Systemic Lupus Erthematosus

Question 1

Define SLE

Answer 1

Multisystem inflammatory autoimmune disorder
American College of Rheumatology >4 out of 11 diagnostic criteria
• Serositis – pleuritic, pericarditis
• Oral ulcers
• Arthritis (e.g. Jaccoud’s arthropathy)
• Photosensitivity
• Blood disorders – haemolytic anaemia, leucopenia, thrombocytopenia
• Renal disease – proteinuria, haematuria, casts
• Antinuclear antibodies
• Immunological disorder – anti-dsDNA, anti-Sm, anti-cardiolipin
• Neurological disease – psychosis, seizures
• Malar rash
• Discoid rash

Question 2

What are the causes/risk factors of SLE?

Answer 2

Unknown aetiology

The strong female preponderance also suggests a role for hormonal factors. It is 10 times more common in women during reproductive years but only 2-3 times more common during childhood or post-menopause.

Other environmental agents include:
• Viruses e.g. EBV
• Drugs e.g. isoniazid, phenytoin and procainamide

Question 3

What are the signs and symptoms of SLE?

Answer 3

• Constitutional Symptoms: FLAWS
• Raynaud’s Phenomenon - Exposure to cold leads to a change in the colour of the hands to white then blue due to arterial spasms. Then, the skin turns red due to returned perfusion –this is often accompanied by swelling and paraesthesia.
• Regional lymphadenopathy –non-tender and variably sized nodes.
• Malar Rash - butterfly rash, primarily affecting the cheeks and the bridge of the nose.
• Discoid Rash - Red, raised scaly patches which heal with scarring and pigmentation.
• Mouth ulcers –often large and painless, and are noticed on physical examination.
• Alopecia (hair loss) may be present

Systemic Manifestations:
• Musculoskeletal - Arthritis tends to be symmetrical and is typically non-erosive. It is worse in the morning and accompanied by stiffness. Myositis is also present with muscle weakness and pain.
• Renal - Hypertension, nephrotic syndrome and renal failure. Haematuria, proteinuria and casts are also present.
• CNS - Confusion, headaches, seizures, psychosis, depression and strokes.
• Heart - Pericarditis, myocarditis, arrhythmias and Libman-Sacks endocarditis.
• Lungs - Pleuritis –pleuritic chest pain with pleural effusion and lung collapse.

Question 4

What invetsigations are carried out for SLE?

Answer 4

• Autoantibodies - ANA
- Anti-dsDNA: 60% of cases
- Rheumatoid factor: 30–50% of cases
- Anti-ENA
- Anti-RNP: 30% of cases
- Anti-Sm: 30% of cases
- Anti-Ro (SSA): 30% of cases
- Anti-La (SSB): 15% of cases
- Anti-histone: In drug-induced lupus
- Anti-phospholipid/Anti-cardiolipin
• FBC - anaemia, thrombocytopaenia and leukopaenia/ lymphopaenia.
• Clotting Screen - prolonged APTT, PT or TT –this should prompt checking for anti-phospholipid antibodies.
• U&Es - elevated urea and creatinine indicates renal failure.
• ESR/ CRP - elevated ESR and CRP should prompt a search for infection but could also be due to active disease.
• Complement Levels - active disease may result in low C3 levels, but increased synthesis due to an acute phase response may confound interpretation. Although activation products can be measured, they are not frequently available. Sequential values are of use to monitor the response to treatment.
• Skin Biopsy - skin biopsy of affected areas may show classic immune deposits at the dermal-epidermal junction on immunofluorescence or non-specific inflammation.
• X-Ray of Joints - inflammation and non-erosive arthritis
• Creatinine Phosphokinase - performed in patients with myalgia and weakness. May be elevated.
• Urinalysis - to assess renal involvement and should be done in anyone suspected of having SLE. May show haematuria, casts (red cell, granular, tubular, or mixed) or proteinuria.
• 24-Hour Urine - proteinuria
• Renal Biopsy - immune deposits, mesangial hypercellularity; focal, segmental, or global glomerulonephritis.
• Coombs’ Test - ordered if initial blood count shows an anaemia as well as features of haemolysis such as elevated MCV and reticulocyte count. May indicate haemolytic anaemia.
• Brain MRI - white matter changes
• CXR - pleural effusion, infiltrates, cardiomegaly.
• Chest CT - lung fibrosis and pleural effusions
• PFTs - restrictive Patern
• Pleural Aspirate - excudative
• ECG - may exclude other causes of chest pain and show arrhythmia.
• Echo - may show cardiac complications.