemic lupus erythematosus (musculoskeletal manifestations)
Musculoskeletal manifestations in patients with systemic lupus erythematosus are common and often symptomatic. Characteristic manifestations are seen in approximately 80% of patients, but many less characteristic manifestations are important to be aware of. Multiple different presenting complaints are possible.
For a general discussion, and for links to other system specific manifestations, please refer to the article on systemic lupus erythematosus.
Seen in 75-90% of patients with varying degrees of severity, it represents the most common presenting complaint clinically, usually worse in the morning. Areas of involvement most commonly include the small joints of the hand, knees, wrists, and shoulders.
Plain radiographs demonstrate soft tissue swelling of the involved joints, periarticular osteoporosis, and normal joint spaces. Carpal instability may be seen in 15% of patients 2.
Deforming non-erosive arthropathy
When articular abnormalities are present, approximately 5-40% will develop a deforming non-erosive arthropathy due to ligamentous laxity (not articular destruction) and muscle contracture. This is more common in those with long-standing disease. In the hands this can be classically seen on Nørgaard views but absent on AP views and are termed as reducible deformities.
Due to their frequently reducible nature, deformities are seldom disabling.
Hands and feet
Symmetric involvement of interphalangeal joints is most common, showing swan neck and boutonniere deformities, subluxation with ulnar deviation at MCP joints, subluxation of the 1st metacarpophalangeal joint, a widened forefoot, and hallux valgus.
Joint space narrowing is uncommon, and when present is likely due to disuse atrophy or pressure from an adjacent subluxed bone. Altered stresses across the joint may also cause a "hook erosion" at the metacarpal heads due to capsular stress, mimicking findings of rheumatoid arthritis. This is more often observed on the radial side.
Spinal manifestations are uncommon and nonspecific, but a higher incidence of spinal findings is seen in those with deforming arthropathy. Up to 10% may have atlantoaxial subluxation/dislocation.
Clinically observed in 30-50% of patients, true myositis occurs in approximately only 4% of patients. Elevated serum levels of muscle enzymes may or may not be observed.
The most common location of osteonecrosis is the femoral head, but nearly any site may be affected. This is more commonly seen in younger patients and those with Raynaud phenomenon and other signs of vasculitis. This may also be seen as a complication of steroid therapy.
Spontaneous tendon weakening and rupture
Typically observed about weight bearing joints as a complication of steroid therapy.
Soft tissue calcification
Linear or nodular calcification in the subcutaneous and deep soft tissues may be seen, especially in the lower extremities. Associations with diuretic therapy and vitamin D supplementation has been documented.
Osteomyelitis and septic arthritis
Lupus patients are at increased risk of bacterial and mycotic infections, in large part due to steroid administration and renal disease. Osteomyelitis and septic arthritis involvement are less common than infection elsewhere.
- 1. Resnick DL. Diagnosis of bone and joint disorders. Saunders. (2002) ISBN:0721689213. Read it at Google Books - Find it at Amazon
- 2. Lalani TA, Kanne JP, Hatfield GA et-al. Imaging findings in systemic lupus erythematosus. Radiographics. 2004;24 (4): 1069-86. Radiographics (full text) - doi:10.1148/rg.244985082 - Pubmed citation
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