Systemic Lupus Erythematosus (SLE)

Related Subjects: | Systemic Lupus Erythematosus (SLE) | Drug-Induced Lupus Erythematosus | Discoid Lupus Erythematosus (DLE) | Neonatal Lupus Erythematosus | Rheumatology Autoantibodies

🌸 Systemic Lupus Erythematosus (SLE) is a chronic autoimmune connective tissue disorder, mainly affecting young women. The most serious complication is lupus nephritis 🩺, which requires early recognition and aggressive management to prevent renal failure.

📖 About

• 🌐 Chronic multisystem autoimmune disease.
• 🧬 Autoantibodies against nuclear and intracellular components.
• 👩 Strong female predominance (9:1, especially age 20–40).
• 🌍 More common in Afro-Caribbean and Asian populations.
• 💊 Certain drugs (hydralazine, isoniazid, procainamide, penicillamine) can trigger Drug-Induced Lupus.

🧬 Aetiology & Risk Factors

• Genetic: HLA-B8, DR2, DR3, A1; complement deficiencies (C1q, C2, C4).
• Concordance ~25% in monozygotic twins.
• Hormonal: oestrogen effect (also seen in Klinefelter’s).
• Environmental triggers: UV light, drugs, viral infections.

🔬 Pathology

• Immune complex deposition → complement activation → tissue injury.
• Defective apoptosis may expose nuclear antigens.
• Fibrinoid necrosis in vessels, haematoxylin bodies, LE cells.
• Splenic “onion-skin” lesions (arterial concentric fibrosis).
• ↑ IL-10, ↑ interferon-α → drive autoimmunity.

📋 American College of Rheumatology Criteria (≥4/11)

• 🌸 Malar rash – spares nasolabial folds.
• 🔴 Discoid rash – scaly plaques, follicular plugging.
• ☀️ Photosensitivity.
• 👄 Oral/nasal ulcers.
• 🦴 Non-erosive arthritis.
• 🫁 Serositis (pleuritis/pericarditis).
• 🩺 Renal – proteinuria >0.5 g/24h or casts.
• 🧠 CNS – seizures, psychosis.
• 🩸 Haematological – cytopenias, haemolytic anaemia.
• 🧪 Immunological – anti-dsDNA, anti-Sm, anticardiolipin.
• 🧫 ANA positive (95%).

🩺 Clinical Features

• Systemic: Fatigue, fever, malaise, weight loss.
• Dermatology: 🌸 Butterfly rash, discoid rash, alopecia, urticaria, livedo reticularis.
• Neuro: 🧠 Strokes (APS), psychosis, seizures, cranial neuropathies.
• Renal: 🩺 Lupus nephritis → nephrotic/nephritic syndromes, CKD.
• Haematology: Anaemia, leucopenia, thrombocytopenia.
• Cardiac/Vascular: ❤️ Pericarditis, Libman-Sacks endocarditis, Raynaud’s, premature atherosclerosis.
• Pulmonary: 🫁 Pleurisy, shrinking lung syndrome, pulmonary HTN.
• MSK: Arthritis, Jaccoud’s arthropathy.
• Pregnancy: 👶 Risk of neonatal lupus & congenital heart block (SSA/SSB positive).

🌸 Lupus Rash

🔎 Investigations

• 🩸 FBC: Anaemia, leucopenia, thrombocytopenia.
• 🧪 Autoantibodies: ANA (sensitive), anti-dsDNA (specific), anti-Sm, anti-Ro/La, antiphospholipid antibodies.
• 🧬 Complement: Low C3/C4 in active disease.
• 📈 ESR ↑, but CRP normal unless infection (useful discriminator).
• 🩺 Renal: Proteinuria, casts. Biopsy for nephritis classification (I–VI).
• 🫀 Echo: Check for Libman-Sacks endocarditis.

🧾 Renal Disease Classification

• I – Minimal mesangial.
• II – Mesangial proliferative.
• III – Focal proliferative.
• IV – Diffuse proliferative (worst prognosis).
• V – Membranous nephritis.
• VI – Advanced sclerosing.

💊 Management

• 🟢 Mild (skin/joints): Hydroxychloroquine ± NSAIDs. Sun avoidance, topical steroids.
• 🟡 Moderate: Oral steroids (prednisolone), steroid-sparing agents (azathioprine, mycophenolate).
• 🔴 Severe (renal/CNS): High-dose steroids + immunosuppressants (cyclophosphamide, mycophenolate). Rituximab if refractory.
• 💉 APS: Lifelong anticoagulation (warfarin).
• 🤰 Pregnancy: Hydroxychloroquine safe. Avoid teratogens (MMF, cyclophosphamide, methotrexate). Use LMWH/aspirin if APS.

📚 References

• SLE and Pregnancy – PubMed
• ACR 2023 SLE Guideline

Case 1 – Lupus nephritis

26F with fatigue, photosensitive rash, painless oral ulcers, oedema and ↑BP. Urine: proteinuria (uPCR 450 mg/mmol), RBC casts. Labs: ANA+, anti-dsDNA high, low C3/C4. Provisional Dx: proliferative lupus nephritis → start prednisolone + mycophenolate (or cyclophosphamide if severe), ACEi/ARB, PJP prophylaxis; arrange renal biopsy and close BP/renal monitoring.

Case 2 – Neuropsychiatric SLE

32F with weeks of arthralgia and malar rash develops new generalised seizures and cognitive slowing. MRI: small WM lesions; CSF sterile. Labs: anti-dsDNA↑, C3/C4↓. Manage as NPSLE after excluding infection/drugs: IV methylpred → oral taper ± cyclophosphamide/rituximab; neurology input; VTE risk assess.

Case 3 – Serositis flare

28F with SLE presents pleuritic chest pain and dyspnoea. Exam: pericardial rub; echo: small effusion; troponin normal. Treat pericarditis from SLE: NSAID + colchicine if mild; add glucocorticoids if inadequate; optimise hydroxychloroquine and consider steroid-sparing therapy if recurrent.

Case 4 – Pregnancy with aPL

30F, 10 weeks pregnant, SLE with anti-Ro/La and triple-positive antiphospholipid antibodies; prior miscarriage. Plan: continue HCQ; start LMWH + low-dose aspirin; serial fetal echo (risk congenital heart block); tight BP control; avoid teratogens (MMF, methotrexate, ACEi); coordinate rheumatology–obstetrics care.