Seronegative arthritis Flashcards
What is seronegative arthritis?
> Negative rheumatoid factor
> May be associated with HLA- B27
> Usually an asymmetric arthritis
> Involvement of axial skeleton (spine)
> Enthesitis
> Extra-articular features- uveitis, inflammatory bowel disease
Different clinical presentations to consider in seronegative arthritis?
> Ankylosing Spondylitis > Psoriatic arthritis > Bowel related arthritis (Crohn’s, UC) > Reactive arthritis > Others
The spondyloarthropathies
What is ankylosing spondylitis?
Chronic inflammatory rheumatic disorder with a predilection for axial skeleton and entheses
Aetiology of ankylosing spondylitis?
> Onset in second to third decade of life
> Males > Females
> Prevalence varies in different parts of the world
What can ankylosing spondylitis lead to?
Axial sponyloarthritis
What is a marker seen in the majority of those with ankylosing spondylitis?
HLA-B27:
> Positive in 80 to 95% of patients with AS
Although not diagnostic
What is the issue surrounding using HLA-B27 as a marker of ankylosing spondylitis?
> Positive in only 80-95% = False negatives
> In Europe - 10% of the population are HLA-B27 positive yet only 1% have AS = False positives
How might HLA-B27 lead to Ankylosing spondylitis?
1) HLA-B27 trimolecular complex leads to activation of CD8+ T cells
2) HLA-B27 free heavy chain homodimers activates NK cell, T cells, B cells.
3) Components of HLA-B27 molecules yet properly assembled and folded inside the cell –> ER unfolded protein response –> TH17 cell activation
Which test can be used in Ankylosing spondylitis - Modified Schober?
Spinal mobility - Modified Schober test:
> Patient stands erect
> Mark an imaginary line connecting both posterior superior iliac spines
> A mark is placed 10cm above
> The patient ends forward maximally, measure the difference between the two marks
> Report the increase (In cm to the nearest 0.1cm)
> The best two tries is recorded
Which test can be used in Ankylosing spondylitis?
> Spinal mobility - Modified Schober test:
> Spinal mobility - Lateral Spinal Flexion
> Spinal mobility - Occiput to wall and Tagus to wall
> Spinal mobility - Cervical rotation
Which test can be used in Ankylosing spondylitis - Lateral spinal flexion?
> Heels and back rest against the wall. No flexion in the knees, no bending in knees forward
> Place a mark on the thigh (1)
> Bend sidewards without bending knees or lifting heels (2)
> Place a second mark and record the difference (3)
> The best of two tries is recorded for left and right separately
> Finally, the mean of left and right calculated (in cm to nearest 0.1cm)
Which test can be used in Ankylosing spondylitis - Spinal mobility - Occiput to wall and Tagus to wall?
> Heels and back rest against the wall
> Chin at usual carrying level
> Maximal effort to move the head (Occiput) against the wall
> Report the best two tries (in cm) for the occiput to wall distance and the mean of left and right for the triages to wall distance
Which test can be used in Ankylosing spondylitis - Cervical rotation?
> The patient sits straight on a chair, chin at usual carrying level, hands on the knees
> The accessor places a goniometer at the top of the head in line with the nose (1)
> The accessor asks to rotate the neck maximally to the left, follows with the goniometer, and records the angle between the sagittal plane and the new plane after rotation (2)
> A second reading is repeated for the right side
> The mean of left and right is recorded in degrees (0-90 degree)
What are the clinical features of ankylosing spondylitis?
> Inflammatory back pain
> Limitation of movements in antero-posterior as well as lateral planes at lumbar spine
> Limitation of chest expansion
> Bilateral sacroiliitis on X-rays
Management of ankylosing spondylitis?
> Physiotherapy > NSAIDs > DMARDs- Sulfasalazine > Anti-TNF > Anti-IL-17 > Treatment of osteoporosis > Surgery- joint replacements & spinal surgery
