NBME 22 Answers : Block 1 : #26 = A 42-year-old man comes to the physician ...

NBME 22 Answers ↦

nbme22/Block 1/Question#26 (35.9 difficulty score)
A 42-year-old man comes to the physician ...
Hydrochlorothiazide🔍
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+8 upvote downvote
submitted by meningitis(397),

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ohraoiczihohyldetdro is OCD orf ipncogNeehr aDeiebts usniipdis euceabs it dylalparociax sacesu an anreisce in BP by nsnrciigae dumsio oribtsapon nad suth atwer apsino,btro oPmthaa apxsnile shit i.lneyc

seniospsemrD is ocenctrir eubaesc npou igfants fidul( istnreritc)o HAD is ndicsreea aigmnen DHA is binge seraeedl llenyCatr ubt is ont wgkrino in teh ynkeisd at teh 2V ceetpsror fo hte plelitehai ealrn selcl ta eotglcCinl u.dtc

nO atht ne,to eAoidmilr is sude for tLiuimh cddueni oenchipngre ID.

hello Where in Pathoma? I couldn't find it. +1

almondbreeze also sketchy says that thiazide s decrease the amount of lithium cleared--> lithium toxicity +1

paperbackwriter Agh confused as well because FA2019 (pg 562) says that thiazides are implicated in lithium toxicity D: +

paperbackwriter OOPS, please ignore last comment. I just realized that this Q stem never mentioned lithium. And on top of that @meningitis mentioned that amiloride is used if lithium induced. Apologies. +

+4 upvote downvote
submitted by gh889(86),

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cogincadr ot tpeotaud iaisthedz uaces a dmli ociompeylhv atest usht yuro CTP illw ees roem Na dna H2O -;>- yb icpplenir thta eht CPT aswlay srseorabb %06 of hwta it ee,ss it illw obasebrr reom awrte nad .aN

almondbreeze in sketchy as well +

+0 upvote downvote
submitted by asapdoc(50),

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Ptiaent ahs nehcgponrie asitbeDe ps.uinIids neO fo the saerttemnt si .hczHiahddiroyotlre

meningitis hydrocholorothiazide is DOC for Nephrogenic Diabetes insipidus because it paradoxically causes an increase in BP by increasing sodium absorption and thus water absorption, Pathoma explains this nicely. Also you shouldn't have chosen Desmopressin because upon fasting (fluid restriction) ADH is increased meaning ADH is being released Centrally but is not working in the kidneys at the V2 receptors of the epithelial renal cells at Collecting duct. On that note, Amiloride is used for Lithium induced nephrogenic DI. +1

-1 upvote downvote
submitted by waterloo(53),

Just to add thought process. Pt has excessive thirst, and urinating frequently but his Serum osmolality is increased...which means he has to omuch solute in his blood and his ADH is not working.

ADH not working can be due to Central DI or Nephrogenic DI. Central DI is when pt has lack of ADH but in this vignette they say the ADH is increased --> must be nephrogenic.

I don't think you need to know that HCTZ paradoxically works for nephrogenic. I think you can save time and just memorize FA's tx choices for Nephrogenic DI - HCTZ, amiloride, and indomethacin. You could argue it's good to know mechanisms, but I think knowing the drug names and their MOA, you'd be able to figure it out if they went for a 4th order reasoning (there's already enough thinking to do in this question)