NBME 22 Jejunum (NBME Answers)

NBME 22 Answers

nbme22/Block 1/Question#29 (reveal difficulty score)
A 28-year-old man comes to the emergency ...
Jejunum 🔍 / 📺 / 🌳 / 📖
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submitted by ∗hpsbwz(98)

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The way I got this was first based off the MRI, it's definitely not the stomach, as it's no where near the stomach. Going off that, the duodenum comes right off the stomach, leading me to also cross that out. Then from the stem it said LEFT MIDabdominal pain, allowing me to cross out appendix (also no fever) and therefore cecum as well. Only remaining choice you're left with is jejunum!

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kevinsinghkang CT, not MRI* +

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submitted by ∗mcl(670)

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These images are useful in combination.

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submitted by ∗medstudent(18)

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This is how I narrowed it down:

It is on the left. Not cecum, appendix, or stomach (it’s the way left on CT and small).

This leaves jejunum and duodenum. It is cut in cross section which means it would have to be retroperitoneal (2nd portion of duodenum). You can see the kidneys and descending colon way behind it. Likely not retroperitoneal.

This leaves jejunum.

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submitted by ∗hello(429)

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Please help - how are you able to tell that the CT image is not at the level of duodenum?

I don't know what I'm looking for to compare and contrast a CT at the level of the duodenum vs the CT given in this Q.

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submitted by iviax94(7)

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CT shows mass on the left side of his abdomen and you’re told it’s intussusception. Asks which part of the GI tract is most likely to cause the pain. I immediately looked for ileocecal junction ... not an answer choice. Why is the answer jejunum (vs. duodenum)?

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liverdietrying The picture is key here. You’re right that ileocecal is most common, but ileo-ileal and jejuno-jejunal are the next most common (I think I might just know this from having done clerkships already, not sure). Ileo-ileal isn’t an answer, so that rules that out. Look at where the arrows are pointing in the picture as well. Its on the L, ruling out appendix and cecum. And the slice is not at the level of the duodenum, ruling out that answer. So by process of elimination based on the picture you could get this one too. +6

dr.xx Duodeno-duodenal intussusception is a rare because of the retroperitoneal fixation of the duodenum. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4529645/ +2

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submitted by ∗usmleuser007(464)

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Intussusception is generally caused by a blockage in the GI tract caused by a tumor, polyp, diverticulum, or just immobility at part of the tract.

1) My thought was that the patient had a Meckel diverticulum yes it happens in 2 feet from the ileocecal valve; but that is in about %2 of the population

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hpsbwz Meckel diverticulum itself occurs in 2% of the population. Also it would present much sooner rather than in a 28 year old man. +2

osler_weber_rendu Meckels is an incidental finding in 98% patients. (only 2% symptomatic) It is a well known lead point for intussusception +3

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submitted by ∗lnsetick(107)

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How are you able to tell that the CT slice is not at the level of duodenum?

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zelderonmorningstar I think the small intestine narrows as you go along, so jejunum would most likely intuss into the duodenum. +1

yotsubato Duodenum is fixed to the retroperitoneal wall, and also has lots of named vessels attached to it, along with the pancreaticobiliary duct and ampulla. It cant really intussuscept. +1

gh889 You should also know that the duodenum is almost purely on the right side of the body +36

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