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Welcome to smc213’s page.
Contributor score: 169


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 +20  visit this page (nbme23#28)
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To be completely clear!

This patient has Cystinosis a rare autosomal recessive lysosomal storage disorder and most common cause of Fanconi syndrome in children. Cystinosis is systemic and leads to cystine crystal deposits in cells and tissues throughout the body.

Although Wilsons disease can lead to FS, the crystals in the corneas does not correlate with Wilsons disease.
More info: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4841061/

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highyieldboardswards  Thank you! You are a legend for figuring this out! +
paulkarr  Appreciate you. +
drzed  And even if it was Wilson disease, it would have the exact same consequence leading to Fanconi syndrome. +3
abhishek021196  Fanconi syndrome Generalized reabsorption defect in PCT = Increased excretion of amino acids, glucose, HCO 3 – , and PO 4 3– , and all substances reabsorbed by the PCT May lead to metabolic acidosis (proximal RTA), hypophosphatemia, osteopenia Hereditary defects (eg, Wilson disease, tyrosinemia, glycogen storage disease), ischemia, multiple myeloma, nephrotoxins/drugs (eg, ifosfamide, cisplatin), lead poisoning. Polyuria, renal tubular acidosis type II, growth failure, electrolyte imbalances, hypophosphatemic rickets = Fanconi syndrome (multiple combined dysfunction of the proximal convoluted tubule). +2

 +5  visit this page (nbme23#14)
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Mucor, Rhizopus, Absidia (Zygomycophyta) Irregular, broad, nonseptate hyphae branching at wide angles. Sporangiospores are inhaled from soil. The fungi penetrate the cribiform plate (no barriers), proliferate in blood vessel walls, progressing rapidly from sinuses into the brain tissue. • Mucormycosis: Rhinocerebral, frontal lobe abscess; cavernous sinus thrombosis. Characterized by paranasal swelling, necrotic tissues (black necrotic eschar on face), hemorrhagic exudates from nose and eyes, mental lethargy, headache, facial pain; may have cranial nerve involvement. • Occurs in ketoacidotic diabetic and neutropenic (leukemic) patients Treatment: debridement of necrotic tissue and amphotericin B or isavuconazole started immediately. Fatality rate is high due to rapid growth and invasion.

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jboud86  FA 2019 page 153. +1




Subcomments ...

submitted by yb_26(316), visit this page
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abnormal test result means that test detects cancer =>

  • 35 of 50 men with prostate cancer have abnormal test result => n of pts with cancer = 50. Test shows cancer in 35 men => TP=35 => we can calculate FN = 50-35 = 15

  • 20 of 100 men without prostate cancer have abnormal test results => FP =20 => we can calculate TN = 100-20=80

  • now we can calculate specificity = TN/(TN+FP) = 80/100 = 0.8 (in % will be 80%)

here is my 4/4 table: [https://www.reddit.com/r/usmlestep1/comments/ccul3w/biostat_question_from_nbme23/]

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smc213  Exactly what I did! +
smc213  I googled the meaning of abnormal test results just to make sure. A positive test is one in which the result of the test is abnormal; a negative test is one in which the test's result is normal. +4


submitted by yb_26(316), visit this page
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abnormal test result means that test detects cancer =>

  • 35 of 50 men with prostate cancer have abnormal test result => n of pts with cancer = 50. Test shows cancer in 35 men => TP=35 => we can calculate FN = 50-35 = 15

  • 20 of 100 men without prostate cancer have abnormal test results => FP =20 => we can calculate TN = 100-20=80

  • now we can calculate specificity = TN/(TN+FP) = 80/100 = 0.8 (in % will be 80%)

here is my 4/4 table: [https://www.reddit.com/r/usmlestep1/comments/ccul3w/biostat_question_from_nbme23/]

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smc213  Exactly what I did! +
smc213  I googled the meaning of abnormal test results just to make sure. A positive test is one in which the result of the test is abnormal; a negative test is one in which the test's result is normal. +4


submitted by mousie(272), visit this page
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Can someone please explain this to me? I don't understand why starting the other drug would not count as exclusion criteria?

