GTS HEMONC - b12 deficiency Flashcards
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| 3983481228 | pernicious anemia | - characterized by gastric atrophy, megaloblastic anemia, neurologic degeneration (demyelination of posterior column) | 0 | |
| 3983493456 | pernicious anemia | - anemia sx (fatigue, DOE, pallor) - peripheral neuropathy (parethesias, numbness) - dyspepsia | 1 | |
| 3983499416 | pernicious anemia | laboratory exam - blood smear and bone marrow (megaloblastic maturation -- synchronization of chromatin packing and cytoplasmic maturation) - hemolysis (hyperbilirubinemia, LDH) - thrombocytopenia, leukopenia - elevated gastric pH | 2 | |
| 3983523032 | hemolysis (hyperbilirubinema, LDH), thrombocytopenia, leukopenia, elevated gastric pH | - pernicious anemia lab exam | 3 | |
| 3983527973 | vitamin b12 | - cobalamin - synthesized only by microorganisms - dietary sources (liver, glands, muscle, eggs) | 4 | |
| 3983536538 | 2-5mg | - body stores of b12 - liver stores most | 5 | |
| 3983538874 | 2-5ug | - daily needs of b12 - 0.1% of stores - excreted in bile, extensive reabsorption via enterohepatic circulation | 6 | |
| 3983549806 | terminal ileum | - only place you can absorb b12 | 7 | |
| 3983551296 | TCII | - takes Cbl from IF in small intestine and carries Cbl from terminal ileum through blood to tissue | 8 | |
| 3983562244 | methyl transfer, hydrogen transfer | - 2 b12 reactions | 9 | |
| 3983564469 | methyl transfer | - methylation of homocystein to generate methionine - b12 is cofactor, accel rxn - methyltetrahydrofolate supplies the methyl group (substrate) - THF req for thymine and purine generation (crucial for rapidly dividing tissues) | 10 | |
| 3983573354 | hydrogen transfer | - generation of succinyl coA from methylmalonyl coA - crucial for myelin maintenance | 11 | |
| 3983586474 | malabsorption | - most common b12 deficiency - acquired | 12 | |
| 3983597961 | malabsorption b12 deficiency | - salivary gland dysfunction - loss of gastric function resulting in intrinsic factor deficiency/loss of gastric acid secretion - pancreatic disease - terminal ileum disease (sprue, IBD) | 13 | |
| 3983615291 | autoimmune, atrophic gastritis (h. pylori), gastrectomy, aging, H2 blockers | - causes loss of gastric function - causes malabsorption b12 deficiency | 14 | |
| 3983623968 | acquired b12 deficiency | - inadequate ingestion (vegans, brest-fed infants of vegans, breast-fed infants of deficient mothers) | 15 | |
| 3983632865 | congenital b12 deficiency | - transcobalamin II deficiency - Imerslund-Grasbeck syndrome | 16 | |
| 3983637090 | Imerslund-Grasbeck syndrome | - mutation of receptor for IF-b12 - causes congenital b12 deficiency | 17 | |
| 3983654587 | low serum b12 levels (<200pg/ml), PNS/CNS disease, methylmalonic acidemia | - clinical findings specific to a deficiency of vitamin b12 | 18 | |
| 3983666308 | falsely normal serum b12 | - caused by intestinal bacterial overgrowth, liver disease, myeloid disorders - more TCI and TCI analogue compared to TCII | 19 | |
| 3983671935 | falsely low serum b12 | - caused by pregnancy, lymphoid disorders, aging, racial differences - low TCI (no analog) and no TCII analog | 20 | |
| 3983707775 | pernicious (b12) anemia | - tx b12 injection monthly for life - gastrectomy - tx of bacterial overgrowth in small bowel - oral vitamin supplementation in dietary deficiency, food malabsorption | 21 | |
| 3983717566 | pernicious anemia | - can present with anemima w/ or w/o neurologic symptoms (30%) - can present with just neurologic presentations with mild or no anemia (30%) | 22 | |
| 3983725812 | dietary methionine and folate, polymorphisms in enzymatic activity | - cause of variation in presentation of PA | 23 | |
