Rheumatology 2 - Spondyloarthridides Flashcards
What are shared features of SpA?
- Inflamm back pain
- Peripheral arthritis
- Enthesitis
- Dactylitis
- Extra-articular - ant uveitis, psoriasiform rash, enteric lesions
- Imaging changes of SIJ and spine
- Shared genetic background - HLA-B27
What are criteria for IBP?
Age onsef =4/5 required for Dx
What are features of peripheral arthritis in SpA?
Oligoarticular - inflammation of
What are features of enthesitis?
inflammation at sites where ligaments, tendons and joint capsules attach to bone
Typically at sites subjected to greater physical stresses
also affects the axial skeleton including hip and shoulder girdles
MASES score
What are clinical features of dactylitis?
diffuse fusiform swelling of toe or finger (sausage digit) flexor tendon sheath inflammation psoriatic arthritis, reactive arthritis uncommon in AS DDx = gout, sarcoidosis
What are extra-articular features of SpA?
Anterior uveitis (iritis) Skin - psoriasis/psoriasiform lesion - keratoderma blenorrhagicum - circinate balanitis Enteric mucosal lesions
What are other causes of anterior uveitis (other than SpA)?
behcet’
sarcoidosis
What is the grading system for SI joint changes?
0 - normal
1 - suspicious
2 - early sacroilitis - minor sclerosis, limited erosion, joint narrowing
3 - definite sacroilitis - severe sclerosis, clear cut erosions, joint space widening, some ankylosis
4 - advanced sclerosis - ankylosis, fusion
look at lower 1/3 of the joint, monitor with imaging every 24 months
What is the clinical criteria for AS?
Mod new york criteria:
- clinical criteria
- low back pain and stiffness for >3 months which is improved by exercise, not by rest - limitations in motion of the lumbar spine in both saggital and frontal planes
- limitation in chest expansion relative to normal values
- radiological criterion - sacroilitis grade >=2 bilaterally or grade 3-4 unilaterally
Need 1 clinical and 1 radiological criterion to make Dx
What are features of Osteitis Condensans Ilii (OCI)?
Multiparous women
often bilateral
triangular area of dense sclerosis on iliac side, adjacent to lower 1/2 SIJ
Does not involve SIJ!
CT useful in differentiating between OCI and SIJ
What are abnormalities noted on MRI in SIJ disease?
- inflammatory change on stir images (bone oedema, osteitis)
- structural change - T1 weighted images - visualise cartilage and subchondral bone, erosion, sclerosis and ankylosis, also look for post inflammatory fatty change
What is the relative Sn of MRI vs XR and CT wrt sacroilitis?
XR and CT are both more sensitive to structural Abn than MRI
What predictors have the strongest LR for AS at 8 years?
SIJ osteitis grade 3 with B27 +ve = LR 8.0
What are features of diffuse idiopathic skeletal hyperostosis?
Ossification of anterior longitudinal ligament
8-10% prevalence
Associated in males, older than 50y, 20% DB, NOT HLA-B27.
Treat with NSAIDs, simple analgesics
What is the concordance between twins and AS?
MZ twins 63%, DZ twins, 12.5%
What are features of HLA-B27?
Class Ia MHC molecule, 8% caucasians
1/3 patients with chronic back pain are HLA-B27 +ve, expected to have Ax-Spa
Less than 5% of HLA-B27 patients develop SpA (20% if 1st deg relative with AS)
What is HLA-B27 most strongly associated with?
Ankylosing spondylitis 85-90% Reactive arthritis 70% Psoriatic SpA 60-70% IBD-associated SpA 50-60% Acute anterior uveitis 50% Peripheral psoriatic arthritis 25%
What genes have been assocaited with AS on GWAS?
ERAP1
Il23R
Region within the IL-1 gene complex
What are functions of ERAP1?
trimming peptides for optimal length for MHC Class I presentation
cleaves cell surface receptors for the proinflammatory cytokines IL-1, IL-6, and TNF, downregulating signalling
What are ASAS classification criteria for Axial spondyloarthritis?
Pt with >=3 months of back pain at age =1 SpA feature OR HLA-B27 plus >=2 SpA features.
What are SpA features?
Inflammatory back pain arthritis enthesitis (heel) uveitis dactylitis psoriasis crohn's colitis good response to NSAID Family Hx for SpA HLA-B27 elevated CRP
What are features of inflammatory markers in AS?
What are predictors of severe disease in AS?
juvenile onset poor response to NSAIDs dactylitis, oligoarthritis poor social supports smoking hip arthritis ******
What is the relationship between OP and AS?
50% have t-score