MSD 2.85-92 Flashcards
(215 cards)
What type of AI disease are CTD?
Systemic! Because involve nuclear Ag found ubiquitously
How does CTD start?
as uCTD, then usually becomes one of: SLE, DM/PM, Sjogrnes, SSc, MCTD.
Symptoms of SLE?
- Lungs: tachypnoea, cough, pleural inflammation and effusion, PE
- Skin: photosensitive rash, butterfly rash over cheeks (sparing nasolabial folds), livedo, discoid, alopecia. SICCA, mucosal ulcers.
- Systemic inc. lymphadenopathy, anaemia, thrombocytopenia, leukopenia
- CVD: Raynaud’s, pericarditis, vasculitis, thrombosis (particularly if have APS)
- Renal: lupus nephritis, proteinuria, haematuria
- CNS: neuro disorders, migrainous headaches, seizures, aseptic meningitis
- MSK (arthralgia, arthritis, myositis)
- Reproductive: menorrhagia/amenorrhoea, prematurity, stillbith, recurrent miscarriage. Lupus more likely to flare during pregnancy.
Risk factors for SLE?
F, child-bearing age, FHx, genes (HLA-DR2/3), Afro Caribbean>Asian>Caucasian, drug-induced
Key pathophysiology?
Defective clearance of apoptotic cells exposes nuclear antigens to IS; following DNA damage, get autoantibodies to nuclear proteins, forming immune complexes and recruiting complement to damage tissue, releasing more Ag. Autoantibodies opsonise DS DNA.
Natural history of SLE?
Preclinical; autoantibodies form. Clinical get inflammation and involvement of first organs. Then get flares, more organs involved, damage. Eventually to disease and treatment get irreversible organ damage, malignancy, atherosclerosis, diabetes, osteoporosis. Incurable.
Joints affected in SLE?
Typically small joints of hands and feet. Non-erosive
LE cells?
(Lupus erythematous cell) are PMNs or macrophages that have ingested another cells nuclear material; classically seen in SLE.
VDRL test in SLE?
Get false positive
ANA patterns?
Homogenous, nucleolar, speckled and centromere-B; associated with different ANAs and therefore different CTD.
Use of ANA?
Autoantibodies; sensitive but not specific for SLE; umbrella term which can be differentiated into ENAs. Presence detected with ELISA. Increased frequency with age, so titre is important as not all ANA = AI. Get +ve ANA then do ENA panel.
dsDNA? And its signifiance?
Fairly specific for SLE; low levels in RA/MCTD/AIH. Important in SLE because associated with risk of ESRD in SLE.
Homogenous ANA?
Associated with dsDNA staining and therefore SLE
Sm (smith)?
Very specific for SLE but no very sensitive
Ro/La? And significance of Ro?
Associated with Sjogrens and SLE (particularly with skin disease); get speckled ANA. Ro can cross placenta and cause congenital heart block
Anti-RNP?
Associated with SLE and MCTD. Nucleolar ANA.
Antiphospholipid antibodies?
Anti-cardiolipin, lupus anticoagulant (DRVVT), anti-B2 glycoprotein. Prothrombotic. Need two +ves 3 months apart. Can be used to support SLE diagnosis too.
APLS?
Livedo rash, CNS disease, obstetric problems, worse prognosis in LN.
Antibodies for drug-induced SLE?
Anti-histone antibodies!
Drugs causing drug-induced SLE?
Minocyclie, procainamide, sulfasalazine, AEDs, anti-TNFa (infliximab) for RA, Crohns, eye disease.
Why are cell counts low in SLE?
Ab mediated; get haemolysis etc. (direct Coombes test) Platelets low due to this and APLS Abs.
Differentiating SLE flare and infection?
Neutrophils normal in SLE! And discordant rise in ESR
ESR and CRP in SLE?
CRP often slightly raised; ESR often very high.
SLICC criteria SLE?
- Biopsy proven lupus nephritis and ANA/dsDNA
- Or 4 criteria, at least 1 immunological. Clinical = acute/chronic cutaneous LE, oral ulcer, alopecia, synovitis, serositis, renal, neurlogi, haemolytic anaemia, lecopenia/lymphopenia, thrombocytopenia.
Immune = ANA, dsDNA, Anti Sm, APLS Abs, Low complement, direct Coombs.