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Spondyloarthropathies are a group of chronic inflammatory arthritides that primarily affect the axial skeleton, including ankylosing spondylitis, psoriatic arthritis, reactive arthritis, and enteropathic arthritis. These conditions share common clinical features including sacroiliitis, enthesitis, and strong association with HLA-B27. Early diagnosis and treatment are crucial to prevent progressive spinal fusion and functional disability.
The pathophysiology involves aberrant immune responses in genetically susceptible individuals, particularly those with HLA-B27, leading to chronic inflammation at entheses (tendon-bone insertions) and synovial joints. Pro-inflammatory cytokines, especially TNF-α and IL-17, drive the inflammatory cascade, resulting in bone erosion followed by compensatory new bone formation. This dual process of destruction and repair leads to the characteristic radiographic changes including syndesmophyte formation and eventual ankylosis.
Diagnosis relies on recognizing the pattern of inflammatory back pain (insidious onset, morning stiffness >30 minutes, improvement with exercise) combined with extra-articular manifestations such as uveitis, psoriasis, or inflammatory bowel disease. Laboratory markers include elevated inflammatory markers and HLA-B27 positivity, while imaging shows sacroiliitis on MRI or X-ray. The Assessment of Spondyloarthritis International Society (ASAS) criteria help standardize diagnosis and guide early intervention with NSAIDs and biologics to prevent irreversible structural damage.