systemic lupus erythematosus Flashcards
features of lupus dx (systemic vs. local, type of disease, organs, severity)
systemic autoimmune disease of unknown cause
chronic disease with unpredictable exacerbations and remissions
can affect any organ
severity is mild to life-threatening
epidemiology of lupus
african americans > caucasions, usually diagnosed ages 16-55, usually more women than men
more common in African Americans
What are some factors that contribute to the development of SLE?
genetics, immunologic factors, hormonal factors, environmental factors (including EBV)
genetics: about 40% concordance in MZ twins. ‘90% of ppl with homozyougs c1q deficiency get lupus (c1q is part of complement, which is needed for clearance of immune complexes)
manifestations of SLE
RASH OR PAIN mnemonic Rash: malar or discoid arthritis soft tissues/serositis hematologic disorders (cytopenias and hemolytic anemias) oral/nasopharyngeal ulcers renal disease; Raynaud's Photosensitivity antinuclear antibodies immunologic disorder/immunosuppression neurologic disorders: seizures, psychosis need 4 or more criteria
malar vs. discoid rash
malar: fixed erythema in a “butterfly” pattern that spares the nasolabial folds
discoid: erythematous raised patches with adherent keratotic scaling and follicular plugging. can cause scarring
photosensitivity: definition and why present in lupus
skin rash as a result of unusual rxn to sunlight
sunburns cause apoptosis. apoptosis causes exposure to self-antigens and can trigger lupus in susceptible populations
characteristics of ulcers in SLE
oral or nasopharyngeal. usually painless
arthritis in SLE
non-erosive arthritis with 2 or more peripheral joints. see tenderness, swelling, or effusion.
DDx for polyarticular arthritis
PAIRS
psoriasis, ankylosing spondylitis, IBD, rheumatoid arthritis, SLE
serositis in SLE
pleuritis: hx of pleruitic pain or rubbing, or pleural effusion
pericarditis: seen by ECG, rub or evidence of pericardial effusion
can also have inflammation of the abdominal lining
renal manifestations of SLE
screen for persistent proteinuria and cellular casts in pts with SLE.
renal disease with SLE can be serious- can cause end-stage kidney disease
lab findings in SLE, prognostic significance
immunologic disorder: anti-DNA antibody, anti-smith antibody, positive antiphospholipid antibodies
anti-DNA abs have a poor prognosis.
anti-cardiolipin can cause a false positive on a syphilis screen
separately, anti-nuclear antibody are sensitive but not specific
what might be seen in the kidney biopsy of a pt with SLE
diffuse proliferative changes with complex deposition via immunofluorescence. Causes a nephritic syndrome (type III hypersensitivity; lumpy bumpy on immunofluorescence)
or, membranous glomerulonephritis that causes a nephrotic syndrome (type II hypersensitivity, smooth on immunofluorescence)
What is a general idea of the pathogenesis of SLE?
autoantibodies develop due to defective B cell tolerance for self-antigens. We think that anti-DNA and anti-ribunucleoprotein antbodies develop after exposure to these antigens on apoptotic cells. this causes IFN-alpha production. auto-antigen exposure is a source of early break in B cell tolerance and for propagation of the disease. this can be a type II, III, or IV hypersensitivity. problems may arise due to autoantibodies tha ccause direct cellular damage or from immune complex deposition. Immune complexes fix complement, induce inflammation ,and act as toll-like receptor ligands (they often include dsDNA and RNA, which are recognized by the innate immune system).
most common presentation of SLE
rash, joint pain, and fever, most commonly in an African American woman of reproductive age
