Systemic lupus erythematosus (SLE) Flashcards
Define SLE.
- SLE is a chronic autoimmune multisystem disorder
- of unknown aetiology
- characterised by the presence of ANA
- it most frequently involves the skin and joints
What criteria is used to diagnose SLE?
2019 EULAR/ACR classification system
Entry criterion = Antinuclear antibodies (ANA) at a titre of ≥1:80 on HEp-2 cells or an equivalent positive test (ever)
If absent, do not classify as SLE; if present, apply additive criteria: These do not need to occur simultaneously and only need to occur once. Only count highest in each domain. SLE classification requires at least one clinical criterion and ≥10 points:
Clinical domains and criteria
- Constitutional
- Fever, 2 points
- Haematological
- Leukopenia, 3 points
- Thrombocytopenia, 4 points
- Autoimmune haemolysis, 4 points
- Neuropsychiatric
- Delirium, 2 points
- Psychosis, 3 points
- Seizure, 5 points
- Mucocutaneous
- Non-scarring alopecia, 2 points
- Oral ulcers, 2 points
- Subacute cutaneous OR discoid lupus, 4 points
- Acute cutaneous lupus, 6 points
- Serosal
- Pleural or pericardial effusion, 5 points
- Acute pericarditis, 6 points
- Musculoskeletal
- Joint involvement, 6 points
- Renal
- Proteinuria >0.5 g/24 hours, 4 points
- Renal biopsy class II or V lupus nephritis, 8 points
- Renal biopsy class III or IV lupus nephritis, 10 points
Immunology domains and criteria
- Antiphospholipid antibodies
- Anticardiolipin antibodies OR anti-beta2-glycoprotein 1 antibodies OR lupus anticoagulant, 2 points
- Complement proteins
- Low C3 OR low C4, 3 points
- Low C3 AND low C4, 4 points
- SLE-specific antibodies
- Anti-double-stranded (ds)DNA antibody OR anti-Smith antibody, 6 points
What is the epidemiology of SLE?
- F>M
- Peaks at 30-70yo
- Increasing incidence
What are the aetiological factors for SLE?
Genetics
Drugs - commonly procainamide, minocycline, terbinafine, sulfasalazine, isoniazid, phenytoin, and carbamazepine
Infectious agents - EBV, PVB19, CMV, HIV1
What is the pathophysiology of SLE?
Failure of immune tolerance to your own antigens during rapid clearance of cells through apoptosis
What antibodies are associated with SLE? Which are most specific?
- ANA
- anti-dsDNA - very specific
- anti-Sm - most specific
- ati-histone - associated with drug induced SLE
- antiphospholipid antibodies
- anti-Ro
anti-Sm are part of the ENA panel
What are anti-RNP antibodies characteristic of?
Mixed connective tissue disease
What investigations would you do for diagnosis of SLE?
Bedside/bloods:
- Urinalysis - haematuria, casts or proteinuria (PCR/ACR)
- ANA, anti-dsDNA, anti-Sm, antiphospholipid antibodies
- FBC -anaemia, leukopenia, thrombocytopenia; rarely pancytopenia
- U&Es - elevated urea and creatinine
- aPTT - may be prolonged in presence of antiphospholipid antibodies
- ESR and CRP
Imaging:
- ECG - exclude other causes of chest pain
- CXR - pleural effusion, infiltrates, cardiomegaly
Other (not necessary for diagnosis):
- Renal biopsy/USS
- Complement levels
- Pulmonary function tests
- Brain MRI
- Echo
- Skin biopsy
What are the signs and symptoms of SLE?
- Malar rash
- Photosensitive rash
- Discoid rash
- Fatigue
- Weight loss
- Fever
- Oral ulcers
- Alopecia
- Arthralgia/arthritis - usually of large joints
- Fibromyalgia
- Raynaud’s phenomenon
- Chest pain and SOB
- V/A thrombosis
- HTN
- Nephrosis (e.g. oedema signs)
- Lymphadenopathy
- Abdo pain, vomiting or diarrhoea
What HLA are associated with SLE?
HLA-B8
HLA-DR2
HLA-DR3
What type of endocarditis occurs in patients with SLE?
Libman-Sacks endocarditis
What is shown?
SLE malar rash
a) Photograph of a face with skin rashes sparing the bridge of the nose and malar area. b) Photograph of a face showing asymmetric hyperpigmented, polycylic, and annular scaly plaques with scaling involving pre-auricular area and cheek
What are the dermatological features of SLE?
- Acute:
- Malar rash - spares nasolabial folds, hyperkeratosis will be seen on darker skin
- TEN-like rash
- Generalised rash
- May look like ringworm
- Subacute
- Anuular
- Papulo-squamous
- Drug-induced
- Rowell syndrome
- Chronic
- Lupus panniculitis
- Discoid lupus
Other
- Oral ulcers
- Non-scarring alopecia (diffuse thinning or hair fragility with visible broken hairs)
- Raynaud’s phenomenon
Fatigue, fever, weight loss
Lymphadenopathy
Synovitis involving two or more joints, characterised by swelling or effusion OR tenderness in two or more joints and 30 minutes or more of morning stiffness
Serositis
Pleuritis
Pleural effusions
ILD
pulmonary hypertension
Cardiovascular
pericarditis
Myocarditis
endocarditis
arterial and venous thrombosis
premature atherosclerosis
Renal
Lupus nephritis
Neurological
Seizures
Cranial nerve abnormalities
Psychosis
Fibromyalgia
What are the cardiovascular and pulmonary features of SLE?
Cardiovascular:
- Pericarditis
- Myocarditis - may present with tachycardia, arhythmias, conduction defects, unexplained cardiomegaly
- Endocarditis - Libman-Sacks non-bacterial
- Arterial and venous thrombosis
- Premature atherosclerosis
Pulmonary:
- Pleuritis
- Pleural effusions
- Interstitial lung disease
- Pulmonary hypertension (echo for this)
- PE
- Shrinking lung syndrome
What are the features of joint involvement in SLE?
- Symmetrical
- Peripheral
- Pain worse in mornings and associated with stiffness
- Deformity e.g. correctable ulnar deviation and joint subluxations
- No damage to joints i.e. no radiographical damage
Whcih investigations are used for monitoring disease activity in SLE? What questionnaire is used?
Physical examination
Bloods:
- ESR
- Complement - C4 decreases first, then C3
- Anti-dsDNA
- WCC
- Plt
Other:
- Spirometry - 6 -12 monthly depending on disease
- Spot urine for PCR
- Urinalysis
- Echo - for pulmonary hypertension
SLEDAI score (below) - 5 or less is remission
What is Rowell syndrome?
Rare disease consisting of erythema multiforme-like lesions associated with lupus erythematosus. It is a chronic cutaneous manifestation of SLE. Only 96 cases reported.
In contrast to erythema multiforme, the lesions are not in acral or mucosal areas.
What is shown?
Lupus profundus/lupus panniculitis
- Can develop at any site
- Present as persistent, firm, deep, tender nodules
- Resolve to leave dents in the skin due to atrophy of the fat.
