Spondyloarthritis

Disorder included:

• Psoriatic arthropathy
• Undifferentiated spondyloarthropathy
• Ankylosing spondylitis
• Reactive arthritis ( includes Reiter's )
• Enteropathic SpA ( IBD and Coeliac's )
• Juvenile onset SpA
• HIV associated SpA

Epidemiology:

• Overall prevalence of 0.5 %.
• 1.5 % if HLA - B27 +ve.
• 10-20 % if 1st degree relative
• Concordance rate in identical twins 60% indicating environmental contribution to etiology.

Generally accepted that B27 is involved in pathogenesis.

Ankylosing spondylitis >90% association
Psoriatic arthritis 15-50% association

Clinical Manifestations:

• Inflammatory sounding spinal pain
• Reduced lumbar ROM & chest wall expansion
• Sacroillitis: buttock pain, examination unreliable.
• Non-axial: planter fasciitis, achilles tendonitis, periarthritis, dactylitis
• Extra-articular: uveitis, bowel mucosa lesions, skin problems, CVS disease.

Of all patients who present with back pain <>

1) Inflammatory spinal pain ( 15% +ve PPV for SpA ) - inflammatory back or neck pain, insidious onset, minimum of 3 months, EMS > 20 mins, improves with exercise , onset <>

2) 2 or more other features - alternating button pain, entesitis, dactylitis, acute anterior uveiitis, IBD, psoriasis, abnormal examination, raised ESR/CRP, +ve HLA-B27 + ve family history, XR sacroillitis.

Laboratory Testing:

• In general, not very helpful-variable increase in ESR/CRP, mild anaemia of inflammation.
• Role of HLA-B27 testing controversial but in practice commonly done- most useful when history of inflammatory back pain+ 1 other SpA features.
• Testing for bacterial infection may be useful - particularly urine PCR for C. trachomatis DNA or stool cultures.
• Consider HIV testing if atypical pattern or at risk.

Imaging:
May aid diagnosis & several features are fairly specific
Plain XR of SI joints reveal sacroillitis in 5-30 % of patients with early disease ( better sensitivity with CT or MRI )

Ankylosing Spondylitis:

• Male: Female 3:1
• Symmetric sacroillitis in virtually 100%
• Peripheral joint involvement 25%
• Eye involvement 25-30 % ( unilateral uveitis with tendency to recur )
• Cardiac involvement 1 -4% ( Aortitis, CHB )
• Rarely - amyloidosis, neurologic, ventilatory insufficiency

Treatment

• Mild to moderate: NSAIDs + exercise /physiotherapy
• Severe: Above + DMARDs
• SSZ ( salazopyrin ): modest efficacy in peripheral artritis
• Methotrexate: no clear benefit in small trials using very low doses
• TNF antagonists ( infliximab, etanercept )

Psoriatic Arthritis
skin psoriasis affects 5-8% of the community
Male and female has equal incidence
75% skin precedes arthritis, 15 % synchronous, 10 % arthritis precedes skin

Patterns of arthritis in Psoriasis

• Spondylitis
• Distal Interphalangeal joint arthritis
• Oligoarticular asymmetric arthritis
• Polyarticular symmetric arthitis _ identical to RA
• Arthritis mutilans

Management:

• Basic principles similar to RA treatment
• Early aggressive therapy important in subsets
• DMARDs ( particularly MTX & SSZ ) the mainstay of treatment ( persistently inflammatory, eroding on XR and deformity )
  
• Tend to avoid hydroxychloroquine & care with systemic corticosteroids.
• Infliximab, etanercept & adalimumab all have an indication for PsA with similar outcome data in treating both the skin & articular manifestations
• Efalizumab = anti-CD 11a Ab that blocks ICAM interaction is only indicated for skin psoriasis ( sometimes flares the arthritis )
  

Reactive Arthritis

• Typically onset acutely 2-4 weeks following certain GU or GI infeciton ( but <>
• Organisms _ Chlamydia, Campylobacter, Shigella, Salmonella, Yersinia, Clostridium.
• Articular manifestations typically appear last, after symptoms of urethritis, ocular inflammation or gastroenteritis.
• Mostly occurs in yound men
• additive asymmetric oligoarticular with predilection ofr lower limb joints with enthesitis
• 60% lower back pain but plain X rays only show spondylitis/sacroillitis in 10-15 %.

self-limited in the majority
10% have chroinic course which may be disabling or destructive.