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25 Cards in this Set
- Front
- Back
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a man has been shown to have a macrocytic anemia by MCV. What is the best next step in workup? |
get a peripheral smear - this would show hyperseg's and tell you he needs B12/folate right off the bat |
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some causes of B12 deficiency |
-vegan diet- B12 is high in concentration in meats - pernicious anemia- autoimmune attack on the parietal cells so you lose intrinsic factor - pancreatic insufficiency
Malabsorption syndromes like Celiac, Crohn's, tropical sprue
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what infection causes B12 deficiency? |
Diphyllobothrium latum (fish tapeworm) |
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what specific dietary deficiency can lead to folic acid deficiency? |
if you use only goat's milk |
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what 2 medications are linked to folic acid deficeincy to give megaloblastic anemia? |
Mtx bactrim
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2 drugs that interfere with folate absorption in the small intestine |
phenytoin sulfa drugs |
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does any other cause of megaloblastic anemia give hypersegs? |
no this is pretty specific to B12/folate deficiency |
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what is the most common neurological abnormality seen with B12 deficiency? |
peripheral neuropathy |
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but what types of neurological abnormalities can be seen with B12 deficiency? |
pretty much any type of neurologic symptom- some are rare and others are common (neuropathy) |
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what is the LEAST common manifestation of B12 deficiency? |
dementia probably |
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what spinal cord syndrome is linked to B12 deficiency? |
subacute combined degeneration- shows defects in the posterior columns pathways |
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what are some 2 random lab values linked to both B12 and folate deficiency? |
high bilirubin high LDH
so there is some sort of hemolytic element as well or something |
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What amino acid is very high in B12 and folate deficiency? |
homocysteine |
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so both B12 and folate deficiency lead to an increase in homocysteine, but what is one lab that is SPECIFIC to B12 deficiency? |
methylmalonic acid (MMA) |
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so is a B12 level in the serum very reliable for dx of adequate B12 levels? |
no- B12 levels can be normal even in deficiency because transcobalamin (the carrier protein of B12) is considered an acute phase reactant |
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so if they have any sort of trauma, infection, cancer and so on... |
then they can have an increased transcobalamin and appear as if they have a normal B12 |
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so if the history suggests B12 deficiency and the level turns out normal... |
go ahead and check a MMA level too |
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2 confirmatory tests for pernicious anemia |
anti-intrinsic factor anti-parietal cells antibody |
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is the reticulocyte count high or low in megaloblastic anemia? |
it's low- this is because the RBCs get destroyed as they leave the marrow (also explains why the LDH and bili is high) |
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What other cell lines can be affected by B12 and folate deficiency> |
all cell lines- it can give pancytopenia |
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Why does pancreatic insufficiency predispose to B12 def.? |
because the enzymes help free it from the carrier protein |
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What is the prognosis of neurologic symptoms in B12/folate deficiency |
they will improve if they are minor (e.g. just peripheral neuropathy), short duration and you replace the B12 |
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does folate replacement help neurologic symptoms of B12 def.? |
no not at all |
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what electrolyte abnormality can be seen while you replace B12 and folate? |
you can see hypokalemia because of significant cell turnover as the marrow gets turned back on |
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so i imagine if you have pancreatic insufficiency |
then you would need to give enzyme replacement therapy also |
