Ankylosing Spondylitis is Classified as a Spondylopathy
Ankylosing spondylitis is the disease classified as a spondylopathy among the options listed. 1, 2
Definition and Classification
Ankylosing spondylitis (AS) is the prototype of spondyloarthritis (SpA), a family of inflammatory rheumatic diseases that primarily affect the spine and sacroiliac joints. 2, 3 The disease is characterized by:
- Chronic inflammatory disease primarily affecting the axial skeleton (spine and sacroiliac joints), with sacroiliitis, enthesitis, and a strong tendency for spinal and sacroiliac joint fusion 2
- Formation of vertical bony bridges (syndesmophytes) between vertebral bodies, representing ossification of the outer fibers of the annulus fibrosus 1
- Progressive ankylosis leading to the classic "bamboo spine" appearance from extensive ligamentous ossification and vertebral joint fusion 1, 2
Why the Other Options Are Not Spondylopathies
The other diseases listed belong to different categories of rheumatic disease:
- Rheumatoid arthritis is a systemic autoimmune disease primarily affecting peripheral joints symmetrically, not classified as a spondyloarthropathy 4
- Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multi-organ involvement; while SLE and AS can rarely coexist in the same patient (only 8 reported cases in English literature), they are distinct disease entities with different genetic backgrounds 5
- Osteoarthritis is a degenerative joint disease, not an inflammatory spondyloarthropathy 1
Key Diagnostic Features of AS as a Spondylopathy
The American College of Rheumatology and Assessment of SpondyloArthritis international Society (ASAS) define AS by:
- Universal sacroiliac joint involvement, forming the core of the modified New York classification criteria 1
- Axial skeleton inflammation with 99% of patients having active inflammatory lesions in the axial skeleton 1
- Loss of spinal flexibility due to progressive ankylosis that eliminates normal spinal movement 2