step 1 studying deck 2 Flashcards

Question

what is mitochondrial vacuolization

Answer 1

this is NOT mitochondrial swelling which is associated with reversible injury this IS being able to see the vacuoles and phospholipid containing densities within the mitochondria which is associated with irreversible injury (permanent inability for mitochondria to further make ATP via oxidative phosphorylation)

Answer 2

1. myofibril relaxation in cardiac myocytes (seen in the first 30 mins after a severe ischemia)... this is due to ATP depletion and lactate accumulation 2. disaggregation of polysomes (seen in hypoxic/ischemic injury due to ATP depletion and detatchment of ribosomes from the rough ER) 3. disaggregation of nuclear granules or clumping of nuclear chromatin (secondary to decreased pH intracellularly) 4. TG droplet accumulation in liver, striated muscle, and kidney cells (injury causes decreased production of lipid acceptor proteins that incorporate TG into lipoproteins) 5. glycogen loss (due to low ATP... also myocardial glycogen stores may be completely depleted within 30 mins of severe ischemia)

Answer 3

IE look for a new onset murmur!

Answer 4

blood flow per minute must be closely matched between the two to maintain blood flow throughout the body (otherwise the LV would soon empty completely or soon be overloaded) exception= bronchial circuit (oxygenates the pulmonary parenchyma and drains into the LA... sort of an independent right to left shunt... but this is only <5% of the total CO)

Answer 5

drastically reduces preload/venous return to the heart due to widespread venous and arteriolar dilation and increased capillary permeability (afterwards the CO increases to try and maintain blood pressure)

Answer 6

intracellular iron golden cytoplasmic granules in macrophages turning blue with a prussian blue stain are consistent with hemosiderin laden macrophages (siderophages) these was seen in a patient with HF due to LV dysfunction which caused repeated pulmonary edema... this disrupted the blood gas barrier over time and led to alveolar hemorrhage... the RBC were eventually phagocytosed by macrophages and the iron from hemoglobin was converted to hemosiderin (that were subsequently stained with prussian blue)

Answer 7

chronic elevation of pulmonary capillary hydrostatic pressures leading to extravasation of RBCs commonly caused by left HF

Answer 8

large elastic arteries ``` ABDOMINAL AORTA #1 coronary arteries #2 popliteal arteries #3 internal carotids #4 circle of willis #5 ``` also involved is aorta, carotid, and iliac arteries also large to medium muscular arteries (coronary and popliteal arteries)

Answer 9

Jervell and lange nielsen syndrome AR predisposition to syncope and sudden cardiac death due to mutation in the potassium channels (KCNQ1 and KCNE1 genes) that encode for the alpha and beta subunits of vg K+ channels

Answer 10

brugada syndrome AD mutation in cardiac sodium or L type calcium channels ekg= pseudo RBBB or STE in leads V1-V3

Answer 11

dystrophin= structural membrane protein in the heart that stabilizes the plasma membrane of myocytes Duchenne muscular dystrophy x linked mut in dystrophin present with progressive proximal muscle degeneration and weakness also causes cardiomyopathy and conduction abnormalitis

Answer 12

thats when there is chronic myocardial ischemia and subsequent decreased contractility in that portion fix this with coronary revascularization and restoration of blood flow

Answer 13

repetitive episodes of angina prior to an MI can delay the time to cell death during complete occlusion and provide a greater time for myocardial salvage with revascularization!

Answer 14

arrhythmias microvascular dysfunction with myocardial stunning myocyte injury and death

Answer 15

constipation (v>d) new onset second degree AV block syncope (diltiazem and verapamil) used for HTN stable angina atrial arrhythmias block L type calcium channels (phase 0 of the pacemaker cell AP) thus slow down conduction through the SA and AV nodes (which cause AV block) dont forget the negative HR and contractility effects

Answer 16

-dipine mostly only vasodilator effects, practically none on cardiac

Answer 17

a thiazide

Answer 18

ventricular (typically ischemic)

Answer 19

true they can cause AV block too not associated with constipation though this patient also has COPD and is on oxygen (and you cant give nonspecific beta blockers to lung patients because it impairs bronchodilation via beta 2)

Answer 20

-zosin (alpha 1 blockers) it treats BPH and mild HTN

Answer 21

1. deep poorly localized chest pain or arm pain 2. pain reproducible with exertion or emotional stess 3. relieved within 5 mins of resting or with sublingual nitroglycerin stable angina atherosclerosis must occlude at least 75% of the lumen to cause any symptoms (asymptomatic less than 75%)

Answer 22

unstable angina (or sub-endocardial infarction)

Answer 23

metalloproteinases activated macrophages infiltrating the atheroma help break down collagen by secreting metalloproteinases this ongoing inflammation destabilizes the plaque via the metalloproteinases and leads to plaque rupture

Answer 24

a mediator that cross links lysine and hydroxylysine residues (with copper as a cofactor) which strengthens collagen fibers

Answer 25

an enzyme that cleaves the ends of procollagen that comes from fibroblasts or smooth muscle cells to make tropocollagen tropocollagin then aggregates to form collagen fibrils

Answer 26

the enzyme that hydroxylates proline on procollagen into the stable collagin triple helix (uses vitamin C as a cofactor)

Answer 27

PDA= clubbing and cyanosis without BP or HR changes means a large PDA complicated with eisenmenger syndrome (also remember that it is basically children with symptoms of heart failure)... this kid had only clubbing and cyanosis of the toes because the PDA delivers unoxygenated blood distal to the left subclavian artery so the upper extremities still get oxygenated blood Coarct= lower extremity cyanosis (but would see a difference in pulses from upper to lower extremities here) right to left shunt= when severe will cause whole body cyanosis TOF= whole body cyanosis

Answer 28

the region of the skull where the frontal, parietal, temporal, and sphenoid bones all meet in one spit the bone is thin there and overlies the middle meningeal artery (a BRANCH of the MAXILLARY ARTERY... which comes off the external carotid artery... enters the skull at the foramen spinosum and supplies the dura mater and periosteum) lacerating the middle meningeal artery causes an epidural hematoma (emergency treatment needed to prevent cushing reflex-HTN/bradycardia/resp depression, brain herniation-uncal herniation with oculomotor nerve palsy, and death)

Answer 29

syndenham chorea (acquired chorea of childhood) the neurologic manifestations of ARF!! (occurs 1-8 months s/p GAS infection) due to ab's that cross react with the basal ganglia theyre at risk for chronic rheumatic heart disease

Answer 30

displacement of a malformed tricuspid valve into the right ventricle presents soon after birth with cyanosis and HF from severe tricuspid regurg

Answer 31

liver angiosarcoma a rare malignant vascular endothelial cancer associated with carcinogen exposure due to: arsenic (pesticides) thorotrast (radioactive contrast medium) polyvinyl chloride (plastic) CD31= PECAM1 (platelet endothelial cell adhesion molecule) which is expressed on endothelial cells to function in WBC migration thus the tumor came from vascular endothelial cells and liver angiosarcoma is a vascular endothelial cell cancer

Answer 32

ARP exposed= 100 x [(risk in the exposed - risk in unexposed)/risk in exposed] basically attributable risk percent in the exposed measures the impact of a risk factor, its the excess risk you get by being in a population that is exposed to whatever it is that you're measuring (like smoking)... it is very similar to the relative risk equation ARP exposed= 100 x [(RR-1)/RR] where the RR in this case is the risk in the exposed over the unexposed in this case it said during a 10 year follow up smokers have a 5 x risk of esophageal cancer compared to non smokers (with RR= 5.0; 95% CI being 2.9-7.1) thus: ARP exposed= 100 x [(5-1)/5]= 100 x (4/5)= 100 x 0.8 = 80% of esophageal cancer is attributed to smoking

Answer 33

mean= average median= middle number (doesn't have to exist in the data set) mode= most frequent number

Answer 34

Predictive values are performance measures of diagnostic tests and depend on the prevalence of a disease youre looking for PPV= probablility that someone who tests positive actually has the disease PPV= TP/(TP + FP) (aka the true positive over all the positives) true positives depends on the sensitivity and the false positives depends on the specificity as a disease prevalence increases, the number of true positives also increases which increases PPV (you'll be more likely to catch people with the disease if the disease is more prevalent) similarly the NPV will increase as the disease prevalence decreases (you will catch more people without the disease if the disease is super rare)

Answer 35

they indicated how a positive or negative test will influence the pretest probability of having the disease (how likely it is you actually have the disease) likelihood ratios >1 indicate that the test result is associated with the presence of the disease likelihood ratios <1 mean the test is associated with the absence of the disease these are based on the test's sensitivity and specificity

Answer 36

sensitivity= only measure people with the disease (but includes true positives and false negatives) specificity= only measure people without the disease (true negatives and false positives) these are not dependent on prevalence... these are fixed values and also do not vary with pretest probability

Answer 37

if the patient has a high pretest probability of an outcome (such as a patient testing for thyroid cancer who had significant radiation to her thyroid as a child).... then she will have a low negative predictive value (meaning her NPV is not as strong as someone without risk factors) the opposite is also true, meaning that someone with no risk factors (and thus a low pretest probability) will have a higher NPV (meaning that her negative predictive value is much stronger, indicating that it is much more likely that she is truly negative for the disease)

Answer 38

validity = the accuracy (that the test is actually measuring what it is supposed to be measuring)

Answer 39

prevalence= (incidence) x (duration of disease)

Answer 40

in case control study when cases are chosen from the entire population of people with a disease as a opposed to people who are newly diagnosed if this study was on cancer and you chose people who were not only newly diagnosed, you would end up with a higher proportion of people with more benign cancers and would liver longer (it makes sense because you could be recruiting people with breast cancer who had it for 5 years and maybe their case wasn't a bad one... a bunch of these people would make it look like a population with breast cancer lived loner than the average person newly diagnosed)

Answer 41

effect modification= when the effect of an exposure on an outcome is modified by another variable (a variable that changes the observed outcome of a risk factor on disease) confounding= a third variable that influence both the dependent and independent variables you can distinguish between these two using stratified analysis (looking at the cohort as different subgroups) with effect modification, the groups will have different measures of association where as with confounding, stratification will reveal no significant different between groups This question stem mentions that theyre measuring risk of DVT in women who smoke vs dont smoke who are taking a new estrogen agonist drug... the RR of women who smoke is 1.70 p=0.01 and the RR of women who do not smoke is 0.96 p=0.68 the effect modification here is smoking on DVT (outcome) in women taking estrogen (exposure)... the difference in measures of association was evident when they showed that one group (the smokers) had a real significant association (p<0.05) and the non smokers had no significant difference (p>0.05) if this was confounding then the difference would disappear in BOTH groups. effect modification is not a bias and is not due to flaws in the design or analysis. it is a natural phenomenon that should be described, not corrected

Answer 42

also known as a prevalence study its where there are simultaneous measurements of exposure and outcome its a snapshot study that often measures using surveys super easy to perform and are cheap!

Answer 43

the observer effect which is when study subjects change their behavior as a result of awareness that they are being studied can seriously affect the validity of the study common in studies of behavioral outcomes or outcomes influenced by behavior must keep the subject unaware they are being studied (beware of ethical problems)

Answer 44

think: Dr. Berkman ~ berksons (hospital cause thats where he worked) the selection bias created by choosing hospitalized patients as the control group (the control group are more likely to encounter the exposure than the general population)

Answer 45

the apparent prolongation of survival that arises from a screening test that detects a disease earlier there is no real effect on prognosis of the disease but it appears as if the patient is living longer because they were detected earlier

Answer 46

describes the fact that the researcher's beliefs in the efficacy of the treatment can affect the outcome this is the classroom effect where teachers unconsciously facilitated the success of students they were told had higher IQs

Answer 47

falsely saying there was no difference when there actually was the probability of a type 2 beta error is determined by the power (the power is how likely the study is to detect a difference if one actually exists... power = 1 - beta) the larger the sample size the greater the power

Answer 48

RR= risk to exposed/ risk to unexposed RR= [a/(a+b)] / [c/(c+d)] (helps to put it in standard format contingency table so that you recognize that RR= [outcome A/ total group with that exposure] / [outcome B/ total group with no exposure] sometimes they dont give you the total and you have to add the outcomes together for the same exposure to get the denominator

Answer 49

this is the cross multiplying one within the middle of the table OR= (a x d)/ (b x c) the odds ration is used in case control studies because you cannot get a RR (you cannot determine the risk of an outcome because you hand picked the outcome in your case group)

Answer 50

the 68/95/99 rule states that 68% of all observations lie within 1 SD of the mean 95% within 2 SD and 99.7% within 3 SD (this applies to a normal bell shaped distribution) the actual numbers are a little different though with 95% within 1.96 [z-score] SD and 99% within 2.58 [z-score] SD because you can only test a sample of the whole population, you end up getting some variability between means (thus you need to account for standard error [SE]... basically it estimates how far the sample mean probably is from the true population mean) SE= SD/ (square root of sample size) so calculating the likely true range for the unknown population mean (the confidence interval) you would calculate CI of the mean= mean +/- [z-score for confidence level] x [SE} thus (for 95% CI): CI= mean +/- 1.96 x (SD/ square root of n)

Answer 51

the cutoff point was changed to a lower value (shift to the left) thus sensitivity of the test would increase because more people with the disease will be caught (more true positives... but probably not by much) that being said there will be more false positives and a decreased specificity

Answer 52

<1 is decreased risk of disease =1 means null value >1 means increased risk of disease thus the 95% CI for RR cannot cross 1 whereas the 95% CI for Absolute risk cannot cross 0

Answer 53

95% CI corresponds to a p value <0.05 99% CI corresponds to a p value < 0.01

Answer 54

the process of enabling people to increase control over their health and determinants, and therby improving their health aka improve diet exercise regularly dont smoke lose weight if needed its primary prevention

Answer 55

primary= before disease secondary= after disease before symptoms -case finding tertiary= after symptoms to minimize progression or complications

Answer 56

a health risk assessment which is a questionaire that uses demographics, medical info, lifestyle, and family history info to calculate the patient's "risk age" if the risk age>chronological age then they have a higher risk of death than the average person their age

Answer 57

assessment of a patient's readiness to change a problem behavior ``` precontemplative contemplation preparation action maintenance ``` mostly used for smoking

Answer 58

1 - beta (aka power) beta= type 2 error (saying there is no difference when there really is) theyre very similar but the question asked which should be MAXIMIZED and you would want to maximize the power (chance of detecting a true difference) and you would want to minimize a type 2 error

Answer 59

with alpha alpha is the max probability of making a type 1 error the researcher is willing to accept (type 1 error= finding a difference that does not exist) generally alpha is compared to the p value ex= if the alpha is set to 0.05 then there is a 5% chance of type 1 error and significance will be set at p value <0.05

Answer 60

the fact that a risk factor itself can lease to extra diagnostic investigation and more probability that the disease is identified ex- patients who smoke may have more imaging surveillance due to smoking which detects more cancer in general

