Master Rheumatology
for MRCP Part 1

What the MRCP Part 1 Tests in Rheumatology

Rheumatology in MRCP Part 1 tests the ability to diagnose and manage inflammatory arthritis, connective tissue diseases, vasculitides, and crystal arthropathies. Candidates must know classification criteria (e.g., ACR/EULAR for RA, SLE, gout), first-line disease-modifying drugs (e.g., methotrexate, hydroxychloroquine), and biologic therapy indications (e.g., TNF inhibitors, rituximab). Key presentations include monoarthritis (septic vs crystal), polyarthritis (seropositive vs seronegative), and systemic features (rash, renal, pulmonary). Emphasis is on interpreting autoantibodies (ANA, anti-dsDNA, ANCA, anti-CCP), acute-phase reactants, and imaging (X-ray, MRI, ultrasound). Guidelines from NICE and EULAR are referenced. Candidates must differentiate mimics (e.g., fibromyalgia, polymyalgia rheumatica) and recognise emergencies (e.g., scleroderma renal crisis, cauda equina syndrome).

High-Yield Concepts

• RA Diagnosis and DMARDs: ACR/EULAR 2010 criteria: ≥6/10 from joint involvement (0-5), serology (RF, anti-CCP; 0-3), acute-phase reactants (CRP/ESR; 0-1), symptom duration ≥6 weeks (0-1). First-line DMARD: methotrexate 7.5-25 mg weekly with folic acid. NICE recommends TNF inhibitor (adalimumab, etanercept) after failure of two conventional DMARDs, including methotrexate, with DAS28 >5.1.
• SLE Diagnosis and Management: ACR 1997 criteria: 4/11 (malar rash, discoid rash, photosensitivity, oral ulcers, arthritis, serositis, renal disorder, neurologic disorder, hematologic disorder, immunologic disorder, ANA). First-line for mild-moderate: hydroxychloroquine 200-400 mg/day (risk retinal toxicity, annual eye screen). For major organ involvement (lupus nephritis): mycophenolate mofetil or cyclophosphamide plus high-dose steroids.
• Gout: Acute and Chronic Treatment: Acute: NSAID (naproxen 500 mg BD) or colchicine 0.5 mg TDS (max 1.5 mg/day) or oral prednisolone 30-40 mg/day for 5 days. Chronic urate-lowering: allopurinol 100 mg/day, titrated to target serum urate <360 μmol/L (<300 μmol/L if tophi). Prophylaxis with colchicine 0.5 mg BD or NSAID for first 3-6 months. Febuxostat second-line (caution in CVD).
• ANCA-Associated Vasculitis (GPA, MPA, EGPA): Granulomatosis with polyangiitis (GPA): c-ANCA/PR3 positive; microscopic polyangiitis (MPA): p-ANCA/MPO positive; eosinophilic GPA (EGPA): p-ANCA/MPO positive in 40-50%. Induction for organ-threatening: cyclophosphamide (IV 15 mg/kg every 2-3 weeks) or rituximab (375 mg/m² weekly x4) plus high-dose steroids. Maintenance: rituximab or azathioprine.
• Seronegative Spondyloarthropathies: Includes ankylosing spondylitis (AS), psoriatic arthritis (PsA), reactive arthritis, enteropathic arthritis. AS: modified New York criteria (sacroiliitis on X-ray plus inflammatory back pain). First-line: NSAIDs (naproxen). Second-line: TNF inhibitors (adalimumab, etanercept) if BASDAI ≥4 and failure of ≥2 NSAIDs. PsA: CASPAR criteria; treat with methotrexate or leflunomide for peripheral disease; TNF inhibitors for axial or severe.
• Polymyalgia Rheumatica and Giant Cell Arteritis: PMR: age >50, bilateral shoulder/pelvic girdle pain, morning stiffness >45 min, ESR/CRP elevated, rapid response to prednisolone 15-20 mg/day. GCA: new-onset headache, scalp tenderness, jaw claudication, visual loss; urgent high-dose prednisolone 40-60 mg/day; temporal artery biopsy within 1 week (positive shows giant cells). NICE: if high suspicion, start steroids immediately, do not wait for biopsy.
• Septic Arthritis and Crystal Arthropathy Differentiation: Septic arthritis: monoarticular, hot, red, swollen, joint fluid WBC >50,000/μL (predominantly neutrophils), Gram stain positive, culture positive. Crystal arthropathy: gout (negatively birefringent monosodium urate crystals), pseudogout (positively birefringent calcium pyrophosphate crystals). Empiric antibiotics for septic: flucloxacillin 2 g IV QDS (if MRSA risk, vancomycin). Do not delay antibiotics for aspiration.

Common Traps in Rheumatology Questions

• Mistaking pseudogout for gout: pseudogout shows positively birefringent calcium pyrophosphate crystals on polarised light microscopy, not negatively birefringent urate.
• Using allopurinol during an acute gout flare: start after inflammation resolves (2-4 weeks) to avoid prolonged flare.
• Forgetting to check for retinal toxicity with hydroxychloroquine: annual screening after 5 years or earlier if risk factors (dose >5 mg/kg, renal disease).
• Missing scleroderma renal crisis in a patient with systemic sclerosis and new-onset hypertension: treat with ACE inhibitor, not steroids (which can precipitate crisis).
• Delaying steroids in suspected giant cell arteritis while awaiting biopsy: start prednisolone immediately to prevent blindness.
• Failing to distinguish between fibromyalgia and inflammatory arthritis: fibromyalgia has no synovitis, normal CRP/ESR, and tender points; management is non-pharmacological (exercise, CBT, amitriptyline).

How to Revise Rheumatology for the MRCP Part 1

For MRCP Part 1 Rheumatology, prioritise memorising classification criteria (RA, SLE, gout, AS, scleroderma) and first-line drug choices (methotrexate for RA, hydroxychloroquine for SLE, allopurinol for gout). Questions often present a clinical scenario with lab results (autoantibodies, urate, CRP) and ask for the most appropriate next step (diagnosis, drug, or referral). Pay close attention to differentiating between seropositive and seronegative arthritis, and between septic and crystal arthritis. Practice interpreting ANCA patterns (c-ANCA/PR3 vs p-ANCA/MPO) and their associated vasculitides. Also, know the emergency presentations: scleroderma renal crisis, GCA with visual loss, and septic arthritis. Use NICE and EULAR guidelines as your reference; exam questions align with these. Focus on high-yield facts rather than rare diseases.

Practise it: MedLumen has 50 Rheumatology questions for the MRCP Part 1, each with a full explanation and references.