Makindo Medical Notes

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

• Ankylosing Spondylitis: A Review (EMJ)