Answer 61

``` categorical/qualitative= disease status blood type groups (this example patients are divided based on serum fibrinogen levels and again based on simvastatin exposure... the outcomes are not reported in mg/dL which would be quantitative but are categorized into high vs low which is a category) ``` - chi square test for independence/association (2 categorical variables) - logistic regression (2 categorical variables or a categorical outcome) quantitative/continuous= numerical values body weight glucose levels - correlation coefficient (2 numerical variables) - linear regression (2 numerical variables or a numerical outcome) - t test and ANOVA (numerical outcome)

Answer 62

so the drug/standard therapy combo must be 8% - (40% of 8%) = # so 40% OF 8% is 0.40 x 8%= 3.2% thus the maximum acceptable recurrance is 8% - 3.2% = 4.8% is the maximum reoccurance rate acceptable if the drug will be approved is 4.8% recurrance

Answer 63

RRR= (absolute risk in the control - absolute risk in the treatment) / absolute risk control this can overestimate the effectiveness of an intervention because RRR would be 50% if the drug reduced disease from 2% to 1% and likewise if the drug reduced disease from 50% to 25% (2-1)/2= 50% (50-25)/50= 50%

Answer 64

accuracy= validity aka the test is measuring what it is supposed to (specifically the numbers... so if a new test measures 200 three times in a row but the gold standard measures 280 then it is not measuring what it is supposed to and has low accuracy) *when the darts are near the center circle (aka close to the gold standard of measurement) precision= reliability (the test gives similar results with repeated measurements... the example above measured 200 three times in a row on the same sample and has great precision but all three numbers are way off from the actual value and thus has low accuracy) *when the darts are clustered close to the other darts

Answer 65

the "tail" is on the side of the skew negative: the hump on the right side because there are more outliers in the lower numbers which makes a "tail" in the negative direction positive: the hump on the left side because there are more outliers in the higher numbers which makes a "tail" in the positive direction ``` mode= tip of the hump mean= most towards the outliers median= in between (the better measure of central tendency) ```

Answer 66

when a study measures populations and not individuals (they are kind of like a cross sectional studies but in populations instead of individuals) useful for generating hypothesis but not for conclusions about the individuals within these populations (this would be an ecological fallacy)

Answer 67

they start with a cohort study in which people are followed over time and the participants who develop an outcome of interest become the cases for a case control study

Answer 68

one that focuses on discussion groups and interviews for narrative information that can be crucial for explaining the quantitative results

Answer 69

that the temporal relationship between exposure and outcome is not always clear (its a snapshot in time and wont tell you if one thing likely caused the other)

Answer 70

when subjects are randomly allocated to a sequence of 2+ treatments given consecutively (one group does A then B and the other group does B then A ) basically each group CROSSES OVER to the other treatment but in different orders this allows patients to serve as their own controls drawbacks= effects of one treatment may carry over and alter the response of the subsequent treatment (to avoid this, a "washout phase" of no treatment is added between the treatments)

Answer 71

a descriptive study that tracks patients with a known condition to document the natural history or response to treatment

Answer 72

CI= (new cases) / (total population at risk) does not account for deaths or time in the denominator (whereas incidence RATE does consider time because it is reported as cases per year) DOES account for those who already had the disease Cumulative incidence= (new cases) / (total population - starting prevalence)

Answer 73

increase in prevalence= (new cases - [deaths or cures])/ total population

Answer 74

prevalence= ([existing prevalence + new cases] - death) / (population - total deaths)

Answer 75

each of the 8 blood samples is an independent event each has a 95% chance of correctly testing negative (0.95) thus the probability is (0. 95) x (0.95) x (0.95) x (0.95) x (0.95) x (0.95) x (0.95) x (0.95)= 0. 95 ^ 8 on the other hand, the probability of at least 1 event turning out differently is 1-P (P being all the events being the same) so 1 - [0.95 ^8]

Answer 76

since the 1980's (female use of cigarettes peaked in the 1950's and incidence of lung cancer increased 20-50 years later) it started to decline slightly in 2000 do to decreased use on a graph its starts low, peaks the highest, and rises rapidly starting 1980

Answer 77

breast cancer the one that stays constantly pretty high on the graph, surpassed by lung cancer around 1980 mortality started to decrease in 1990's due to adjuvant chemo and or radiation

Answer 78

decreased since the 1950's due to better surgery techniques and adjuvant chemotherapy also protective against colon cancer: colorectal cancer screening menopausal hormone therapy in women aspirin use

Answer 79

incidence and mortality have increased in women and has become the 4th most common cause of cancer death in women they follow the pattern of increased smoking in women but lung cancer kills way more

Answer 80

incidence and mortality decreased drastically over the first half of the 20th century because of better refrigeration and food preservation (thus decreased salt intake), better sanitation, and more adequate housing (decreased h pylori infection rates)

Answer 81

``` incubation period (for infectious disease) or latent period (for non-communicable chronic disease) ``` in the question stem, men who took supplements longer than 5 years had protection from stroke and men who took it less than 5 years didnt have protection (p value >0.05)... the explanation could be that there is a discrepancy because reduction of stroke with supplements is associated with a long latent period (aka you need to take supplements for a long time to see an outcome effect) latent period concept can be applied to disease pathogenesis and exposure to risk modifiers

Answer 82

you can adjust for the differences in baseline characteristics related to behaviors to reduce the effect of this bias

Answer 83

confounding

Answer 84

in a case control study for rare diseases you assume that the OR approximates the RR when the incidence is low (<10%)

Answer 85

so if youre asked to look for how many are above a certain number, remember that its half of that 5%!!!

Answer 86

detection bias or expectancy bias important when outcomes are subjective (the pathologists at the hospital are much more likely to diagnose the disease maybe because they know what the study is looking for or they have medical historys whereas outside pathologists may be blinded to the study objective or medical history) the investigators evaluation is affected by preconceived expectations or prior knowledge leading to an overestimation of disease association or treatment effects fix this by blinding the study

Answer 87

ARR= control rate- treatment rate (remember to use the rate of people, aka the number over the total, not the absolute number of people presented in the 2x2 table) RRR= ARR/ control rate RR= treatment rate/control rate

Answer 88

NNT= 1/ARR first there were 25 people with MI out of 1000 total in the control group control event rate= 25/1000= 0.025 there were 10 out of 1000 people with MI in the experimental group experimental event rate = 10/1000= 0.01 so the ARR was 0.025 - 0.01= 0.015 aka 1.5% the NNT = 1/ 0.015 = 66.6 =~ 67 67 patients need to be treated with the experimental drug to prevent MI the ideal NNT is 1 meaning that all patients would benefit...

Answer 89

in the columns label the table dementia present and dementia absent in the rows label test result positive and test result negative in the total column place the numbers 100 under the bottom of each dementia present and absent since the sensitivity was 90% the top left box will have 90 TP tests meaning that the bottom left box will have 10 FN since the specificity is 80%, then the bottom right box will have 80 TN and in the top right will have 20 FP add up the totals across the rows and use that information to calculate the NPV NPV= TN/ (all negatives)

Answer 90

a type of selection bias that results from a loss of follow up with subjects the remaining subjects are at a disproportionately different risk of outcome than the original population attrition bias is not the loss of subjects at random between both the exposed and unexposed groups, it happens mainly to one group

Answer 91

either the outcome or exposures is not identified correctly but they affect all groups the same ex= when BPs are taken on all adult subjects with a child size BP cuff accidentally

Answer 92

risk= only the number of people with the exposure over the total with that outcome for what you are looking for ex= 18 people with low beta carotene got alzheimers out of 45 people with low beta carotene... thus his risk of getting alzheimers with low beta carotene is 40% (you do not take into account the people who got alzheimers with normal beta carotene levels because that would be relative risk) be sure to read carefully which one they want

Answer 93

power = 1 - beta | beta is the type 2 error- aka not finding a difference that actually does exist

Answer 94

Analysis of variance used to find a significant difference between the means of 2+ groups (the outcome must be measured as a quantitative number, not a categorical group

Answer 95

when you want to predict the probability of a binary outcome (aka presence or absence of cancer based on one or many independent variables that can be either numerical or categorical)

Answer 96

measure the strength and direction of a linear relationship between two numerical values

Answer 97

cases= children with AML control= children without AML cases and controls should be selected regardless of exposure to chemicals (selecting subjects based on exposure status is inappropropriate because comparing the frequency of exposure between the groups is what determines whether the exposure was more prevalent among cases compared to controls) aka if you're fixing the outcome you can not fix the exposure otherwise its not really a study

Answer 98

NNH= 1/ ARI (absolute risk increase) ARI= (adverse event rate in experimental group) - (adverse event rate in control group)

Answer 99

the number of people with a disease who died divided by the total number of people who had that disease

Answer 100

CF= AR disease with recurrent sinopulmonary infections, pancreatic insufficiency, and malabsorption different mutations all affect the CF transmembrane conductance regulator gene (CFTR) The most common CFTR mutation is delta F508 (70% of cases)= a 3 base pair deletion of phenylalanine at amino acid position 508 **this causes abnormal post translational processing of the transmembrane protein (improper folding and glycosylation which is seen by the ER who sends it for proteasomal degredation) drugs like lumacaftor can partially correct the folding defect and increase the functional CFTR

Answer 101

1. you can have decreased transcription/amount of normal CFTR (milder, dx in adults) 2. mutation affecting chloride conduction through CFTR (defect in the formation of the channel) 3. a truncated protein on the cell surface due to a premature termination (leads to recognition and degredation... common in ashkenazi jews) 4. protein withdecreased response to cAMP and ATP (mut that reduce the ability of the channel to open) BUT, again remember that delta F508 is the most common and impairs post translational processing of the transmembrane protein

Answer 102

a picture is used that has a brown clumpy string of circles that looks like a turd histo= epithelioid macrophages and multinucleated giant cells (the turd)... these are the predominant cells of granulomas granulomas are formed when macrophages cannot easily digest or remove foreign substances interferon gamma (from mature TH1 cells) contributes most to the granulomas because interferon gamma activates macrophages to improve their myocobacteria killing ability for most people the granulomas effectively controls TB infection dont forget TB live in macrophage phagolysosomes

Answer 103

IL-12= tell helper T cells to become TH1 (because TH1 secretes interferon gamma which helps macrophages kill ingested mycobacteria) TNF alpha= to recruit more monocytes and macrophages to help fight infection

Answer 104

stimulates mast cell histamine release histamine increases vasc permeability and vasodilation

Answer 105

a complement fragment or peptide

Answer 106

tells T cells to become TH2, increases B cell growth, and promotes class switches to IgE

Answer 107

promotes B cell growth/differentiation promotes eosinophil growth/diff simulates class switching to IgA

Answer 108

C4, D4, E4= vasoconstriction, increased vasc permeability, and bronchospasm

Answer 109

causes platelet aggregation vasoconstriction bronchoconstriction and increased leukocyte adhesion to endothelium at super low concentrations it can have the opposite effect (vasodilation and increased permeability)

Answer 110

its a powerful platelet aggregator and vasoconstrictor

Answer 111

macrophage immunity to TB is led by TH1 cells without TH1 cells helping make granulomas the host couldn't fight the infection granuloma formation and maintenance requires: interferon gamma IL 12 TNF alpha TB causes caseating granulomas

Answer 112

corticosteroids give to women in preterm labor (for premie babies born before 32 weeks) to increase surfactant production this decreases the risk of respiratory distress syndrome and decreases mortality works by accelerating the maturation of type 2 pneumocytes

Answer 113

DPPC (a type of lecithin)... aka dipalitoylphosphatidylcholine surfactant is lipoprotein rich in phospholipids which helps create a lipid rich monolayer that separates alveolar gas from underlying aqueous fluid prevents atelectasis and end expiratory collapse and increases compliance until 33 weeks gestation, lecithin:sphingomyelin levels are about equal... after 33 weeks lecithin rises dramatically and a ratio of 2 indicates mature fetal lungs you can test the markers because the fetus effluxes the lung fluid into the amniotic fluid

Answer 114

it causes high insulin levels in the baby the high insulin inhibits the effects or cortisol on the maturation of surfactant proteins (their babies are at higher risk for resp distress) even though steroids raise blood sugars, their benefit given to preterm mommas has benefits that far outweight the risks

Answer 115

it has been shown to decrease the risk for cerebral palsy (which results in permanent neurologic disability) though lung function in premies is more important and the more common cause of death

Answer 116

Nifedipine (CCB- causes myometrial relaxation by inhibiting myosin light chain kinase mediated phosphorylation) terbutaline (beta agonst that increases cAMP in myometrial cells in order to inhibit myosin light chain kinase and relax smooth muscle)

Answer 117

mut= inactivating mutation of BMPR2 gene (which is pro-apoptotic) PAH presents as SOB and exercise intolerance in women 20-40

Answer 118

lung transplant vasodilators can improve symptoms until they can get a transplant ex= bosentan (endothelin receptor blocker) leads to vasodilation of the pulmonary arteries endothelin is a potent vasoconstrictor that also causes endothelial proliferation (can slow progression of cor pulmonale)

Answer 119

it inhibits ADP-induced platelet aggregation used for atherosclerotic ischemic disease to prevent clots in stents that are placed

Answer 120

its an ACEI treats CHF HTN DM nephropathy

Answer 121

it inhibits TNF activity by binding TNF and preventing its interaction with its own receptor TNF is proinflammatory blocking TNF is used to treat RA, psoriasis, and psoriatic arthritis

Answer 122

an NSAID (non specific COX inhibitor) that suppresses prostaglandin synthesis used as an anti inflammatory and pain reliever

Answer 123

OSA= recurrent upper airway collapse during sleep due to a neuromuscular weakness of upper airway dilator muscles tx= stimulation of the hypoglossal nerve (CN 12) using an implantable nerve stimulator causes the tongue to move forward slightly, increasing the diameter of the airway loud snoring and gasping respirations indicates an oropharyngeal cause of OSA rather than diaphragm dysfunction

Answer 124

gram pos cocci in chains= strep (remember staph is clusters) group A and B strep are beta hemolytic ``` but, strep pyogenes (GAS) is bacitracin sensitive ``` so the answer is strep agalactiae (GBS)

Answer 125

if the mom is colonized it can be transmitted to the baby and cause: neonatal septicemia neonatal meningitis pneumonia Baby Brains get Beta hemolytic Bacitracin Blocking (resistant) group B strep during Belabored deliver

Answer 126

universal screening for colonization of the vaginal and rectum at 35-37 weeks gestation positive culture or previously infected infant= treat with INTRAPARTUM (aka during labor) antibiotics prophylaxis 1st line tx= penicillin (or ampicillin) this lasts for about 4 weeks

Answer 127

health care workers immigrants from endemic countries prison inmates

Answer 128

its a cytotoxic T cell TH1 cells release INF gamma and IL-2 which activate cytotoxic T cells cytotoxic T cells kill infected host cells during viral infection

Answer 129

NK cells are part of the innate immune system and do not require host stimulation to function they help kill malignant and virally infected cells

