Flashcards in SLE Deck (30):
Diff hypersensitivity rxns and examples?
- type I: immediate (anaphalytic, atopic)
- type II: cytotoxic: target cell receptors, platelet-thrombocytopenia, target fixed tissue ag; good pastures, MG
- type III: immune complex; vasculitis, SLE
- Type IV: cell mediated
a) tuberculin rxn
b) cytotoxic cells destroy target cells - allograft rej
What is SLE?
- multisystem autoimmune disorder of unknown cause and is strongly assoc w/ various autoabs
- deposition of ag-ab complexes along vascular and tissue basement membranes
- is sometimes referred to as the great imitator because it affects many diff body systems
- skin, its, serosal surfaces, muscles, kidneys, heart, lung, CNS, RBCs, and platelets
Incidence and prevalence of SLE?
- 50-70 new cases/1 million/year
- prevalence: 500/million
- women:men = 9:1
- occurs in childbearing yrs 20-40
- higher incidence in blacks, Native Americans, Puerto Ricans, Chinese
Factors for SLE?
influenced by combo of following:
- genetic: x'some 6: HLA-DR3 and linked specificities DR2 and DQw1 increase risk by a factors of 3
UV light (rash)
bacterial and viral infections
abnormal stimulation of immune system
- endocrine: sex hormes - most cases develop after menarche and b/f menopause
- drug induced:
lupus like syndrome - MC: procainamide, hydralazine
Pathogenesis of SLE?
- b-lymphocyte hyperactivity w/ exaggerated ab production
- ag-ab complexes deposited along basement membranes of vasculature and tissue
- localized inflammator responses:
cell-mediated tissue injury
- onset may be insidious or acute (more devastating)
- course is characterized by exacerbations and remissions
- as in other autoimmune disorders - immune system attacks body cells and tissues, result is inflammation and tissue damage
- type III autoimmune rxn caused by ab- immune complex formation
MC sxs of SLE?
- systemic: low grade fever, photosensitivity
- mouth and nose: ulcers
- jts: arthritis
- muscles: aches
- psych: fatigue, loss of appetite
- face: butterfly rash
- pleura: inflammation
- pericardium: inflammation
- fingers and toes: poor circultation
Clinical manifestations of SLE?
- wt loss
- butterfly rash (malar)
systemic: polyarthritis, arthralgias, jt pain (polyarthritis is symmetrical, but doesn't not involve articular destruction)
- fingertip lesions
- periungual erythema
- nail fold infarcts
- splinter hemorrhages
- raynaud's phenomen (about 20% of pts)
How common is renal involvement in SLE? Presentation? What can be prognostic?
- occurs in approx 50% of pts
- lupus nephritis:
nephrotic syndrome: proteinuria, hyaline casts
- renal bx can be prognostic:
tubular atrophy = poor outcome
- chronic renal failure more common than acute
Ocular features of SLE?
- transient or permanent monocular blindness
- blurred vision
- cotton wool spots on retina
MSK features of SLE?
transient polyarthritis w/ symmetric involvement:
- small and large jts
- no signs of inflammation on exam of jts
- 10% develop rheumatoid like hand deformities
- bony erosions not present
osteonecrosis of the hips
fibromyalgia often present
Pulm features of SLE?
- occurs in 40-50% of pts
- transient basilar pneumonic infiltrates = lupus pneumonitis:
- pleural effusions
- restrictive lung disease
- rare: alveolar hemorrhage w/ massive hemoptysis, death
Cardiac features of SLE?
- occurs in 30-40% of pts
- increased muscle enzymes:
MB or CPK
- libman sacks endocarditis:
V. surface vegetations on valves
vegetation breakoff may allow colonizations
Serositis of SLE?
- fluid less than 3000 WBC/mm3 = monocytes and lymphocytes
- reduced complement
Vascular features of SLE?
- raynaud's phenomenon
- arterial or venous thrombosis
- lupus vasculitis: palpable purpuric lesions on the shins in a pt w/ lupus and necrotizing vasculitis of the skin, kidney, and brain
- livedo reticularis: pt has antiphospholipid abs - can result in ulcer formation
GI sxs of SLE?
