Seronegative Arthropathies Flashcards
What are Seronegative Spondyloarthropathies?
This refers to any joint disease of the axial skeleton with a negative serostatus (RF negative). Depending on the type of disease, there may be an associaton with HLA-B27.
The shared features between spondyloarthropathies include:
- Seronegativity
- HLA-B27 association
- Axial Arthritis - spine and SI joints
- Asymmetrical lare-joint oligoarthropathies or monoarthritis
- Enthesitis
- Dactylitis - inflammation of entire single digit
- Extra-articular manifestations
What are the subclassifications of Spondyloarthropathies?
- Ankylosing Spondylitis
- Psoriatic arthritis
- Bowel related arthritis (Crohn’s, UC)
- Reactive arthritis
- Others
What is Ankylosing Spondylitis?
Ankylosing spondylitis (AS), which has a prevalence of between 0.5% and 1%, is the principal inflammatory disease of the axial skeleton, with variable inolvement of peripheral joints and nonarticular structures.
What is the cause of AS?
Aetiology is unkown, although 90% of patients are HLA-B27 positive
What groups does AS most commmonly affect?
- Males>Females - men present earlier
- Onset in 2/3rd decade
- 90% are HLA-B27 positive
What are the clinical features of AS?
Men <30 yrs old
- Gradual onset lower back pain - radiates from SI joint to hip/buttocks, improves towards the end of the day
- Spinal Stiffness - worse in the morning, releived with exercise, worse at night
- Decreased thoracic expansion - due to loss of spinal movement
- Thoracic kyphosis + cervical hyperextension
- Decreased ROM - antero-posterior and lateral planes of lumbar spine
- Enthisitis - Achilles tendonitis, Plantar fasciitis, Tibial and ischial tuberosities and Iliac crests
- Acute Iritis - 1/3rd patients
- Chostochondritis
How would you clinically assess for AS?
Clinical Diagnosis - decreased spinal mobility and chest expansion
- Modified Schoeber
- Lateral spinal flexion
- Occiput to wall and tragus to wall
- Cervical rotation
What imaging would you do to assess for AS?
Imaging
-
X-ray
- Sacroiliitis
- Vertebral syndesmophytes - bony proliferations originating inside a ligament due to enthesitis between ligaments and vertebrae
- Ankylosis - fusion of vetebral bodies as a result of bony proliferations from enthisitis
- BAMBOO SPINE
What are the more systemic features of AS?
- Anterior uveitis
- Aortitis
- Aortic Regurg
- AV node block
- Apical pulmonary fibrosis
- Amyloidosis
- Achilles tendonitis
What are the clinical features of PsA
- Dactylitis
- Enthesitis
- Oligoarthritis - particularly in weight-bearing joints
- DIP joint involvement - usually in association with psoriatic nail disease
- Sacro-iliitis
- Osteolysis - leading to ‘telescoping’ of digits following loss of bone from phalanges
- Nail changes - onycholysis, ridging, pitting
What bloods could help with determining a diagnosis of AS?
Bloods
- FBC (normocytic anaemia)
- ESR, CRP - can be raised
- HLA-B27 +ve - not diagnostic
How would you manage someone with a diagnosis of AS?
- Physiotherapy
- NSAIDs
- DMARDs - Sulfasalazine
- Anti-TNF
- Treatment of osteoporosis
- Surgery - joint (inc hip) replacements & spinal surgery
What is Psoriatic arthritis?
Inflammatory arthritis that is associated with psoriasis (occurs in 10-40% of those with psoriasis)
HLA-B27 positive - 60-75%
Consistent differences in synovial histology between psoriatic arthritis (PsA) and RA
- More prominent angiogenesis
- Less expanded lining area
- Increased neutrophil infiltration in PsA
What investigations can be done to confirm PsA?
Bloods
- RF - negative
- HLA-B27 - 60-75% +ve
Imaging
- X-ray - Osteolysis of digits → Pencil cup deformity
What are the extra-articular features of Reactive arthritis?
- Skin - keratoderma blennorrhagica (brown, raised plaques on soles or hands), circinate balanitis (prepuce)
- Eyes - Conjunctivitis, uveitis (rarely)
- GU - Urethritis
- GI - mouth ulcers
