SLE Flashcards
define SLE
Multi-system inflammatory autoimmune disorder.
4 out of 11 diagnostic criteria of the American College of Rheumatology provides 95% specificity and 85% sensitivity for SLE or biopsy-proven lupus nephritis with positive ANA or anti-DNA.:
- malar rash
- photosensitivity
- non-erosive arthritis
- renal disease - urine casts/proteinuria
- neurological seizures - psychosis/seizures
- haematological - haemolytic anaemia/leukopenia/thrombocytopenia
- immunological disorder - anti-dsDNA/anti-Sm/anti-phospholipid
- ANA
- discoid rash
- oral ulcers
- pleuritis/pericarditis - serositis
aetiology of SLE
unknown
tissue damage may be mediated by vascular immune complex deposition related to auto-Ab
Ab are made against a variety of autoAg (eg ANA) -> immune complexes
inadequate clearance of immune complexes = host of immune responses = inflammation and damage
Combination of hormonal, genetic (HLA clustering) and exogenous factors (e.g. drugs such as hydralazine and procainamide can cause a reversible SLE-like disorder).
epidemiology of SLE
common
prevalence 1-2 in 1000
more common in young 20-40yrs, 15% cases >60yrs
more common in Afro-Caribbean and Chinese
more in females
f HLA B8, DR2, or DR3 +ve.
~10% of patients have a 1st- or 2nd-degree relative with SLE.
general Sx of SLE
fever
fatigue
weight loss
malaise
myalgia
lymphadenopathy
splenomegaly
raynaud’s phenomenon - seen in 30%
oral ulcers
alopecia (scarring)
nail fold infarcts
non-infective endocarditis (Libman-Sacks syndrome)
Raynaud’s
strike
retinal exudates
skin involvement in SLE
malar (butterfly) rash - cheeks and bridge of nose - fixed erythema, flat or raised over the malar eminances, spare nasolabial folds
Bullous lupus, toxic epidermal necrolysis variant of SLE, maculopapular lupus rash, photosensitive lupus rash, or subacute cutaneous lupus (non-indurated psoriasiform and/or annular polycyclic lesions that resolve without scarring).
discoid lupus - red and scaly patches (eg on face) with follicular plugging +- atrophic scarring, later heal with scarring and pigmentation. aff ecting ears, cheeks, scalp, forehead, and chest: erythema -> pigmented hyperkeratotic oedematous papules -> atrophic depressed lesions
atypical rashes - photosensitivuty, vasculitic (digital infarcts), urticaria, purpura, bullae, livedo reticularis, atypical erythema multiforme-like rash (Rowell’s syndrome), hair loss
MSK sx of SLE
arthritis - inflammatory
synovitis - (Involving two or more joints or two or more tender joints with >30 minutes of morning stiff ness.)
tendonitis
myopathy
avascular necrosis of the femoral head
heart sx of SLE
pericarditis
myocarditis
arrhythmias
Libman–Sacks endocarditis (non-infective mitral valve disease)
aortic valve lesions
pericardial effusion
lung sx of SLE
symptoms of pleuritis
pleural effusions
basal atelectasis
restrictive lung defects
dx criteria: a) Lung (pleurisy for >1 day, or pleural eff usions, or pleural rub; b) pericardial pain for >1 day, or pericardial effusion, or pericardial rub, or pericarditis on ECG.
neuro sx of SLE
headache
stroke
cranial nerve palsies
confusion
chorea
fits
peripheral neuropathy
psychiatric sx of SLE
depression
psychosis
seizures
mononeuritis multiplex
myelitis
peripheral or cranial neuropathy
cerebritis/acute confusional state in abscence of other cause
renal sx of SLE
symptoms of glomerulonephritis
Ix for SLE
blood
- FBC
- UE
- LFT - can get hepatitis
- high ESR with normal CRP
- clotting
- complement - low C4 then low C3 (more severe)
auto-Ab
- 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: See anti-phospholipid syndrome.
urine - happens before high creatinine
- haematuria
- proteinuria
- microscopy - for casts
joints
- plain radiographs
heart and lung
- CXR
- ECG
- echo
- CT
- lung function
kidney
- renal biopsy of glomerulonephritis is suspected
CNS
- MRI
- lumbar puncture
+ve direct Coombs test
immunology of SLE
>95% are ANA +ve
a high anti-dsDNA Ab titre is highly specific but only +ve in 60% acses
ENA may be +ve in 20–30% (anti-Ro, anti-La, anti-Sm, anti-RNP)
40% are RhF +ve;
antiphospholipid antibodies (anticardiolipin or lupus anticoagulant) may also be +ve.
SLE may be associated with other autoimmune conditions: Sjögren’s (15–20%), autoimmune thyroid disease (5–10%).
monitoring activity in SLE
3 blood tests
- anti-dsDNA Ab titre
- complement - low C3 C4 - consumption of complement
- ESR - high
BP
urine for casts/protein
FBC
UE
LFT
CRP - normal
drug induced lupus
causes (>80 drugs) include isoniazid, hydralazine (if >50mg/24h in slow acetylators), procainamide, quinidine, chlorpromazine, minocycline, phenytoin, anti-TNF agents
associated with antihistone antibodies in >95% of cases
Skin and lung signs prevail (renal and CNS are rarely aff ected).
The disease remits if the drug is stopped.
Sulfonamides or the oral contraceptive pill may worsen idiopathic SLE.