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seagull  This has to do with Intention-to-treat analysis. Essentially, when participants are non-adherent but the data shouldn't be lost. They just undergo another statistical model to account for their changes. Here is a nice video https://www.youtube.com/watch?v=Kps3VzbykFQ&t=7s +23
dr.xx  Where does the question mention "intention-to-treat"? +
notadoctor  They seem to be pretty obsessed with "intention-to-treat" it's been asked in one way or another in all the new NBMEs that I've done. (Haven't done 24 as yet) +8
wutuwantbruv  They don't, intention-to-treat is just the best way to go about it @dr.xx +1
yex  I agree with @notadoctor !! +
ergogenic22  i think if it were per protocol, both groups would be excluded, the ones that were inconsistent, the ones that dropped out, and the ones that switched. But answer choices only allow ITT or exclusion of one group. +2


submitted by thomasalterman(181), visit this page
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Patient is current breast-fed, so we can eliminate fructose (fructose is found in honey and fruits and some formula, but not in breast milk). Patient has reducing substances but no glucose in the urine, so he must some non-glucose sugar. My differential for reducing non-glucose sugars in the urine is disorders fructose metabolism or galactose metabolism. We have eliminated fructose, so that leaves us with galactokinase deficiency or classic galactosemia.

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sympathetikey  & Galactokinase deficiency would be much milder. +9
smc213  Big was soybean formula not giving any issues. Soy-milk can be used as a substitute formula in patients with Classic Galactosemia since it contains sucrose (->fructose and glucose). +4
oslerweberenu  Why can't this be glucose 6 phosphatase deficiency Confused me +
almondbreeze  @oslerweberenu G6PD - increased RBC susceptibility to oxidant stress (eg, sulfa drugs, antimalarials, infections, fava beans) -> hemolysis; has nothing to do with presence of reducing sugar +1
makinallkindzofgainz  @almondbreeze; Glucose-6-phosphatase deficiency is Von Gierke disease, they are not referring to G6PD deficiency (an entirely seperate disease) +9


submitted by imnotarobotbut(184), visit this page
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The key is the free air in the abdominal cavity. Ulcers, especially duodenal ulcers, can perforate into the abdominal cavity. This can cause a pneumoperitoneum (free air under the diaphragm). Not a listed symptom in this question, but this can also cause referred pain to the shoulder by irritating the phrenic nerve. FA 2019 pg 374

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et-tu-bromocriptine  To add on to this, anterior* duodenal ulcers tend to perforate (makes sense because closest to the abdominal cavity) whereas posterior duodenal ulcers tend to bleed (due to proximity to the gastroduodenal artery). +15
smc213  Acute pancreatitis can also occur with a posterior duodenal ulcer rupture. Source: Pathoma +6
victor_abdullatif  Fun fact: anterior duodenal perforation are more common than posterior because of the physics of the flow of chyme from the stomach into the duodenum. It travels in a manner that hits the anterior portion of the duodenum, therefore leading to ulcer / perforation. +2


submitted by bigbootycorgi(5), visit this page
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I thought of this as squamous cell carcinoma of the lung causing increased PTHrP and hypercalcemia.

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d_holles  I thought this was medullary thyroid cancer but demographically SCC works better. +
smc213  Medullary thyroid carcinoma increases calcitonin levels leading to decreased serum Ca2+ by increasing Ca2+ renal excretion. So high levels of calcitonin secreted by the tumor may lead to hypOcalcemia. Source: Pathoma +24
brise  actually according to pathoma, you rarely see hypocalcemia even though calcitonin is high! +3


submitted by mguan1993(13), visit this page
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Does being recently diagnosed vs having CKD for a while change this answer? the "recently diagnosed" part threw me off

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smc213  @mguan1993 yes it does! With secondary hyperPTH due to CKD = incr. phosphate, dec. Ca2+ and incr. PTH. This can then progress to tertiary hyperPTH from longstanding secondary hyperPTH as a result of parathyroid HYPERPLASIA --> autonomously (refractory) functioning parathyroid. This will actually lead to INCREASED Ca2+, and significantly INCREASED PTH. Treatment would be surgical removal of the parathyroid glands. Sources: DIT and FA18 p340 +5


submitted by fenestrated(32), visit this page
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What puts internal rotation over adduction? Subscapularis muscle does both

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smc213  probably because the subscapularis m. is the only SITS muscle that does internal rotation & adduction along with the teres minor m. action being adduction & external rotation. +1


submitted by mousie(272), visit this page
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Cholera = Fecal oral /Legionnaires = Legonalla pneumo = NO person to person only by inhalation of bacteria contaminated water /Lyme = tick bite /Meningiococcal = sharing respiratory and throat secretions (saliva or spit). Generally, it takes close (for example, coughing or kissing) or lengthy contact to spread these bacteria (CDC) /RMSF = tick bite

