NBME Form 30 Incorrects Flashcards
(122 cards)
Frank-Starling mechanism of the cardiomyocytes. Frank starling curve for CO curve has shifted down. what does this indicate?
for any given preload, there is reduced CO compared to normal» occurs in decreased inotropic states like CHF, negative inotropes, increased afterload.
cardiac tamponade had decreased filling (via compression), in absence of other factors affecting afterload/contractility, it would not be depressed. **cardiac tamponade would affect the VR curve, apparently?
57yr man dies 5 days s/p stroke. He refused tx for his progressively severe HTN over the past 2yrs. BP just prior to stroke was 220/110. Which of the following is the most likely histology of his kidneys at autopsy?
hyperplastic arteriolitis> chronic HTN associated w/ arteriosclerosis- thickened vessel walls, w/ loss of elasticity> either hyaline or hyperplastic.
hyaline= protein deposition in the vessel walls
hyperplastic= concentric thickening of the vessel wall w/ proliferation of smooth muscle cells
chronic pyelonephritis develops in the setting of
recurrent infections of the GU tract w/ reflux into the renal pelvis.
obstructive uropathy, nephrlithiasis, vesicoureteral reflux> kindeys atrophy, calyceal deformities, fibrosis of renal parenchyma
nodular glomerulosclerosis is associated with
diabetic nephropathy, amyloidosis> nephrotic syndrome
renal papillary necrosis associated with
severe ischemic injury to the kidney» sickle cell disease, obstructive nephropathy, NSAIDs, DM, severe pyelonephritis.
transgenic animal containing targeted mutation in the gene coding for macrophage-CSF is prepared. What is the generalized skeletal abnormalities expected in this animal?
osteopetrosis» imbalance in the fxn of osteoclasts:osteoblasts, given excess bone mineral deposition w/ dense, abnormally mineralized bones.
osteoclasts originate from the monocyte/macrophage lineage> inhibition here would prevent differentiation of these cells.
what are the genetic abnormalities associated with osteopetrosis?
RANKL, RANKr, CLCN7 (channelopathies), CA2 (carbonic anhydrase 2) deficiencies.
osteoblast arise from
mesenchymal stem cells (unlike osteoclasts that arise from macrophages lineage)
4yr old boy has viral URI for the past 3 days. clearance of the virus is most dependant on?
MHC class I= CD8 T cells most likely clear the virus.
virus: obligate intracellular pathogen.
CD8 T realease granzyme, perforin= pore formation to apoptosis the infected cell.
also release cytokines INFg TNFa
which cytokines activate macrophages
IL 12, INFg
what is the role of CD4 T
assist B cells in making antibodies, recruit macrophages, activates CD8+, and leukocytes to site of activation.
…they do contribute to viral clearance, but are incapable of DIRECTLY killing infected cells (unlike CD8)
23yr old F comes to the doc b/c 1wk history of intermittent episodes of fever/chills w/ rash. She had 4 operations to correct scoliosis, w/ tonsilectomy, appendectomy, removal of lipoma, dermabrasion for acne. She admited 1yr ago with n/v of unexplained origin. Pt has 12 evenly spaced punctate marks in linear pattern on abdomen and upper/lower extremities. No marks on face, or back. most likely diagnosis?
factitious disorder> pts consciously produce symtoms for primary gain> generally to be cared far, which is an unconscious motivator for pt’s conscious production of symptoms.
elective surgery history + linear, spaced marks= self inflicted pattern of care seeking
tx: regular f/u with doc who oversees mangement, possible psychotherapy
immune thrombocytopenic purpura presents in what areas
dependent body area> feet, legs, hands
53yr M comes to doc b/c 6day history of SOB, cough, pleuritic chest pain. 102T, respirations 35/min. Sputum is rust colored, gram+ diplococci, L side lobar consolidation. Which of the following anatomical structures allowed rapid spread of organisms btw alveoli to involve entire L lobe?