Answer 130

its a purple empty circle surrounded by dark purple cells that almost form a full encaseating circle around the center ("multiple nuclei peripherally shaped as a horshoe") this is a caseating granuloma and in the center is a Langhans giant cell (not the same thing as a langerhan cell which is an antigen presenting cell of the skin and mucosa)

Answer 131

alpha 1 antitrypsin is made in the liver and is meant to stop neutrophil elastase from degrading the alveolar walls (esp lower lungs) deficiency of this protein means they get excessive degredation of their alveolar elastin presents as early onset, lower lobe emphysema

Answer 132

interchain cross links involving lysine elastin is a fibrous CT protein that provides elasticity to skin, blood vessels and pulm alveoli it is made as tropoelastin and contains proline and lysine unlike collagen it has little hydroxylation tropoelastin is secreted extracellularly where it interacts with the fibrillin microfibril scaffold lysyl oxidase and copper alters the lysine and forms desmosine cross linkages which accounts for the rubber like properties of elastin

Answer 133

procollagen is made and then it undergoes post translational hydroxylation and glycosylation then disulfide bridges are formed between the C- terminals of the three collagens at the alpha chain to make the triple helix

Answer 134

stimulation test used during anesthesia to asses the degree of paralysis induced by agents that block the NMJ a peripheral nerve is stimulated 4 x in quick succession and the muscular response is recorded... the height of each bar is the strength of each twitch (higher bars= more individual muscle fibers)

Answer 135

nondepolarizing= vecuronium competitive inhibitor of post synaptic Ach receptors prevent activation and cause progressively decreasing twitches ("fading pattern" because less Ach is released with each impulse) depolarizing= succinylcholine two phases of action. phase 1. initially prevent repolarization and show equal reduction of all 4 twitches (because presynaptic Ach receptor stimulation helps mobilize presynaptic Ach vesicles for release) phase 2. persistent exposure to sux causes eventual desensitization and inactivation of Ach receptors (functionally similar to nondepolarizing blockers)... phase two seen in patients with the abnormal cholinesterases cholinesterase inhibitors can reverse non-depolarizing NMJ blockers or depolarizing in phase 2 only

Answer 136

depolarizing NMJ blocker (muscle relaxant) used for rapid sequence intubation due to rapid onset (<1 min) duration is typically <10 mins due to metabolism by cholinesterase some patients are homozygous for an atypical plasma cholinesterase which breaks down sux super slow (these patients end up with paralysis for hours with sux and must be placed onto mechanical ventilated until it wears off)

Answer 137

malignant hyperthermia and neuroleptic malignant syndrome (similar but to neuroleptics/antipsychotics) dantrolene is a skeletal muscle relaxer works by reducing the amount of calcium released by the SR

Answer 138

non depolarizing NMJ blockers these do not function in phases and their Train of Four responses are always a fading pattern cholinesterase inhibitors (like neostigmine) reverse nondepolarizing blockers

Answer 139

major basic protein is a potent anti-helminthic (worm) and anti-parasitic toxin capable of causing damage to epithelial and endothelial cells of the lungs in patients with atopic (extrinisc allergic) asthma it attaches to and disrupts the outer membrane of helminths

Answer 140

granules stain dark blue, are irregularly sized, and obscure the nucleus they contain: heparin histamine and SRS-A (slow reacting substance of anaphylaxis, a mixture of leukotrienes)

Answer 141

a mold that is inhaled as spores and can cause disease in immunosuppressed or neutropenic patients presents with cough and hemoptysis (here in a patient with past TB infection, treated, and smoking history)... or can be asymptomatic causes aspergilloma (mycetoma) which represents aspergillus colonization... it develops in old lung cavities (like ones from TB, emphysema, or sarcoidosis)... aspergillus colonizes the cavity and forms a "fungus ball" seen on xray as a radiopaque structure that shifts when the patient changes position aspergillomas are not contagious aspergillus can cause allergic bronchopulmonary aspergillosis (ABPA) in patients with asthma (presents with wheezing and migratory pulmonary infiltrates...dx with increased IgE titers and ab's to aspergillus)

Answer 142

lung volume is always positive, chest wall is almost always negative, they oppose one another equally at the functional residual capacity (FRC) resulting in an airway pressure of zero at FRC, lung volume is zero, alveolar pressure is zero, and pleural pressure is -5 (always negative) makes sense if you look at each graph seperately, those are the values where the graphs fluctuate around the consequence of a constantly negative pleural pressure= puncturing the pleura only brings air inward into the intrapleural space and thus a pneumothorax will develop the FRC is also thought of as the air left in the lungs after a passive exhale (aka the residual volume plus the expiratory reserve volume)

Answer 143

panacinar emphysema liver cirrhosis smoking dramatically increases the risk of panacinar emphysema by inducing inflammation (neutrophils and macrophages release neutrophil elastase= permanently inactivates A1AT via oxidation of methionine residues) smokers get symptomatic around 35 whereas nonsmokers get symptoms at 50

Answer 144

normally you might assume its an AIDS related opportunistic pathogen like pneumocystis jiroveci (asociated with counts <200) BUT a normal adults CD4 count is 400-1400 and our patient's is 800 (meaning that he is currently not immunocompromised) that being said, the most common cause of community acquired pneumonia in an immunocompetent adult is strep pneumoniae (70%)

Answer 145

mycoplasma pneumoniae school age children military recruits college students (dont forget strep pneumoniae is the most common cause of CAP in adults)

Answer 146

``` obstruction of air leaving the lungs bronchiectasis chronic bronchitis emphysema asthma ``` decreased FEV1/FVC ratio

Answer 147

SOB productive cough obstructive pattern prolonged smoking history chronic airway inflammation that destroys parenchyma (emphysema) and causes airway remodeling (chronic bronchitis) the major cells in the pathogenesis= neutrophils macrophages CD8 T cells neutrophile elastase damages alveoli, reduce ciliary motion, and increase mucus secretion the inflammatory cells dont work well either and COPD people are at risk for CAP

Answer 148

its a yeast with a major virulence factor (antiphagocytic polysaccharide capsule- stains red with mucicarmine and is clear and unstained with india ink)... its the only pathogenic fungus with a polysaccharide capsule identified using a methenamine silver stain (look up histology picture) c. neoformans usually affects immunocompromised patients (ex= transplant patients) its a neurotropic fungus, transmitted via respiratory route, presents with meningoencephalitis cryptococcal lung disease can also look like pneumonia diagnosis via cryptococcus in the sputum, bronchoalveolar washings, or tissue samples

Answer 149

silver stain shows septate hyphae

Answer 150

it causes lung disease and disseminated mycosis (fungal infection) it is a round yeast with broad based budding on a thick doubly reflective wall

Answer 151

causes oropharyngeal, mucocutaneous, and esophageal disease it looks like budding yeast with pseudo hyphae on a potassium hydroxide preparation

Answer 152

causes lung disease in immune competent people and disseminated mycosis in immunosuppressed patients it looks like large irregular thick walled spherules that contain small round endospores

Answer 153

its a dimorphic fungus that causes a TB like pulmonary disease can cause disseminated mycosis in immunosuppressed patients it is found intracellularly in tissue macrophages and it looks like small, ovoid, budding yeast cells

Answer 154

causes rhino-orbito-cerebral infection but can cause pulmonary disease in immunosuppressed histology shows broad hyphae with irregular branching and rare septations

Answer 155

as the airway caliber decreases (trachea to medium bronchi to terminal bronchi), the percentage of total airway resistance initially rises (and peaks with the highest percentage of total airway resistance occurring at the medium bronchi) and then declines until it reaches 0% at the terminal bronchioles This pattern occurs because the upper respiratory tract accounts for roughly half the total airway resistance the remainder derives from the lower respiratory tract (trachea + ~23 generations of airways)... airflow resistance increases at the medium sized bronchi because of the highly turbulent flow... resistance is maximal between bronchial generations 2-5 but drops in subsequent generations (bronchioles) because the cross sectional area massively increases (and thus low resistance laminar airflow is achieved)

Answer 156

obesity alters respiratory compliance due to the increased weight and the microatelectasis to compensate, obese patients have increase respiratory rates with reduced tidal volumes (rapid shallow breathing) the most common indicator of obesity related disease is a reduction in expiratory reserve volume (ERV)- aka the max air expired after a normal passive exhale... thus it also affects FRC obesity has minimal effect on residual volume ``` pattern is as follows: FEV1 decreased FVC decreased FEV1/FVC normal (because a proportional decrease) ERV is decreased RV normal TLC decreased ```

Answer 157

``` FEV1 decreased FVC normal to decreased FEV1/FVC decreased ERV normal RV increased TLC increased ```

Answer 158

``` FEV1 increased FVC normal to increased ERV increased RV increased TLC increased ```

Answer 159

obesity is BMI 30+ presents with chronic fatigue, SOB, difficulty concentrating, increase PaCO2, and obesity increased CO2 production because of increased overall mass and surface area, sleep disordered breathing, and reduction in lung volumes and compliance a normal Aa gradient is 5-15mm Hg this patient has hypoxemia in the setting of a normal Aa gradient which means that PO2 is low in the alveoli and arteries (this is due to alveolar hypoventilation such as in OHS or inspiration of air at high altitude) remember that hypoventilation is evident when PaCO2 is >45 while awake

Answer 160

yes, it causes an elevated Aa gradient

Answer 161

Candida albicans Candida gives rise to true hyphae (aka "germ tubes") when incubated at 37 degrees C for 3 horus germ tubes= C albicans it is the most common opportunistic mycosis (mycosis= disease via fungus) it frequently colonizes human skin and mucous membranes (thus before entering the sputum it probably came from the oral cavity) it can cause superficial infection (thrush, vulvovaginitis, and cutaneous candidiasis) and is associated with antibiotic use, steroid use, DM, HIV, and immmunosuppression it can cause disseminated disease in neutropenic patients and will affect the esophagus, heart, liver, and kidney Candida doesnt cause lung disease. based on his history he probably has TB but the culture grew Candida probably because his oral cavity is colonized (its a normal inhabitant of the GI tract in 40% of the population and is often a contaminant of sputum cultures) candida in the sputum does not equal disease

Answer 162

trick question, the trachea, the large bronchi, and the small bronchi are typically sterile

Answer 163

presents as respiratory failure hypoxia thickened bronchial walls with neutrophilic infiltrates and mucous gland enlargement characterized by chronic productive cough with airflow limitation and is on the spectrum of COPD most commonly caused by tobacco smoking-behavioral (and other inhaled environmental substances) ``` biopsy= thick bronchial walls neutrophils lymphocytes mucous gland enlargement increased number of goblet cells increased mucous patchy squamous metaplasia of the bronchial mucosa ```

Answer 164

silica dust exposure leading to lung disease can lead to nasal and lung cancer cancer does not lead to chronic bronchitis though, tobacco smoking does

Answer 165

CF= recurrent sinopulmonary infections and exocrine gland (fibrotic) atrophy in a young white guy pancreatic insuff causes deficiency in fat soluble vitamins vit A in particular contributes to squamous metaplasia of the epithelial lining of pancreatic exocrine ducts... (which are already injured and predisposed to squamous metaplasia by thickened mucus) this is because vit A (and its metabolite retinoic acid) are required to maintain orderly differentiation of specialized epithelia (including the eye, lungs, GU tract, pancreas, and other exocrine ducts) ... vit A deficiency causes metaplasia into keratinizing epithelium

Answer 166

could cause infertility and decreases in some serum phospholipids

Answer 167

normal PO2 of inspired air is 160mm Hg which decreases to 150 in the trachea due to partial pressure of water vapor her tracheal PO2 is normal meaning she is breathing room air without supplemental oxygen normal alveolar PO2 is 104 mm Hg (between tracheal 150 and venous blood 40) normal alveolar PCO2 is 40mm Hg (between tracheal 0 and venous blood 45) normally O2 and CO2 diffuse across the alveoli and completely equilibrate in the first 1/3rd of the pulmonary capillary (meaning they are perfusion limited)... thus perfusion determines the rate that the gases equilibrate if perfusion is poor, O2 and CO2 equilibrate slowly or not at all severe perfusion defect= PE (block in blood flow) thus this patient has very poor alveolar perfusion (evident by the failure of alveolar gas to equilibrate)

Answer 168

in situations like: emphysema pulmonary fibrosis exercise (high pulm rate of blood flow) CO2 diffuses easier than O2 and is not affected the same way

Answer 169

older patients who are incidentally found with pleural thickening calcification of the posterolateral midlung zones and diaphragm calcified lesions= pleural plaques= hallmark of asbestos exposure (typically affect the parietal pleura betwen the 6th and 9th ribs) benign pleural effusions can also occur there is a 20-30 year latency between asbestos exposure and onset of symptoms (thus most patients are asymptomatic) some patients develop full blown asbestosis (slowly progressive diffuse pulm fibrosis and interstitial lung disease which affects the lower pulm zones and is seen on xray as linear interstitial densities)

Answer 170

``` resembles sarcoidosis due to nodular infiltrates large lymph nodes non caseating granulomas ```

Answer 171

on xray it looks like multiple discrete nodules (1-4mm) prominent in the upper lung zones

Answer 172

NO2 is a toxic byproduct of combustion at risk are firefighters welders farm silo workers present looking like asthma or COPD imaging shows pulmonary edema

Answer 173

it is due to inhalation of organic dust results in diffuse nodular interstitial infiltrates

Answer 174

looks like nodular densities and | eggshell calcifications of the hilar nodes

Answer 175

pneumonia due to mycoplasma pneumoniae low grade fever malaise chronic dry nagging cough CXR appears much worse than clinical appearance mycoplasma pneumoniae require cholesterol to grow because their cell membrane is a single cholesterol rich lipid phospholipid bilayer no cell wall, envelope, or capsule seen in military recruits young adults college dorms

Answer 176

both are fungi, grow on standard fungal culture media, and cause a similar illness BUT coccidioides immitis= causes San Joaquin Valley fever ("valley fever") histoplasma capsulatum= localized to the Mississippi and Ohio River Valleys

Answer 177

an intracellular parasite that causes Q-fever (a pneumonia like illness from inhaling the spores that contaminate animal hides) must be provided a cell culture to grow

Answer 178

a bacteria that requires special medium to grow chocolate agar (heat lysed blood agar) supplemented with factor 10 (hematin) and factor 5 (NAD+)

Answer 179

a bacteria classically seen in an alcoholic coughing up red jelly like sputum ("currant jelly sputum") it can be grown on standard agar but MacConkey is preferred because it contains bile which will inhibit the growth of contaminant organisms

Answer 180

bacteria requires L-cysteine supplemented agar to grow

Answer 181

bacteria that causes lobar consolidation on CXR organism can grow well on standard unenriched blood agar but its bile soluble (so not MacConkey) and it cannot grow with optochin around (optochin sensitive)

