AIM LEARNING CYCLE | FINAL YEAR MBBS | KMU CURRICULUM
Student Memory Support
Topic 8. Systemic Autoimmune & Connective Tissue Diseases
MS Module | High-Yield Memory Reinforcement | Last-Minute Revision
1. HIGH-YIELD FLASHCARDS
Tap each question to reveal its answer.
What is the principal mechanism of tissue injury in SLE?
Autoantibody formation and immune-complex deposition activate complement and cause multisystem inflammation.
What is the significance of a positive ANA test?
ANA is sensitive for SLE but poorly specific. Clinical findings and disease-specific investigations are required for diagnosis.
Which antibody and complement pattern suggests active lupus nephritis?
Rising anti-dsDNA antibodies with falling C3 and C4 may indicate active immune-complex disease, especially when urinary abnormalities are present.
What are the main manifestations of SLE?
Photosensitive rash, oral ulcers, inflammatory arthritis, serositis, cytopenias and possible renal or neurological involvement.
Which antibody is characteristically associated with drug-induced lupus?
Anti-histone antibodies. Hydralazine and procainamide are classic causative drugs; symptoms commonly improve after withdrawal.
Which lupus nephritis classes are proliferative?
Class III is focal proliferative (<50% of glomeruli); Class IV is diffuse proliferative (≥50% of glomeruli).
Which lupus nephritis class is commonly associated with nephrotic syndrome?
Class V — membranous lupus nephritis, producing heavy proteinuria and edema.
Which three antibody tests are used in APS assessment?
Lupus anticoagulant, anticardiolipin and anti-β2-glycoprotein I antibodies. Persistent positivity requires repeat testing at least 12 weeks apart.
Why can lupus anticoagulant prolong aPTT while increasing thrombosis risk?
It interferes with phospholipid-dependent clotting assays in vitro but is associated with thrombosis in vivo.
What is the usual long-term anticoagulant for thrombotic APS?
Warfarin is generally preferred for secondary thrombosis prevention, particularly in high-risk APS.
What are the key pathogenic processes in systemic sclerosis?
Microvascular dysfunction, immune activation and progressive fibrosis of the skin and internal organs.
Which antibodies are associated with limited and diffuse systemic sclerosis?
Anti-centromere: limited cutaneous disease. Anti-Scl-70 (anti-topoisomerase I): associated with diffuse disease and interstitial lung disease.
What suggests scleroderma renal crisis and what is the essential treatment?
New severe hypertension with acute kidney injury suggests renal crisis. Prompt ACE-inhibitor treatment is essential.
What are the characteristic features and antibody of Sjögren syndrome?
Dry eyes and dry mouth due to exocrine-gland inflammation; anti-Ro/SSA is commonly associated.
Which renal abnormality can occur in Sjögren syndrome?
Tubulointerstitial nephritis may cause distal renal tubular acidosis with normal anion gap metabolic acidosis and hypokalemia.
How are polymyositis and dermatomyositis clinically distinguished?
Both cause proximal muscle weakness. Dermatomyositis additionally has characteristic heliotrope rash and Gottron papules.
What are important complications of adult dermatomyositis?
Dysphagia with aspiration risk, interstitial lung disease and an increased risk of malignancy.
What is particularly important about childhood-onset SLE?
Major-organ involvement, especially renal and hematological disease, may be prominent. Growth, development, disease activity and treatment toxicity require monitoring.
2. MNEMONICS
Mnemonic 1 — Important SLE Manifestations
RASH
R — Renal involvement
A — Arthritis
S — Serositis
H — Hematological abnormalities
A reminder of four major systemic manifestations, not a complete diagnostic criterion set.
Mnemonic 2 — Lupus Nephritis Classification
M–M–F–D–M–S
I — Minimal mesangial
II — Mesangial proliferative
III — Focal proliferative
IV — Diffuse proliferative
V — Membranous
VI — Advanced sclerosing
Mnemonic 3 — CREST Features of Limited Systemic Sclerosis
CREST
C — Calcinosis cutis
R — Raynaud phenomenon
E — Esophageal dysmotility
S — Sclerodactyly
T — Telangiectasia
3. MEMORY TABLES
Table 1 — SLE vs Drug-Induced Lupus
| Feature | Idiopathic SLE | Drug-Induced Lupus |
|---|---|---|
| Trigger | Multifactorial autoimmunity | Medication exposure |
| Antibodies | ANA, anti-dsDNA, anti-Sm | Often anti-histone |
| Complement | May be low in active disease | Usually normal in classic cases |
| Renal/CNS involvement | May be significant | Less typical |
| Main management | Severity-based immunomodulation | Withdraw causative drug |
Table 2 — Major Autoimmune Disorders: Diagnostic Clues
| Disorder | Clinical Clue | Investigation Clue |
|---|---|---|
| SLE | Rash, arthritis, serositis, nephritis | ANA, anti-dsDNA, low complement |
| APS | Thrombosis, pregnancy morbidity | Persistent antiphospholipid antibodies |
| Systemic sclerosis | Raynaud, sclerodactyly, fibrosis | Anti-centromere or anti-Scl-70 |
| Sjögren syndrome | Dry eyes and dry mouth | Anti-Ro, Schirmer test |
| Inflammatory myopathy | Proximal weakness ± characteristic rash | CK, MRI, EMG or biopsy |
4. RAPID REVISION POINTS — LAST-MINUTE REVISION
- ANA is sensitive for SLE but cannot confirm the diagnosis alone.
- Anti-dsDNA + low complement may support active SLE, especially renal inflammation.
- Lupus nephritis: Class III is focal, Class IV is diffuse and Class V is membranous.
- Hydroxychloroquine is important background SLE therapy; retinal toxicity requires monitoring.
- Mycophenolate is used in lupus nephritis but is contraindicated in pregnancy.
- APS: persistent antibody positivity is assessed at least 12 weeks apart.
- Systemic sclerosis: sudden hypertension with AKI suggests renal crisis.
- Sjögren syndrome: persistent parotid enlargement raises concern for lymphoma.
- Dermatomyositis: proximal weakness with heliotrope rash and Gottron papules.
- Renal disease in RA: consider medication toxicity, associated glomerular disease and AA amyloidosis.
5. CLINICAL MEMORY HOOKS
Clinical Hook 1
Photosensitive rash + arthritis + proteinuria → SLE with possible lupus nephritis → urine protein and renal assessment.
Clinical Hook 2
Unexplained DVT + recurrent pregnancy loss → suspect APS → persistent antiphospholipid antibody testing.
Clinical Hook 3
Raynaud phenomenon + skin tightening + new severe hypertension → scleroderma renal crisis → urgent ACE inhibitor.
Clinical Hook 4
Difficulty climbing stairs + heliotrope rash + high CK → dermatomyositis → evaluate swallowing, lungs and malignancy risk.
6. STARRED HIGH-YIELD EXAM POINTS
- ⭐ SLE: anti-dsDNA with low C3/C4 supports active immune-complex disease; assess the kidneys.
- ⭐ Lupus nephritis: Class III affects <50% of glomeruli; Class IV affects ≥50%.
- ⭐ APS: lupus anticoagulant can prolong aPTT but is associated with thrombosis.
- ⭐ Thrombotic APS: warfarin is generally preferred for long-term secondary prevention.
- ⭐ Systemic sclerosis renal crisis: new hypertension with AKI → urgent ACE-inhibitor treatment.
- ⭐ Sjögren syndrome: sicca symptoms with anti-Ro/SSA; important lymphoma risk.
- ⭐ Dermatomyositis: proximal weakness with characteristic rash; consider malignancy and interstitial lung disease.