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smc213  Also, when Meningococcal meningitis is treated ... close contacts are also treated prophylactically whereas the others typically are not. There's also a subunit vaccine for n. meningitis due to high infectivity rate especially in crowded establishments. +7
dentist  So, Cholera is also p2p but Mening is more likely? +1
usmlecharserssss  in cholera people to water => water to people +
qball  Remember the fire sprinklers from Sketchy for M. Meningitis. as respiratory droplets are the easiest to transmit from person to person. +
drschmoctor  but the poop water comes from people so.... +1
llamastep1  Respiratory dropplets is easier than fecal-oral tho +2
lowyield  Can also reason that n. meningitidis is common in college students because they live in close quarters which suggests high rate of transmission even amongst immunocompetent individuals +2
peridot  I can see why fecal-oral can seem like person-to-person transmission. What helped me reason it was that in countries with lots of cases of cholera, the primary reason is lack of water sanitation. Even when you google cholera, you get pictures of people collecting dirty water and how the WHO is aiming to reduce cases of the disease by improving water sources. Therefore it's more of a systemic/environmental problem rather than the fact that one person accidentally touched another person's poopy parts and then transmitted it to their own mouth, making this less of a person-to-person thing, especially when compared to another answer choice such as Meningococcal meningitis. +
bbr  To add, think of the water in cholera as a reservoir. The bug is going to hang out there between infecting another person. In meningitis it seems we are going from 1 persons saliva to another. Without much of a reservoir inbetween. (might be using the word reservoir incorrectly). +1
weirdmed51  Rocky Mountain spotted fever: dermacenter TICK +


submitted by gabeb71(51), visit this page
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Lomustine ia an alkylating nitrosourea compound used in chemotherapy. Alkylating agents crosslink DNA.

Cyclophosphamide metabolizes into a phosphoramide mustard. Phosphoramide mustard forms DNA crosslinks both between and within DNA strands

Cholchicine and Vinblastine work on microtubules

Methotrexate and 5-FU both work on purine metabolism.

Cytosine arabinoside interferes with the synthesis of DNA. Its mode of action is due to its rapid conversion into cytosine arabinoside triphosphate, which damages DNA when the cell cycle holds in the S phase (synthesis of DNA). Rapidly dividing cells, which require DNA replication for mitosis, are therefore most affected.

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smc213  To clarify Methotrexate (inhibits dihydrofolate reductase) and 5-FU (inhibits thymidylate synthase) in the Pyrimidine synthesis pathway. 6-MP inhibits Glutamine PRPP amidotransferase in the PURINE synthesis pathway +7


submitted by sajaqua1(607), visit this page
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Plasma membranes are a lipid bilayer, typically with phosphate heads on each surface and long carbon tails on the inside. These carbons are neutral, and undergo hydrophobic interactions for an energetically favorable state.

Integral membrane proteins pass through this lipid bilayer, and so must be capable of interacting both with the polar solvents of intracellular and extracellular space, as well as the hydrophobic core of the layer. The transmembrane portion often has alpha-helical secondary conformation, with hydrophobic residues like glycine on the outside towards the carbon tails with polar amino acid residues tucked in.

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makinallkindzofgainz  "high school biology" lmao we really out here +9
fatboyslim  This question can honestly f off +2
chaosawaits  ohhhhhh my dumb ass was thinking about integrins and so I went with disulfide bond formations. +
kcyanide101  I have seen a Uworld Q, where there listed Amino Acids and asked to identify which of them is a part of the cell membrane component +


submitted by step420(32), visit this page
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Integral membrane proteins are found within the plasma membrane and span the whole length across. The inside of the membrane is very hydrophobic due to the long carbon chains. Extensive hydrophobic interactions between the protein side chain and the lipid tails will help anchor the protein in the membrane.

