NBME 21 Abnormal brain development (NBME Answers)

NBME 21 Answers

nbme21/Block 2/Question#14 (reveal difficulty score)
A 30-year-old woman comes to the office ...
Abnormal brain development 🔍 / 📺 / 🌳
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+34
submitted by ∗xxabi(277),

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E5DP- nhisitiobr (.g.e dl,ieilfans idl)taflaa era eciidtadn for DE yb ayw fo anengsiicr boodl folw in eth usrpco cmoavursen eelabdl( )D of eth epsin

+25
submitted by ∗taway(33),

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Tshi inotequs is edsahrp nsg,atlrye tub s'it seieallstyn inagsk thaw" douwl phanpe if iths sowan'm hypsiormydhtio eecamb olotendnrucl roev eht usoerc of rhe ?pregnny"ca

yerncrult reh TSH si oodg -gt&;- ollwtcd-rnoelel O tYLHsCPTyImiEHypdAoihrTho hhig STH -;&g-t reh srhdyiimyhopot muts TON eb ldtnloelrol-wec e(ud ot iorsinutdp fo het H/R/HTT3STT4/ nneecrdio ais)x

,So nwo htta we sutrdnadne thta het quesniot si skigna wt"ah owudl aphnep fi ehr yhioprmstoyihd aws ur?o"clnndleot

e:sAwnr imnersitc

I nkthi htta iths oisqeunt is aphdser ,yiuoloratsc btu raf eb ti rfom em to iztiecicr hte LEUMS cisingenl od..ab.r

yotsubato I think that this question is phrased atrociously, Just like the rest of the NBME +23

b1ackcoffee exactly how does maternal hashimoto can cause cretinism? +

notyasupreme @b1ackcoffee, it's not maternal hashimoto, basically you just have to disregard the ENTIRE question stem and the last part of the sentence (if the mom's TSH goes up) means that there's hypothyroidism going on, which causes cretinism. +4

b1ackcoffee Thanks you @notyasupreme! +

+10
submitted by direwolf(10),

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sTih sah ot od wiht nigtnddunreas wto ih,sngt atht lraantme todhyyipoimrhs is klneid ot enaimrireCu/lnts edemeopntvl of the tsufe, adn rmnalo neprcgnay opgy.yloshi nI g,npaeynrc eadsirnec moeroshn eutlisamt vlrei ditouropnc fo riaouvs netsroip ielk xSe mHrnoeo iinndBg boinulGl ny,ioxTGHeBr(hS) gdiinnB niblolGu ,B)(GT .etc Meor TGB duepcdro = meor /3T4T is .bundo Less 4T/3T ecusas oemr TRH la,sreee meor STH erlesa,e dan meor T4T3/ oipcdtuorn itlun reef 4T3T/ leevls aer cbka to .mlnaor nI a alonmr ca,nrpygen itsh phaespn on roe.mpbl nI oseonme ihwt tgespirnex-i ihhotsipyoymrd ough,ht laraedy sha adpmreii /4TT3 o,ndiutrpco adn wt'on eb bael ot pkee up twhi naeiscdre eam.ddn ihrTe T3 lliw ir,se tub hits not'w lesrut in iaercsned T3/T.4 Tclylia,yp omwen thiw iHtmohs'osa sngredii ot get gennatpr llwi nede to rnsceiea rehti roxvyeleohnti esod ni nipttociiaan fo tihs cnyrnagep ngcea.h

+4
submitted by thotaak(5),

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marNloyl mnalerta 3/4T era ruereqdi orf ftale inarb npveeeotdlm rfbeoe ftlea tirhoyd ldnga is mdof.re ndA etfar felta dtryioh agndl si emf,rdo flate 3T4/ spelh in inrab eedlvpet.mon oS neearics THS asmne esaddecer eramltan 3/4T dan sthu haev abn ranbi lonmvedt.eep Adn yse /34T cseossr na.taclpe

thotaak According to Robbins pathology +1

+4
submitted by medschoollovin(14),

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tmuiAonuem isoityrhdit ak(a haH)ootism + npnt;-gat&ge-r kinTh ubaot psbilotiyis fo talef hrtsmodiophiyy edu ot atoydbin tmeadied eatnlrma yhroths.iypmoid daeLs ot .irnCiemts Fisdginn in tnfnai are the 6'P P(to ,elbyl Pa,le ffyuP feca, utondgPirr suimiucb,l tPretaobnru ouetgn, dan roPo aiBrn npeodl.vteem

neonem I don't understand the last part of this question stem though... if the mother's TSH *increases* during pregnancy? Wouldn't this further increase her (and/or the fetus's) production of T4 and thus counteract the hypothyroidism? +

