About Spondyloarthritis

Spondyloarthritis is a group of related disorders, including:

  • Psoriatic arthritis
  • Ankylosing spondylitis
  • IBD-associated arthritis
  • Reactive arthritis

Typically negative for RA antibodies (RF, CCP)

Disease Overview & Clinical Presentation

  • Inflammatory arthritis of DIPs – PsA high on DDx
  • Inflammatory back pain of young – start with SI joint radiographs
  • Classic triad of reactive arthritis = conjunctivitis, urethritis, and arthritis (most patients do NOT have all three features)

Diagnostic Workup & Differential Diagnosis

  • High suspicion for sacroiliitis but negative XR consider STIR MRI of pelvis
  • HLA-B27 positive has high population prevalence. HLA-B27+ doesn’t equate to spondyloarthritis diagnosis.
  • If suspicious for psoriatic arthritis but don’t see obvious psoriasis – examine ears, scalp, umbilicus, gluteal cleft
  • Spinal fusion in ankylosing spondylitis associated with increased risk of spinal fracture

Treatment

  • NSAIDs first line for spondyloarthritis

Typical Manifestations

  • “Inflammatory back pain”
    • Age < 40
    • Better with exercise
    • Worse with immobility
    • Nocturnal symptoms
    • Alternating buttock pain
  • Other arthritis
    • Predilection for knees, ankles
  • Enthesitis
  • Dactylitis (“sausage digit”)
  • Uveitis

Association with Derm and GI diseases

  • Psoriatic arthritis (look for nail pitting)
  • Gut disease:
    • Crohn’s disease
    • Ulcerative colitis
    • Celiac disease
  • Infection (Reactive)
    • Usually GU/GI infection

Lab workup

  • CBC, CMP, ESR, CRP
  • HLA-B27

Synovial fluid

  • Inflammatory (2K-50K WBC/microL)

Imaging

  • Sacroiliac joints
    • XRay
    • MRI with STIR: sclerosis, erosions, “pseudo-widening”,
      fusion if advanced
  • Peripheral joints
    • Can show “pencil-in-cup” deformity for hand
    • Hand Psoriatic arthritis associated with nail disease 
  • +/- Extra bone formation at entheses: nonspecific

Other rheumatic

  • Rheumatoid arthritis
  • Lupus
  • Crystalline arthritis (gout, CPPD)

Infectious

  • Gonococcal arthritis
  • Infectious sacroilitis (typically unilateral)

Non-inflammatory

  • Osteoarthritis
  • Mechanical back pain/degenerative disease
  • Fibromyalgia
  • DISH

Peripheral Arthritis

  • NSAIDs
  • Conventional DMARDs: sulfasalazine, methotrexate
  • Biologics (inhibitors of TNF, IL-17, IL-23, IL-12/23)
  • JAK inhibitors
  • Apremilast

Axial Arthritis

  • NSAIDs first line
  • TNF inhibitors
  • IL-17 inhibitors
  • JAK inhibitors

General Measures

  • Treat infection
  • Physical therapy
  • Coordinate with derm or GI as necessary

Monitoring

  • Monitoring for complications of therapy
  • Reactive arthritis
    • Many cases resolve (months), but minority develop chronic arthritis requiring ongoing treatment

Complications/Associations

  • Inflammatory eye disease – uveitis, conjunctivitis
  • Ankylosing spondylitis
    • Aortic regurgitation
    • Aortitis
    • Apical pulmonary disease