Related Subjects:
| Monoarticular Arthritis
| Polyarticular Arthritis
| Seronegative Spondyloarthropathies
| Ankylosing Spondylitis
| Enteropathic Spondyloarthritis
| Reactive Arthritis
| Psoriatic Arthritis
🦴 Seronegative Spondyloarthropathies (SpA) are a group of inflammatory arthritides affecting the spine, sacroiliac joints, and entheses, characterised by the absence of RF/anti-CCP.
🔑 Hallmarks: inflammatory back pain, HLA-B27 association, enthesitis, asymmetrical oligoarthritis, and extra-articular features (uveitis, psoriasis, IBD).
📖 About: Characteristics
- Axial skeleton involvement (spine + sacroiliac joints).
- Chronic inflammatory back pain 🛌 (insidious onset, morning stiffness, improves with activity, not rest).
- Typically age of onset <45 years ⏳.
- Asymmetrical lower limb oligoarthritis.
- Inflammation at entheses (e.g. Achilles tendon, plantar fascia) 🦶.
- Strong link with HLA-B27 🧬.
🧬 Aetiology
- Genetic predisposition: HLA-B27 carriage (not all carriers develop disease).
- Environmental triggers: GI or GU infections (esp. in reactive arthritis).
🌈 Types of Seronegative SpA
- Ankylosing spondylitis (AS) 🔒 – axial fusion ("bamboo spine").
- Reactive arthritis 🦠 – post-GI or GU infection (Reiter’s triad: arthritis, conjunctivitis, urethritis).
- Psoriatic arthritis 🎨 – linked with psoriasis; nail pitting, onycholysis.
- Enteropathic arthritis 💩 – seen with Crohn’s disease or ulcerative colitis.
🔑 Major Criteria
- Inflammatory back pain (≥3 months, insidious onset, worse at night/morning, improves with exercise).
- Oligoarthritis – asymmetrical, lower limb predominance.
➕ Minor Criteria
- Enthesitis (Achilles tendon, plantar fascia).
- Alternating buttock pain 🍑.
- History of preceding infection (GU/GI).
- Extra-articular: Psoriasis 🎨, IBD 💩.
- Dactylitis ("sausage digit" 👉).
- Anterior uveitis 👁️ – painful red eye with photophobia.
- Positive family history.
🔎 Investigations
- Bloods: Anaemia of chronic disease, ↑ CRP/ESR.
- HLA-B27: Supportive but not diagnostic.
- Imaging:
– X-ray: sacroiliitis (sclerosis, erosions, fusion).
– MRI 🖥️: detects early sacroiliitis (bone marrow oedema, synovitis).
- Microbiology: screen for Chlamydia or enteric pathogens in reactive arthritis.
💊 Management
- Physiotherapy 🏃 – cornerstone, maintain posture & mobility.
- NSAIDs 💊 (esp. slow-release at night for morning stiffness).
- DMARDs (Sulfasalazine, Methotrexate) – useful for peripheral arthritis, not axial.
- Biologics 🧬 – anti-TNF (etanercept, adalimumab) or anti-IL17 (secukinumab) in refractory axial disease.
- Corticosteroids – systemic or local injections for flares; topical drops for uveitis.
- Surgery (e.g. hip replacement, spinal corrective surgery) in advanced cases.
- Treat underlying infection in reactive arthritis (e.g. chlamydia).
⚠️ Extra-articular Features
- Uveitis 👁️ (recurrent, unilateral).
- Psoriasis 🎨 (skin + nails).
- IBD 💩 (Crohn’s, UC).
- Aortic regurgitation & cardiac conduction defects ❤️.
- Restrictive lung disease (apical pulmonary fibrosis) 🫁.
📚 References
