15/10/2025
is inflammation of one or both sacroiliac joints, which connect the sacrum (base of the spine) to the ilium (pelvic bone).
It may occur as an isolated condition or as part of a systemic inflammatory disorder.
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Causes
1. Inflammatory (Autoimmune)
Ankylosing spondylitis
Psoriatic arthritis
Reactive arthritis
Inflammatory bowel disease–related arthritis
2. Infectious
Bacterial infection (e.g., Staphylococcus aureus)
Tuberculosis (rare)
3. Mechanical / Traumatic
Injury, overuse, leg-length discrepancy
4. Pregnancy-related
Ligamentous laxity and altered load during pregnancy
5. Degenerative
Osteoarthritis of sacroiliac joint
Clinical Features
Pain: Dull, aching pain in the lower back, buttocks, or posterior thigh
Aggravating factors: Standing, walking, or sitting for long periods
Morning stiffness (in inflammatory causes)
Tenderness over sacroiliac joint (positive FABER or Gaenslen’s test)
Reduced spinal movement if associated with spondyloarthritis
Occasionally fever (in infectious sacroiliitis)
Investigations
X-ray / MRI of sacroiliac joint – shows joint space narrowing, sclerosis, or erosion
Blood tests:
↑ ESR, ↑ CRP (in inflammatory or infective causes)
HLA-B27 positivity (in spondyloarthropathies)
Joint aspiration – for culture if infection suspected
Treatment
1. Medical Management
NSAIDs – for pain and inflammation
Corticosteroid injections – intra-articular for severe pain
DMARDs / Biologics – in autoimmune conditions (e.g., sulfasalazine, TNF inhibitors)
Antibiotics – if infection present
2. Physiotherapy
Stretching and strengthening exercises
Posture correction
3. Lifestyle Measures
Avoid prolonged standing or sitting
Weight management
Regular low-impact exercise