Answer 182

caused by staph species that produce the exofoliatin exotoxin (exotoxin mediated skin damage) ``` Nikolsky's sign= skin slipping off with gentle pressure epidermal necrolysis fever pain skin rash ``` most common in infants and young children (not fatal unless it becomes secondarily infected) the exfoliative toxins blister only the superficial epidermis ("epidermolytic")... aka it doesnt scar they act as proteases and cleave desmoglein in desmosomes bullous impetigo is a more localized form of SSSS with bulla formation being another effect of exofoliative toxin

Answer 183

endotoxin mediated inflammatory response during gram negative and some gram positive (listeria) infections the LPS fragment "lipid A" is gram negative bacteria component of the cell membrane and is not commonly secreted from the cell the way exotoxins are

Answer 184

cell mediated hypersensitivity mediated by sensitized TH1 cells that secrete cytokines which attract macrophages to the area this is the mechanism of contact dermatitis and positive skin tests for TB (PPD) and for anergy (candida antigen)

Answer 185

adenovirus infection is self limiting, common, and caused by direct contact/fecal oral/or resp droplets its a double stranded DNA genome adenovirus infection occurs year round and has outbreaks in crowded quarters (day cares, camps, and military barracks) upper respiratory involvement is most common (pharyngoconjunctival fever- acute fever, cough, congestion, pharyngitis, and conjunctivitis) oropharynx is red with bilateral follicular conjunctival injection and serous discharge a small percentage of patients get pneumonia (aka focal crackles)

Answer 186

coxsackievirus it causes painful vesicles in the oropharynx, on the palms, fingers, and soles of the feet it can also cause herpangina (fever, posterior pharyngeal vesicles,and no rash)

Answer 187

``` influenza virus causes acute high fever cough muscle aches malaise peak incidence in the winter ``` ``` complications in kids febrile seizures vomiting acute otitis media pneumonia ```

Answer 188

rapid onset self limiting gastroenteritis in outbreak settings (restaurants, day care, cruise ships) ``` norovirus causes vomiting diarrhea fever headache malaise ```

Answer 189

erythema infectiosum (fifth disease) in school age children fever malaise classic "slapped cheek" rash parvovirus B19 can precipitate bone marrow failure and aplastic anemia (it inhibits reticulocyte formation)... it can also cause non immune hydrops fetalis

Answer 190

lower respiratory tract disease (broncholitis and pneumonia) in infants older kids and adults can get this resp infection and outbreaks do occur in close quarters... BUT RSV is a seasonal virus that peaks in winter

Answer 191

salmonella osteomyelitis (common cause of osteomyelitis in patients with SCD only)... sickling leads to necrosis with transient mucosal breakdown and bacterial seeding in patients with SCD who may have undiagnosed or subclinical salmonella infection.... the vasoocclusive crises causes areas of bone to necrosis within which bacteria can infect vasoocclusion of SCD causes a relative immunodeficiency as the spleen suffers widespread infarction (functional asplenia) putting the patient at risk for infection by encapsulated organisms ``` (aka strep pneumo neisseria haemophilus salmonella) ``` salmonella has a special capsule called "virulence antigen" that protects it from opsonization and phagocytosis summary- SCD patients have functional asplenia from multiple infarctions of the spleen so theyre prone to infection by encapsulated organisms like salmonella. staph aureus (nonmotile and lactose fermenting) and salmonella are common causes of osteomyelitis in patients with SCD and abx coverage should be directed against both types of bacteria

Answer 192

adhesion to collagen staph aureus is non motile and can ferment lactose and mannitol

Answer 193

yes (they both produce toxins) but ecoli is lactose fermenting and shigella is non motile some salmonella produce an exotoxin that may contribute to typhoid fever (not osteomyelitis)

Answer 194

yes, particularly in IV drug users pseudomonas produces a blue green pyocyanin pigment which has toxic effects on nearby molecules it is oxidase positive gram neg rod

Answer 195

``` minors can consent to emergency care STD treatment substance abuse treatment pregnancy care contraception ``` emancipated minor when they're (homeless, a parent, married, in the military, financially independent, and a high school graduate)

Answer 196

HMO= health maintenance organization PPO= preferred provider organization

Answer 197

1. full eval of the child (including permission to interview the patient alone) 2. contact CPS

Answer 198

contact their supervisor and report the problem now (important to report in a timely manner) in a non emergent situation you can contact the hospital committee (physician health program) if thats not possible or doesnt exist you contact the state licensing board

Answer 199

a quality improvement measure used to identify what, how, and why a preventable adverse outcome occurred the first step is to collect data on what caused the outcome (usually through interviewing multiple people involved in the steps leading up to the outcome)

Answer 200

suspected abuse (child or elder... spouse abuse depends on state) knife of gunshot wounds diagnosing a reportable communicable disease threats to self harm or harm to others (with reasonable ability to carry out that threat in the near future)

Answer 201

when the patient is incapacitated or is not present you can share basic info if its in the patient's best interest like telling a distraught wife that the patient is stable but any further information will need permission

Answer 202

always unethical may be acceptable on a case by case bases with former patients (non psychiatric) if the physician patient relationship is terminated well beforehand but usually just no

Answer 203

requiring "dual identifiers" usually a nurse and physician to independently confirm the patient, the site, and the procedure

Answer 204

direct= do not pass through the inguinal canal and are medial to the inferior epigastric (through the weakness of the abdominal wall- aka hesselback triangle) indirect= passes through the deep inguinal ring and canal and begin lateral to the inferior epigastric. They are covered by internal spermatic fascia. (indirect inguinal hernias are common in children.... hydroceles and indirect inguinal hernias both present as an asymptomatic scrotal mass that increases in size during valsalva maneuvers)

Answer 205

during descent of the testes during early gestation, they bring down with them an envaginaiton of the peritoneum called the process vaginalis which then obliterates after the descent is complete if the processes vaginalis fails to obliterate there is a persistent connection between the scrotum and the peritoneal cavity through the inguinal canal if the opening is small and only fluid gets through they get a communicating hydrocele (dx= transillumination of the scrotum or a scrotal US) if the opening is large then abdominal organs can pass into the space and cause an indirect hernia (indirect because they go through the inguinal canal just like the normal descent of the testes)

Answer 206

acute epiglottitis most likely caused by H influenza but this is uncommon due to the Hib vaccine given in early childhoood (first few months of life) thus you would suspect this child missed a vaccination or was not vaccinated at all acute epiglottits in a child= fever, trouble swallowing... adult= sore throat (+ inspiratory stridor and drooling) if youre going to look at the epiglottis be prepared to provide a surgical airway via tracheostomy H.flu causes: epiglottitis meningitis sepsis

Answer 207

malaria= Africa HIV= Africa and Haiti coccidioides immitis= southwest USA blastomycosis= Mississippi river valley histoplasmosis= Ohio river valley

Answer 208

``` ranges from: rash hives angioedema bronchospasm anaphylaxis ```

Answer 209

postpartum hemorrhage frequently caused by a failure of the uterus to contract and compress the placental site of blood vessels risks= prolonged labor and twins (because they lead to uterine atony- loss of uterine tone- which is described as a boggy uterus) tx= uterine massage and uterotonic medications... if that fails to control bleeding then you go to surgery to ligate (suture) both the internal iliac arteries (the uterine artery comes off these) dont worry though you dont need a hysterectomy because there is plenty of collateral blood flow via the ovarian arteries is sufficient to maintain uterine function (collaterals run through the infundibulopelvic ligament aka the suspensory ligament)

Answer 210

1. proliferative phase = the hepatocyte expresses the viral HBsAg and HBcAg along with expressing MHC I to T cells. T cells then destroy the infected hepatocytes (mechanism of liver injury in Hep B is T cell mediated, the virus itself is not cytotoxic) 2. integrative phase = when Hep B virus incorporates its DNA into the host genome (in the liver cells that survived the T cells).... infectivity stops when liver damage tapers off, the ab's appear, and replication of the virus stops (but because the Hep B DNA is in the host genome there is still risk for hepatocellular carcinoma) ``` ab-ag complexes cause the symptoms and complications of Hep B BUT NOT the liver damage (ex= joint pain arthritis hives immune complex glomerulonephritis cryoglobulinemia vasculitis) ```

Answer 211

Ag mimicry with generation of self-Ag recognizing helper T cells that cause damage to hepatocytes

Answer 212

SCD (aka Hb S anemia aka E6V) = where valine replaces glutamate at the 6 position on beta globin chain) the result is that part of the beta globin chain fits into a site on the alpha globin chain of another hemoglobin (promotes aggregation when oxygen isnt around to bind those Hb sites)... but remember its the tetramer of globin chains that fold not only the beta globin Sickling= initial gel then into a meshwork of fibrous polymers which causes the sickle shape sickling occurs when= low oxygen [oxygen unloading... organs where blood moves slowly have lower oxygen and acidity= spleen and liver] low acidity low blood volume [dehydration] sickling occludes microvasculature and causes microinfarcts and cause painful vasoocclusive crises organs with high metabolic demands (like brain, muscles, placenta) promote sickling by extracting more oxygen from blood fetal Hb seems to be protective of sickling

Answer 213

binds the two beta globin chains and stabilizes the Taut (T) deoxyhemoglobin this decreases oxygen affinity and shifts the curve left high levels would precipitate oxygen unloading from Hb and thus sickling in SCD patients

Answer 214

Pasteurella multocida infection usually within 24 hours characteristic mouse like odor (= indole positive species) tx= amoxicillin-clavulanate (clav= beta lactamase inhibitor)

Answer 215

cat= pasteurella (most common) bartonella (lymphangitis in immunosuppr) ``` dog= pasteurella streptococci staph aureus capnocytophaga canimorsus ``` human= anaerobes streptococci eikenella corrodens (clenched fist injury "fight bite")

Answer 216

bartonella henselae self limiting LAD

Answer 217

campy= GI (diarrhea) proteus= UTI

Answer 218

clostr perfringens= causes necrotizing skin and soft tissue infections s/p trauma leading to myonecrosis and gas gangrene erysipelothrix= causes erysipeloid (bacterial skin infection)

Answer 219

coxiella= Q fever (mild pnu) fusobacterium= part of oral flora causing aspiration pneumonia or pharyngitis (complication= lemierre's disease= infectious thrombophlebitis of the internal jugular vein)

Answer 220

tularensis= tularemia a zoonotic infection from lagomorphs (prey- type animals) and rodents variable presentation from ulcerative disease at inovulation site to severe febrile pulmonary infection

Answer 221

genetic reassortment in this case the patient was infected with an orthomyxovirus (aka influenza) which is a respiratory virus affecting humans, birds, pigs, and other species virulence factors for infectivity= hemagglutinin (HA) and neuraminidase (NA) the immune system can target those virulence factors so influenza has constant selective pressures to maintaine virulence and evade immune recognition orthomyxoviruses have a segmented genome with HA and NA on different RNA segments allowing for genetic reassortment (this is adventitious to the virus and can lead to a novel strain of the virus which can infect human to human in this case, especially since the novel stain has no resistance to it yet) this is known as antigenic SHIFT (not drift) reassortment of the RNA segments is what causes influenza epidemics and pandemics (pan= entire= global epidemic in a way)

Answer 222

point mutations in genes that only slightly alter the protein products but allow the proteins to evade immune recognition this may increase the infectivity of the virus changing the species to species transmission needs a major modification though such as reassortment

Answer 223

when two different stains of a mutant organism can produce a wild type offspring typicall both parents are homozygous for mutations in different genes with the same metabolic pathway when the are crossed, the offsprin inherits 1 normal allele from each parent allowing them to bypass both the metabolic blockades and display the wild type phenotype

Answer 224

when 2 viruses infect the same cell the progeny then exhibits a coat or envelope protein not coded for by the genetic material packed within them the subsquent progeny only express the proteins in their genome if a virus changes species and is SUSTAINED, that would NOT be an example of phenotypic mxing

Answer 225

the HIV cDNA genome is a provirus once it has been integrated into the host cell genome

Answer 226

Zidovudine= AZT = a nucleoside reverse transcriptase inhibitor used to treat HIV AZT competitively binds RT and is incorporated into the viral genome [mediated by integrase] as a thymidine analog (the azido group replaces what would have been a hydroxyl group and prevents DNA chain elongation) thus preventing 3' to 5' phosphodiester bond formation

Answer 227

Thrombotic thrombocytopenia purpura due to decreased ADAMTS13 level (which leads to uncleaved vWF multimers which causes platelet trapping and activation) hereditary or acquired(via auto antibody) causes: hemolytic anemia (increased lactate [anerobic metabolism], decreased haptoglobin [clears free Hgb]) with schistocytes thrombocytopenia +/- renal failure, neurologic symptoms, and fever tx= plasma exchange, steroids, rituximab [for cancer and autoimmune disease] mortality= 90%

Answer 228

