Welcome to tyrionwillโs page.
Contributor score: 22
Comments ...
tyrionwill
probably cannot find any abnormality on the skin surface or no obvious mass found along body. only biopsy from the painful muscle can detect the larve of trichinella spiralis. however, skin change due to onchocerca is popular to be easily found when doing PE
+
Subcomments ...
tyrionwill
how would I know where is superficial and where is the deep layer?
+
sexymexican888
@tyrionwill if you look at D and E they look more like muscular tissue than glandular tissue (like A,B,C) so thats how you can orient yourself and know that the bottom layer is by D and E so A must be more superficial.
+
frijoles
I don't see where it says that gout is associated with kidney stones. Gout is more commonly caused by underexcretion than overproduction, yes? And this patient has renal insufficiency, yes? So if anything, they have LESS uric acid in the urine and are LESS likely to have stones. It's the reason they have gout to begin with (because it's out of the urine and into the blood).
This answer would make sense if the gout was due to overproduction but there is no evidence of that here. This isn't a very good question imo. Please lmk if I'm missing something here.
+3
tyrionwill
hyperuricemia may cause kidney stone if urine turns to be acidic or condensed. so I think this question is asking a general possible complication.
+
i_hate_it_here
I think that what they were trying to ask was what could also occur due to the predisposing factor that led to gout. The patient was on a loop diuretic which can lead to hypovolemia. Kidney stones and gout occur more frequently when the substrates are able to concentrate in low volume.
+3
kard
furosemide and acetazolamid---> Nephrolithiasis!
+1
millan
I thought it was osteoporosis due to calcium loss????
+
ibashli
I also put osteoporosis at first but I think that's with chronic use of furosemide. She has only been on it for 1 month so it's more likely that she will develop a stone from uric acid accumulation than osteoporosis from a little excess loss of calcium, especially because of her "Gradually increasing serum creatinine," suggesting that she is getting gradually worse and worse at filtering out the uric acid from her body --> worsening arthritis and risk of stones.
+
hello
...COVID-19 is transmitted via respiratory droplets.
+4
123ojm
Right but some research has come out saying it's also spread fecal-orally. So I'm wondering what I'm missing in this question.
+
tyrionwill
Don't trust US CDC in this pandemic. They always downplayed the truth. Cronavirus does spread mainly by droplets, when they drop, they contaminate the surface, then fecal-oral could be a second pathway. Wearing mask, social distancing are both to prevent a droplet.
+
boostcap23
I thought covid used to be low yield when this test was made and they didn't mention helical so I didn't pick it smh I'm an idiot.
+1
neonem
I don't think you could have *totally* ruled out the other answers - I picked glycogen breakdown because it sounded kind of like Von Gierke disease (glucose-6-phosphatase) to me: characterized by fasting hypoglycemia, lactic acidosis, and hepatomegaly since you're not able to get that final step of exporting glucose into the blood. However, I guess in this case you wouldn't see that problem of glycerol/fructose infusion not increasing blood glucose. Nice catch.
+28
vshummy
I think you were super smart to catch Von Gierke! Just to refine your answer b/c I had to look this up after reading your explanation, von gierke has a problem with gluconeogenesis as well as glycogenolysis. So theyโd have a problem with glycerol and fructose but also galactose since they all feed into gluconeogenesis before glucose-6-phosphatase. Great thought process!
+24
drmomo
glycerol and fructose both enter the pathway thru DHAP and glyceraldehyde-3-ph. Galactose enters thru Gal-1-ph to glu-1-ph conversion
+3
linwanrun1357
In this cause (fructose bisphosphatase deficiency.,),fructose should help to increase serum glucose, bcz it can become into glucose-6-P by hexokinase.
Therefore, this question makes me confused....
+
krewfoo99
According to uworld, fructose infusion will not increase blood glucose levels in Von Gierkes Disease as well
+
atbangura
I believe Von Gierke is not a plausible answer choice because a galactose infusion would still not see an elevation in glucose levels. Remember, galactose could be converted to galactose 6 phosphate, but in order to complete gluconeogenesis and allow glucose to leave the Liver for an increase of its concentration in the blood, the patient would still need glucose 6 phosphatase which is eliminated in Von Gierke.
