BONE PATHOLOGY CASE STUDIES

CASE 9 - Rheumatoid arthritis

Clinical History:

This 58 year old female has suffered from arthritis with pain and swelling of her hands and feet that is aggravated by movement. Over the past decade she has noted increasing deformity of her hands and feet, making it difficult to walk and to perform simple daily activities such as buttoning a blouse or even combing her hair. She has no history of any trauma. Radiographs show ankylosis of the carpals with residual evidence of MP joint erosion and decreased bone mass of the metacarpals and carpals. Physical examination reveals firm, non-tender, less than 1 cm nodules over the elbows.
  1. What is the diagnosis?

    2. Rheumatoid arthritis (RA).

  2. What is the major differential diagnosis for this arthritis and what further testing is helpful?

    3. Osteoarthritis (also called degenerative joint disease) has an insidious onset and generally is oligoarticular, involving "wear and tear" joints such as knee or hip with loss of articular cartilage. The presence of an elevated rheumatoid factor (RF) test is helpful, but not specific for the diagnosis of RA. Slide 9.6 shows just such an osteoarthritic process, and it was also accompanied by the proliferative synovitis in slide 9.7, but such gross joint changes could also appear with long-standing rheumatoid arthritis.

    For those who looked carefully at slide 9.7 and noted the tremendous size of the tissue obtained, your suspicions will be rewarded by learning that slides 9.6 and 9.7 are from an elephant hip (the world's best example of a weight-bearing joint).

  3. In whom and at what sites is this disease most common?

    4. Although about 1% of the population will develop some form of RA, middle-aged women are most often affected. The joint involvement is symmetrical and mainly small joints of the hands and feet. The presence of rheumatoid nodules over bony prominences suggests more severe disease.

  4. What is the pathogenesis of the lesions?

    5. The latest theory is that there is a genetic predisposition in some persons to the initiation of an autoimmune process by some arthritogenic agent (perhaps microbial). Most persons with RA are HLA- DR4 or DR1 or both. The inflammatory pannus in the synovium has many CD4 lymphocytes and there are activated macrophages secreting a variety of cytokines. The pannus is destructive of the joint, leading to erosion and eventual ankylosis with marked deformity.