pores of Kohn> connections btw alveoli
consists of type 2 alveolar cells that allow for air passage, fluid, phagocytes, and w/ pneumo bacteria to adj alveoli
»really useful in allowing equilibration of adj alveoli, aid normal oxygenation, and prevention of atelectasis.
do alveolar capillaries provide direct connect btw adj alveoli (has intact beings)
no» they surround each alveolus and cruical for gas exchange, but not for bacteria/air/fluid/phagocytes
20yr M w/ 4hr history of abd pain, n/v. Had been drinking ethanol all weekend, took 3 doses of actaminophen w/in 2hr after onset of severe headache mon morning. Patient at increased risk for liver injury…
via induction of cyp450 enzymes that activate actea to hepatotoxic metabolities> acetamin poisoning is SUPER common w/ alcohol/hepatotoxic drugs.
alcohol makes more NAPQI from acetamin> drastically depleting glutathione» give N-acetylcysteine.
decreased acetaminophen clearance via glucuronidation does not occur w/ alcohol exposure» alcohol doesn’t effect capacity of liver to perform glucuronidation
alcohol increases the capacity of liver to produce NAPQI thru induction of p450 enzymes
Study conducted to assess the accuracy of new rapid test to detect a virulent infection. Infections has 80% mortality rate if it’s not identified early; prompt antibiotics is 5%. The graph shows distribution of infected and non-infected according to results of test. what is the optimal diagnostic cut point? *graph shows bimodal distribution where the two curves touch in middle.
the cut point of test should be set that all persons w/ infection result as positive so there’s few false negatives= set to optimize sensitivity, specificity, or both depending on the clinical utility of test. a sensitive test should be employed when ruling out significantly mortal diagnosis. pt B shows the max #pts without disease, so select this point to all for “catching” early if you will
4yr old girl has aggressive, non-responsive ALL. Doc recommends palliative care and suggests parents talk to their daughter about impending death. The parents ask doc to help them respond to her questions; the parents should understand that child will understand death as
view death as temporary and reversible.
age 5: begin to understand that death is inevitable/irreversible, often incomplete due to lack of experience of death, and media images of ghosts.
age 10: general understanding death is universal, irreversible, and renders people inanimate (vs ghosts idea)
…infants have no understanding of death. toddlers begin to understand and aware of death over time
who is a 4yr in pallative care likely to blame for death
parents> unlikely to blame God for illness or death (very abstract concept). depending on parent’s religious beliefs she may believe death represents in going to Heaven, without the abstract understanding of heaven itself.
An investigator studying effects of a new spider venom. Isolated nerve bathed in solution with venom, decreased end plate potential amplitude following stimulation. The presence of venom doesn’t change amp of nerve AP or potential in response to Ach at NMJ. Blockade of what by venom is the reason for dec end plate potential amplitude?
presynaptic, voltage gated Ca2+ channel> which would then lead to subsequent downstream decreased synaptic Ach concentration> decreased end plate amplitude.
Investigator studies PO2 in experimental animal. Found PO2 in renal vein higher compared to other organs. Why?
blood flow/g tissue is greater in kidneys than other organs
kidney has low metabolic demands compared to other organs, matched with high flow> small differences in renal arterial/venous PO2. other organs depend on flow to meet metabolic demands
Do fenestrations in glomerular capillaries do not promote the convective transport of O2 from BS to efferent arteriole…fenestrations in glomerulus function to filter plasma solutes and water, creating ultrafiltrate in BS
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29yr F w/ 6 day hx rash, joint pain, fatigue. BP 150/90. Raised, red, blotchy malar rash and mild peripheral edema. Tenderness and swelling of several joints. Labs show ANA+, antidsDNA+, protein, RBC casts. What is likely to produce a false positive in this patient?
rapid plama reagin> which is test for syphillis (RPR) the test looks for antibodies against cardiolipin-cholesterol-lecithin agent= “reagin” antibodies.
pt has SLE, potentially antiphospholipid antibodies, anticardiolipin antibodies, lupus anticoagulant…predisposes to venous/arterial thrombosis, recurrent preggo loss» antibodies also interfere with the test.