| 3983738543 | folic acid | - synthesized by higher plants and microorganisms - daily requirement 50ug - body stores are 5mg (deficiency takes 3-4mo) - absorbed in proximal jejunum and throughout small intestine - sources are leafy greens, asparagus, broccoli, spinach, liver, kidney, fruits, mushrooms | 24 | |
| 3983747373 | proximal jejunum | - location of folic acid absorption | 25 | |
| 3983753311 | dietary folate | - primarily methyl forms of the acid - conjugated with multiple glutamic acid residues and are heat labile - deconjugation occurs in the intestine before absorption - reduced to FH4 within intestinal cells and transported to portal circulation - FH4 is polyglutamated in tissue (resistant to hydrolysis and leakage from cell) | 26 | |
| 3983771931 | otc folic acid | - folic acid that does not need to be methylated | 27 | |
| 3983775422 | methionine synthase | - enzyme that mediates rxn with folate and b12 to convert homocysteine to methionine | 28 | |
| 3983783536 | cystathionine beta synthase | - enzyme that mediates homocysteine to cysteine | 29 | |
| 3983788563 | methylene TH4 reductase | - demethylates folate with NADPH | 30 | |
| 3983796066 | folate deficiency | - defect in DNA synthesis is the result of uracil misincorporation into DNA, with resulting DNA strand breaks, inducing cell cycle slowing or arrest - anemia is the result of the heavy DNA synthesis requirements of the bone marrow, although all rapidly dividing cells in the body are affected - macrocytosis | 31 | |
| 3983808057 | macrocyctosis of folate deficiency | - asynchronous maturation of nucleus vs cytoplasm - retarded DNA synthesis (missing divisions) - retarded maturation, accommodation of MCHC | 32 | |
| 3984123961 | folate deficiency | - megaloblastic anemia identical to that produced by b12 deficiency | 33 | |
| 3984141775 | folate deficiency | - dietary deficiency state usually in a setting of general malnutrition, so other vitamin deficiencies may be present | 34 | |
| 3984149616 | folate deficiency | - causes neither combined system disease nor specific neuropathy | 35 | |
| 3984151932 | inadequate ingestion, inadequate absorption, metabolic block in utilization, increased requirement) | - causes of folate deficiency | 36 | |
| 3984160006 | folate deficiency (causes) | causes - inadequate ingestion (poor diet, chronic alcoholism, scurvy) - inadequate absorption (celiac disease, IBD; drugs - dilantin, barbiturates) - metabolic block in utilization (DHF reductase inhibitors, b12 loss) - increased requirement (pregnancy, infancy, hemolytic anemia) | 37 | |
| 3984180900 | folate deficiency | diagnosis - serum levels < 3ng/ml (reflect recent levels) - red cell levels less than 135ng/ml (reflect chronic status) | 38 | |
| 3984199643 | hyperhomocyteinemia (causes) | causes - cystathionine beta synthase --> >200mmol/L - b12 deficiency --> 20-241 - folate deficiency --> 15-50 - renal disease --> 17-20 - MTHFR gene polymorphisms --> 8-15 - normal --> 4-12 | 39 | |
| 3984219128 | folate deficiency | - deficiency associated with fetal neural tube defects - take 400ug during pregnancy (140ug/day for childbearing age) | 40 | |
| 3984239878 | yes, yes | megalobastic anemia in b12, folate? | 41 | |
| 3984242434 | yes, no | combined system degeneration in b12, folate? | 42 | |
| 3984242435 | rare, common | poor diet associated with b12, folate deficiency? | 43 | |
| 3984244998 | no, yes | other dietary deficiencies present in b12, folate? | 44 | |
| 3984248245 | yes, yes | induces increase homocysteine in b12, folate? | 45 | |
| 3984254417 | yes, no | intrinsic factor required in b12, folate? | 46 | |
| 3984256697 | yes, no | association with increase methylmalonic in b12, folate? | 47 |