Pathoma Ch 1-3 Flashcards
1. Growth Adaptations, Cellular Injury, Cell Death 2: Inflammation, Inflammatory D/o, Wound Healing 3. Principles of Neoplasia
X-linked agammaglobulinemia
(a) Mutation
(b) Age of presentation
X-linked agammaglobulinemia
(a) Mutation in bruton tyrosine kinase, signaling molecule needed for B cell maturation
(b) Presents around 6 mo of age once maternal Ig wear off
Protooncogene mutated/translocated (activated) in the following cancers
(a) Astrocytoma
(b) Certain breast cancers
(c) GI stromal tumors
(d) Mantle cell lymphoma
Protooncogene associated w/
(a) Astrocytoma = PDGF-1 (plt derived growth factor)
(b) HER2neu receptor
(c) GIST = KIT
(d) Mantle cell lymphoma = cyclin D1- cyclin that allows cell to move from G1 into S in the cell cycle
Would the scar be larger in primary or secondary intention healed wounds
(a) Key feature in secondary intention
Primary intention healing (ex: stitched up) is when the edges are reapproximated- get a smaller scar
Secondary intention healing: edges are not approximated so more granulation tissue develops (larger scar) and tissue contracts
-contraction*** of granulation tissue/scar by myofibroblasts
What is fibrinoid necrosis?
(a) Typical histological appearance
Fibrinoid necrosis = necrotic damage to BV wall
(a) Proteins leak into the vessel wall => bright pink stain on histo
Seen in malignant HTN and vasculitis
Mast cells: immediate vs. delayed/late response
(a) Fxn of delayed response
Mast cells: immediate response is release of pre-formed histamine granules
-then histamine => vasodilation of arterioles and increased permeability of post-capillaries venules
Delayed response = release of leukotrienes
(a) To maintain the acute inflammatory response
What amyloid is deposited in Alzheimer disease?
Amyloid deposition = general term for misfolded protein deposited in extracellular space, generally around blood vessels
In Alzheimer is is Abeta-amyloid that is deposited, which is derived from a beta-amyloid precursor protein
-beta-amyloid precursor protein is encoded for gene on chromosome 21 (hence link to Trisomy 21 = Downs)
Deficiency in which complement proteins result in an increased risk of Neisseria infections
Deficiency in any proteins that make up the MAC (membrane attack complex) = increase Neisseria risk
MAC made up by C5,6,7,8,9 (C5-C9)
What is the histologic hallmark of UC vs. Crohns
UC = crypt abscess Crohns = noncaseating granulomas
Explain the mechanism of reperfusion injury
Dead tissue now gets return of O2 and inflammatory cells (in blood)
- setting up for free radical tissue injury! (b/c no enzymes in cells to oxidize free radicals)
- then free radicals create continued tissue damage
Classic ex: continual rise of trops after cath lab
Enzyme deficiency resulting in SCID
Adenose deaminase deficiency = 2nd MC cause of SCID, MC enzyme defect cause
Adenosine deaminase needed in purine synthesis => necessary for the very mitotically active cells of the immune system
So w/o adenose deaminase => no B or T cells (hence combined immunodeficiency)
MC cause of Budd Chiari
MC cause of Budd Chiari = polycythemia vera = overproduction of RBC = increased viscosity of blood
Name the two things necessary for B cell activation
B cell activation requires two signals
- B cell presenting antigen on MHCII bound to matching antibody on CD4 T cell
- CD40 on B cell binds to CD40L on helper T
Name the chemical attractants for neutrophils once they undergo transmigration
Big 4 chemical attractants = general 4 signals that attract/activate neutrophils
- C5A (complement protein)
- LTB4 (leukotriene B4)
- IL-8
- Bacterial products
Differentiate hyperplasia from hypertrophy
(a) Mechanism
Growth adaptation of tissue to increase in stress
Hyperplasia = increase in number of cells
(a) Stem cells produce more of the cell type => only done in non-permanent tissues (not neurons)
