All right, today we're going to be talking about Vitamin B12 deficiency and Vitamin B12 is really

a vitamin that's found in meats and in dairy product.

So patients who are strict vegetarians, strict vegans might develop B12 deficiency, but you can't assume that this is going to happen because it really takes years for this to happen.

Really the body can store up to 5,000 micrograms of B12, half of which is going to be in the

liver, but we only need a daily intake of 6 to 9 micrograms a day. This means that these patients have

to go on a strict vegan diet for up to five years to really start developing B12 deficiency.

Now, B12 deficiency can present with either symptoms or they can present asymptomatically. So today we're going to be

talking about the different presentations, how to work patients up, and how to

treat vitamin B12 deficiency. Now when discussing the ideology of vitamin B12 deficiency, really what's most talked about is going to be pernicious anemia, which is an auto amide disorder.

But aside from that, other things can cause vitamin B12 deficiency as well, things like gastritis, gastricomy, HIV infection, medication side effects,

inadequate intake, alcoholism.

These are all things that can really prevent the absorption of vitamin B12. Now when

dealing with Pernicius anemia specifically we're going to be looking at

antibodies. These antibodies are going to be directed towards the gastric parietal

cells which are going to occur

in about 90% of patients and or intrinsic factor. And intrinsic

factor is a really specific antibody for pernicious anemia. It's estimated that

up to 90% or it's 90% specific in diagnosing perinicious anemia.

Now when talking about an intrinsic factor,

this works in two ways.

The antibodies either block the B12 to the intrinsic factor so that complex never forms in the first place

or the vitamin B12 and the intrinsic factor do form but it's going to prevent this complex from being absorbed

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