Pathoma: Macrocytic Anemia Flashcards
Why do macrocytic anemias occur?
Because the body doesn’t have enough nutrients for DNA precursors, leading to fewer divisions and hence a bigger RBC
The body takes folate in as ________. That molecule then needs to get rid of its __________.
tetrahydrofolate; methyl group, which it does by giving it to vitamin B12
Vitamin B12 gives its methyl group to __________.
homocysteine, which then becomes methionine
Vitamin B12 and folate deficiency anemias result in ________.
megaloblastic anemia, hypersegmented neutrophils
What are other causes of macrocytic anemia?
Alcoholism, liver disease, and some drugs (such as 5FU)
Some causes of folate deficiency include _________.
increased need (such as in pregnancy), poor diet (common in alcoholics and the elderly), and folate antagonists (methotrexate is a dihydrofolate reductase inhibitor)
Symptoms of folate deficiency include ________.
glossitis, macrocytic anemia, increased serum folate, increased serum homocysteine, normal methylmalonic acid, and hypersegmented neutrophils
Vitamin B12 binds _______ in the salivary glands and then __________ in the stomach.
R binder; intrinsic factor (produced by parietal cells of the stomach)
Vitamin B12 deficiency most often occurs by __________.
autoimmune destruction of the parietal cells of the stomach (which produce intrinsic factor)
__________ can also lead to vitamin B12 deficiency, because the ________ produces the proteases that cleave vitamin B12 from R binder.
Pancreatic insufficiency; pancreas
Symptoms of vitamin B12 deficiency include _________.
megaloblastic anemia, high methylmalonic acid, high serum homocysteine, hypersegmented neutrophils, glossitis, decrease in serum vitamin B12, and subacute combined degeneration of the spinal cord (which is not seen in folate deficiency)