+2
lilyo
So what disease is this??? I mean couldnt we have just answered the question based on the fact that the patient responds to galactose being infused and we know that galactose feeds into gluconeogenesis?? I am so confused.
+1
djtallahassee
Its Hereditary Fructose intolerance right? gets sick after fructose and I guess glycerol can jump in via aldolase B on this pathway via page 74 of FA2019. It looked like a fructose thing to me so I just marked out the other ones and moved on.
+1
paperbackwriter
@djtallahassee I was wondering same, but hereditary fructose intolerance also results in inhibition of glycogenolysis :/ confusing question.
+
amt12d
A much simpler way to think about this, without trying to figure out a diagnosis, I looked at the time frame for when the child was presenting. He has eaten poorly for 3 days, by now, his glycogen breakdown is gone. His body would be trying to make glucose, therefore, gluconeogenesis is impaired, not glycogen breakdown.
+7
tyrionwill
if fructose kinase is not available (fructose intolerence), then some fructose may go to F-6-P by hexokinase, then goes to G6P if gluconeogenesis is needed. however this patient's fructose kinase was intact, so no fructose would have go to F6P, so there would be no blood glucose increment after injection of fructose.
+1
shayokay
You had to know that fructose and glycerol enter glycolysis at DHAP/G3P, and galactose enters glycolysis at G6P (gal-> gal-1-p -> glu-1-p -> glu-6-p). This means that one of the 3 enzymes between G6P and DHAP/G3P is not functioning properly. Most likely this would be fructose-1,6-bisphosphatase because there does not appear to be anything wrong with glycolysis.
"Fructose-1,6-bisphosphatase (FBP1) deficiency is characterized by episodic acute crises of lactic acidosis and ketotic hypoglycemia, manifesting as hyperventilation, apneic spells, seizures, and/or coma. Acute crises are most common in early childhood; nearly half of affected children have hypoglycemia in the neonatal period (especially the first 4 days) resulting from deficient glycogen stores. Factors known to trigger episodes include fever, fasting, decreased oral intake, vomiting, infections, and ingestion of large amounts of fructose."
https://www.ncbi.nlm.nih.gov/books/NBK550349/
+1
shayokay
Also, even though Von Gierke is categorized as a glycogen storage disease it is really a problem with gluconeogenesis not glycogen breakdown. So even if you thought this was VG, you still could have gotten the right answer. In VG, any monosaccharide other than glucose (fructose, galactose, glycerol, etc.) will not raise the plasma glucose level because they all require gluconeogenesis to be converted into glucose and this cannot happen because there is no glucose-6-phosphatase. This is why the treatment for VG is frequent oral glucose in the form of cornstarch and avoidance of fructose and galactose.
+
tyrionwill
Yes, VG makes the liver into muscle, where all sugars (except glucose) can only be burned to lactate+glycerol(from glycolysis), ATP (from TCA metabolism, to give uric acid), and fat deposit (from glycerol+pyruvate going to FA+TG) to worsen the situation. Sugar cannot be made into glucose in liver for other tissues.
+
tyrionwill
in the question, it says absence of MHC-I presenting cells. I guess the meaning is lack of MHC-I. IF TAP is missing or dysfunction (bare lym syn type-1), MHC-I should be there, however Ag cannot be loaded to the MHC-I. Can anyone help me to understand more.
+1
peridot
@tyrionwill From wiki: "The TAP proteins are involved in pumping degraded cytosolic peptides across the endoplasmic reticulum membrane so they can bind HLA class I. Once the peptide:HLA class I complex forms, it is transported to the membrane of the cell. However, a defect in the TAP proteins prevents pumping of peptides into the endoplasmic reticulum so no peptide:HLA class I complexes form, and therefore, no HLA class I is expressed on the membrane. Just like BLS II, the defect isn't in the MHC protein, but rather another accessory protein."