``` Hemolysis Elevated Liver enzymes Low Platelets ```

Answer 229

``` endometrial carcinoma endometrial hyperplasia (unopposed estrogen since LH>>FSH) ``` PCOS results from increased activity of 17 alpha hydroxylase; 17,20 lyase; and 3 beta hydroxysteroid dehydrogenase (overexpression of these leads to androgen side effects) the excess androgens prevent the development of a monthly dominant follicle and thus anovulatory cycles the oligomenorrhea results in decreased progesterone and unopposed estrogen PCOS is also a risk factor for DM2 due to the increased insulin resistance

Answer 230

cushings also has HTN, abdominal striae, and supraclavicular fat pads due to excess cortisol

Answer 231

vaginal adenosis= persistence of glandular columnar epithelium in the vagina precursor for clear cell adenocarcinoma of the vagina increased risk to female offspring of mothers who were exposed to DES (diethylstilbestrol) while pregnant presents with vag dx or vag cysts

Answer 232

because the ovaries are no longer producing estrogen which is the normal negative feedback for FSH

Answer 233

(Non Nucleoside Reverse Transcriptase Inhbitors) nevirapine efavirenz these prevent the synthesis of DNA from viral RNA template NNRTIs do NOT require activation via intracellular phosphorylation ADRs: flu like symptoms abd pain jaundice fever or HEPATIC FAILURE (usually in the first 6 weeks) or life threatening skin reactions (like SJS/TEN)

Answer 234

zidovudine and emtricitabine nucleoside RT inhibitors must be converted to their monophosphate forms by a cellular kinase (cellular thymidine kinase) becore becoming the active triphosphate form

Answer 235

enfuvirtide= HIV fusion inhibitor (binds the the HIV envelope gp140 and blocks conformational change needed for fusion) site of action is outside the cytoplasm ritonavir= HIV protease inhibitor that prevents maturation of the virus *the virions made instead are non functional and non infective

Answer 236

1. inflammation fibrin clot, release of cytokines that call in neutrophils and macrophages 2. proliferation phase fibroblast proliferation, neovascularization 3. maturation scar formation in normal healing fibroblasts are recruited via PDGF (platelet derived growth factor) and TGF beta (transforming growth factor beta) TGF beta stimulates connective tissue synthesis and remodeling of extracellular matrix in hypertrophic or disfiguring scars (the normally decreased TGF beta in the maturation phase is persistantly elevated and leads to hypertrophic scar (increased TGF beta receptor expression) summary: TGF beta contributes to wound healing and scar formation

Answer 237

anti- viral cytokine decreases WBC movement across the blood brain barrier analogs for INF beta can be used to treat MS

Answer 238

Th 17 helper cells make IL 17 to invite neutrophils and make anti-microbial peptides specifically useful against fungi and bacteria at epithelial and mucosal surfaces dysregulation of IL17 has been implicated in many autoimmune conditions

Answer 239

its a pro inflammatory transcription factor that regulates cytokine production, adhesion molecule expression, and cell survival increased NF kappa B is found in many cancers and inflammatory diseases [like RA and IBD]

Answer 240

tumor necrosis factor alpha is proinflammatory it is secreted by macrophages and T cells to invite other WBCs around it increases inflammatory response [fever, acute phase proteins] and regulates apoptosis

Answer 241

increase fibroblast activity!

Answer 242

true (it doesnt) reduced parenchymal compliance is the hallmark of pulmonary fibrosis (=reduction in the slop of the lung pressure volume curve)

Answer 243

stasis= venous dilation and compression of IVC and iliac veins from the uterus/baby hypercoag= increases in F7, F8, F10, vWF, and fibrinogen (to protect from hemorrhage during miscarriage or childbirth) endothelial damage=due to unterine infection or intrapartum vascular trama

Answer 244

its a septic pelvic thrombophlebitis often a complication of vaginal deliver or c-section present a week after delivery with persistent fever after delivery, localized abdominal pain, and no response to abx (presumed uterine infection) dx= CT or MRI ovarian venous drainage is asymmetric the left ovarian vein drains into the left renal vein the right ovarian vein drains directly into the IVC (OVT is more commonly right sided but the mortality/morbidity of a PE is low)

Answer 245

the roughly 6 weeks after child birth where a womans organs return to their non pregnant condition

Answer 246

distinguished by calcification of the rim of hilar noes ("eggshell calcifications") and birefringent silica particles surrounded by fibrous tissue (=histo) silicosis has long been associated with increased risk of TB (because silicosis impairs macrophage function [and also increases macrophage apoptosis] which are needed to control the infection) although silicosis does cause interstitial fibrosis, fibrosis alone does not greatly predispose to TB (scarred lung tissue would actually be less susceptible)

Answer 247

centriacinar emphysema= dilated airspaces exertional SOB heavy smoking hx pathogenesis= 1. oxidative injury to bronchioles 2. activated macrophages from the smoke 3. macrophages recruit neurophils 4. neutrophils release proteases to degrade extracellular matrix and generate ROS to impair any protease inhibitors around (ex- antitrypsin) acinar wall destruction and irreversible airspace dilation seen in emphysema is the result of protease-antiproteast imbalance A1AT def= panacinar emphysema acinar wall damage seen in emphysema also kill type 1 pneumocytes (95% of the inner epithelial lining of the alveolli) remember that type 2 pneumocytes= surfactant and stem cells

Answer 248

formerly called clara cells theyre secretory cells in the lungs that secrete surfactant components and help detoxify inhaled substances

Answer 249

cause cell death through two mechanisms 1. DNA double strand breakage 2. free radical formation (ROS) affects rapidly dividing cells most (aka cancer cells but also the gut mucosa and skin)

Answer 250

chloramphenicol was used to treat the patient's bacterial meningitis (fever, HA, confusion) chloramphenicol inhibits the 50S ribosomal subunit ``` ADRs= dose related anemia leukopenia thrombocytopenia (reversible upon stopping med) dose independent irreversible (idiosyncratic) aplatic anemia (severe and fatal without treatment which would be a bone marrow transplant) ```

Answer 251

clinda= c diff pseudomembranous colitis genta= (an aminoglycoside) causes vestibular and cochlear ototoxicity, nephrotoxicity, and neuromuscular paralysis metro= GI and neuro.... disulfiram like reaction when taken with alcohol vanco= red man syndrome (histamine release and flushing)... also causes dose related nephrotoxicity and ototoxicity

Answer 252

in normal T cells, calcineurin is a protein phosphatase that gets activated calcineurin then dephosphorylates NFAT (Nuclear Factor of Activated T cells) after dephosph, NFAT goes to the nucleus to bind an IL-2 promoter the IL2 promoter triggers growth and differentiation of T cells needed for proper immune response drugs that target calcineurin (and prevent T cell maturation) = cyclosporine and tacolimus

Answer 253

Bcl-2 = apoptosis inhibitor that gets over expressed in cancer cells (implicated in follicular cell lymphoma- t(14;18) translocation) E cadherin = facilitates epithelial cell adhesion (loss of this is associated with metastasis) neurofibromin= tumor suppressor protein encoded by NF1 gene on chr 17. It suppresses Ras and protects against cancer (remember that Ras activates cell growth and proliferation and needs to be suppressed) p53= tumor supressor (ineffective in majority of cancers)

Answer 254

helicase= unwind and separate the DNA topoisomerase 2 (DNA gyrase)= relieves supercoil tension DNA pol 3= elongation of the strand (requires an RNA primer)... can also proofread (3' to 5' exonuclease) primase= synthesizes the RNA primer for DNA pol 3 to elongate (this is a DNA dep RNA pol) ligase= seals the okazaki fragments on the lagging strand DNA pol 1= removes the RNA primers and replaces them with DNA (this is the ONLY bacterial DNA pol with 5' to 3' exonuclease activity)

Answer 255

treats MRSA works by disrupting the bacterial membrane [and membrane potential] and creating transmembrane channels that cause intracellular ion leakage leads to cell death (only for gram +) inactivated by pulmonary surfactant ADRs= muscle pain and elevated creatine phosphokinase (CPK)

Answer 256

contact dermatitis granulomatous inflammation TB skin test candida extract skin reaction these are type 4= T cell mediated responses Ag is taken up by dendritic cells, presented to helper cells on MHC II (which usually stimulates Th1 cell differentiation which will then release INF gamma to invite macrophages to wall off infections)

Answer 257

predominance of neutrophils (aka acute infection) neutrophil numbers can be falsely elevated in a patient with recent steroid use

Answer 258

a semi-synthetic derivative of a plant alkaloid (podophyllotoxin) that targets topoisomerase 2 (**chemo drug**) remember that topoisom 1 makes single stranded nicks to relieve supercoiling but topoisom 2 induces transient breaks in both DNA strands simultaneously to releave supercoiling etoposide and podophyllin inhibit topoisomerase 2's ability to seal the breaks it make (leads to cell death) etoposide is used to treat testicular cancer and small cell lung cancer podophyllin is used to treat genital warts

Answer 259

chemo drugs that interfere with nucleotide metabolism (inhibiting elongation of DNA) ex= 5- fluorouracil and 5-deoxyuridine are antimetabolites that inhibit thymidylate synthase (enzyme needed to make thymidine) methotrexate is an antimetabolit that inhibits DHFR (enzyme needed to make thymidine)

Answer 260

T cells Th1 cells that release INF gamma to recruit macrophages

Answer 261

its a chemo drug that targets topoisomerase 2 (causes double strand nicks) and prevents topo 2 from sealing the nicks it made which results in chromosomal breaks that accumulate in dividing cells and lead to cell death

Answer 262

tazobactam decreases destruction of piperacillin abx are given in cholecystitis to prevent secondary infection with e.coli and klebsiella due to biliary stasis (esp DM or immunosuppr patients) tazobactam is a beta lactamase inhibitor it is added to piperacillin to help avoid destruction by beta lactamases (resulting in an increased antimicrobial spectrum of activity) ``` beta lactamase inhibitors= tazobactam clavulanate sulbactam (these by themselves have no antimicrobial activity) ``` drugs like the 3rd gen cephalosporins are beta lactamase resistant and are essentially two drugs in one

Answer 263

tazobactam clavulanate sulbactam

Answer 264

anaerobes: above the diaphragm= clindamycin below the diaphragm= metronidazole

Answer 265

enhanced ability to penetrate bacteria penicillins inhibit cell wall synthesis which allows aminoglycosides to access the cell interior where then inhibit 30S

Answer 266

1. MAP kinase = increases proliferation (mutation causes uncontrolled growth/cancer) 2. PI3K(phosphoinositide 3 kinase)/Akt(protein kinase B)/mTOR(mammalian target of rapamycin) = important for increasing cell proliferation... mTOR goes to the nucleus to induce gene transcription... mTOR is inhibited by PTEN (cancers usually have increased PI3K/Akt or loss of PTEN) 3. Inositol phospholipid = Gq increases phospholipase C which increases cytoplasmic calcium levels through an IP3 mediated calcium efflux from the ER 4. cAMP = Gs increases adenlate cyclase and increases cAMP levels 5. JAK/STAT = (most cytokine receptors)... intracellular tyrosine kinase JAK activates STAT (signal transducer and activator of transcription) which dimerize and go to the nucleus to influence transcription

Answer 267

it is a PDE inhibitor that prevents degredation of cGMP into GMP thus cGMP's effects will be enhanced and prolonged (cGMP will vasodilate... specifically here will vasodilate the corpus cavernosum bu inhibiting PDE5)

Answer 268

cryptococcus neoformans (opportunistic pathogen) its found in soil and pigeon droppings (and gets inhaled) healthy people clear the bug with macrophages and T cells BUT in immunosuppressed patients it causes meningoencephalitis cryptococcal meningoencephalitis seen in patients with HIV, sarcoidosis, leukemia, or high dose steroid regimen dx= stain the CSF with india ink and you'll see red budding yeast with peripheral clearings (or "halos") due to the lack of polysacc capsules you can also do serologic testing to detect the Ag lung infection is usually caused first by this infection but is asymptomatic (the meningoencephalitis will be symptomatic)

Answer 269

candida presents with pain with swallowing

Answer 270

mucormycosis (strongly associated with DM) and also aspergillosis fumigatus

Answer 271

they irreversibly bind the PBPs (an example of PBPs= transpeptidases) ceftriaxone inhibits the transpeptidases

Answer 272

on gram negative bacteria they can be used to develop anx resistance (by preventing abx diffusion through the outer membrane)

Answer 273

via structural changes in PBPs (change in protein structure) that prevent ceftriaxone from binding [five PBPs identified and the resistance is why now there is only two bands on electrophoresis) you can also get resistance via beta lactamases but that would prevent binding to the PBPs in the first place and unbound ceftriaxone would likely accumulate on the electrodes and no bands would be seen on electrophoresis

Answer 274

transmembrane efflux pumps

Answer 275

the lipid A septic shock= release of endotoxins into the bloodstream endotoxins are found on the outer membrane of gram negative bacteria which is composed of LPS LPS is made of the O antigen, the core polysaccharide, and lipid A Lipid A is the toxic portion! (activates shock by activation of macrophages and granulocytes which increases pyrogens IL1/prostaglandins/inflammatory mediators- [TNF alpha and interferon])... IL1= causes fever by acting on the hypothalamus cytokines= hypotension, increased vasc permeability with third spacing of fluids, diarrhea, DIC, and death LPS is NOT actively secreted by bacteria (it is released during division or bacteriolysis) signs and symptoms of septic shock= IL1 and TNF alpha from macrophages

Answer 276

latent TB (fatigue, positive TB skin test)... bone marrow aspirate shows sideroblastic anemia due to isoniazid use complication= sideroblasic anemia (ring sideroblasts) dx via bone marrow exam with prussian blue stain isoniazid directly inhibits pyridine phosphokinase pyridoxine (B6)-----(pyridine phosphokinase)---> pyridoxal 5' phosphate pyridoxal 5' phosphate is a cofactor for delta aminolevulinic acid (ALA) synthase (the rate limiting step in heme synthesis) thus decreased activity of delta AMINOLEVULINATE SYNTHASE (ALA synthase) explains the sideroblastic anemia thus you prescribe pyridoxine with isoniazid to avoid this

Answer 277

1. x linked sideroblastic anemia (due to delta aminolevulinate synthase mutation) 2. myelodysplastic syndrome 3. alcohol abuse 4. copper deficiency 5. medications (isoniazid, chloramphenicol, linezolid)

Answer 278

delta aminolevulinate DEHYDRATASE

Answer 279

homocysteinuria AR marganoid body habitus and hypercoagulability cystathionine-----(cystathionine synthase + pyridoxine)-------> homocysteine

Answer 280

nomocytic normochromic anemia increased reticulocyte count decreased haptoglobin (which binds free Hb)

Answer 281

AR hemolytic anemia normocytic normochromic anemia increased reticulocytes elevated indirect unconj bilirubin

Answer 282

isoniazid inhibits pyridoxine phosphokinase leading to pyridoxine (B6) deficiency pyridoxine's active form is the cofactor for delta ALA synthase (the enzyme that catalyzes the rate limiting step of heme synthesis) inhibition of this step leads to sideroblastic anemia

Answer 283

acid fast stain is used to detect mycobacterium and some nocardia species 1. smear treated with aniline dye (carbolfuchsin) 2. dye (red) penetrates bacterial cell wall where it binds mycolic acids* 3. slide treated with hydrochloric acid and alcohol 4. acid alcohol dissolves the outer membrane of non TB bacteria (mycolic acid prevents the decolorization of mycobacteria) 5. counterstain with methylene blue thus the mycobacteria is red and the non acid fast bacteria is blue mycolic acid= waxy long chain fatty acid with sugars within the cell wall

Answer 284

ergosterol (the sterol component of fungal cell membranes) humans have cholesterol in their cell membranes instead

Answer 285

skin infections PSGN ARF catalase neg beta hemolytic gram pos cocci ``` bacitracin sensitive PYRROLIDONYL ARYLAMIDASE (PYR) test POSITIVE ```

Answer 286

risk factors = maternal viral load and HBeAg positive [>90% chance of infection when mom has HBeAg... progression to chronic hep B without tx is 90%] Clinical findings (of baby) = infants immune tolerant (really no obvious symptoms... they dont have enough T cells to cause liver damage yet), high risk for chronic infection, high viral load and *HBeAg positive*[immature immune system] prevention= maternal antiviral therapy, newborn hepB vaccine* and immunoglobulin* within 12 hours, routine immunization, serology roughly 3 m after 3rd dose of vaccine mother to child transmission most commonly occurs during delivery (transplacental is more rare) complications = cirrhosis and hepatocellular carcinoma hepatic injury from hep B is due to T cells absence of HBsAg [appears within a few days of infection] and anti-HBs by 2 m old means the infant was not infected

Answer 287

AR dx via hgb electrophoresis (you'll see Hb S) read the question carefully.... the child had a 75% chance of receiving one or more mutant allele

Answer 288

Diffuse injury to alveolar epithelium and pulmonary microvascular endothelium which results in leaky capillaries and causes significant edema pancreatitis is a major risk factor for ARDS because it releases a ton of inflammatory cytokines and pancreatic enzymes into circulation (and thus neutrophils infiltrate the pulmonary interstitium and alveolar spaces causing injury) ARDS= progressive hypoxemia with no improvement on oxygen diffuse intersitial edema no cardiac cause lines the alveoli with waxy hyaline membranes made of fibrin, protein remnants, and necrotic epithelial cells

Answer 289

protects from meningitis (also bacteremia, pnu, and epiglottitis) haemophilus influenzae= gram neg coccobacillus encapsulated (serotypes a-f) or not (non typeable) type B is the most invasive strain due to its polyribosylribitol phosphate (PRP) capsule which inhibits complement mediated phagocytosis vaccine= PRP conjugated with a toxid (like tetanus or diptheria) to activate T cells to activate B cells (and ab's)

Answer 290

African type Burkitt lymphoma causes a jaw tumor EBV immortalizes lymphoma cells and looks like a "stary sky" on histology due to the presence of macrophages and apoptotic bodies in a sea of medium sized lymphocytes 90%+ of burkitt lymphoma is associated with c-Myc oncogene overexpression = tumor growth (the translocation is the c-Myc gene on chr 8 onto the Ig heavy chain region of chr 14... aka t(8;14) burkitts lymphoma is high grade and is very aggressive. good prognosis to short term intense high dose chemo

Answer 291

follicular lymphoma over expression of the anti-apoptotic BCL2 causes generalized LAD

Answer 292

found in CML (chronic myelogenous leukemia) and some forms of ALL (acute lymphoblastic leukemia) translation causes increased tyrosine kinase activity

Answer 293

neuroblastoma

Answer 294

X linked recessive easy bruising excessive bleeding (tooth extraction) deficiency in F8 can be caused by a variety of mutations in the F8 gene (including deletions in the enhancer sequence... **enhancer sequences (and thus this mutation) can be located upstream, down stream, or within introns of the gene) enhancer sequences bind activater proteins that facilitated DNA bending to allow proteins to interact with transcription factors which increase the rate of transcription. silencers can also be upstream, downstream, or within a transcribed gene these both affect rate of transcription

Answer 295

1. TATA (hogness) box (25 bases upstream from the gene being transcribed) 2. CAAT box (70-80 bases upstream from the gene)

Answer 296

its an IV anesthetic it induces and or maintains anesthesia it decreases blood pressure, reduces ICP, has a low incidence of post op nausea and vomiting, and it increases GABA (A) it is highly lipophilic... it gets delivered to well vascularized areas first (brain, liver, kidneys, lungs) and over time redistributes to the poorly vascularized areas (skeletal muscle, fat, bone) which has the highest volume of distribution for lipophilic agents because the drug is highly lipophilic, it redistributes rapidly and thus has a short duration of action

Answer 297

an arrangement in which payer (usually an employer) pays a fixed predetermined fee to cover all medical services required by a patient capitation is the payment structure underlying an HMO (health maintenance organization) the provider can reduce expenses capitation payments are made to a private insurance company who negotiates networks of care providers or large physician groups can contract directly with employers providers are paid a lump sum regardless of how many services the empolyees use

Answer 298

where the insurer pays one price to cover all the expenses associated with a specific type of care typically used to cover surgeries and includes pre op and post op visits

Answer 299

a primary care model where a personal physician coordinates care and sees the patient through all aspects of care

Answer 300

requires patients to have a primary care provider needs referrals for specialty consultations unlike an HMO, patients can see providers outside of network but its at a higher copay/deductible

Answer 301

1. on serosal surface (subserosal) = more often cause *irregular uterine enlargement* because theyre confined by uterine tissue and can put pressure on adjacent organs causing pelvic pressure, constipation [relieved with manual deflection of the obstruction], urinary urgency or incomplete emptying 2. within the uterine wall (intramural) = may cause repro difficulty 3. below the endometrium (submucosal) = may cause repro difficulty and submucosal specifically causes prolonged heavy periods a posterior vaginal wall prolapse (rectocele) would not explain a large uterus advanced cervical cancer can cause constipation and pelvic pressure but is less likely without abnormal bleeding, visible lesion, or HPV infection hx

Answer 302

high waist circumference (visceral fat measure is strongly associated with insulin resistance)... esp useful for patients in the BMI range 25-35 the patient likely has DM2 (= defective insulin secretion and insulin resistance) causes of insulin resistance 1. genetics (mut to insulin receptor or the post receptor) 2. environmental (sedentary life, obesity) waist circ >40 in men >35 in women this measurement is associated with higher risk of insulin resistance, DM, and CAD lipid profile in insulin resistance is high TG and low HDL (not an increase in LDL) seeing ketones in the urine means an absolute insulin def (aka DM1)... DM2's high insulin supresses ketone formation

Answer 303

