Lange 24. Flashcards
What is the initiating force of an acute disease usually?
exogenous
What activates regional blood vessel endothelium?
proinflammatory cytokines (TNF, IL1)
IL-12
produced by infected monocyte-macrophages skew lymphocyte toward TH1
TH1 cell cytokine production
IL-2, interferon-gamma, TNF (Tcells)
IL-4
TH2 lymphocyte creation
TH2 cell cytokine production
IL-4, 5, 6, 10 (B-cells)
Classical complement pathway is activated when?
when antibody binds to its specific antigen (induces inflammatory cell recruitment and activation)
myelomonocytic cells
neutrophils and macrophages
proinflammatory mediators
TNF, IL-1, IL-6, prostaglandins, leukotrienes
Autoimmune diseases are characterically driven by what?
antigen
T cells induce apoptosis in which ways?
Fas-Fas-ligand pathway, perforin, granzymes
SLE autoantibody
Ro
Gout
crystal-induced inflammation of synovial joints
What is the most frequent cause of decreased excretion of uric acid?
decreased glomerular filtrating rate
What are primary causes of hyperuricemia through overproduction?
primary defects in the prime salvage pathway leading to an increase in de novo purine synthesis and high flux through the purine breakdown pathway
What are secondary causes of hyperuricemia through overproduction?
increased cell turnover and DNA degradation
What is formation of crystals markedly influenced by?
physical factors (temperature and blood flow)
What makes monosodium crystals NOT biologically inert?
negatively charged surface function as efficient initiators of the acute inflammatory response - activating the classic complement pathway (making C3a and C5a) - chemoattractants for neutrophil influx - also activate kinin system (local vasodilation, pain, swelling)
What is the mechanism that the acute inflammatory response is able to down modulate itself in gout?
- efficient phagocytosis 2. increased heat and fluid influx (crystal solubilization) 3. coating of crystals with serum proteins (make less inflammatory) 4. recreation of anti-inflammatory cytokines 5. phagocytosis of previously activated apoptotic neutrophils
podagra
severe inflammatory arthritis at the first metatarsophalangeal joint (most frequent manifestation of gout)
How does podagra typically present?
patient describes waking in middle of night with dramatic pain, redness, swelling, warmth of the area
Common sites of gout flares
toes, midfoot, ankles, knees
Which drugs, and how, reduce duration of a gouty flare?
NSAIDs (reduce prostaglandin synthesis), Colchicine (reduce neutrophil migration), corticosteroids (decrease activation of myelomonocytic drugs
How is gout diagnosed?
examination of synovial fluid under polarizing microscope. MSU crystals = negatively birefringent needle-like structures - engulfed by polymorphonuclear neutrophils
Chronic gout
formation of tophi - firm, irregular subcutaneous deposits of MSU crystals
Where do tophi most often form?
along tendinous tissues on the extensor surfaces of joints and tendons
How do tophi appear on examination?
extruding chalky material containing urate crystals onto skin surface
Chronic erosive polyarthritis
uric acid increases over the years, deposits occur in multiple joints resulting in a persistent but more indolent inflammatory arthritis associated with remodeling of the thin synovial membrane into a thickened inflammatory tissue - can also result in renal tubular injury and nephrolithiasis
Treatment of acute gouty arthritis
agents that decrease inflammatory cell recruitment and activation to the involved joints
Treatment of chronic gouty arthritis
chronic therapy to decrease serum uric acid levels into normal range - uricosuric agnets (probenecid), allopurinol and febuxostat (impede uric acid synthesis by inhibition of xanthine oxidase, pegloticase (converts uric acid to allantoin)
Which drugs are most appropriate for treatment of uric acid overproduction?
allopurinol and febuxostat
Which drugs is best for the treatment of uric acid underexcretion?
probenecid
Which drug is best for rare cases of refractory gout?
pegloticase
Immune complex vasculitis
acute inflammatory disease of small blood vessels due to ongoing antigen load and an established humoral immune response
Which tissues are affected by immune complex vasculitis? Why?
skin, joints, kidney - highly enriched in small blood vessels
What normally clears immune complexes?
reticuloendothelial system
When do immune complexes become pathogenic?
when circulating immune complexes are deposited in the sub endothelium where they set in motion the complement cascade and activate myelomonocytic cells
When does deposition of immune complexes happen?
If foreign antigens is in excess as compared to antibody (usually antibody in excess)
What is an example of altered pathogenicity of immune complexes?
serum sickness - initial antigen load is great, immune response stimulated, immune complexes appear followed by fever, arthritis, rash, glomerulonephritis, antibodies begin to exceed antigen, immune complexes resolve
What do acute immune complex glomerulonephritis cause?
proteinuria, hematuria, formation of red blood cell casts due to disruption of the glomerular basement membrane
What are the “pauci immune” vasculitis processes?
