Autoimmune disorders from pathoma Flashcards
What are the primary mechanisms that the body uses to prevent autoimmunity?
negative selection of T cells in the thymus or bone marrow via apoptosis
anergy in the periphery- get rid of self-reactive cells if they don’t get a second signal
SLE: What kind of hypersensitivity? Demographics?
this is a type II (cytotoxic) and a type III (antigen-antibody complex) mediated disorder
most common in women, esp. African Americans
Clinical features of SLE
they will have fever and weight loss RASH OR PAIN mnemonic: rash (malar or discoid) arthritis serositis: pleuritis or pericarditis hematologic disturbances like anemia, thrombocytopenia, or leukopenia d/t autoantibodies against cell surface proteins oral ulcers or nasopharyngeal ulcers renal disease; raynauds photosensitivity antinuclear antibodies immunosuppressants neurologic disorders like seizures or psychosis
Common causes of death in SLE
CV disease, infections, and renal disease
What is the most common renal lesion seen in pts with SLE?
diffuse proliferative glomerulonephritis
What are important CV findings in SLE?
Libman-Sacks endocarditis: small, sterile deposits on BOTH sides of the mitral valve. these are deposition of ab-antigen complexes
What are the important autoantibodies in SLE?
ANA (sensitive, but not specific), and anti-dsDNA antibodies (very specific)
(don’t memorize, but if you’re going crazy, remember that anti-Smith is an ANA specific for lupus)
What characterizes drug-induced SLE? What are common offenders and what is the treatment?
antihistone antibody
common offenders: isonizid, hydralazine, and procainamide
usually resolves with removal of the drug
What is antiphospholipid syndrome? Associations, manifestations, relevant abs, tx
syndrome that may be associated with SLE (30% of cases)
characterized by autoantibody against proteins bound to phospholipids
most commonly, look at anticardiolipin and lupus anticoagulant
this disease casues arterial and venous thrombosis, including DVTs, hepatic vein thrombosis (Budd-Chiari), placental thrombosis, and stroke
requires lifelong anticoagulant therapy. remember that warfarin is contraindicated in pregnancy
What do I need to know about anticardiolipin antibodies and lupus anticoagulant?
they can lead to false-positives on syphilis tests and falsely elevated PTT lab studies, respectively.
note that elevated PTT is paradoxical, because these antibodies actually increase the risk of arteriovenous thromboembolism)
What is Sjogren syndrome? What type of hypersensitivity rxn?
autoimmune destruction of the lacrimal and salivary glands
this is a lymphocyte-mediated type IV hypersensitivity rxn with fibrosis
Presentation of Sjogren and relevant autoantibodies
presents as dry eyes (keratoconjunctivitis), dry mouth (xerostomia), and recurrent dental caries in older woman (50-60 yrs)
characterized by ANA and anti-ribonucleoprotien antibodies (anti-SSa/Ro and anti-SSB/La)
What diseases are associated with Sjogren syndrome
other autoimmune diseases, esp. rheumatoid arthritis
incr. risk for B cell (marginal zone) lymphoma, which presents as unilateral enlargement of the parotid gland
What is scleroderma? Subcategories?
autoimmune disease characterized by activation of fibroblasts and deposition of collagen
divided into localized and systemic scleroderma
What should I know about localized scleroderma?
involves skin only
most common subtype is called morphea
highly associated with antibodies to DNA topoisomerase II