``` young african american cough SOB bilat hilar LAD biopsy showing non caseating granuomas that stain neg for fungi and acid fast bacilli high calcium (from high vit D) high ACE ``` +/- skin lesions, uveitis, lofgren syndrem [acute sarcoidosis presenting with rash, bilat hilar LAD, and joint pain] sarcoidosis= macrophages accumulate and form non caseating granulomas in different dissues (mostly the lungs>skin>eyes) distinguishing sarcoidosis from other interstitial lung diseases is done by quantifying the T cell 4:8 ratio this is because in sarcoidosis CD4+ cells are what accumulates (4:8 ratio >2:1 from bronchoalveolar lavage fluid) hypersensitivity pneumonitis (which was first guessed because she was a bird handler) would not explain the high calcium or ACE... it would also be CD8+ dominant

Answer 304

CD 19 CD 20 CD 22 (seen in a precursor B cell lyphoblastic leukemia which can involve the pleura)

Answer 305

increase glucose uptake increase glycogen synthesis increase protein synthesis increases renal absorption of sodium decrease glycogen breakdown decrease glucagon secretion decrease fat breakdown decrease ketone production DKA = insulin def + excess counter reg hormones (glucagon, cortisol, GH)

Answer 306

pheochromocytoma= headache, palp, sweating clinically= HTN, urinary excretion of catecholamines and metanephrines, adrenal mass can be associated with MEN2 (mult endocrine neoplasia type 2)- germline mut in the RET protooncogene 1. pheo 2. medullary thyroid ca (parafollicular c cells) 3. parathyroid hyperplasia (MEN2A) or oral neuroma and marfanoid body (MEN2B) pheo comes from neural crest (and so does thyroid parafollicular c cells and chromaffin cells of the adrenal medulla) mneumonic for what structures come from neural crest = MOTEL PASS ``` M=melanocytes O=odontoblasts T=tracheal cartilage E=enterochromaffin cells L= laryngeal cartilage ``` P=parafollicular cells of the thyroid A=adrenal medulla and all ganglia S= schwann cells S= spiral membrane

Answer 307

``` M=melanocytes O=odontoblasts (tooth dentin) T=tracheal cartilage E=enterochromaffin cells L=laryngeal cartilage ``` P=parafollicular cells of thyroid A= adrenal medulla and all ganglia S= schwann cells (peripheral myelin) S=spiral membrane (aorticopulm septum)

Answer 308

(look up a gross picture) most commonly caused by the tapeworm (echinococcus granulosis= unilocular lesion; echinococcus multilocularis=multilocular) endemic to the Mediterranean, Middle east, south america, Africa, former soviet union, and china... can be seen in the southwest US if they have a sheep and dog (tapeworm life cycle) affects liver>>>lungs>muscles 1. infection 2. larvae implant in capillaries 3. inflammation (monocytes and eosinophils) 4. some larvae encyst (= encapsulated "eggshell calcification" cyst with fluid and budding cells... outer wall is gelatinous with a thick fibrous capsule) tx= surgery, chemo (albendazole), cyst manipulation during surgery to be done with caution because if the cyst contents spill, it causes anaphylactic shock (the patient died)

Answer 309

= acute liver failure ``` causes: viral hepatitis acetaminophen toxicity idiosyncratic drug reactions wilson disease (copper) ```

Answer 310

aka what is unique to the lagging strand? =synthesis of multiple short DNA fragments DNA synthesis is only 5' to 3' (thus unique that the daughter strand which is lagging has to be made in okazaki fragments separated by RNA primers ) RNA primers not unique to the lagging stand, its also used in the leading strand (make by primase- a DNA dep RNA pol)

Answer 311

because it shifts the curve left (impairing oxygen delivery to tissues) it competitively binds hemoglobin and myoglobin with high affinity (disrupting heart's ability to use oxygen and decreasing CO) cellularly, CO binds cytochrome oxidase, inhibiting aerobic metabolism (which exacerbates tissue hypoxia) tx= high flow or hyperbaric oxygen to hasten the dissociation of CO from carboxyhemoglobin PO2 is unchanged methemoglobin is Fe3+ (can be due to congenital NADH methemoglobin reductase def) Fe2+ is better porphyrin in heme is unaffected

Answer 312

globin chain denaturation | due to sulfhydryl group cross linking during oxidant stress

Answer 313

endometrial glandular tissue in the myometrium seen in middle age parous females with heavy bleeding and dysmenorrhea *uniformly enlarged uterus biopsy will be normal because you can only diagnose it with microscopic examination of a hysterectomy specimen

Answer 314

no but it is irregular

Answer 315

``` bone pain fatigue anemia kidney disease hypercalcium ``` ``` (remember the resident's mneumonic CRAB- C=calcium R=renal A=anemia B=bone pain) ``` cancerous B cells become plasma cells (which make abs- spec light chains IgG and can cause amyloidosis).... immunoglobulins are proteins and since its cancer there is increased protein production tx= attack the rapidly producing protein cells with proteasome inhibitors (like bortezomib- a boronic acid containing dipeptide) targetting the proteasome will induce cell apoptosis (inhibiting proteasomes causes accumulation of toxic intracellular proteins and imbalance of pro-apoptotic proteins both of which will induce apoptosis) treat multiple myeloma's high calcium (tumor induced bone resorption) with fluids, steroids, and biphosphonates (inhibit OC)

Answer 316

bacillus anthracis infection from contact with infected animals or animal products (or as a biological weapon) thus we need to know the patient's occupational history to see if there is exposure to animals or if its a potential bioterrorism and we should contact public heath authorities (as a biological weapon it has near 100% mortality of the pulmonary form) super rare in the US. may be seen in people who handle livestock or animal hides and have not been immunized bacillus anthracis cause the characteristic eschar described at the site of inoculation... it can spread to blood and tissue and can sometimes cause a pulmonary anthrax

Answer 317

develops in the most dependent portions of the lung patients who aspirate while laying flat= right posterior upper lobes and superior lower lobes right main bronchus is larger shorter and more vertical patients who aspirate in the upright position= basilar lower right lobe

Answer 318

MHC class I presents antigens to CD8+ T cells MHC I are on the surface of all nucleated cells each MHC I is made up of: 1. single heavy chain (heavy chains are highly polymorphic allowing them to present a large variety of antigens) 2. associated beta two microglonulin ... these present virus, tumor proteins, and intracellular antigens... ends in apoptosis MHC class II: 1. alpha polypeptide chain 2. beta polypeptide chain .... these are on antigen presenting cells ( B cells, macrophages, dendritic cells, langerhans cells) ... these are for bacterial recognition (antigens presented were eaten and broken down in the lysosome).... ends in activation of Th cells for ab production

Answer 319

CMV (cytomegalovirus) colitis which you know because of the intranuclear and intracytoplasmic inclusions seen CMV treatment= foscarnet foscarnet= mimics pyrophosphate to directly inhibit DNA pol (in herpes) and reverse transcriptase (in HIV) foscarnet does NOT require intracellular activation BUT it must be given IV foscarnet is good for treating CMV that is resistant to ganciclovir or herpes that is resistant to acyclovir (both acyclovir and gancyclovir require intracellular activation)

Answer 320

lamivudine= cytosine analog which is a NRTI... it must be phophorylated to its active form by intracellular kinases oseltamivir= a sialic acid analogue inhibitor of influenza A and B neuraminidase Saquinavir= HIV protease inhibitor that prevents cleavage of polyprotein precursors necessary for the generation of functional viral proteins Sofosbuvir= inhibits non structural protein 5B (NS5B), an RNA dep RNA pol needed for hep C replication... it requires intracellular activation

Answer 321

(the patient vignette reminded me of hunter/hurler syndrome) AR lysosomal storage disorder due to defects in protein targeting proteins targetted for the lysosome are modified with phosphorylated mannose resides (by the golgi body enzyme- phosphotransferase) this phosphorylated mannose allows the proteins to transcerse the golgi network and be sent to the lysosome without the phosphotransferase enzyme these proteins get secreted extracellularly and they accumulate as cellular debris in the lysosome (making the characteristic inclusion bodies) ``` lysosomal storage issue in this case causes the symptoms: failure to thrive cognitive deficits physical features (coarse facial features, corneal clouding) ``` I cell disease is fatal in childhood

Answer 322

``` fever profound fatigue LAD lymphocytosis (with atypical lymphocytes) splenomegaly** ``` EBV is spread through saliva transfer (asymptomatic virus shedding)

Answer 323

SLE! autoimmune multisystem vasculitis in SLE, autoantibodies bind autoantigens and form immune complexes that deposit on vessel walls (leads to compliment mediated injury) acute phase= fibrinoid necrosis of the vessel wall chronic vasculitis= fibrosis and narrowing of the lumen the autoantibodies normal seen are: 1. ANA (anti nuclear ab) - almost all SLE patients and in patients with connective tissue disorders 2. anti-dsDNA ab's- specific to SLE but only seen in like 60% of patients 3. anti-snRNPs (small nuclear ribonucleoproteins) aka anti-Smith ab's- highly specific but only in 20-30% of SLE patients

Answer 324

primary biliary cirrhosis middle aged woman with jaundice, pruritus, hepatosplenomegaly, and hypercholesterolemia

Answer 325

its an IgM directed against the Fc fragment of self IgG found in patients with rheumatoid arthritis also found in other collagen tissue disorders RA= morning stiffness greater than 1 hour... spares the DIP joint of the fingers anti CCP ab testing is more specific to RA

Answer 326

``` CREST syndrome ( a subtype of scleroderma) C=Cutaneous calcification and anti-Centromere ab R= Raynaud phenomenon E= Esophageal dysmotility S= Sclerodactyly (claw hands) T= Telangiectasia ```

Answer 327

the heterophile ab's seen in patients with infectious mono (EBV) this ab is detected by the monospot test

Answer 328

Turner syndrome ``` they also have: low hairline webbed neck broad chest cubitus valgus (the wide carrying angle of the arms) ``` ``` complications: coarctation of the aorta bicuspid aortic valce horshoe kidney streak (atrophic) ovaries/amenorrhea/infertility ``` most common cause of primary amenorrhea = chromosomal abnormalities resulting in ovarian insufficiency they will still have a uterus

