Systemic lupus erythematosus (MSK) Flashcards
What is systemic lupus erythematosus (SLE)?
Multisystem autoimmune disease that predominantly affects women of childbearing age
What type of hypersensitivity reaction is SLE?
Type 3
Describe the epidemiology of SLE. (3)
- F>M
- onset usually at 20-40 years old
- more common in Afro-Caribbeans
What causes SLE?
Genetic predisposition - HLA-DR2/3
Which genes predispose to SLE? (2)
- HLA-DR2
- HLA-DR3
What systems does SLE frequently involve?
- most frequently involves skin and joints
- serositis, nephritis, haematological cytopenias and neurological manifestations may occur during the course of the disease
- pericarditis, myocarditis, pleuritis, pleural effusion
What is SLE characterised by?
Presence of antinuclear antibodies (ANA)
What syndrome is SLE associated with?
Anti-phospholipid syndrome - increased risk of thrombus formation (recurrent PEs and DVTs) and recurrent miscarriages
What are the clinical features of antiphospholipid syndrome (SLE)? (4)
CLOT
- Clots (thrombosis)
- Livedo reticularis
- Obstetric complications (miscarriages)
- Thrombocytopenia
What do investigations show in antiphospholipid syndrome (SLE)? (2)
- prolonged APTT (paradoxical)
- low platelets (thrombocytopenia)
What antibody is antiphospholipid syndrome (SLE) associated with?
Anti-cardiolipin antibodies
How is antiphospholipid syndrome (SLE) managed?
- low dose aspirin (no previous thromboembolic event)
- lifelong warfarin target INR 2-3 (after initial thromboembolic event) - avoid in pregnant women –> give aspirin and LMWH
What would adult-onset Still’s disease (SLE) present like (variant of juvenile rheumatoid arthritis)? (3)
Triad of:
- joint pain
- spiking fevers
- pink bumpy rash
What are the clinical features of SLE?
- malar (butterfly) rash - erythema over cheeks and bridge of nose, sparing nasolabial folds
- photosensitive rash (after sun exposure - painful and pruritus for few days)
- discoid rash - erythematous raised patches
- fatigue, fever, weight loss
- arthritis and arthralgia (distal symmetrical polyarthritis)
- oral ulcers
- pericarditis or myocarditis
- Raynaud’s phenomenon
What is Raynaud’s phenomenon (SLE)?
Colour changes of the digits induced by cold: white –> blue –> red
How do we treat Raynaud’s phenomenon (SLE)?
Nifedipine
What rashes are seen in SLE? (3)
- malar (butterfly) rash
- photosensitive rash
- discoid rash
What are some extra-articular manifestations of SLE? (8)
- pericarditis
- myocarditis
- pleuritis
- pleural effusion
- serositis
- nephritis
- haematological cytopenia
- neurological manifestations
What are some risk factors for SLE? (5)
- female sex
- age >30
- African descent in Europe and US
- drugs (e.g. procainamide, hydralazine)
- family history of SLE
What are the 1st-line investigations for SLE? (9)
- ANA, anti-dsDNA, anti-Smith
- ESR and CRP
- FBC and differential
- APTT
- U&Es
- urinalysis
- CXR
- ECG
- C3/4 complement
What is often used as a rule-out test for SLE?
Antinuclear antibody (ANA) - very sensitive (positive in most patients), but low specificity (may be positive in other conditions)
i.e. a positive ANA is not diagnostic
When can ANA be negative in SLE?
Rarely, especially in anti-Ro-antibody-positive lupus
What are some highly specific tests for SLE? (2)
- anti-dsDNA
- anti-Smith antibodies
- (ANA sensitive but not specific)
What is elevated in SLE according to disease activity?
ESR
What is high in SLE if patient has an infection?
CRP (+ESR)
What is decreased in SLE?
Complement levels C3/C4
What do we see in drug-induced lupus (procainamide or hydralazine)?
Anti-histone antibodies
Why do we do urinalysis in SLE?
Assess renal involvement - check for haematuria, proteinuria, casts (red cell, granular, tubular or mixed)
What does FBC with differential show in SLE?
- anaemia
- leukopenia
- thrombocytopenia
- rarely pancytopenia
What is APTT like in SLE?
May be prolonged in patients with antiphospholipid antibodies
What are some differential diagnoses for SLE? (5)
- rheumatoid arthritis
- antiphospholipid syndrome
- systemic sclerosis
- mixed connective tissue disease
- adult Still’s disease (variant of juvenile RA)
What is the first-line management for SLE?
Hydroxychloroquine (also safe in pregnancy)
What must be done before prescribing hydroxychloroquine (DMARD) in SLE?
- visual acuity testing as can lead to severe and permanent retinopathy:
- reduced colour differentiation
- reduced central visual acuity
- floaters
- Bull’s eye maculopathy (red spot on macula surrounded by ring of retinal epithelial pigment loss)
- baseline ophthalmological examination and annual screening generally recommended
What is the general management for SLE? (4)
- hydroxychloroquine (DMARD)
- NSAIDs (naproxen)
- avoid smoking
- UV light
What is used in SLE when hydroxychloroquine and NSAIDs are inadequate?
IV methylprednisolone
What do we consider in SLE if internal organ involvement e.g. renal, neuro, eye?
Prednisolone, cyclophosphamide
How do we manage severe SLE?
- if organ threatening or refractory to hydroxychloroquine +/- corticosteroid: methotrexate or azathioprine or mycophenolate mofetil
- consider belimumab or rituximab
What is prescribed for skin manifestations in SLE?
Topical steroids (1% hydrocortisone)
What are some complications of SLE? (7)
- anaemia
- leukopenia
- thrombocytopenia
- pericarditis
- myocarditis
- pleuritis
- pleural effusion
What are the most common causes of mortality in SLE? (3)
- cardiovascular disease
- followed by infection and severe disease activity