Hypertrophy = increase in size of cells
(a) Increase in protein production 2/2 gene activation (make more cellular matrix) and organelles (need more mitochondria to give larger cell more energy)
Systemic amyloidosis
(a) MC affected organ
(b) Cardiac manifestation
(c) GI manifestation
Systemic amyloidosis
(a) MC affected organ = kidneys, manifests as nephrotic syndrome (proteinuria, edema)
(b) Restrictive cardiomyopathy
- amyloid deposits cause thick/stiff walls that don’t fill as well
(c) Deposition in gut wall = thickened wall = malabsorption
Differentiate central and peripheral immune tolerance
Central = thymus/bone marrow maturation (positive and negative selection if bind MHC and don’t bind self too tightly)
Peripheral = lack co-stimulatory signal => anergy or apoptosis
Describe the following step of leukocyte arrival in acute inflammation:
Marginalization 2/2 vasodilation
In general cells run in the middle of normal blood vessels because that is where the most organized, laminar flow takes place
W/ vasodilation this slows down flow and allows cells to marginalize towards the boundaries of the lumen
= first step in neutrophils and macrophages exiting from bloodstream into interstitial space
Name the 4 key molecules for neutrophil attraction and activation
Neutrophil attraction/activation
- LTB4 (leukotriene B4)
- C5A (complement 5A)
- IL-8
- Bacterial products
Leukocyte adhesion deficiency
(a) Inheritance
(b) Defect
(c) First clinical sign
(d) Serum abnormality
(e) Ongoing clinical sign
Leukocyte adhesion deficiency- neutrophils and macrophages cannot adhere properly to endothelial surface 2/2
(a) Autosomal recessive
(b) Defect in integrins (binding protein for cellular adhesion molecules) on leukocyte
(c) Hallmark sign = delayed separation of umbilical cord
(d) Increase in circulating neutrophils (b/c less adhered down in lungs specifically)
(e) Recurrent bacterial infections w/o pus
- pus = dead neutrophils, so if neutrophils can’t leave BVs you’re not making pus!!!
Name the two ways in which free radicals damage cells
Free radical tissue damage 2/2
- peroxidation of lipids (damages cell membranes)
- oxidation of DNA (ummm oncogenic) and proteins
2 inorganic minerals necessary for scar formation
Copper needed for collagen cross linking
Zinc needed to replace collagen III (granulation tissue = first step of scar formation) w/ collagen I (strong tough scar)
Name 3 types of infections pts w/ X-linked agammaglobulinemia are susceptible to
X-linked agammaglobulinemia = low Ig of all subtypes 2/2 mutation in signaling molecule necessary for B cell maturation into plasma cells
No IgG => can’t opsonize => bacterial infections
No IgA => can’t protect mucosal surfaces => enteroviral and Giardia infections
So no/low Igs = increased risk of bacterial, enteroviral, and Giardia infections
Type of necrosis seen in
(a) testicular torsion
(b) vasculitis
Type of necrosis
(a) Testicular torsion = red infarction (not white infarction) b/c blood re-enters a loosely organized dead tissue
- torsion constricts vein before artery => ischemia due to venous obstruction but blood still flowing in (hence red)
(b) Vasculitis = Fibrinoid necrosis (damage to BV wall)
What is caseous necrosis?
(a) Differentiate gross appearance of caseous and fat necrosis
Caseous necrosis = soft friable tissue, 2/2 granulomatous Tb or fungal infxn
(a) Caseous necrosis ‘cottage cheese’ appearance (think lung Tb granulomas)
Fat necrosis ‘white chalky’ appearance’- think benign calcification on mammogram
How to diagnose systemic amyloidosis
(a) 2 histological findings
Diagnose systemic amyloid w/ fat pad biopsy- usually of abdominal fat pad or rectum
(a) Amyloid picks up congo red stain- so see red extracellular accumulation around blood vessels
Amyloid exhibits apple-green birefingence under polarized light
What is the defining feature of granulomas?
