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20 Cards in this Set
- Front
- Back
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what is the typical approach to anemia?
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H/P
blood smear reticulocyte count |
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what do you look for in peripheral blood to dx megaloblastic anemias?
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-oval macrocytes
-severe anisocytosis (RBCs are of unequal size) -neutrophil hypersegmentation (>5 lobes -pancytopenia |
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pathophysiology of megaloblastic anemias
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difficulties with DNA synthesis (either by lack of folate or B12) causes impaired nuclear maturation --> and thus, larger sized RBCs that can't properly divide
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if an anemic pt answered "yes" to the question, "Do you eat lettuce?" what would you be able to rule out? what would you dx?
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rule out folate defieincy (bc vegetables are good source of folate). dx with B12 deficiency, instead!
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what are the 2 types of macrocytic anemias? give examples of each.
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megaloblastic: B12 and folate deficiency
non-megaloblastic: sideroblastic, alcohol/lead, liver dz, hypothyroidism |
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both folic acid and b12 deficiency lead to impaired _____ conversion to methioinine
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homocysteine (so you can test for homocysteine levels -- ppl with defiicney will have higher levels)
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high homocysteine is a risk factor for...
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heart attack adn strokes
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name the pathway that B12 is apart of --> of which deficiency will lead to neurological damage
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methylmalonyl CoA --> succinyl CoA (combined system degeneration)
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what are some clinical manifestations of megaloblastic anemias?
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glossitis, jaundiced skin/eyes (pt will be "lemon yellow" -- think Bart Simpson),
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what are the common blood lab findings of megaloblastic anemias?
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high MCV, very high RDW (width of RBCs), low WBC/platelets, high LDH, high indirect bilirubin,
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what lab test differnetiates between FA vs. b12 deficiency?
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MMA = measures amt of methylmalonic acid in blood (if high, then there is a B12 deficiency bc not much of it is being converted to succinyl coA)
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name the common causes of B12 deficiency
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-pernicious anemia
-gastric resection/dz -terminal ileal resection/dz - competition syndromes (bacterial overgrowth; fish tapeworm) - pancreatic insufficiency (rare) - dietary deficincy by extreme vegans (since b12 is found only in animal products...but this is rare due to supplemenation) |
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name 3 main ways to test for b12 deficiency
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- blood smear morphology
- serum b12 and serum/RBC folate - methylmalonic acid and homocysteine (both elevated in b12 deficiency) - intrinsic factor/parietal cell Ab's (for pernicious anemia) |
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tell me about the Schilling's test for b12 deficiency (even though its not used much...will likely be tested!)
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Part 1—After parenteral (cold) B12, oral radiolabeled B12 administered and urine collected for radioisotope quant.
Part 2—Same as above, but Intrinsic Factor administered with the oral radiolabel - if you pee out b12 now, then you have IF deficiency (Part 3—same, with antibiotic pretreatment) - if you pee out b12 now, then you have bacteria in your flora that's competing (Part 4—same, with pancreatic enzymes) - if you pee out b12 now, then you're missing pancreatic enzymes. this uncommon test was used to differentiate b/w the different causes of b12 defienccy anemia |
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define: pernicious anemia
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autoimmune disorder characterized by atrophic gastritis and B12 malabsorption due to lack of intrinsic factor (assoc with disorders like Graves dz, DM, gastric cancer, etc)
- most pts have auto Ab's to their own parietal cells (the rest have them to their IFs that are produced) |
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on a blood smear, whenever you see hypersegmented neutrophils, what should you think??
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MEGALOBLASTIC ANEMIA (it occurs in 100% of pts with MA!)
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tx of b12/folate deficiencies
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give both supplementation by mouth
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what can vit B6 deficiency lead to?
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sideroblastic anemia (where iron accumulates in RBCs bc they don't properly bind to protoporphyrin in order to form heme)
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what are the causes of sideroblastic anemias?
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hereditary: x-linked/autosomal
drugs, chemicals, toxins: alcohol, lead, isoniazid idiopathic acquired (most common - part of myelodysplastic syndromes - MDS) |
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name the most common form of sideroblastic anemia
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idopathic acquired -- seeing ringed sideroblasts is a reliable marker for MDS (acquired anemia, leukopenia and/or thrombocytopenia)
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