+1
j44n
i hate this question because MHCI is on all nucleated cells. So this person is literally a bag of RBC's
+1
soccerfan23
@j44n Not quite. It's true that MHC I is on all nucleated cells. Because of the TAP mutation, these cells don't express MHC I on their membranes. But these cells still exist. That is what is meant when the vignette says "flow cytometry shows absence of class I MHC-expressing cells.
+1
usmile1
Does anyone know if SIADH is associated with hypertension? I don't think it is due to the body's response of downregulating aldosterone, but if someone could verify that I would appreciate it.
+
tyrionwill
SIADH -> excessive ADH -> water retention -> atrium excretes more ANP, ventricule excretes more BNP -> water is excreted more. So that is why not too much plasma volume increment, resulting mostly normal BP.
+
tyrionwill
Yes agree! Lymphocyte count is so low, which suggest HIV.
+
xxabi
Is there a situation where you would pick fibromuscular dysplasia over atherosclerosis if given both options? Thanks for your help!
+6
baconpies
Atherosclerosis affects PROXIMAL 1/3 of renal artery
Fibromuscular dysplasia affects DISTAL 2/3 of renal artery
+65
gonyyong
Why is there โ size in both kidneys? This threw me off
+3
kateinwonderland
@gonyyong : Maybe because narrowed renal a. d/t atherosclerosis led to renal hypoperfusion and decrease in size?
+1
drdre
Fibromuscular dysplasia occurs in young females according to Sattar Pg 67, 2018.
+12
davidw
Normally you will see Fibromuscular dysplasia in a young female 18-35 with high or resistant hypertension. She is older has a history type II DM predispose you to vascular disease and normal to moderate elevation in BP
+9
suckitnbme
@gonyyong there's bilateral renal artery stenosis. The decrease in size of both kidneys should be from atrophy due to lack of renal blood flow.
+5
tyrionwill
1 year ago, she did not present any physical or Lab abnormalities. This means she must not suffer fibromuscular dysplasia, otherwise she must have presented renal abnormalities for a long long time, or even before DM-2.
+2
rockodude
a little surprised that atherosclerosis leading to bilateral renal artery stenosis and shrunken kidneys could happen that quickly after everything was A okay the year prior
+1
tyrionwill
how about the choice of D: 1 in 4 have 50% function, which is true. shall 50% function needs transfusion?
+
tyrionwill
In FA, it defines beta thalassemia into minor (HbA2 >3.5%) and major (both HbF and HbA2 go further up), and the major needs transfusion frequently. How can we take this classification based upon quantitive way like in this question? how much percentage of function left does not need a frequent transfusion?
+
azibird
D says one in TWO, not one in FOUR.
+6
hemehero
Is there a way to know that B+B0 will = 25% function. I was stuck between 25% function and 10% function, but couldn't figure out how to reason between the two of them.
+3
neil_simmons
The question says the mother has a mutation known to cause 50% decrease in beta-globin gene function of one allele. So if one allele is working at 50% (B+) and the other allele is working at 0% (B0), then that would mean that particular set of alleles would function at 25%.
+2
twich22
The Key here is the woman has 50% decrease in function "Of one allele". Its a stupid way to word it, But it means that one allele works at 50%, which would be B+. So if you have a B0/B+ offspring, the B0 gives 0% and the B+ works at 50% capacity, so you only have 25% of normal.
+
murad
some one explain this to me please, how come if the mother with his genotype BB+ has 50% function of one allele. while if we get her offspring punnet square we consider the one that has the same genotype as her BB+ of having 75% function??
+
tyrionwill
how about the choice of D: 1 in 4 have 50% function, which is true. shall 50% function needs transfusion?
+
tyrionwill
In FA, it defines beta thalassemia into minor (HbA2 >3.5%) and major (both HbF and HbA2 go further up), and the major needs transfusion frequently. How can we take this classification based upon quantitive way like in this question? how much percentage of function left does not need a frequent transfusion?
+
azibird
D says one in TWO, not one in FOUR.