Answer 329

``` question stem: baby born at home, no vaccinations bulging anterior fontanel eyes driven downwards cannot track eyes upwards intracranial hemorrhage ``` cause= impaired clotting factor carboxylation vit k def= babies have low stores, dont get much from breast milk, their gut is sterile, little comes from placenta... present with incranial/GI/cutaneous/umbilical/ or surgical site bleeding... prevention= IM vit K at birth vit K is an essential cofactor for gamma glutamyl carboxylase glutamyl residues----(gamma glutamyl carboxylase)---> gamma carboxyglutamates that carboxylation is crucial for clotting factors to work because it creates a place on them for calcium to bind babies are at risk for the first month of their life because their gut and liver are immatue without the exogenous vit K, the baby gets impaired clotting factor carboxylation and gets a propensity to bleed (ex= intracranial hemorrhage= AMS, large head, bulging fontanel, downward driven eyes) if the baby had gotten vit K at birth then we would suspect abusive head trauma

Answer 330

it would look like the myoglobin curve because its also a monomeric protein (shape is hyperbolic and it has a high affinity for oxygen) myoglobin's structure is almost identical to the hemoglobin beta subunit (and the alpha subunit too)

Answer 331

``` via macrophages (aka activated leukocytes)... DONT BE STUPID AGAIN! (leukocytes mean WBCs, NOT lymphocytes, read slower) ``` granulomas occur through interactions between macrophages, multinucleated giant cells [clumped together macrophages], and CD4 T cells.... the CD4 T cells use TNF and INF gamma to stimulate macrophages and other WBCs = cavitary lung lesions (typically in upper lobes)

Answer 332

(trehalose dimycolate) its a virulence factor that acts as part of the cell wall to prevent fusion with lysosomes

Answer 333

exudation and alveloar hepatization are features of pnu caused by strep pneumo red hepatization= RBCs and neutrophils accumulate in the alveolar spaces and look like a liver gray hepatization = the RBCs are destroyed and there are fibrinopurulent exudates

Answer 334

cryptogenic organizing pneumonia here, inflammation causes granulation tissue proliferation that obstructs bronchioles and airways and consolidate the alveoli its idiopathic and resolves with steroids

Answer 335

eczema rash recurrent infections thrombocytopenia (increased bleeding) X linked chr mutation immunodef= B cells and T cells esp hard for them to fight encapsulated organisms (neisseria meningitidis, h flu, strep pneumo) at risk for opportunistic infections like PJ pnu and herpes viridae infections worsen with age and becomes apparent after placental IgG and maternal IgA are degraded by like 6 m old. Tx= HLA matched bone marrow transplant remember the youtube video of the mom who had chemo when pregnant and had PJ the boy with wiskott aldrich syndrome and all they initially found was low platelets, then came the rash and infections and he lived because his sister gave him a BMT)

Answer 336

microangiopathic hemolytic anemia thrombocytopenia acute renal failure

Answer 337

oculocutaneous albinism peripheral neuropathy immunodef (related to dysfunction of the phagolysosome fusion)

Answer 338

ataxia telangiectasia is defined by progressive ataxia with telangiectasias and immunodef immunodef= combined defect of B and T cells

Answer 339

R= Rifampin inhibits bacterial DNA dep RNA pol... causes GI, rash, red orange body fluids, and cytopenias I= Isoniazid inhibits mycolic acid synthesis... causes neurotoxicity without B6 and hepatotoxicity P= Pyrazinamide unclear MOA... causes hepatotoxicity and gout E= Ethambutol inhibits arabinosyl transferase.... causes optic neuropathy Isoniazid would make TB less resistant to decolorization with an acid alcohol agent and would make TB stop proliferating (makes TB lose their acid-fastness) TB's mycolic acids are essential for the proper cell wall structure and virulence factor synthesis (sulfatides, wax D, cord factor)

Answer 340

trichomonas vaginitis bacterial vaginosis dont drink alcohol with metronidazole or you get a disulfiram like reaction (disulfiram is a medication that helps alcoholics from relapsing) disulfiram inhibits acetaldehyde dehydrogenase acetaldehyde--- (acetaldehyde dehydrogenase)----> acetic acid acetaldehyde accumulation causes HA, abdominal cramps, nausea, and flushing

Answer 341

this is the X chromosome that got inactivated during x-inactivation (lyonization) during embryonic development this inactivated X chromosone is associated with low transcription activity* x-inactivation is maintained across cell division resulting in clusters of cells throughout the body that express one X chr skewed lyonization (normally mosaic) may result in females getting an X-linked recessive disorder (ex= classic hemophilia) lyonization turns the inactive X into condensed heterochromatin (aka barr body= compact body at the periphery of the nucleus)... hemocrhomatin consist of heavily methylated DNA (cytosine coverted to methylcytosine) and deacetylated histones (which is why there is low transcriptional activity) a small proportion of genes remain transcriptionally active on the inactive X which is why inheriting an abnormal number of X chromosomes causes clinical manifestations due to a gene dosage effect euchromatin= loosly arranged and exhibits a high level of transcriptional activity

Answer 342

HNPCC aka lynch syndrome

Answer 343

oral rinsing poor inhalation technique causes much of the medicine to deposit on the oral mucosa which can lead to candida infection avoid this by using a spacer and rinsing after inhalation other ADR include dysphonia (difficulty speaking) due to myopathy of laryngeal muscles and mucosal irritation

Answer 344

infection with nocardia seen in an immunosuppressed patient with fever, headache, pulmonary nodules, and ring enhancing lesion like an abscess in the brain sputum shows branching gram positive, catalase positive, rod bacteria found in soil and healthy gingiva they are partially acid fast, beaded branching filaments (look like fungal hyphae but not as wide) Nocardiosis affects the lungs, brain, skin, and immunosuppr Treatment= TMP-SMX (and abscess drainage)

Answer 345

its a gram positive bug causes granulomatous inflammation forms multiple abscesses and sinus tracts that discharge "sulfur granules" presents mostly as neck and face or abdominal disease pulmonary nocardiosis presents with cavitary pneumonia and is often misdiagnosed as TB

Answer 346

appears as septate hyaline hyphae

Answer 347

yeast with branching pseudohyphae it causes superificial skin/esophagitis problems or disseminated candidemia/endocarditis

Answer 348

yeast with a capsule that can be visualized on india ink staining causes meningitis in immunosuppr

Answer 349

cysts or tachyzoites it causes encephalitis and pneumonitis in patients with HIV and is typically diagnosed with serology

Answer 350

cilia ciliated mucosal epithelium lines frm the trachea to the resp bronchioles the airway epithelium gradually changes from a pseudostratified ciliated columnar to ciliated simple cuboidal ciliated cells are not present in the alveolar ducts or the alveoli themselves progression: bronchi-->proximal bronchioles-->termial bronchioles--> respiratory bronchioles--> alveoli

Answer 351

HAART (highly active anti-retroviral therapy) = includes HIV RT inhibitors and protease inhibitors resistance in HIVis attributed to the high mutation rate of the HIV genome and the selective pressure exerted by anti retroviral drugs Pol gene mutations= resistance to protease inhibitors and resistant to NRTI and NNRTIs (these are due to structural changes in the RT due to the pol gene mutation)

Answer 352

HIV1 structural proteins are encoded for by the HIV1 env gene (ab's normally made to this viral envelope glycoprotein) thus viral evasion of ab's (aka "escape mutants" no longer susceptible to ab neutralization) are more likely secondary to a mutation of env

Answer 353

** gram neg coccobacillus ** chronic cough "bursts of coughing" for several minutes followed by vomiting highly contagious resp droplet transmission adult's immunity may have waned think of this in an adult with acute tracheobronchitis with no vaccination boosters (no pulm findings on cxr) 3 phases of bordatella pertussis: 1. catarrhal phase = basically a URI 2. paroxysmal phase = severe coughing spells with inspiratory whoop and or post tussive emesis 3. convalescent phase= cough improves virulence factors= adhesins and toxins vaccine: pertactin (basis of the acellular vaccine) promotes pertussis adherence to the ciliated upper resp epithelium tracheal cytotoxin subsequently promotes local tissue destruction resulting in cough pertussis toxin causes increased adenylate cyclase (aka cMAP) which prevents effective phagocytosis and allows it to live in macrophages and ciliated epithelial cells (causing prolonged disease) pertussis toxin can also trigger lymphocytosis

Answer 354

``` atypical pneumonia persistant non productive cough pharyngitis ear pain constitutional symptoms cxr with diffuse intersitial infiltrate ```

Answer 355

aminoglycosides interfere with the aminoacyl binding site on 30S ribosomal subunit (causing misreading of mRNA) resistance= methylation of the aminoglycoside binding portion of the ribosome or via an enzyme that inactivates the drug by altering its chemical structure or making an efflux pump that decreases its intracellular concentration

Answer 356

penicillins= via beta lactamases, ESBL, mutated PBPs, or mutated porin protein vanco= via mutated peptidoglycan cell wall or impaired influx/increased efflux quinolones= mutated DNA gyrase or impaired influx/increased efflux aminoglycosides= aminoglycoside modifying enzymes, mutated robosomal subunit protein, or mutated porin protein tetracyclines= impaired influx/increased efflux or inactivated enzyme rifamycins= mutated RNA polymerase

Answer 357

acute onset SOB low oxygen low CO2 assuming there is a normal rate of metabolic CO2 production, low CO2 levels imply alveolar hyperventilation this can result if there is a ventilation perfusion mismatch causing obstruction to oxygen and CO2 exhange (such as pnu or PE) low oxygen stimulates peripheral chemoreceptors to increase the resp drive above normal limits which increases the CO2 blown off... BUT the problem hasnt gone away and you still cant absorb more oxygen so both levels drop and the Aa gradient increases tx= treat the underlying disease process otherwise itll end with resp muscle fatigue, hypoventilation, and hypercapnia **arterial PaCO2 is a direct indicator of alveolar ventilation... hypocapnia= HYPERventilatio*** upper airway obstruction, reduced ventilatory drive, resp muscle fatigue, and decreased chest wall compliance can cause HYPOventilation and hypercapnia

Answer 358

lungs! the pulmonary vasculature (vasc resistance decreases in alveoli that are well aerated in comparison to alveoli that are underventilated) this is known as hypoxic vasoconstriction (due to K+ channel modulation or decreased production of ROS that occurs in hypoxia which increases cytosolic calcium levels in the pulm artery smooth muscles) this is opposite of the rest of the body where hypoxic tissues get more blood flow

Answer 359

malpractice= legal determination where treatment is below the standard of practice and results in injury or death to a patient (its not a medical error but a consequence of error that results in harm) near miss= a medical error that is recognized before any harm is done to the patient (ex= lethal dose of meds caught by the pharmacist) non prev adverse event= cannot be prevented given the current state of medical knowledge (allergic reaction to a med in a patient with NKMA) preventable adverse event= harm to the patient by an act of commisision [doing the wrong thing] or omission [not doing the right thing]... aka failure to follow evidence based best practice guidelines (here the dr did not address the patient's high TSH during her first visit when she was diagnosed with depression) sentinel event= unexpected occurrence involving death or serious injury that requires immediate investigation (inpatient suicide, death of a full term infant, retained object s/p surgery)

Answer 360

rokitansky syndrome= mullerian aplasia= vaginal agenesis 46XX female "aplasia" means defective or absent organ/tissue... meaning they can have VARIABLE uterine development [hypoplastic or absent] and no upper vagina (aka a short vagina) they have normal ovaries and normal development of secondary sex traits... all females with mullerian defects should get a kidney ultrasound because up to half will have urologic anomaly **what threw me off here was that the question said she had "shortened vag canal and RUDIMENTARY uterus" which I interpretted to be underdeveloped not absent but recognize in the future this is NOT DEVELOPED!**

Answer 361

``` tall slightly decreased IQ physical features are normal normal sexual development normal life span (because two X's are inactivated) +/- menstrual irregularities normal fertility ```

Answer 362

nucleolus (the dense dark round structure within the nucleus) it contains: ribosomal DNA newly transcribed rRNA for ribosomal proteins primary function of the nucleolus is to synthesize and assemble immature 60S and 40S ribosomal subunits exported from the nucleus to the cytoplasm... all ribosomal RNA is transcribed in the nucleus except for 5S rRNA which is transcribed in the nucleolus Nucleus contains the nucleolus, electron lucent euchromatin, and electron dense heterochromatin typically around the periphery

Answer 363

Coccidioides immitus- a dimorphic fungas that is mole (hyphae) at 25-30C and an endospore (spherules containing endospores, **characteristic) at body temp (37-40C) C immitis is endemic to the Southwest US (California, Arizona, New Mexico, Western Texas), north mexico, and some central/south america recent travel or living in these places increases risk infection via spore inhalation (spores are fragmented hyphae)... inside the lungs the spores turn into spherules that contain endospores rupture = dissemination presents with 1. acute pnu (most common) 2. chronic pnu 3. pulm nodules/cavities 4. extrapulm nonminingeal disease 5. meningitis worse in immunosuppressed (note- the one you were thinking of in the four corners of the southwest [arizona/CO/new mexico/utah] was hantavirus- fever, chills, muscle pain... transmitted by deer mouse... "hantavirus pulmonary syndrome")

Answer 364

yeast form of cryptococcus neoformans causes pulm disease and meningoencephalitis in immunosuppr

Answer 365

histoplasma capsulatum endemic to mississippi and ohio river basins found in bird and bat droppings

Answer 366

mycoses= infection by fungus (such as ringworm or thrush) 1. candida 2. A fumigatus (asthma pts at high risk for allergic bronchopulmonary aspergillosis) 3. mucor 4. rhizopus

Answer 367

surrounding the RS cell is number lymphocytes, like a ton! so this is from a lymph node RS cell = giant binucleated cell appearing as "owl's eyes"... these come from the germinal center B cells and are the neoplastic hallmark of Hodgkin lymphoma (HL) Reed sternberg cells must be present to diagnose HL

Answer 368

strong clinical suspicion, good history and physical... it requires immediate treatment so you have to go off of a presumptive diagnosis culture would take way too long (several days) and the bug is only found at the inoculation site ask about immunization history, booster every 10 years route of entry into body is trauma/wound causes "trismus" = "lockjaw" , facial grimacing "risus sardonicus", muscle spasms, and extensions of truncal muscles resulting in opisthotonos (the back arching)

Answer 369

its an RNA dep DNA pol that makes telomeric DNA to replace the lost chromosomal ends of the telomeres cancer cells increase telomerase for immortality they usually make repeats rich in G's and T's when the telomeres normally get to short, the cell checkpoint gene (TP53) trigger apoptosis Telomerase is made of TERT and TR (telomerase reverse transcriptase and telomerase RNA) most normal human cells dont have a telomerase except for regularly dividing cells like germ cells and some stem cells

Answer 370

its a protein that promotes the G1 to S transition in the cell cycle cells with increased expression of cyclin D result in unchecked cell prolif

