Spondyloarthropathy or spondyloarthrosis refers to any joint disease of the vertebral column. As such, it is a class or category of diseases rather than a single, specific entity. It differs from spondylopathy, which is a disease of the vertebra itself. However, many conditions involve both spondylopathy and spondyloarthropathy.
Spondyloarthropathy with inflammation is called spondylarthritis. In the broadest sense, the term spondyloarthropathy includes joint involvement of vertebral column from any type of joint disease, including rheumatoid arthritis and osteoarthritis, but the term is often used for a specific group of disorders with certain common features, the group often being termed specifically seronegative spondylarthropathies. They have an increased incidence of HLA-B27, as well as negative rheumatoid factor and ANA. Enthesopathy is also sometimes present in association with seronegative spondarthritides.
Seronegative spondyloarthropathy (or seronegative spondyloarthritis) is a group of diseases involving the axial skeleton and having a negative serostatus.
"Seronegative" refers to the fact that these diseases are negative for rheumatoid factor, indicating a different pathophysiological mechanism of disease than what is commonly seen in rheumatoid arthritis.
The following conditions are typically included within the group of seronegative spondylarthropathies:
Percent of people with the condition who are HLA-B27 positive
Extra-articular features, such as involvement of eyes (anterior uveitis), skin, genitourinary tract, and aortic regurgitation
Overlap is likely between several of the causative conditions
Assessment of Spondylarthritis International Society (ASAS criteria) is used for classification of axial spondylarthritis (to be applied for patients with back pain greater than or equal to 3 months and age of onset less than 45 years). It is of two broad types:
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