Rheumatoid Arthritis and Ankylosing Spondylitis

Excerpt

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are among the most common rheumatic diseases. These chronic progressive inflammatory diseases lead to a reduction in physical fitness and increase in joint degeneration. Although very closely related, their symptomatology and etiology are different. In the past, AS was often diagnosed inaccurately as RA, but the two have recently been recognized as separate, distinct clinical entities. The latter has been attributed to advancing diagnostic and laboratory techniques able to differentiate the two conditions. That being said, the diagnostic differentiation still remains a challenging task for clinicians.

Both RA and AS can be similarly characterized by the presenting symptoms, radiographic characteristics, and serological testing. However, RA and AS have widely different characteristics with respect to each one's pathophysiology and underlying genetic parameters. This makes the probability of a patient having both conditions rather low. Considering that the two have some similar clinical manifestation such as changes on radiography or peripheral/morning stiffness, however, the diagnosis can be a challenge, and more tests may be required to establish the correct etiology. Furthermore, authors have reported cases of coexisting AS and RA since 1976.