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yb_26  O-linked glycosylation of secreted and membrane bound proteins is a post-translational event that takes place in the cis-Golgi compartment after N-glycosylation and folding of the protein +21


submitted by killme(14), visit this page
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Intention to Treat Analysis

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usmleuser007  in a per-protocol analysis,[6] only patients who complete the entire clinical trial according to the protocol are counted towards the final results +1
sympathetikey  "In an ITT population, none of the patients are excluded and the patients are analyzed according to the randomization scheme." +7
rio19111  Thx smc213, really helped. +2
trainingrats  Where is this in FA2019? +
teepot123  the video explains it well, no need for fa +1


submitted by hayayah(1212), visit this page
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Septic shock is a type of distributive shock which is marked by massive vasodilation (d/t inflammatory response) causing decreased SVR, decreased preload / PCWP, and increased CO.

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smc213  Septic shock can also present with hypothermia <36C +3
bethune  Why is it not gastrointestinal bleeding? +4
beanie368  GI bleeding would present with increased SVR as a response to hypovolemia +10
mysteriousmantyping  Why would this not be pulmonary embolism? +1
step1passfail  Pulmonary embolism would cause a decrease in cardiac output. There is increased pressure in the high compliant RV which can bulge and compress the LV, decreasing its preload. CO=Heart rate x stroke volume and stroke volume is partially determined by preload. If the pulmonary embolism is large enough, it can also obstruct the pulmonary vessels and subsequently not have enough blood going to the LA and LV, ultimately making the cardiac output near 0. +3
chj7  Out of all the different types of shock, cardiac output is increased only in distributive shock (ie. anaphylactic, septic). +1


submitted by hayayah(1212), visit this page
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Squamous cell carcinoma characteristics: cavitation, hypercalcemia, associated with smoking.

Small cell may actually produce antibodies against presynaptic Ca channels.

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smc213  Increased PTHrP seen in squamous cell lung cancer leads to increased Ca2+ levels +10


submitted by usmleuser007(464), visit this page
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Salivary secretion 1. At low flow = High concentration of potassium; low concentrations of sodium, bicarb, & chloride 2. at high flow = low concentration of potassium; high concentrations of sodium, bicarb, & chloride

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sherry  That's exactly what I was thinking when I was taking the test. But I was sidetracked by same HCO3 level. Can somebody explain this part to me?? +
charcot_bouchard  Because salivary duct removes Na & Cl while secrete K & Hco3 in lumen. In low flow rate HCO3 & K inc because duct is doing its thing for more time. At high flow rate K slightly dec (as cant be secrted as much) but HCO3 stays almost same. the reason is high flow indicates higher metabolism & higher bicarb production. +
cienfuegos  Regarding the bicarb (via BRS Physiology, which explains flow rate as coming down to "contact time" where slow flow allows more reabsorption of NaCl): The only ion that does not “fit” this contact time explanation is HCO3−; HCO3− secretion is selectively stimulated when saliva secretion is stimulated. +3


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Legionella is common causes of pneumonia superimposed on chronic obstructive pulmonary disease.

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asapdoc  Im pretty sure so is strept pneumoniae +4
usmleuser007  COPD is also exacerbated by Viral infection: Rhinovirus, influenza, parainfluenza; and Bacterial infection: Haemophilus influenzae, Moraxella catarrhalis, Streptococcus. however, the questions gives a hint that it may be legionella = "weekend retreat" which may be associated with this infection +5
loopers  From FA 2017 pg 139: Legionnaires’ disease—severe pneumonia (often unilateral and lobar A ), fever, GI and CNS symptoms. Common in smokers and in **chronic lung disease.** +2
kentuckyfan  I also believe that the other attendees showed signs of pontiac fever, which is another hint they tried to get at. +3
luke.10  i did it wrong and chose influenza virus since it is most common infection in COPD but the clue in the Question is that the other attendee didnt get sick since in legionella there is no person to person transmission +2
endochondral   but in Uworld s. pneumo is one of the most common bacterial exacerbation of COPD legionella wasn't even mentioned. How do we rule out s. pneumo ? +5
nala_ula  maybe because in children s.pneumo causes otitis media? +1
smc213  Another hint made in the Q stem is the location being rural Pennsylvania.... Legionnaires disease was first discovered by the outbreak in 1976 at a convention held in Philadelphia, Pennsylvania. Not sure why I know this fact... +10
hpsbwz  Biggest hint towards legionella to me was that they all were at a residence hall... i.e. where there'd be air conditioners and such. +6
stresssweat  it says that other people developed pneumonia without needing to be hospitalized and that some people were asymptomatic. You would think walking pneumonia - Legionella +


submitted by endochondral1(24), visit this page
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how do we know parakeets cause hypersensitivy pneumonitis

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smc213  FA18 p.657 bird exposure--> HSN pneumonitis (restrictive lung disease) and FA18 p.214 granulomatous diseases: foreign material-->HSN pneumonitis. I had to make sense of it since I didn't know it was HSN pneumonitis at first. +5


submitted by hayayah(1212), visit this page
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Case of arteriolosclerosis.