+6
hemehero
Is there a way to know that B+B0 will = 25% function. I was stuck between 25% function and 10% function, but couldn't figure out how to reason between the two of them.
+3
neil_simmons
The question says the mother has a mutation known to cause 50% decrease in beta-globin gene function of one allele. So if one allele is working at 50% (B+) and the other allele is working at 0% (B0), then that would mean that particular set of alleles would function at 25%.
+2
twich22
The Key here is the woman has 50% decrease in function "Of one allele". Its a stupid way to word it, But it means that one allele works at 50%, which would be B+. So if you have a B0/B+ offspring, the B0 gives 0% and the B+ works at 50% capacity, so you only have 25% of normal.
+
murad
some one explain this to me please, how come if the mother with his genotype BB+ has 50% function of one allele. while if we get her offspring punnet square we consider the one that has the same genotype as her BB+ of having 75% function??
+
tyrionwill
probably cannot find any abnormality on the skin surface or no obvious mass found along body. only biopsy from the painful muscle can detect the larve of trichinella spiralis. however, skin change due to onchocerca is popular to be easily found when doing PE
+
tyrionwill
whether resistant or sensitive, depends on the region, not on the species
falci coming from Hatii could be sensitive
+
tyrionwill
also probably B12 deficiency: lost vibration sensory, weakness of extremities, and possible ataxia if more information is collected...
Syphilis will not impair muscle strength.
+
therealslimshady
I remember Boards and Beyond said that you never want to pick any statements that sound "scolding", plus it couldn't be much help to just say "stop arguing", it's better to find out information on what's causing the arguing so that you can stop it entirely, which choice B will allow you to do.
+
tyrionwill
stress is the thing to worse the condition of DM, and will be better after being seen, comforted, and accepted.
+
tyrionwill
low IgG in response to infection/vaccination leads to broad bacteria and virus infection or reactivation.
bacteria: strep pneumonia, Hib
virus: JC, HBV, CMV...
+
tyrionwill
Yes, good point to remember.
In the category of FA stimulants, 2 agents has sympathetic activity: 1)MDMA; 2)PCP
+
jackie_chan
Basically how I solved it, all the other drugs are downers
+
jackie_chan
Even tho ketamine has sympathomemetic effects, they would be widly tripping, they dont call it falling into a K-hole for nothing.
+
tyrionwill
mostly the age difference exceeds 4 years trigger so called "incongruent with their age".
age incongruence plus signs of being forced, like this case which the 4-year-old boy was found crying, lead to suspicious more on sex abuse than sex play.
+2
tyrionwill
under Bortezomib, the proteasome cannot digest viral Ag and presents it to the membrane-bonded MHC-I. Therefore CD8-Tc cannot recognize the host cells containing relapsed VZV. That is probably why shingles is one of the popular side effect of Bortezomib.
+
kcyanide101
The drug inhibits proteosome. Hence there is no fragment available through TAP inside CD4 cell to load unto MHC I.... As such the CD8 presentation to Tcell is prevented. The accumulating proteins inside the CD8 cells which are not being broken down by the proteosome cause it to undergo apoptosis
+
tyrionwill
the question asks the reason of no impact on its survival. if a protein translated from a wrong mRNA loses its function, how can we say the bacteria will still survive well? if there is always fatal error happened during mRNA transcription, and always leading to fatal dysfunctional protein, how can the bacteria and its progeny still survive?
so the point will be whether the fatal errors will always happen during transcription? I dont know...
+
tyrionwill
actually FA and NBME seem to have made a wrong statement that RNA polymerase has no proofreading function. RNA polymerase has more fidelity to DNA than DNA polymerase by 2 ways: 1) highly selection of correct nucleotide, and 2) proofreading.
(Jasmin F Sydow and Patrick Cramer, RNA polymerase fidelity and transcriptional proofreading: https://pure.mpg.de/rest/items/item_1940413/component/file_1940417/content)
however, if survival of the species refers only to the reproduction of progeny, mRNA mutation has nothing with the progeny.