Answer 371

``` increases risk: fam hx infertility nullitparity PCOS endometriosis BRCA1/2 muts lynch syndrome post menopausal hormone therapy ``` decrease risk: COCP multiparity breast feeding tube and ovary removal CA 125 is a marker for ovarian cancer but is not super specific

Answer 372

legionella (LPS chains inhibit gram staining here) mycoplasma= no peptidoglycan cell wall symptoms of legionella= high fever in a smoker, low BP, diarrhea, dx via urine ag test, tx is resp FQs [levofloxacin]and newer macrolides [azithromycin] (aka legionella is CAP with GI symptoms) transmission= contaminated water in aerosolized form legionnaires disease can be a life threatening pnu if not recognized and treated poorly

Answer 373

1. initiation (via intrinsic mitochondrial mediated [display phosphatidylserine or thrombospondin], or extrinsic receptor mediated pathway [TNF bound to TNF-R1 or Fas ligand bound to Fas-R]) 2. control (intrinsic= mediated by bcl2 anti apoptoxic signal, then mitochondrial permeability transtion (MPT) and release of cytochrome c which activate caspases* ... extrinsic = binding of death ligand and death receptor allow pro-caspase molecules into close proximity to one another) 3. destruction (both pathways end in caspase activatio, caspases are proteolytic enzymes that destroy cell components... they contain cysteine and cleave aspartic acid residues [Cystein-ASPartic acid proteASES]. initiator caspases activate effector caspases which cleave proteins and result in apoptosis)

Answer 374

the posterior communicating artery at the junction of the internal carotid artery (CN3 courses between the post cerebral and superior cerebellar arteries as it exits the midbrain in the interpeduncular space and is particularly susceptible to injury from the same side posteriorcommunicating artery aneurysms) this is because the patient has right sided CN3 palsy secondary to the compressing aneurysm 85% of aneurysms come off the anterior circulation (anterior communicating, posterior communicating, middle cerebral arteries) risk= smoking and hypertension CN3 (surface= pupillary light and reflex pathways, interior=all the eye muscles) thus aneurysmal compression of CN3 produces mydriasis (superficial PNS damage) with diplopia, ptosis, and "down and out deviation of the ipsalateral eye (due to somatic efferent fiber injury) side note- the junction of the anterior communicating artery and the anterior cerebral artery is the most common location for saccular aneurysms but this compresses the optic chiasm and causes bitemporal hemianopsia

Answer 375

the middle cerebral artery supplies the lateral brain... occlusion of the middle cerebral artery would affect motor control of the hand (gripping), the face/mouth (whistling), and throat (swallowing) way out of proportion to the leg... middle cerebral artery can also cause broca aphasia (due to damage of the dominant frontal lobe), anosognosia (being in denial kind of), and spatial neglect of the opposite side (parietal lobe damage)... they would also have gaze deviation towards the side of the stroke and opposite side homonymous hemanopsia the anterior cerebral artery extends medially and then superiorly to supply the medial hemisphere from the frontal pole to the parieto-occipital sulcus ... occlusion of the anterior cerebral artery would affect sensory and motor function of the opposite leg and foot while sparing the oposite arm and face ("cortical homunculus")... they would have trouble walking up stairs summary= anterior cerebral arteries supply the medial hemispheres (frontal and parietal lobes) and occlusion causes opposite side motor and sensory deficits of the lower extremities, behavior changes, and urinary incontinence

Answer 376

febrile viral illness rash neurologic manifestations (including encephalitis -confusion, and flaccid paralysis syndrome) WNV is a positive ssRNA flavivirus transmitted by female mosquitos (culex) most commonly in the summer diagnosis= clinical findings (encephalitis, meningitis, and or flaccid paralysis) with positive CSF anti-WNV ab's (PCR not often needed) tx= supportive other ARBOviruses (aka ARthropod BOrne viruses) = transmitted by insect bites cause meningitis... examples: togaviridae (east, west, and venezualan equine encephalitis) bunyaviridae (california encephalitis) these are most common in summer and fall when arthropods are most active poliovirus (an enterovirus) is super unlikely cause its been eradicated in the US)

Answer 377

varicella mumps adenovirus these can cause aseptic meningitis or encaphalitis (meningitis not due to bacteria)

Answer 378

diplopia from being unable to adduct his left eye eye adduction= CN3 and the medial rectus muscle (**dont forget adduct means look towards nose) CN3 originates in the oculomotor nucelus of the midbrain, emerges from the anterior midbrain, and enters the orbit through the superior orbital fissure so a lesion of the superior orbital fissure would cause the symptoms the corneal reflex is mediated by the (sensory) nasociliary branch of the trigeminal nerve (CN V1 aka 5- 1st branch) and the (motor) temporal banch of the facial nerve (CN7) the nasociliary nerve (sensory limb) enters the orbit through the superior orbital fissure too and thus a lesion would cause both the problems other things to enter the superior orbital fissure (trochlear nerve-4, abducens nerve 6, and superior ophthalmic vein) the inferior orbital fissure contains the maxillary division of the trigeminal nerve (CV V2, the infraorbital vessels, and branches of the sphenopalatine gangion) but these do not enter the orbit recap on Superior orbital fissure: CN 3, 5-1, 4, 6, and superior ophthalmic vein

Answer 379

1. alveolar hypoventilation 2. high altitude 3. hypoventilation due to suppressed central respiratory drive (sedative overdose, sleep apnea) 4. diseases that cause decreased inspiratory capacity (myasthenia gravis, obesity) (side note that physiologic shunting does increase the Aa gradient)

Answer 380

the piriform recesses are small cavities that lie on either side of the laryngeal orifice during normal swallowing food is diverted by the epiglottis laterally through the piriform recesses into the esophagus without endangering the airway a thin layer of mucosa overlies the piriform recess which is all there is to protect the superficial internal laryngeal nerve (a branch of CN 10) the internal laryngeal nerve contains only sensory and autonomic fibers and controls the cough reflex (which could be lost if you damaged this nerve) foreign bodies get stuck in the piriform recess and while getting them out you can damage the internal layrngeal nerve (side note- remember that recurrent and external laryngeal nerve carry motor fibers to the muscles involved in vocal cord function and irritation or compression can cause hoarseness)

Answer 381

neonate with posterior neck mass composed of cystic spaces separated by connective tissue = cystic hygroma (due to abnormalities of lymphatic outflow... swelling decreases with age) bilateral non pitting edema to the hands and feet =lymphadema (due to abnormalities of lymphatic outflow... swelling decreases with age) femoral pulses may be diminished =coarctation of the aorta 45XO (loss of paternal X)

Answer 382

caused by meiotic nondysjunction ``` cardiac defects clenched fists rocker bottom feet omphalocele (organs on outside of body) low set ears ```

Answer 383

due to de novo partial deletion of the short arm of chr 5 (5p-) round face cat-like cry microcephaly mental retardation

Answer 384

1. ergot compounds (derived from ergot fungi)= bromocriptine [also treats hyperprolactinemia] 2. nonergot compounds= pramipexole and ropinirole these dopamine agonists are used for treating parkinsons disease these have a long half life and can delay the need to start levodopa therby postponing the development of motor fluctuations until later in the disease course

Answer 385

MAO-Bi= via selegiline this decreases dopamine degredation in the brain amantadine= direct and indirect dopaminergic agent used to alleviate some motor symptoms by enhancing the effects of endogenous dopamine (also has some anticholinergic properties which reduces tumors) decrease the breakdown of levodopa in periphery and increase amount crossing the BBB with both COMT inhibitors [catechol O methyltransferase inhibitors= entacapone, tolcapone....] and dopa decarboxylase inhibitors [carbidopa] treat drug induced parkinsonism and those with tremor from idiopathic parkinsons disease = anticholinergics like trihexyphenidyl and benztropine to inhibit central muscarinic receptors

Answer 386

false, treat with supportive care active cooling does not reduce risk of febrile seizures and may precipitate seizures by inducing shivering and transient rise in core body temperature active cooling is used to treat heat stroke (like babies left in a hot car) and is done with water sponging and icepacks if the patient's temp is above 42.2 C (108 F) then oxidative phosphorylation ceases and ATP becomes rapidly depleted leading to end organ damage in febrile seizures, rule out CNS infections.... there is a minimal risk of developing non febrile siezures (aka epilepsy) within the supportive care you can give anti-fever meds like acetaminophen or ibuprofen to decrease the fever and improve patient comfort (by inhibiting prostaglandin E2) which will lower the thermoregulatory set point in the hypothalamus (but even then anti fever meds dont reduce the risk of further febrile seizures probably because of circulating inflammatory mediators that lower seizure threshold in young kids) febrile seizures are benign sequelae of fever

Answer 387

skeletal muscle relaxant used to treat malignant hyperthermia

Answer 388

anti muscarinic drugs (anti cholinergic) muscarinic activation= MR. BB SLUDGE Miosis (small pupils) Rhinorrhea Bradycardia Bronchoconstriction ``` Salivation Lacrimation Urination Defecation Gastric upset Emesis ``` example= H1 receptor blocker (aka histamine) such as diphenhydramine for his allergic rhinitis and is causing anticholinergic effects the flushing= blocking eccrine sweat glands results in fever and compensatory cutaneous vasodilation

Answer 389

it blocks skeletal muscle nicotinic receptors at the NMJ used during general anesthesia to induce paralysis ADRs= resp paralysis, autonomic ganglionic blockade (causing hypotension and tachycardia)

Answer 390

atropine tricyclic antidepressants (like amitriptyline) H1 receptor blockers (diphenhydramine) neuroleptics antiparkinsonian drugs

Answer 391

myotonia= abnormally slow muscle relaxation classic symptoms: difficulty loosening one's grip after handshake or while releasing a doorknob it is the second most commonly inherited muscle disorder (#1 is duchenne muscle dystrophy= would see necrosis of muscle fibers and fibrofatty replacement) AD abnormal trinucleotide repeat expansion (CTG) of the gene that codes for a myotonia protein kinase anticipation is seen with subsequent generations other common features= cataracts frontal balding gonadal atrophy microscopy: atrophy of muscle fibers, mostly of type 1 fibers

Answer 392

axonal destruction via: trauma ischemia generalized disease (ALS) seen as muscle paralysis and atrophy

Answer 393

dermatomyositis polymyositis

Answer 394

``` with myotonia (abnormally slow relaxation) and episodic hypotonic paralysis often associated with exercise ``` no muscle atrophy is seen on microscopy PAS positive intracytoplasmic vacuoles are found in these conditions

Answer 395

protamine sulfate which will bind heparin and prevent its activity (used to manage LMWH toxicity but it does not completely reverse the anti-10a activity of LMWH) heparin increases natural occurring antithrombin 3 (measure with aPTT) vit K is the reversal agent for warfarin but requires new synthesis of coag factors so it takes time, so in an acute setting of life threatening bleeding due to warfarin you give FFP (contains all blood proteins and clotting factors)... FFP contains antithrombin 3 and would make heparin effects worse. you can also treat warfarin overdose with prothrombin complex concentrates (PCCs) which contain factors 2,7,9, 10

Answer 396

its due to clostridium tetani spores from unhygienic deliveries or cord care mortality close to 100% without treatment ``` trismus (lockjaw) hypertonicity clenched hands arched back eventual resp failure ``` treat= supportive care, abx, tetanus immune globulin prevent= immunize pregnant women and those of childbearing age (pass on transplacental IgG which decreases incidence by 95%), hygienic delivery and cord care vaccination of the child doesnt occur until at least 2 months old because their immune system is immature

Answer 397

1. strep pneumo 2. staph aureus (famously the most common) 3. h flu

Answer 398

collagen is the most abundant protein in the human body and its made of fibroblasts, osteoblasts, and chondroblasts its make of 3 polypeptide alpha chains held together by hydrogen bonds forming a rope like triple helix the triple helix occurs due to the repetative glycine (Gly) that occupies every third amino acid position (Gly - X - Y) its the most abundant because its so somall its the only AA that can fit into the confined space between the individual alpha chains ``` X= typically proline Y= typically hydroxyproline or hydroxylysine ``` proline introduces a kink due to its ring structure which increases rigidity of the structure and hydroxylysine is used for cross linking to increase tensile strength

Answer 399

B cells get activated when they are exposed to antigens as they migrate to lymphoid organs and peripheral tissues activated B cells go to the lymphoid follicles in the lymph node cortex and form germinal centers where they proliferate during an immune response most turn into ab secreting plasma cells and can **isotype switch** there each isotype is classified based off the heavy chain constant region (light chains are antigen specific and do not determine isotype) isotype switching requires CD40 receptor interaction on the B cell with the CD40 ligant (CD 154) on T cells isotype switching= through genetic rearrangement of the heavy chain constant regions which is modulated by T cell cytokines (note to self: negative selection refers to T cells and this happens in the fetal thymus... same with tolerance... also remember that VDJ heavy chain recombination occurs in DNA rearrangement and refers to gene rearrangement of B cells to make different ab's, this all happens in the B cell maturation in the bone marrow)

Answer 400

its a chronic myeloproliferative disorder of the bone marrow characterized by overproduction of myeloid cells 1. primary myelofibrosis= severe fatigue, splenomegaly (causing early satiety and abd discomfort), hepatomegaly (these two are due to compensating extramedullary hematopoiesis, will show teardrop RBCs "dacrocytes" and nucleated RBCs), anemia, and bone marrow fibrosis (resulting in pancytopenia)... due to GOF mut in JAK STAT... megakaryocytes overgrow and stimulate fibroblast proliferation and relace the bone marrow with collagen with the exception of chronic myelogenous leukemia, the chronic myeloproliferatice disorders (esp polycythemia cera) frequently harbor a mutation in JAK2 resulting in constitutive tyrosine phosphorylation activity and activation of STAT pathway STAT then goes on to go to the nucleus and promote transcription tx= JAK2 inhibitor = ruxolitinib

Answer 401

``` 1. CML philidelphia chromosome t (9;22) BCR ABL fusion protein constitutional symptoms splenomegaly *Leukocytosis with marked left shift* (myelocytes, metamyelocytes, band forms) ``` ``` 2. essential thrombocytosis JAK2 mut hemorrhagic and thrombotic symptoms *thrombocytosis* (high platelets) megakaryocytic hyperplasia ``` ``` 3. polycythemia vera JAK2 mut itching erythromelalgia (red palms and soles) splenomegaly thrombotic complications *erythrocytosis* (increased RBCs) thrombocytosis ``` ``` 4. primary myelofibrosis JAK2 mut severe fatigue splenomegaly hepatomegaly anemia *bone marrow fibrosis* ```

Answer 402

t (15;17) leads to the formation of the fusion gene between PML (promyelocytic leukemia) and RARA (retinoic acid receptor alpha) genes the abnormal PML/RARA fusion protein blocks differentiation of myeloid precursors

Answer 403

its a lymphoproliferatice disorder of B cells its marked by lots of WBCs with "smudge cells" on blood smear most express protooncogene BCL2 similar findings in follicular lymphomas

Answer 404

these are high grade NHLs burkitt lymphoma= t (8;14) c-Myc oncogene involvement associated with EBV and classically has a "starry sky" appearance on histo mantle cell lymphoma= low grade NHL with t (11;14) leads to cyclin D1 overexpression