Hyperplastic arteriolosclerosis involves thickening of vessel wall by hyperplasia of smooth muscle ('onion-skin appearance')

  • Consequence of malignant hypertension (>180/120 w/ acute end-organ damage)
  • Results in reduced vessel caliber with end-organ ischemia
  • May lead to fibrinoid necrosis of the vessel wall with hemorrhage; classically causes acute renal failure (ARF) with a characteristic 'flea-bitten' appearance
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masonkingcobra  From Robbin's: Fibromuscular dysplasia is a focal irregular thickening of the walls of medium-sized and large muscular arteries due to a combination of medial and intimal hyperplasia and fibrosis. It can manifest at any age but occurs most frequently in young women. The focal wall thickening results in luminal stenosis or can be associated with abnormal vessel spasm that reduces vascular flow; in the renal arteries, it can lead to renovascular hypertension. Between the focal segments of thickened wall, the artery often also exhibits medial attenuation; vascular outpouchings can develop in these portions of the vessel and sometimes rupture. +1
asapdoc  I thought this was a weirdly worded answer. I immediately ( stupidly) crossed of fibromuscular dysplasia since it wasnt a younger women =/ +26
uslme123  I was thinking malignant nephrosclerosis ... but I guess you'd get hyperplastic arteries first -_- +1
hello  The answer choice is fibromuscular HYPERplasia - I think this is different from fibromuscular DYSplasia (seen in young women); +36
yotsubato  hello is right. Fibromuscular hyperplasia is thickening of the muscular layer of the arteriole in response to chronic hypertension (as the question stem implies) +10
smc213  Fibromuscular Hyperplasia vs Dysplasia...... are supposedly the SAME thing with multiple names. Fibromuscular dysplasia, also known as fibromuscular hyperplasia, medial hyperplasia, or arterial dysplasia, is a relatively uncommon multifocal arterial disease of unknown cause, characterized by nonatherosclerotic abnormalities involving the smooth muscle, fibrous and elastic tissue, of small- to medium-sized arterial walls. http://www.medlink.com/article/fibromuscular_dysplasia +3
smc213  *sorry I had to post this because it was confusing!!!*Fibromuscular dysplasia is most common in women between the ages of 40 of and 60, but the condition can also occur in children and the elderly. The majority (more than 90%) of patients with FMD are women. However, men can also have FMD, and those who do have a higher risk of complications such as aneurysms (bulging) or dissections (tears) in the arteries. https://my.clevelandclinic.org/health/diseases/17001-fibromuscular-dysplasia-fmd +2
momina_amjad  These questions are driving me crazy- fibromuscular dysplasia/hyperplasia is the same thing, and it is NOT this presentation and it doesn't refer to arteriolosclerosis seen in malignant HTN! Is the HTN a cause, or a consequence? I read it as being the cause (uncontrolled HTN for many years) If it was the consequence, the presentation is still not classical! -_- +2
charcot_bouchard  Poor controlled HTN is the cause here +1
charcot_bouchard  Also guys if u take it as Fibromuscular dysplasia resulting in RAS none of the answer choice matches +1


submitted by hayayah(1212), visit this page
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Case of arteriolosclerosis.

Hyperplastic arteriolosclerosis involves thickening of vessel wall by hyperplasia of smooth muscle ('onion-skin appearance')

