Seronegative spondyloarthropathies

• Group of conditions affecting the spine and peripheral joints
• Associated with HLA-B27
• Synovitis similar to RA but is seronegative
• Inflammation of enthesis (junction of ligament/tendon with bone) and joint ankylosis occur more commonly than in RA
• Increased frequency of sacroilitis

Types;

• Ankylosing spondylitis
• Psoriatic arthritis
• Reactive arthritis
• Sexually acquired (Reiter’s disease)
• Post-dysenteric reactive arthritis
• Enteropathic arthritis (UC/Crohn’s)

 

Non articular problems in seronegative spondyloarthropathies

• Uveitis in all types
• Cutaneous lesions in reactive arthritis
• Nail dystrophy in psorisis and reactive arthritis
• Aortitis occasionally in AS and reactive arthritis

 

Aetiology

• Associated with HLA-B27
• HLA-B27 transgenic mice spontaneously develop develop arthritis, skin, gut and genitourinary symptoms
• Infection may play a role possible by molecular mimicry

 

Ankylosing spondylitis

 

• Inflammation of the spine
• Generally affects young adults
• More likely to occur in men, men get more serious symptoms
• Lymphocyte and plasma cell infiltration and local erosion of the bone at the attachments of the intravertebral and other ligaments (enthesis). This heals with new bone (syndesmophyte) formation

 

Clinical features

• Episodic inflammation of the sacroiliac joints is the first manifestation
• Lower back pain and stiffness particular first thing in the morning which is relieved by exercise
• Retention of lumbar lordosis during spinal flexion is an early sign
• Later paraspinal muscle wasting develops
• Anterior chest pain due to costochonditis
• Reduction is chest expansion due to costovertebral joint involvement
• Peripheral joint involvement is asymmetrical and affects larger joints
• Hip involvement leads to fixed flexion deformities
• Severe eye pain, photophobia, blurring of vision due to anterior compartment uveitis

 

Investigations

• Blood – raised inflammatory markers
• HLA testing
• x-rays
  • sclerotic erosions of the sacroiliac joints
  • blurring of upper and lower vertebral rims in the thoracolumnar junction caused by enthesitis at the insertion of the intravertebral ligament. These changes may eventually affect the whole spine
  • persistant inflammatory enthesitis cause bony spurs syndesmophytes
  • sacroiliac joitns may eventually fuse
  • calcification of the intravertebral ligaments and fusion of the spinal facet joints and desmophytes lead to what is called a ‘bamboo spine’

 

Treatment

• Early treatment, exercise to prevent syndesmophytes forming
• NSAIDs
• Local steroid injections
• Sulphasalazine and methotrexate may help peripheral arthritis

 

 

Psoriatic arthritis

 

• Describes a variety of arthritis and enthesitis seen in patients qwith psoarisis or with a family history
• T cell mediated

 

Clinical features

• More limited in distribution and less severe than RA
• Skin disease may be mild and may develop after the arthritis
• Most commonly affected joint is the distal interphalangeal joint
• There is often accompanying nail erosion
• Causes ‘sausage’ finger or toe (dactylitis)
• Erosion of joint is in the middle producing a ‘pencil in cup’ radiological appearance

 

• Arthritis mutilans affects 5% of patients with psoriatic arthritis and causes marked periarticular osteolysis and bone shortening ‘ telescopic fingers’
• Pain generally mild

 

Treatment

• NSAIDs and analgesics help the pain but can worsen skin lesions
• Loca synovitis responds to intra-articular cortiosteriod injections
• Sulphasalazine
• When disease is severe methotrexate or ciclosporin may help
• Anti-TNF agents

 

Reactive arthritis

 

• Sterile synovitis that occurs following an infection
• Develops in 1-2% of patients after an attack of dysentery or a sexually acquired infection

 

Aetiology

• Trigger organisms include;
  • Salmonella
  • Shigella
  • Bacillary dysentery
  • Yersinia enterocolitica
  • Chlamydia trachomatis
• Possibly it is bacterial antigen within the joint which drives the inflammation
• The methods by which HLA-B27 has an effect are;
  • TCR selection
  • Molecular mimicry causing reaction against self-HLA B27
  • Mode of presentation of bacterial derived peptides to T cells

 

Clinical features

• Arthritis is generally acute, asymmetrical and in the lower limbs
• Occurs days to weeks after infection
• Infection may be mild or asymptomatic
• Enthesitis is common including plantar fascities or Achilles tendonitis
• 70% recovery within 6mth but some can relapse
• Skin lesions resemble psoriasis
  • Ulceration of the glans penis – circinate balanitis
  • keratoderma blenorrhagia – painless, red pustules on the skin of the feet and hands
  • Nail dystrophy

 

• Other features;
  • Uveitis
  • Triad of Reiter’disease
    • Urethritis
    • Arthritis
    • Conjunctivis

 

Treatment

• Antibiotics to treat any persisting infection
• NSAIDs
• Corticosteroid injections
• Relapsing cases may require methotrexate and sulphasalazine

 

Enteropathic arthritis associated with inflammatory bowel disease

 

• Enteropathic synovitis occurs in 10% of patients with IBD
• Leaky mucosa may expose patient to antigen with cause synovitis
• Asymmetrical arthritis predominantly lower limbs