Granulomas defining features = epitheliod histiocytes
= macrophages w/ abundant pink cytoplasm
So granulomas are aggregates of epitheliod histiocytes, usually surrounded by giant cells and a rim of lymphocytes
Then can be +/- caseation (central necrosis)
Differentiate the route of spread for carcinomas vs. sarcomas
In general:
- carcinomas spread via lymphatics (ex: breast cancer to axillary lymph nodes)
- sarcomas spread hematogenously
2 key histologic features of acute inflammation
Acute inflammation = edema and neutrophilic infiltrate
Mechanism by which CD8+ T cell is cytotoxic
CD8+ T cells recognizes MHC I then kills the APC by activating apoptosis, CD8+ cell secretes perforin and granzyme
Perforin pokes a pore in the APC membrane, then granzyme enters the pore and activates caspases (enzymes that mediate apoptosis)
2 general categories of causes of acute inflammation
Acute inflammation is caused by either
- infection
- necrosis (neutrphils need to clear the debris)
Name the three free radicals physiologically produced during oxidative phosphorylation
Free radicals (chemical species w/ unpaired electron in outer orbit)
O2 + 1 e- –> O2- = superoxide
O2- + 1e- –> H2O2 = hydroxgen peroxide
H2O2 + 1e- –> OH- = hydroxyl free radical (most dangerous to tissues)
Then OH- + 1e- –> H2O by glutathione peroxidase
-so overall O2 + 4e- –> H2O
Histologic hallmark of cell death
Cell death histologically = loss of nuclei
anucleated cells are dead!
2 things necessary for 2 CD4+ cell activation
T cells need 2 things for activation
- binding of antigen and MHC complex
- costimulatory signal: B7 on APC binds to CD28 on CD4+ cell (28/7 = 4)
HyperIgM syndrome
(a) Mutation
(b) Explain serum findings
Hyper-IgM syndrome
(a) Mutation in part of the CD4-B cell costimulatory signal (so either CD40L on helper T cell or CD40 receptor on B cell defective) => B cells cannot be activated to class switch, so stay as immature B cells which are all IgM
(b) No costimulatory signal => helper T cells don’t secrete IL-4 and IL-5 to cause B cell class switching => B cells stay as IgM secreting cells (immature form)
What is the main molecular mediator of fever in acute inflammation?
(a)Where does this molecule act?
Fever caused by PGE2 (prostaglandin E2)
PG’E’2 f’eeeeeee’ver
(a) PGE2 acts at hypothalamus to increase set point of temp
Name two examples of dystrophic calcification
Dystrophic calcification = mechanism by which dead tissue acts a nidus for Ca2+ deposition
- Psammoma bodies- neoplastic cells outgrowth their blood supply, die, then Ca2+ deposits
- papillary thyroid carcinoma
- meningioma
- serous cystadenoma - Saponification (FFA joining w/ Ca2+) seen in fat necrosis
CO2 poisoning
(a) Caused by what exposures (classically)?
(b) First sign
(c) Classic clinical feature
CO2 poisoning
(a) smoke from fire, exhaust from cars or gas heaters
(b) Key first sign = headache
- can use this to screen pts exposure to smoke from fire, if HA present keep CO2 poisoning on the radar
(c) Classically present w/ cherry-red skin
- b/c Hb is bound (to CO2) which gives color
- ironic b/c they’re tissues are hypoxic
Explain the mechanism of rubor and calor in acute inflammation
(a) Main molecular mediator
Redness and heat are 2/2 increased blood flow to the area which is due to vasodilation
Vasodilation caused by histamine, bradykinin, and prostaglandins
(a) Mainly histamine
What is the shared mechanism of damage in hemochromatosis and Wilson’s disease
Excess metals (Fe and Cu respectively) deposit in tissues and are not bound => produce free radicals
So mechanism of tissue damage in metal storage d/o is by free radicals
Differentiate necrosis and apoptosis
(a) Key aftermath of necrosis
(b) Distribution of death
Necrosis = always pathologic, think of this as homicide
(a) Followed (always) by acute inflammation
(b) Death to a large group of cells
Apoptosis = think of this more as cell suicide
(a) NOT followed by acute inflammation b/c apoptotic bodies are removed by macrophages
(b) Death of a single cell or small group of cells
Type of necrosis seen in
(a) abscess
(b) eclampsia
Type of necrosis seen in
(a) Abscess => liquefactive b/c neutrophils contain lytic enzymes
(b) Eclampsia = a form of malignant HTN => Fibrinoid necrosis where intracellular proteins leak into wall of BV
Type of necrosis seen in ischemia of the lower limb
(a) If this gets infected?