  • Consequence of malignant hypertension (>180/120 w/ acute end-organ damage)
  • Results in reduced vessel caliber with end-organ ischemia
  • May lead to fibrinoid necrosis of the vessel wall with hemorrhage; classically causes acute renal failure (ARF) with a characteristic 'flea-bitten' appearance
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masonkingcobra  From Robbin's: Fibromuscular dysplasia is a focal irregular thickening of the walls of medium-sized and large muscular arteries due to a combination of medial and intimal hyperplasia and fibrosis. It can manifest at any age but occurs most frequently in young women. The focal wall thickening results in luminal stenosis or can be associated with abnormal vessel spasm that reduces vascular flow; in the renal arteries, it can lead to renovascular hypertension. Between the focal segments of thickened wall, the artery often also exhibits medial attenuation; vascular outpouchings can develop in these portions of the vessel and sometimes rupture. +1
asapdoc  I thought this was a weirdly worded answer. I immediately ( stupidly) crossed of fibromuscular dysplasia since it wasnt a younger women =/ +26
uslme123  I was thinking malignant nephrosclerosis ... but I guess you'd get hyperplastic arteries first -_- +1
hello  The answer choice is fibromuscular HYPERplasia - I think this is different from fibromuscular DYSplasia (seen in young women); +36
yotsubato  hello is right. Fibromuscular hyperplasia is thickening of the muscular layer of the arteriole in response to chronic hypertension (as the question stem implies) +10
smc213  Fibromuscular Hyperplasia vs Dysplasia...... are supposedly the SAME thing with multiple names. Fibromuscular dysplasia, also known as fibromuscular hyperplasia, medial hyperplasia, or arterial dysplasia, is a relatively uncommon multifocal arterial disease of unknown cause, characterized by nonatherosclerotic abnormalities involving the smooth muscle, fibrous and elastic tissue, of small- to medium-sized arterial walls. http://www.medlink.com/article/fibromuscular_dysplasia +3
smc213  *sorry I had to post this because it was confusing!!!*Fibromuscular dysplasia is most common in women between the ages of 40 of and 60, but the condition can also occur in children and the elderly. The majority (more than 90%) of patients with FMD are women. However, men can also have FMD, and those who do have a higher risk of complications such as aneurysms (bulging) or dissections (tears) in the arteries. https://my.clevelandclinic.org/health/diseases/17001-fibromuscular-dysplasia-fmd +2
momina_amjad  These questions are driving me crazy- fibromuscular dysplasia/hyperplasia is the same thing, and it is NOT this presentation and it doesn't refer to arteriolosclerosis seen in malignant HTN! Is the HTN a cause, or a consequence? I read it as being the cause (uncontrolled HTN for many years) If it was the consequence, the presentation is still not classical! -_- +2
charcot_bouchard  Poor controlled HTN is the cause here +1
charcot_bouchard  Also guys if u take it as Fibromuscular dysplasia resulting in RAS none of the answer choice matches +1


submitted by radion(21), visit this page
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Hypercarbia causes cerebral vasodilation. If you have ever seen an intra- or acute post-op neurosurgical patient, or really any patient about to herniate, you can remember this because they will be hyperventilated to pCO2 around 25-30 to decrease ICP via cerebral vasoconstriction; in this case, we have the opposite. The curve of pCO2 vs cerebral blood flow is quite steep in the physiologic range meaning small changes in ventilation make a significant difference in CBF.

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smc213  FA 2018 p.486 +3
lynn  2019 - pg 489 +4
jaeyphf  2020 - pg 501 +2


submitted by hayayah(1212), visit this page
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Familial adenomatous polyposis is an autosomal dominant mutation. Thousands of polyps arise starting after puberty; pancolonic; always involves rectum. Prophylactic colectomy or else 100% progress to CRC.

Autosomal dominant diseases have, on average, 50% chance of being passed down to offspring.

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sympathetikey  I would say this is Lynch Syndrome (APC is usually thousands of polyps) but lynch syndrome would generally have a family history of other cancers as well, so you might be right. Either way, both autosomal dominant so win win. +3
smc213  uptodate states: Classic FAP is characterized by the presence of 100 or more adenomatous colorectal polyps +
dickass  @sympathetikey Lynch Syndrome is literally called "Hereditary NON-POLYPOSIS colorectal cancer" +14
fatboyslim  I think this actually is Lynch syndrome. Lynch syndrome can also develop colonic polyps but not nearly as bad as FAP. FAP has so many polyps you can't even see the normal mucosa. If you Google Lynch colonoscopy you can see that they develop a few polyps. +
rockodude  I forgot it was AD inheritance but regardless at the time I was confused because APC is a tumor suppressor so it needs two hits. I guess AD inheritance and then you need another hit to develop CRC kind of like familial retinoblastoma or li fraumeni syndrome +


submitted by haliburton(224), visit this page
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Mycoplasma pneumoniae cold agglutinins, no response to amoxicillin.

