Macrocytic Anemia Flashcards
What is the major problem with folate deficiency?
no DNA synthesis
Folate is required to reduce homocysteine to methoinine AND to perform 1 carbon transfers that convert dUMP to dTMP
Where does folate get absorbed?
jejunum (as monoglutamate)
What is the main cause of folate deficiency?
dietary proglems in alcoholics, elderly, pregnant and poor (because you cannot store a lot in the body)
What lab tests do you do to confirm folate deficiency?
Serum folate Increased homocysteine (can lead to MI/thrombosis)
How do you treat a folate deficiency?
BE SURE TO CHECK FOR B12 DEFICIENCY FIRST!
-Oral folate
What is the first enzyme met by Vitamin B12 in the body?
Haptocorrin, binds B12 and stays with it until the stomach
What enzyme attaches to Vitamin B12 when haptocorrin is taken off?
IF
Where is IF made?
gastric parietal cells make IF which binds to B12 and transcobalamin and carries it to the distal ileum to be absorbed.
What are the major causes of Vitamin B12 deficiency?
Decreased intake (not as common except in vegans, have 5 year store in body) Decreased absorption (pernicious anemia) Pancreatic insufficiency or Crohn's disease
What do you need B12 for in the body?
- Regenerate THF from N5-Methyl THF
- Convert methylmalonic acid to succinly-CoA (for TCA cycle)
- Generation of MET from homocyteine
What causes the neurological problems associated with B12 deficiency?
demyelination due to increased levels of methylmalonyl CoA
What is pernicious anemia and why does it cause B12 deficiency?
it is an autoimmune destruction of stomach parietal cells that leads to an IF deficiency
What does a peripheral smear of folate deficiency and B12 deficiency show?
megaloblasts (mature cytoplasm/immature large nucleus) and hypersegmented polys
How do you diagnose B12 deficiency?
Serum B12
MMA levels
Homocysteine levels could be folate too!
What does a CBC look like for someone with B12 deficiency?
Increased RDW and MCV
Decreased RBC, Hgb, Hct, Platelets, and reticulocytes
