SLE

Question 1

What is Systemic Lupus Erythematosus (SLE)?

Answer 1

• Multisystemic autoimmune diseases
• Autoantibodies made against variety of autoantigens (eg. ANA) which form immune complexes
• Inadequate clearance of immune complexes results in a host of immune responses which cause tissue inflammation + damage
• Typically affects women of child-bearing age
• Commoner in black people

Question 2

SLE is a remitting and relapsing illness. Features are often non-specific (malaise, fatigue, myalgia and fever) or organ-specific and caused by active inflammation or damage.

Diagosis of SLE is appropriate in clinical setting if >4 criteria are present (at least 1 clinical + 1 lab) or biopsy-proven lupus nephritis with positive ANA or anti-DNA.

What are the clinical criteria?

Answer 2

• Acute cutaneous lupus → Malar rash/butterfly: fixed erythema, flat or raised, over the malar eminences, tending to spare the nasolabial folds
• Chronic cutaneous lupus → Discoid rash: erythematous raised patches with adherent keratotic scales and follicular plugging +/- atrophic scarring
• Non-scarring alopecia
• Oral/nasal ulcers
• Synovitis → Involving two or more joints or two or more tender joints with >30 minutes of morning stiffness
• Serositis → Lung = Pleurisy or pleural effusions OR Pericardial pain for >1day
• Urinanaylsis → Presence of proteinuria (>0.5g/d)
• Neurological features → Seizures, psychosis, mononeuritis multiplex, peripheral or cranial neuropathy
• Haemolytic anaemia
• Leucopenia → WCC <4
• Thrombocytopenia → Platelets <100

Question 3

What are the lab criteria for SLE?

Answer 3

1. Positive ANA (+ve in >95%)
2. Anti-dsDNA
3. Anti-Smith antibodies present
4. Antiphospholipid Abs present
5. Low complement
6. +ve Direct Coombs test

Question 4

Which investigations are important for SLE?

Answer 4

• BP / Urinalaysis / FBC / U+Es / LFTs / CRP
• Anti-dsDNA positive in 60%
• Complement → reduced C3/4
• ESR → raised, during active disease the CRP is normal
• >95% ANA positive
• ENA positive in 20% (anti-Ro, anti-La, anti-Sm)
• RF positive in 40%

Question 5

What is drug-induced lupus?

Answer 5

• >80 drugs → Isoniazid / Hydralazine / Procainamide / Quinidine / Chlorpromazine / Phenytoin
• Associated with anti-histone antibodies in >95% cases
• Skin & lung signs prevail (renal and CNS are rarely affected)
• Disease remits if the drug is stopped
• Sulfonamides or the oral contraceptive pill may worsen idiopathic SLE

Question 6

What are general measures for treatment for SLE?

Answer 6

• High-factor sunblock
• Hydroxychloroquine, unless contraindicated, reduces disease activity and improves survival
• Screen for co-morbidities and medication toxicity
• For skin flares, first trial topical steroids

Question 7

What is the treatment for maintenance in SLE?

Answer 7

• NSAIDs (unless renal disease) and hydroxychloroquine for joint and skin symptoms
• Azathioprine, methotrexate and mycophenolate as steroid-sparing agents

Question 8

What is the treatment for severe flares in SLE?

Answer 8

• If life- or organ-threatening, e.g. haemolytic anaemia, nephritis, severe pericarditis or CNS disease
• URGENT high-dose steroids, mycophenolate, rituximab, cyclophosphamide

Question 9

CLOTS

Antiphospholipid syndrome can be associated with SLE (20-30%). It often occurs as a primary disease.

What can antiphospholipid antibodies cause?

Answer 9

• Coagulation defect (arterial & venous)
• Livedo reticularis
• Obstetric (recurrent miscarriage)
• Thrombocytopenia

Question 10

What is the management for antiphospholipid syndrome?

Answer 10

• Initial venous thromboembolic events: evidence currently supports use of warfarin with a target INR of 2-3 for 6 months
• Recurrent venous thromboembolic events: lifelong warfarin; if occurred whilst taking warfarin then increase target INR to 3-4
• Arterial thrombosis should be treated with lifelong warfarin with target INR 2-3