- transient, nonspecific abdominal pain
- increased incidence of primary biliary cirrhosis w/ SLE
- vasculitis of mesentery can cause infarction or perforation of bowel w/ high mortality
What are CNS features of SLE?
- occurs in 30-75% of pts
- confusion, memory deficits, disorientation, hypomania, delirium, and schizophrenia
- grand mal seizures, temporal lobe seizures
- severe HAs, MC neuropsych sx, sometimes w/ scotomata like migraines
- stroke: anti-phospholipid abs
- ACR recognizes 19 neuropsych syndromes in SLE
MC of death in SLE pts?
- those due to nephritis - usually occur w/in first 5 yrs of sx onset
- CV disease and malignancy which may be related to chronic inflammation and cytotoxic therapies, and common etiologies of late mortality
- infectious complications related to active SLE and immunosuppressive tx are now the most common COD in early active SLE
CBC findings in SLE? ESR, CRP, UA?
normocytic, normochromic, hemolytic
- leukopenia: lymphocytopenia common, indicative of disease activity
- thrombocytopenia: 50-100k
- prolonged PTT:
from antiphospholipid abs, false positive tests for syphilis
- ESR and CRP: both be elevated
cellular or hyaline casts
Rheum lab findings in SLE?
- ANA (esp rim, cartwheel or peripheral): sensitivity 99%, specificity 49%
- anti dsDNA
- anti ssDNA
- anti ENA: anti SM, anti RNP
- elevated nonspecific IgG, IgM levels
- reduced complement levels (C3, C4)
- decreased IgA levels
- can have false positive for syphilis
- anti-histone: drug induced - ANA abs often this type
DDx for SLE?
- antiphospholipid syndrome
- hep C
- lyme disease
- lymphoma, B cell
- mixed CT disease
- polyarteritis nodosa
- rheumatic fever
- rheumatic arthritis
- serum sickness
How do you dx SLE?
- no one test or feature is fully dx
- criteria for classification of SLE
What is the criteria for dx SLE?
- characteristic rash across cheek
- discoid lesion rash
- oral ulcers
- inflammation of membranes of the lungs, heart or abdomen
- evidence of kidney disease
- evidence of severe neuro disease
- blood disorders, including low red and white blood cell and platelet counts
- immunologic abnormalities
- positive ANA
* pt must experience 4 of the criteria b/f a doctor can classify the condition as SLE, these criteria proposed by ACR are not to be relied upon solely for dx however
Physical and lab findings in SLE?
- butterfly (malar rash)
- discoid lesions
- ANA (particularly cartwheel, rim or peripheral)
- anti Sm ribonuclear protein
Tx of SLE?
incurable but tx
tx aimed at:
- reducing inflammation
- suppressing immune system
- closely follow pts clinically to ID disease features as early as possible
- pt education and prevention of disease flares:
sunscreen and protective clothing
protective, warm clothes
avoidance of vasoconstrictive drugs
- pharm tx:
plasmapheresis (Lupus nephritis)
Belimumab - fully human monoclonal ab (benlysta)
Survival rate for SLE pts?
- 95% at 5 yrs
- 90% at 10 yrs
- 78% at 20 yrs
Presentation of drug induced lupus?
- sex ratio nearly equal
- primarily msk, pulm, polyserositic sxs
- renal and neuro disease uncommon
- abs themselves not harmful
- no hypocomplementemia
- anti-nuclear abs present, but return to normal w/ withdrawal of drug
- reversal w/ d/c of drug
- procainamide and hydralazine MC culprits
Drugs that can cause drug induced lupus syndromes?
What is discoid lupus?
- chronic cutaneous lupus
- involves plaque like lesions of head, scalp, and neck
- first appear as red, swollen patches or skin
- later scarring, depigmentation, plugging of hair follicles
- 90% of discoid lupus pts have disease that involves skin
- probably occurs in genetically predisposed individuals, but the exact genetic connection hasn't been determined
- pathophys of DLE isn't well understood
DDx for discoid lupus?
- actinic keratosis
- granuloma annulare
- lichen planus
- subacute cutaneous lupus
- squamous cell carcinoma