+1
fatboyslim
@tyrionwill That's a good question. I think though it is less likely for a transcription error to cause a fatal protein error. Maybe it can cause the bacteria to be less virulent or something...
+
tyrionwill
the question asks the reason of no impact on its survival. if a protein translated from a wrong mRNA loses its function, how can we say the bacteria will still survive well? if there is always fatal error happened during mRNA transcription, and always leading to fatal dysfunctional protein, how can the bacteria and its progeny still survive?
so the point will be whether the fatal errors will always happen during transcription? I dont know...
+
tyrionwill
actually FA and NBME seem to have made a wrong statement that RNA polymerase has no proofreading function. RNA polymerase has more fidelity to DNA than DNA polymerase by 2 ways: 1) highly selection of correct nucleotide, and 2) proofreading.
(Jasmin F Sydow and Patrick Cramer, RNA polymerase fidelity and transcriptional proofreading: https://pure.mpg.de/rest/items/item_1940413/component/file_1940417/content)
however, if survival of the species refers only to the reproduction of progeny, mRNA mutation has nothing with the progeny.
+1
fatboyslim
@tyrionwill That's a good question. I think though it is less likely for a transcription error to cause a fatal protein error. Maybe it can cause the bacteria to be less virulent or something...
+
tyrionwill
Yes! The key point is the normal electrophoresis. Hemoglobin will not show any abnormalities until least one single allele of Hb fully develops mutation.
alpha chain of Hb is contributed by two points within one single allele, while beta chain of Hb is made of only one point in one single allele, therefore:
-- in alpha thalassemia Hb electrophoresis will be normal if only one point gets mutation, i.e., aa/a- which we call it the "minima type". If two points get mutation, i.e., cis aa/--, or trans a-/a-, the "minor type", the Hb electrophoresis will be either abnormal(Hb Barts 3-8%) or still normal. overall, we assume the parent both are the minima type, so their children have 50% chance to be the minor type, 25% to be fully normal, and 25% to be the trans minor.
-- However in beta thalassemia, the mutation of one allele will lead to whole allele changed, so we just need the mutation once to generate an abnormal Hb electrophoresis result.
+1
uslme123
No hepatosplenomegaly, ascites, or edema through me off. We that being said, I shied away from cirrhosis. I thought that he showed signed of depression, so I went with the thyroid. But who's to say he isn't injection anabolic steroids?!
+7
catch-22
The principle is you can get liver dysfunction without having HSM, ascites, etc. Liver disease is on a progressive spectrum.
+14
notadoctor
He likely has hepatitis B/C given his history of intravenous drug use. I believe both can have liver dysfunction but may or may not have ascites, whereas the type of damage we would expect from alcohol that would match this presentation would also show ascites.
+
charcot_bouchard
For Ascities u need to have portal HTN. Thats a must. (unless exudative cause like Malignancy)
+2
paulkarr
For anyone who needs it; the FA photo is kinda burned into my mind for these questions. NBME has some weird infatuation with this clinical presentation.. FA (2019) Pg: 383 "Cirrhosis and Portal HTN".
+5
snripper
@paulkarr the problem was that the FA image was burned into my mind so without no ascites or edema threw me off of cirrhosis.
+
tyrionwill
cirrhosis doesn't present hepatomegaly, instead, the liver could be shrunken.
+2
avocadotoast
Cirrhosis (most likely due to alcoholism in this patient) leads to an increase in sex hormone binding globulin, causing a relative increase in estrogen compared to androgens. Cirrhosis doesn't always have to present with ascites and adema. I agree with @catch-22 that liver disease is a spectrum. This patient does not have ascites because his liver is still able to produce enough albumin to maintain oncotic pressure in the blood.
+1
yotsubato
His glycogen concentration is high, since he's been hyperglycemic with lots of insulin until birth.
+6
alexb
Also explains why he's 12 pounds.
+4
krewfoo99
Also, think of it like this:
Insulin causes hypoglycemia, thus this baby must have increased insulin. It is also an anaobolic hormone which is clear by the babys weight.
