Normal Schilling test

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Normal Schilling test

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92306
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03/10/07 - 08:37 AM

A patient who is being screened for vitamin B12 deficiency undergoes a Schilling test, 1 mg of cobalamin administered intramuscularly 1 h after the administration of radiolabeled cobalamin. A normal Schilling test, excretion of >10 % of the labeled cobalamin in a 24-h urine specimen, would be most likely in which of the following situations?

A) Intrinsic factor deficiency
B) Chronic pancreatitis
C) Surgically absent terminal ileum
D) Achlorhydria
E) Celiac sprue

robin082006
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03/10/07 - 09:23 AM

weird, all above diseases may have anormal test

A) Intrinsic factor deficiency--> anormal test

B) Chronic pancreatitis: cannot release B12 from intrinsic factor-->anormal test

C) Surgically absent terminal -> cannot absorpt

D) Achlorhydria-----> may have no intrinsic factor

E) Celiac sprue ->malabsorption

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babydoc4usmle
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03/10/07 - 09:35 AM

it is weird, because if you give vitamine intramuscularly you will not be able to distinguish these conditions that are connected with absorbtion of vit B12 from the gut
looking at the choices, the last one may not involve the terminal ileum (part necessary for vit absorbtion) so in this case we would have normal test (but still can't make connection with IM cobalamine)
saying that - my choice is E

dr in trouble
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03/10/07 - 08:31 PM

but if u r giving IM cobalamin test shud b normal in all cases bcoz IM cobalamin doesnt require intrinsic factor to absorb.

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huyniid
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03/10/07 - 08:54 PM

checked. weird Qs! If I have to choose, probably E, because celiac mostly involves the proximal jejunum and deodenum

robin082006
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03/10/07 - 10:11 PM

huyniid wrote:
checked. weird Qs! If I have to choose, probably E, because celiac mostly involves the proximal jejunum and deodenum

Check Google, Celiac has anormal Schilling test.

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huyniid
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03/10/07 - 10:13 PM

I posted the idea from uptodate 14.3

new_n_lost
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03/10/07 - 10:13 PM

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babydoc4usmle
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03/11/07 - 08:47 AM

my major problem in this Q is how can you distinguish beyween problems in the GUT if you bypass by giving vit IM???? raised eyebrow

babydoc4usmle
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03/11/07 - 09:23 AM

#10

thinking more about it....not celiac disease....cant make anything out of the choices given
disapproval

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