FA 2017: Classic cause of atypical “walking” pneumonia (insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate). X-ray looks worse than patient. High titer of cold agglutinins (IgM), which can agglutinate or lyse RBCs. Grown on Eaton agar. Treatment: macrolides, doxycycline, or fluoroquinolone (penicillin ineffective since Mycoplasma have no cell wall). ABC = Africa, Blindness, Chronic infection. D–K = everything else. Neonatal disease can be acquired during passage through infected birth canal. No cell wall. Not seen on Gram stain. Pleomorphic A. Bacterial membrane contains sterols for stability. Mycoplasmal pneumonia is more common in patients < 30 years old. Frequent outbreaks in military recruits and prisons. Mycoplasma gets cold without a coat (cell wall).

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johnthurtjr  Have you mixed Chlamydia in with Mycoplasma? +4
smc213  I mean the Q stem is not about Chlamydiae, but Chlamydiae does lack the classic PTG cell wall d/t decreased muramic acid = beta-lactam abx ineffective. FA 2018 p.148 +2


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In eukaryotic cells, two major pathways—the ubiquitin-proteasome pathway and lysosomal proteolysis—mediate protein degradation.

The major pathway of selective protein degradation in eukaryotic cells uses ubiquitin as a marker that targets cytosolic and nuclear proteins for rapid proteolysis.

The other major pathway of protein degradation in eukaryotic cells involves the uptake of proteins by lysosomes and digestion by proteases.

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missi199  Could I ask why it is not Lysosomal protease +8
smc213  "Certain viruses have evolved to recruit the cellular E3 ligases to induce the degradation of cellular proteins that might have harmful effects on the viral life cycle. For instance, the protein E6 of Human papillomavirus (HPV) recruits the cellular E3 ubiquitin ligase E6-AP to induce ubiquitination and degradation of p53, thereby allowing viral replication." from: https://www.mdpi.com/1999-4915/9/11/322/htm +5
smc213  USMLE Kaplan: A majority of cellular proteins are degraded via the ubiquitin proteasome pathway, including many proteins that play a role in maintaining cellular homeostasis. These include proteins that regulate the cell cycle, apoptosis, etc. +4


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In eukaryotic cells, two major pathways—the ubiquitin-proteasome pathway and lysosomal proteolysis—mediate protein degradation.

The major pathway of selective protein degradation in eukaryotic cells uses ubiquitin as a marker that targets cytosolic and nuclear proteins for rapid proteolysis.

The other major pathway of protein degradation in eukaryotic cells involves the uptake of proteins by lysosomes and digestion by proteases.

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missi199  Could I ask why it is not Lysosomal protease +8
smc213  "Certain viruses have evolved to recruit the cellular E3 ligases to induce the degradation of cellular proteins that might have harmful effects on the viral life cycle. For instance, the protein E6 of Human papillomavirus (HPV) recruits the cellular E3 ubiquitin ligase E6-AP to induce ubiquitination and degradation of p53, thereby allowing viral replication." from: https://www.mdpi.com/1999-4915/9/11/322/htm +5
smc213  USMLE Kaplan: A majority of cellular proteins are degraded via the ubiquitin proteasome pathway, including many proteins that play a role in maintaining cellular homeostasis. These include proteins that regulate the cell cycle, apoptosis, etc. +4


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I think this one has to do with "late dumping syndrome"-- basically, starchy foods cause hyperglycemia --> release of insulin --> catecholamine surge --> diarrhea, etc.

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merpaperple  It's not necessarily late dumping syndrome, this is the dietary guideline for early dumping syndrome too. Based on UpToDate and ScienceDirect this is how it works: Absent or dysfunctional pyloric sphincter -> food is rapidly emptied from the stomach into the small bowel -> hypertonic solution forms in the jejunum -> rapid fluid shifts from the plasma into the bowel -> hypotension and SNS response (eg. colicky abdominal pain, diarrhea, nausea, tachycardia) Simple carbohydrates are more hypertonic, I think. https://www.sciencedirect.com/topics/medicine-and-dentistry/dumping-syndrome +5
j44n  starches are complex carbs= more than 2-3 sugar molecules, if they have dumping syndrome they have decreased gastric transit time= more undigested carbs are delivered to the intestines and that gives you more carbs for bacteria to break down (flatulence and osmotic diarrhea) +


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