Folate and B12 Metabolism Deficiency Flashcards

3965781771	What was the historic "extrinsic factor"?	Vit B12	0
3965781772	What is cobalamin and coenzyme B12?	Both are names for Vit B12	1
3965781773	Where is Vit B12 made?	by microorganisms	2
3965781774	What are the dietary sources of Vit B12?	liver, glandular tissue, muscle, eggs, diary products, seafood	3
3965781775	What is the body storage level of Vit B12? How much is used daily?	stores 2-5 mg, and use 2-5 ug (0.1%)	4
3965781776	Where is B12 absorbed?	only in the terminal ileum	5
3965781777	What two reactions does Vit B12 mediate?	(1) methyl transfer: methylation of homocystein to generate methionine. crucial for dividing tissues (like blood cell progenitors) (2) hydrogen transfer: generation of succinyl coA , crucial for myelin maintenance (explains neurological symptoms)	6
3965781778	What is the most frequent cause of B12 deficiency?	malabsorption: due to salivary gland dysfunction, loss of intrinsic factor (gastric), pancreatic disease, terminal ileum illness, IBS	7
3965781779	Can B12 deficiency be caused by congenital deficiency states or inadequate ingestion?	yes, but it is very rare	8
3965781780	What are the 3 main clinical features of pernicious anemia?	Gastric atrophy (no folds), megaloblastic anemia, neurological degeneration (demyelenation)	9
3965781781	What does the bone marrow of pernicious anemia pts look like?	huge bone marrow cells - megaloblasts	10
3965781782	What would a CBC and blood smear reveal with pernicious anemia?	hemolysis because megaloblasts are dying in the bone marrow, thrombocytopenia, leukopenia,	11
3965781783	What clinical/lab findings are specific to Vit B12 deficiency?	low serum B12 levels (<200) Peripheral and central nervous system disease methylmalonic acidemia elevated gastric pH	12
3965781784	What's the difference between TC1 and TCII B12?	TC II B 12 -- is biologicallly useful! TCII can have a B12 analogue, though TCI can't be absorbed.	13
3965781785	Under what conditions can serum B12 levels read falsely normal?	intestinal bacterial overgrowth, liver disease, myeloid disorders	14
3965781786	Under what conditions can serum B12 be falsely low?	pregnancy, lymphoid disorders, ageing, racial differences	15
3965781787	What is the most reliable marker for Vit B12 deficiency?	MMA (methylmalonic acid)	16
3965781788	What is the therapy for Vit B12 deficiency?	B12 injections monthly for a lifetime	17
3965781789	T/F: there can be lots of variation in the presence of neurologic manifestations with Vit B12 deficiency.	true	18
3965781790	What is Tropical Macrocytic anemia?	an anemia identical to B12 deficiency but not associated with atrophic gastritis or neurologic disease	19
3965781791	What synthesizes folic acid?	higher plants and microorganisms	20
3965781792	How much folic acid do you store? How much do you use daily? Where is folate stored?	store 5 mg and use about 50 ug. Both folate and Vit B12 are stored in the liver	21
3965781793	What are some dietary sources of folate?	leafy greens, asparagus, broccoli, spinach, liver, kidney, fruits, mushrooms	22
3965781794	How folic acid transformed, from the time it enters the body?	dietary folate is mostly in methylated form. it is deconjugated in the intestine before absorption. It is reduced to N5-methyl tetrahydrofolate (FH4), and once in the tissues, it is polyglutamated	23
3965781795	How do folate and Vit B12 interface?	Vit B12 is there to allow methioniine syntase to convert 5-methyl TH4 folate to TH4 folate	24
3965781796	What are the consequences of folate deficiencies?	poor DNA synthesis. Get uracil misincorporation into DNA, leading to DNA strand breaks and cell cycle arrest... that is why you get macrocytosis.	25
3965781797	Is folate deficiency anemia micro or macrocytic?	macrocytic, because of problem with DNA synthesis, and those cells being stuck in that phase of the cell cycle	26
3965781798	T/F: both folate and B12 deficiency result in systemic disease and neuropathy	false! neurological disorders result from B12, not folate, deficiencies	27
3965781799	What are the causes of folate deficiency?	inadequate ingestion (very common), inadequate absorption, metabolic block in utilization, increased requirement	28
3965781800	How do you assess short term folate levels? Long term folate levels?	Short term : serum folic acid levels (< 3 ng/mL is bad) Long term/chronic: red cell folate levels (<135 ng/mL is bad)	29
3965781801	Besides folate levels, what other metabolite can suggest folate deficiency?	high levels of homocysteine... but how elevated matters (normal is 4-12... for folate deficiency its 15-50, and for B12 deficiency its 20 - 241)	30
3965781802	B12 or folate deficiency: megaloblastic anemia?	both	31
3965781803	B12 or folate deficiency: combined system degeneration?	B12	32
3965781804	B12 or folate deficiency: poor diet associated with deficiency state?	B12 - rare; folate - common	33
3965781805	B12 or folate deficiency: other dietary deficiencies present?	folate	34
3965781806	B12 or folate deficiency: dietary source?	B12: muscle, liver, milk, eggs Folate: liver, leafy greens	35
3965781807	B12 or folate deficiency: deficiency induces high homocystein?	both	36
3965781808	B12 or folate deficiency: site of absorption?	B12: terminal ileum folate: all small bowel	37
3965781809	B12 or folate deficiency: intrinsic factor required?	B12	38
3965781810	B12 or folate deficiency: deficiency associated with high methylmalonic?	B12 only	39