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NBME 22 Answers

nbme22/Block 1/Question#26

A 42-year-old man comes to the physician because of ...

Hydrochlorothiazide

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 +7  upvote downvote
submitted by meningitis(269),

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.

Desmopressin is incorrect 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.

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(55),

according to uptodate thiazides cause a mild hypovolemic state thus your PCT will see more Na and H2O --> by principle that the PCT always reabsorbs 60% of what it sees, it will reabsorb more water and Na.

almondbreeze  in sketchy as well +  




 +1  upvote downvote
submitted by asapdoc(31),

Patient has nephrogenic Diabetes Insipidus. One of the treatments is Hydrochlorthiazide.

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