(b) Wet vs. dry gangrene
Ischemia of the lower limb (think diabetic food) => gangrene necrosis- basically coagulative necrosis w/ gross appearance of mummification (ew…)
(b) W/o infection = dry gangrene
(a) W/ infection you get superimposed liquefactive necrosis = (b) wet gangrene (wet like all the pus…even more ew)
How to differentiate chronic granulomatous disease and MPO deficiency
Both are defects in O2-dependent killing after phagocytosis:
O2 –> (NADPH oxidase) –> O2- –> H2O2 –> (MPO) –> HOCl-
NBT test detects O2- production during oxidative burst (catalyzed by NADPH oxidase)
=> NBT test abnormal in CGD (NADPH oxidase defect), while normal in MPO deficiency
Buzzword: delayed separation of umbilical cord
Dx?
Dx = leukocyte adhesion deficiency = autosomal recessive defect in integrin on neutrophil/macrophage surface that inhibits cells from binding to endothelial surface => neutrophils/macrophages can’t exit blood vessels into tissue in response to acute inflammation
Name an exception to the concept that pathologic hyperplasia can increase risk of cancer
Pathologic hyperplasia = increase in cell size due to an underlying process
-almost always leads to increased risk of cancer (metaplasia –> dysplasia –> carcinoma)
Exception = BPH = benign prostatic hyperplasia
-no increase in prostate cancer
Triad of features of Wiskott-Aldrich Syndrome
(a) Mode of inheritance
Wiskott-Aldrich syndrome
(a) X-linked recessive mutation in Wiskott-Aldrich gene
Triad:
- thrombocytopenia
- eczema
- recurrent infections
Name two mechanisms by which cytotoxic T cells kill targets
Cytotoxic T cells kill by inducing apoptosis in their targets by
- Secretes perforins (pokes hole in membrane) then granzymes that enters hole and activates caspases
- extrinsic receptor-ligand pathway: FASligand on T cell binds Fas death receptor on target cell to activate caspases
In general what are amyloid disorders?
(a) Systemic vs. localized
Amyloid d/o = deposition of misfolded proteins in the extracellular space, especially around blood vessels
(a) can be systemic (in multiple body systems) or localized deposition in a single organ
Key distinguishing feature of dysplasia vs. carcinoma
Dysplasia can be reversible w/ removal of the stressor
Then if the stress persists long enough and carcinoma develops it is irreversible
Give 3 Ddx for enlarged LN
(a) Dx if biopsy shows proliferation of lymphocytes in 20:1 ratio
Ddx for enlarged LN is 3-fold
- Hyperplasia 2/2 response to infection
- Lymphoma
- Mets
(a) Cancer is monoclonal => 20:1 ratio is 2/2 lymphoma
Ddx for caseating granulomas and stains
Ddx for caseating granulomas
- Tb (AFB stain)
- fungal infections (GMS stain)
Immunohistochemical stain indicative intermediate filament indicative of
(a) Epithelial cell
(b) Mesenchyme
(c) Neuroendocrine cell
(a) Epithelial cell = keratin stain
(b) Mesenchymal = vimentin
(c) Chromgrannin stain = neuroendocrine cells
- carcinoid tumor
- small cell carcinoma
Key complement protein
(a) Activate mast cells
(b) Attract/activate neutrophils
(c) Mark stuff for phagocytosis
(d) Forming MAC
Complement proteins
(a) C3A and C5A activate mast cells (to release histamine)
(b) C5A attracts/activates neutrophils
(c) C3B opsonizes molecules for phagocytosis
(d) C5B along w/ C6-C9 form membrane attack complex to poke hole in membrane
Explain the mechanism of rubor and calor in acute inflammation
(a) Main molecular mediator
Redness and heat are 2/2 increased blood flow to the area which is due to vasodilation
Vasodilation caused by histamine, bradykinin, and prostaglandins
(a) Mainly histamine