Ankylosing Spondylitis (AS)

• Early symptoms: Chronic inflammatory back pain (worsens at rest, improves with activity). Morning stiffness >30 minutes, nocturnal pain.
  Sacroiliitis (buttock/hip pain).
• Advanced disease: Reduced spinal mobility (e.g., limited lumbar flexion, chest expansion).  Kyphotic deformity (“question-mark posture”).
• Extra-articular manifestations:
  Anterior uveitis (acute eye pain/redness). Inflammatory bowel disease (IBD), psoriasis.
  Cardiovascular involvement (aortitis, conduction defects).
  Osteoporosis (increased fracture risk).
• Red flags: Neurological deficits (e.g., cauda equina syndrome—rare but serious).

• Etiology: Strong genetic association with HLA-B27 (present in >90% of patients).
  Environmental triggers (e.g., gastrointestinal or genitourinary infections) may initiate immune activation.
• Pathophysiology: Autoimmune-mediated inflammation at entheses (sites where tendons/ligaments attach to bone). Progressive ossification and fibrosis, leading to bony fusion and loss of spinal mobility. Systemic inflammation involving cytokines (e.g., TNF-α, IL-17).

• Prevention: No known prevention; early diagnosis and treatment slow progression.
  Regular exercise to maintain mobility and posture.
• Follow-up: Regular monitoring of disease activity (e.g., BASDAI, ASDAS scores). Imaging (X-ray/MRI) to assess structural damage. Screening for extra-articular manifestations (e.g., eye exams for uveitis). Bone density monitoring and fracture prevention.

Note: AS requires lifelong management. Multidisciplinary care (rheumatology, physiotherapy, ophthalmology) is essential. Newer biologics (e.g., JAK inhibitors) are expanding treatment options. Patient self-management and adherence to therapy are critical for optimizing outcomes.