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NBME 21 Answers

nbme21/Block 3/Question#6

A 40-year-old African American woman comes to the ...

1,25-Dihydroxycholecalciferol

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 +7  upvote downvote
submitted by nosancuck(43),

This b has Sarcoidosis so her granulomas be activatin dat VitD

sbryant6  Your mom activates my VitD. +  




This patient definitely has Sarcoidosis. Clues in question stem: -African American Female -Erythema Nodosum -Bilateral Hilar Adenopathy -Hypercalcemia (due to 1α-hydroxylase–mediated vitamin D activation in macrophages).

FA 2018 (P. 658)





 +2  upvote downvote
submitted by dr.xx(47),

In sarcoidosis, hypercalcemia normally suppresses the release of PTH and therefore the production of calcitriol (1,25-dihydroxycholecalciferol), but in sarcoidosis and other granulomatous diseases, activated mononuclear cells (particularly macrophages) in the lung and lymph nodes produce calcitriol (1,25-dihydroxycholecalciferol) from calcidiol (25-hydroxycholecalciferol) independent of PTH.

https://www.uptodate.com/contents/hypercalcemia-in-granulomatous-diseases

dr.xx  ~~In sarcoidosis,~~ +  
hello  Probably a typo in the first 2 words of the explanation -- not sure what they meant to say instead +  
drdoom  I believe @dr.xx meant to strikeout "In sarcoidosis" from his comment; double-tilde is the markdown plaintext that usually accomplishes that. +  




 -13  upvote downvote
submitted by rocmed(0),

A "serum Ca concentration of 16 mg/dL" as well as "bilateral hilar adenopathy" indicate squamous cell carcinoma which commonly produces PTHrP, NOT PTH!!! PTHrP will act just as PTH, stimulating the kidney to produce 1,25-(OH)2 Vit D.