see also:

• The adult with back pain in the ED
• The elderly patient with back pain in the ED
• arthritis - clinical patterns

• pain localisable to the sacro-iliac joints, and buttocks
• pain may be referred down the legs
• pain often aggravated by:
  • prolonged standing
  • stair climbing
  • bearing more weight on one leg than the other
  • running
  • taking large strides

• traumatic injury such as MVA or falls from a height
• osteoarthritis
• pregnancy
  • progesterones and relaxins cause ligamentaous laxity to allow the sacro-iliac joints to loosen and stretch to accommodate childbirth
  • this may result in additional stress on the joints and deranged biomechanics
• ankylosing spondylitis
  • 10% start before puberty, peak onset 15-25yr olds
• other seronegative spondyloarthopathies:
  • psoriasis
    • 5% of pts with psoriasis
  • Reiter's disease
    • males mainly; non-specific urethritis, polyarthritis (esp. sacro-iliac, lower limbs), conjunctivitis
  • enteropathic spondylitis
    • associated with inflammatory bowel disease (IBD)
  • rheumatoid spondylitis (Bechterew's disease)
    • assoc. with chronic prostatitis, enteropathy, recurrent UTI or psoriasis, iritis.
• infective:
  • tuberculosis (TB)
  • brucellosis
    • sacroiliitis is the most common presentation of arthritis from Brucella
  • septic arthritis
    • rare
• other:
  • recurrent polyserositis (familial Mediterranean fever)
  • ochronosis (alkaptonuria)
  • consider also osteoporotic sacral insufficiency fracture (SIF)
• see arthritis - clinical patterns for more details