granulomatosis with polyangiitis (GPA) and polyarteritis nodosa
GPA clinical hallmarks
granulomatosis with polyangiitis - granulomatous inflammation of the upper airway (sinusitis) and lower airway (trachea, lungs), as well as a necrotizing vasculitis involving the kidneys and other organs
What antibodies are highly specific to granulamatosis with polyangiitis? (GPA)
ANCA antibodies (antineutrophil cyotplasmic antibodies) - directed against components situated within neutrophil cytoplasmic granules - can bind and activate neutrophils at the interface of the plasma and vessel wall causing vascular damage
Polyarteritis nodosa. What is the hallmark?
vasculitis affecting medium-sized muscular arteries and arterioles. Hallmark = intense and destructive myelomonocytic cellular infiltrate in the blood vessel wall (fibrinoid necrosis) leading to vessel occlusion, marked luminal narrowing,and obsolescence
What are common manifestations of polyarteritis nodosa?
infarction of nerve trunks, bowel ischemia, kidney ischemia, deep cutaneous ulcerations
SLE
prototypic systemic autoimmune rheumatic disease - chronic inflammatory injury to and damage of multiple organ systems
What is a key feature of SLE?
unique adaptive immune response driven by antigen contained in self tissues
What are tissues frequently affected in SLE?
skin, joints, kidneys, blood cell lines, serial surfaces, brain
Who is SLE most common in?
black women
What is a strong risk factor in development of lupus?
genetic deficiencies of the proximal components of the classic complement pathway (C1q, C1r, C1s, C4)
What is the classic complement pathway required for?
efficient noninflammatory clearance of apoptotic cells by macrophages
What is the initiation of SLE?
unique form of apoptotic cell death that occurs in a promise context
What is a critical susceptibility defect for the development and propagation of SLE?
impairment of normal clearance of apoptotic cells in tissues
How is SLE propagated?
- generation and deposition of immune complexes (esp kidney, joints, skin) 2. autoantibodies bind to extracellular molecules in the target organs and activate inflammatory effector functions at that site, causing tissue damage 3. autoantibodies directly induce cell death by ligating cell surface molecules or by penetrating into living cells and exerting functional effects
Where is antigen derived from in SLE?
damaged and dying cells
Type I interferons in SLE
play a central role in amplification pathways - induce differentiation of monocytes into potent antigen-presenting dendritic cells
SLE flares
reflect immunologic memory, responding more rapidly and vigorously
What is a frequent major cause of morbidity and mortality in SLE?
renal disease
Sjogren Syndrome
slowly progressive autoimmune rheumatic disorder in which the exocrine glands are the primary target - more frequent in women
Manifestation of Sjogren Syndrome
dryness of eyes and mouth
Other problems associated with Sjogren syndrome
susceptible to dental problems, skin and vaginal dryness, dryness in respiratory track
What do more than half of sjogren syndrome patients also affected with?
autoimmune thyroid disease
What is the treatment for sjogre syndrome?
symptomatic improvement (artificial tears, regular supply of becerages, sugar-free gum)
Inflammatory myositis
gradual development of progressive motor weakness affecting the arms and legs and trunk with histologi evidence of muscle inflammation
What are hallmarks of inflammatory myositis?
difficulty rising from seated position, getting out of bed, ascending a flight of stair, brushing hair (weakness predominantly proximal rather than distal in location)
Common antibody in inflammatory myositis?
anti Jo-1 antibodies or anti-Mi-2 antibodies (specific to dermatomyositis)
What are the similarities between polymyositis and dermatomyositis?
patchy involvement, presence of inflammatory infiltrates, areas of muscle damage and regeneration
Polymyositis
inflammation located around individual muscle fibers and infiltrate is T-cell and macrophage predominant
Dermatomyositis
atrophy at periphery of muscle bundles and predominantly B cell and CD4 T cell infiltrate, also some activation of the complement cascade
What are the 4 characteristic criteria for diagnosis of polymyositis?
- weakness 2. elevated laboratory parameters of muscle tissue (creatine phosphokinase of aldolase) 3. an irritable electromyogram upon electrodiagnostic evaluation 4. an inflammatory infiltrate upon histologic evaluation (5. skin rash for dermatomyositis)
What is an additional clinical feature of inflammatory myopathies?
finding of association with cancer (either co-occurrence or subsequent development within 1-5 years)
What is treatment for inflammatory myositis?
corticosteroids - often required in high doses
Rheumatoid arthritis
chronic systemic inflammatory disease characterized by persistent symmetric inflammation of multiple peripheral joints
Where does that majority of inflammatory activity in RA occur?
joint synovium
What is normal synovium composed of?
thin cellular lining (1-3 cells thick) and underlying interstitial
What does the synovium normally do?
provide nutrients and lubrication to adjacent articular cartilage
What genetic factor implicates RA?
MHC class II alleles (HLA-DR4)
Cytokine elaboration in RA is biased towards what?
Th1
What is the most important upstream principle in the propagation of RA?
TNF
Treatment of RA
methotrexate and anti-TNF therapy (new)
RANK
expressed on osteoclasts - osteoblast stimulates osteoclast with RANK-L
PTH in bone formation
stimulates osteoblasts to release RANK-L, cause bone resorption and release of Ca++
What stimulates growth of osteoclasts?
macrophage colony stimulating factor
