Inflammatory Back Pain and Ankylosing Spondylitis

• What is inflammatory back pain? - First need to understand:

  • Spondyloarthropathies (SpA) = group of chronic inflammatory rheumatic conditions that share overlapping features:
  • Sacroiliitis - inflammation of sacroiliac joint
  • Enthesitis
  • Extra-articular manifestations (e.g. uveitis, psoriasis, Inflammatory Bowel Disease )
  • HLA B27 positivity
  • Familial aggregation
• Spondyloarthropathies - Predominantly axial spondylo-arthropathy(Spine and sacro-iliac joints):

  • Non-radiographic spondyloarthropathy (i.e. no visible irreversible x-ray changes. May have MRI changes)
  • Ankylosing Spondylitis (visible x- ray changes)
• Spondyloarthropathies - Predominantly peripheral spondylo-arthropathy (Peripheral joints):

  • Reactive arthritis
  • Psoriatic arthritis
  • Arthritis with inflammatory bowel disease
  • Undifferentiated spondyloarthropathy
• Ankylosing Spondylitis (axial spondyloarthropathy):

  • ANKYLOS meaning stiffening
  • SPONDYLOS meaning vertebra
  • -ITIS meaning inflammation
  • Systemic condition
  • Inflammatory
  • Autoimmune
  • Predominantly affects spine but peripheral joints involved too
  • Potentially leads to fusion of the joints (‘ankylosis’)
• What is Inflammatory back pain?:

  • Common link between many of these conditions
  • May represent the first symptom of a spondyloarthropathy
  • Presents an opportunity for early diagnosis and management -> better outcome for patient
• Night pain and early morning stiffness are common symptoms of inflammatory diseases
• Making a diagnosis:

  • clinical features
  • imaging
  • MRI (Gold standard – shows bone marrow oedema indicating inflammatory response)
  • X-RAYS (show irreversible bony changes)
  • blood tests
  • ESR/CRP – measures of inflammation
  • HLA B27 - indicator of genetic susceptibility
• HLA B27:

  • HLA B27 – a human leucocyte antigen
  • Axial Spondyloarthropathy has a genetic link
  • HLA B27 is a strong predictor for axial SpA
  • Approximately 80-95% of patients with AS and 46-75% of patients with nr-axSpA are HLA B27 positive
  • HLA B27 positivity is associated with earlier onset and uveitis
  • Approx 9.5% of the population are HLA B27 positive but only approximately 5% will develop a form of spondyloarthritis
• Pathology – “enthesitis” or “enthesopathy”:

  • ENTHES = site of attachment to bone of tendon, ligament, or joint capsule
  • 4 ZONES:
  • Bands of collagen fibres which provide strength and traction resistance
  • Un-mineralised fibrocartilage with chondrocytes
  • Mineralised fibrocartilage directly adjacent to the bone
  • Bone matrix
  • Summary – tendon fibres become compact, then cartilaginous and then calcified
• Common sites for enthesitis:

  • Sacro-iliac ligaments
  • IV discs
  • Achilles Tendon
  • Plantar Fascia
  • Symphysis Pubis
  • Manubriosternum
  • Greater Trochanter
  • Hip Adductor origin
  • Iliac Crest
  • Sternocostal joints
  • Sternoclavicular joints
• Typical Pathology in A.S – sacro-iliac joints:

  • Spontaneous bilateral inflammation in the iliac portion of the sacro-iliac joints
  • Erosions and sclerosis
  • Subsequent reactive bone formation and bridging from ilium to sacrum
  • Leads to restriction of lumbo-pelvic movement
• Typical changes In the spine:

  • Ligamentous changes
  • Calcification of interspinous ligaments, anterior longitudinal ligament and posterior longitudinal ligament
  • Osteitis
  • Bony erosions on anterior corners of vertebra -> squaring
  • Syndesmophytosis
  • Ossification of the outer fibres of the annulus fibrosis, A.L.L and paravertebral connective tissue
  • Erosions and destruction of bone
• A.S. in the spine:

  • Discal Calcification
  • May be caused by immobilisation of a segment and subsequent poor nutrition
  • Osteoporosis
  • Reduced bone turnover
  • Diminished trabecular density
  • Systemic effect of the disease
• “Clues” for detecting early AS:

  • Young patients (2nd and 3rd decades)
  • E.M.S and sleep disturbance (second half of night)
  • Bilateral sacro-iliac pain (can be unilateral or alternating)
  • Costo-chondral pain
  • Temporomandibular joint (joins jawbone to skull) Pain
  • Adductor pain
  • Multiple sites of spinal pain
  • BETTER WHEN EXERCISING, WORSE WHEN RESTING
• Presence of other Spondyloarthropathy features:

  • Heel pain (enthesitis)
  • Dactylitis - inflammation of a digit
  • Uveitis (30%) (eye problems)
  • Family history
  • Crohn’s disease (3-10%)
  • Psoriasis
  • Asymmetrical arthritis
  • Positive response to NSAIDs
  • Raised inflammatory markers (CRP/ESR)
• Questions to ask:

  • Sleep - do they wake during the night in pain or feeling stiff and need to turn over?
  • EMS – duration and severity
  • Does it hurt when you sneeze? (anterior chest wall)
  • Changes in bowel habit? (ulcerative colitis/Crohns) - going to toilet more frequently
  • Areas of dry/ scaly skin, dandruff (psoriasis)
  • Family history
  • Any problems with their eyes? – unilateral red painful eye (irits/anterior uveitis)
• Objective Clues:

  • Posture – may have flattened lordosis
  • decrease in spinal ROM- especially lateral flexion
  • decrease in Chest expansion
  • decrease in Hip ROM
  • SLR negative ( but may have hamstring tightness++)
  • Enthesitis points, eg achilles, adductors
• Summary - IBP parameters:

  • Age at onset < 40 years
  • insidious onset
  • Improvement with exercise
  • No improvement with rest
  • Pain at night (with improvement on getting up)
  • Diagnosis depends on 4 out of these 5 being present.