Insulin increases glycogen synthase activity, and causes an increase in concentrations of glycogen. Decrease in insulin would do exactly the opposite
+1
tyrionwill
fetus of a mom with DM will develop pancreatic beta cell hyperplasia, which leads to insulinemia trying to reduce the blood glucose. after birth, the excessive blood glucose will be automatically withdrawn while the insulin at that moment is still high, which leads to hypoglycemia.
+3
eimal786
high insulin causes positive effect on Fructose 2 6 bisphophate, which will stimulate PFK1 and inhabits F.2.6 Bisphosphatase, this turns off gluconeogenisis.....what the question is exactly asking about.....
+
uslme123
Standard lab values are incorrect, way to go NBME.
+3
wutuwantbruv
I think they mean to put mm Hg. Normal CSF pressure is about 100-180 mm H20 which equates to about 8-15 mm Hg.
+4
alexb
I lost a bit of time wondering about that ugh lol
+1
mjmejora
I thought there must be an obstruction in the ventricles somewhere preventing csf from getting to the spine. so pressure is low in spinal tap but in the head it must be really high.
+2
llamastep1
Pseudo tumor cerebri can have normal ICP. Who knew
+1
tyrionwill
Hi, mjmejora, MRI did not see anything abnormality, couldn't this mean that there was no obstruction in the ventricles?
+1
tyrionwill
95%CI = M ยฑ Z(SE) instead of SD
116-113 = 3 within 2SE, not 2SD
SE = SD/extract the square root of n = SD/2 and SD = 2SE
+
tyrionwill
Sorry I made a mistake, neglect the abobe
+
tyrionwill
if you use Mean ยฑ 2SD = 95%CI to know SD, then use Mean ยฑ 3SD to only know 99.7%CI, a bit larger than 99%CI
+
tyrionwill
95%CI = M ยฑ Z(SE) instead of SD
116-113 = 3 within 2SE, not 2SD
SE = SD/extract the square root of n = SD/2 and SD = 2SE
+
tyrionwill
Sorry I made a mistake, neglect the abobe
+
tyrionwill
if you use Mean ยฑ 2SD = 95%CI to know SD, then use Mean ยฑ 3SD to only know 99.7%CI, a bit larger than 99%CI
+
tyrionwill
95%CI = M ยฑ Z(SE) instead of SD
116-113 = 3 within 2SE, not 2SD
SE = SD/extract the square root of n = SD/2 and SD = 2SE
+
tyrionwill
Sorry I made a mistake, neglect the abobe
+
tyrionwill
if you use Mean ยฑ 2SD = 95%CI to know SD, then use Mean ยฑ 3SD to only know 99.7%CI, a bit larger than 99%CI
+
yb_26
They are just asking about side effect of statins, not about treatment of hypothyroidism
+5
mjmejora
Hypothyroidism is just a red herring.
+
ususmle
statins cause both hepatotoxic and mypopathy so I want for hepatotoxic:( I thought usmle expects different stuff
+1
drzed
Statins don't cause 'toxic hepatitis' they just cause a mild asymptomatic rise in LFTs that is reversible with discontinuation of the drug. The more worrisome side effect is of course, myopathy
+2
tyrionwill
statins cause both liver injury and myopathy in a dose related, so kidney failure increases their dose, which leads both liver and muscle risk elevated;
Pravastatin is said less liver concerns but the myopathy, so choose myopathy when renal failure.
+1
tyrionwill
When I got 25.9 and found nothing exactly matched, I guessed that the maintenance dose might be a bit more due to the bioavailability. So this antibiotic probably was not an I.V. formula, but an oral one, with a roughly 90% BA.
+2
eradionova
Well then it could have been equally likely that it had a 50% BA and the answer would be 51.8 exactly. I almost considered picking that but in the end stuck with the one that was closest to my answer lol
+2
probably only 2 parasites are related to nodules: 1. trichinella spiralis: muscle mass, muscle ache, systemic symptoms 2. onchocerca volvulus: skin nodules, without significant systemic signs until blindness