Seronegative spondyloarthritis Flashcards
What are the different types of spondyloarthritis?
ankylosing spondylitis
psoriatic arthritis
reactive arthritis (secondary to STDs, dysentry, reiter’s disease)
enteropathic arthritis (secondary to UC or Crohns)
What does is a spondyloarthropathy?
A group of related inflammatory joint disorders.
Characterised by enthesitis as well as synovitis and occur in patients who are seronegative for rheumatoid factor.
What is the genetic association between the spondyloarthropathies?
HLA-B27
most prevalent in ankylosing spondylitis (85-95%).
This antigen is carried in approximately 10% of healthy caucasians.
Describe the pathology in spondyloarthritis?
Initial inflammation and erosion are followed by fibrosis and ossification which can result in ankylosis of the joints
How does the clinical presentation vary between RA and spondyloarthritis?
- affects the spin and peripheral joints
- joint involvement is more limited than in RA
- enthesitis and joint ankyloses develop more commonly than in RA
- increased sacroillitis than in RA
- RF negative, anti- CCP is usually negative
What are the shared features of the spondyloarthropathies?
1 - seronegativity (RF -ve)
2 - HLA B27 association
3 - axial arthritis
4 - asymmetrical large joint oligoarthritis
5 - enthesitis
6 - dactylics (inflammation of entire digit)
7 - extra articular manifestations (uveitis, skin lesions etc)
What is the epidemiology of ankylosing spondylitis (AS)?
- prevalence of 0.5-1%
- 3 times more common in men
- tends to develop in early adulthood, with peak age of onset being mid-20s
always consider in young people with inflammatory sounding back pain
What are the clinical features of AS?
- pain in the lower back and buttocks that is worse in the morning/after long periods of rest
- stiffness
- symptoms improve with exercise
- patients are asymptomatic between episodes
- disease in costovertebral joints can produce chest pain
What are the signs seen in AS?
- retention of the lumbar lordosis during spinal flexion (early)
- paraspinal muscle wasting (late)
- Shoeber’s test shows spinal stiffness
What is the classic history of a patient presenting with AS?
- gradual onset lower back pain
- worse at night
- spinal morning stiffness relieved by exercise
- pain radiates from sacroiliac joints to hips/buttocks and improves towards the end of the day
- progressive loss of spinal movement (all directions) –> decreased thoracic expansion
What is the diagnostic criteria for AS?
presence of 3 of the 4 following factors…
patient <50 years, chronic back pain
1) morning stiffness >30 mins
2) improvement with exercise not rest
3) awakening in the second half of the night due to back pain
4) alternating buttock pain
What are the extra-spinal manifestations of AS?
- enthesitis (achilles, plantar fascitis)
- anterior mechanical back pain due to chostrochondritis and fatigue
- acute iritis (occurs in 1/3 of patients and is an emergency)
- osteoporosis
- aortic valve incompetence
- pulmonary apical fibrosis
What is the pathology of AS?
- inflammation of the ligaments around the vertebrae with lymphocytic infiltrate
- healing by ossification occurs and there is fibrosis of the ligaments
- vertebral column eventually becomes fused, inflexible and rigid (bamboo spine)
What investigations can be used in AS for diagnosis?
diagnosis is clinical
supported by imaging
MRI is most sensitive and better at detecting earlier disease
ESR and CRP can be raised in active phases of the disease
What radiographic changes are seen in AS?
- earliest manifestation is blurring of the upper/lower vertebral rims of thoracolumbar junction due to enthesitis at insertion of vertebral ligaments
- loss of cortical margins at the sacroiliac joints
- bony spur formation causing stiffness and ankyloses
- fusion of sacroiliac joints and costovertebral joints
- calcification of intervertebral ligaments
- bamboo spine