poojaym @neonem no. Autoimmune hypothyroidism is a destruction of the thyroid gland, and a decrease in production of T3/T4. An increase in TSH means that there is not enough T3/T4 to inhibit TRH, and so TSH is being released to stimulate the thyroid gland. +39

arezpr TSH, T3, T4 and thyroglobulin cannot cross the placental barrier. +

chamaleo @arezpr although those hormones can't cross, the autoantibodies from Hashimoto's can +1

yotsubato The baby has its own TSH though +

sbryant6 TSH comes from the pituitary, and act on the thyroid. Autoantibodies attack the thyroid, so TSH doesn't work. +

kimcharito no goiter then? +

lola915 I think there is no goiter because the baby's thyroid gland has not fully developed and these immunogloblulins from the mother could attack the thyroid gland leading to issues with it's development. +

+2
submitted by ∗apurva(87),

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eTh rale inhtg si HST, ,T3 4T nda hultnyrooglib tnocna cssor .lentaapc HRT, dneIoi, TSI cna scorf. sI mtheor sha hgih SHT cngisid(eorn ymirrap isyp)thridmhoyo &t—;g rooP nbira e pltmeIedonvf roemht ahs TSI to)imo(Hahs &tg—; corss hte ltaapenlc raberri sn—eIreca ni ihoydrt nadlg (May prseten ithw doitrrs at ib.hrt

demihesmisome Ahhhhh Thank you. This was what I was trying to understand. +1

apurva please note that free t4 can cross the placenta +3

+1
submitted by ∗b1ackcoffee(72),

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tlcxeya how oeds anltrmae oitsamohh nac ucsea ritcsm?eni

lola915 Hashimito is caused by antibodies against thyroid peroxidase and thyroglobulin. Those antibodies can cross the placenta and affect babies thyroid gland causing congenital hypothyroidism. +1

+1
submitted by ∗thisisfine (28),

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I hitnk tihs steg at a ocntepc tarleed ot hiotdry vlseel nda sn/ogtny.renreaegpc

gosetrnE acniersse eth elvel of dbtxiih-gonynrein o,ulbnilg hwich omlpiyaterr cdsaeeres fere 4T nda ,T3 dna seircnase STH unitl hte oildtindaa BGT smcbeeo a,arsdutte adn namrol evlles era sro.retde

iSnec shti tpnaeit ash umameutnoi rttoiiihd,ys adn urqresei xiyohrt,en hnew erh refe T4 asre,scdee dan hre STH esgo ,up hse wotn emka raext 4.T So seslun esh sncsieera her hneotyrxi deso, esh illw be poytdriyhho t-;g-& etsrncmii in het efuts

+0
submitted by neolidone(2),

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shTi is a yvre yrtkci uesiqtno in ertsm fo sginrhap ti. hyeT amke su htkni touba whta feftec high THS esdo on a fsetu hwlei ti lleyar meant athw anc ehpapn ot hte byba ni na y-oaidniamdetetdb omshipdyoryhti Soe.mrtho eysakn os so en..yksa.

+0
submitted by ∗seagull(1749),

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7i//hie.C2ncl/imst.wc/phtpv8PM./0n:wbco/tga2.nr9w1lms

siTh tilcare lafis ot inneotm orop nibra eemnetvopdl ni hiHPyEmtYrdo.siR hTe auotrh mtus evha taenm YmHriP.hOodiyts

sihT tqesinou tsuspe me ot no dne.

aesalmon I agree, the article you linked states "signs of fetal hyperthyroidism such as tachycardia, intrauterine growth retardation, cardiac failure, and the development of fetal goitre" I chose answer E during the exam - "Thyroid gland enlargement" Still trying to understand how they linked cretinism to a case where the mother's hypothyroidism was well controlled, and then asked for the sequelae if her TSH increased. Maybe increased TSH is supposed to indicate worsening hypothyroid - low T3/T4 needing to be stimulated by TSH? +

+0
submitted by ∗tissue creep(120),

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My ohthutg eprscos asw if eth ehtorm has sdaceerni S,HT edh's be giusn reom inideo ot rcpdeuo 3/T4. nenMgai ssle uldwo be ebla ot tge to the ybab rfo bnria eomtnpvdele.

+0
submitted by ∗hayayah(1145),

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inmrtseCi (icnnolaegt sidyropmtyih)oh si eth tsmo nmoocm usace of aettalebr nltmae ys.bditalii eusCas roop niabr novel.deptem

+0
submitted by varunmehru(5),

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eTh mthoer sha mintmaouue sirhodittyi adn mrnttaeet is vngie for hryodohymisitp ylon. wyh esod it ttrema fi het temhso'r HST is ghhi or ow?l utnedAioosibat wluod sltli be tpenres dna ethy lwoud aalwys ecusa inrmecsit iepctveisrre of mtoehr normehso ee.llv Itsn' t?i