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67 Cards in this Set
- Front
- Back
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What are the main nutrients that are needed for RBC production?
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Iron
Folic acid B12 |
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What's the most common type of acquired anemia?
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Iron deficiency
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Where is the iron stored in the body?
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Essentially all of it is bound to proteins:
Heme: 70% Ferritin/hemosiderin: 30% The minority is in the plasma, where it's bound to TRANSFERRIN |
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Where does iron intake happen?
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GI tract
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What are some of the other proteins that require iron for synthesis?
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Cytochromes
Myoglobin |
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What are some of the different ways that iron is absorbed?
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Heme iron: absorbed as-is
Non-heme iron: -Absorbed as FERROUS (2+) -Inhibited by grain, tea; enhanced by vitamin C |
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Where is ferrous iron absorbed?
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Duodenum
Proximal jejunum |
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How much of ingested iron is typically absorbed?
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10%
Adjusted based on how much iron you've got already |
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What is hepcidin?
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Regulator of iron homeostasis
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What is the activity of hepcidin?
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Limiting GI absorption:
-Inhibiting iron absorption in the GI tract -Inhibiting iron recycling |
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How is iron transported in the blood?
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Transferrin
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How much iron is bound to transferrin?
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300 ug Fe/dL
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What impacts the total iron binding capacity?
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Increased:
-Iron deficiency -Pregnancy -Estrogen therapy Decreased: -Inflammation -Malignancy -Liver disease -Nephrotic syndrome/malnutrition |
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What is the transferrin saturation?
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Serum iron/TIBC
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How does iron get from transferrin to the RBCs?
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Endocytosis of the transferring/transferrin receptor complex
Once inside the cell, the iron is released and the transferrin goes back into the plasma |
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What are some of the proteins that store iron?
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Ferritin
Hemosiderin |
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Which is more useful: ferritin or hemosiderin?
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Ferritin - more accessible
Hemosiderin: more permanent; can hold more, but it's less accessible |
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How is iron excreted?
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It's not!
The only way that you can lose cells is when you lose cells that have iron: -Bleeding -Epithelial cells getting sloughed off |
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How is iron regulated?
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Through absorption, as we can't do anything about excretion
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What are some visible symptoms of iron deficiency anemia?
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Esophageal webs (trouble swallowing)
Blue sclerae Pica: craving for chewing on ice Koilonychia: pitting of nails |
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What labs should you order if you suspect iron deficiency?
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CBC
Serum iron Transferrin saturation Serum ferritin Bone marrow aspiration |
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Ferritin of what levels is diagnostic of an iron deficiency?
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< 12 ug/L
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What are some things that can cause an inflated serum ferritin level?
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Inflammation
Infection Malignancy Hemolysis JUST BECAUSE YOU'RE ABOVE 12, DOESN'T MEAN THAT YOU'RE NOT DEFICIENT! |
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What do red cells look like if you're iron deficient?
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Hypochromic
Central pallor |
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What is responsible for differences in serum levels between men and women?
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Puberty!
Men have androgenic hormones kicking in, leading to them having MORE serum ferritin |
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What are the first changes that you find in iron depletion? Middle? Last?
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First to change: plasma ferritin levels, marrow iron stores
Second to change: plasma iron Last to change: erythrocyte morphology |
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What stain do you use to look at iron in bone marrow?
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Prussian blue
This normally isn't done |
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What are some physiologic causes of iron deficiency?
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Growth
Pregnancy Lactation |
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What are some pathologic causes of iron loss?
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Blood loss
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What are some causes of inadequate iron supply?
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Low iron containing foods
Impaired iron absorption Transferrin problems |
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What's the normal level for transferrin levels?
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10%
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What's the treatment for iron deficiency?
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Give them iron!
Oral is best: -Ferrous sulfate -Other salts |
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What's the treatment for people who can't absorb iron?
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Prenteral iron
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What is the cause of the megaloblastic anemias?
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Defects in DNA synthesis that cause the nucleus to stay big; the nucleus doesn't mature as fast as the rest of the cell
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What's the typical appearance of cells with megaloblastic anemia?
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Immature nucleus
Normal cytoplasm Larger than normal cell volume |
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What are the most common causes of megaloblastic anemia?
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B12
Folic acid |
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When looking at a peripheral blood smear, can you tell the difference between a megablastosis due to B12 vs. folate?
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NO
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What is anisocytosis?
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A variation in size of RBCs
Elevated RDW |
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What is poikilocytosis?
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Variation in the shape of the RBCs
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What changes happen tot he WBCs with B12/folate deficiency?
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PMNs with more lobes than normal!
5% with 5 lobes 1 with 6 |
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What does the bone marrow look like in megaloblastic anemias?
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Hypercellular!
The bone marrow can't finish the job...and the cells don't get released until they're finished developing. Bad news. |
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What's on the differential for megaloblastosis?
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Congenital problems
Erythroleukemia Exposure to drugs Macrocytosis (splenectomy, liver, lung) Artifactural (agglutinination, hyperglycemia) |
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What are some abnormalities that are SPECIFIC (you need to know this!) for B12 deficiency?
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NEUROLOGIC CHANGES! anywhere.
-Peripheral neuropathies -Dorsal column problems -Spinal degeneration -Psychiatric disorders |
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What is the function of B12 in the body?
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Homocysteine --> methionine (required for DNA synthesis you need FOLATE!!!)
Methylmalonyl CoA --> succinyl CoA |
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What is regenerated in the reaction of homocysteine to methionine?
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Tetrahydrofolate
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What is the ultimate source of B12?
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Bacteria and fungi
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What are our dietary sources of B12?
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Animal muscle that has B12 inside of it
Plants (legumes) contaminated with B12 producing bacteria |
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Where are the bacteria that produce B12 located?
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In the large intestine...which is too far down for us to absorb anything!`
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Where is B12 stored in the body?
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The liver!
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What proteins made in the stomach are responsible for the absorption of B12?
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Intrinsic factor
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What receptors are responsible for the uptake of B12 in the intestine?
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IF receptors
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What protein in the saliva binds to B12?
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R protein
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What are causes of B12 deficiency?
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Inadequate intake: (vegetarian, babies with deficient mothers)
Problems with absorption |
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What are some causes of inadequate absorption of B12?
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Lack of gastric acid/pepsin
Lack of IF Lack of IF receptors (SURGERY, crohns) Pancreatic insufficiency Zollinger-ellison syndrome NO |
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What are the labs that you do for B12 deficiency?
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Homocysteine, methylmalonic acid levels
Schilling test IF/Parietal cell Abs |
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What's the treatment for B12 deficiency?
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Give them B12 (parenterally, typically)
Pancreatic extracts |
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What SHOULDN'T you give someone with B12 deficiency? Why?
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Folic acid: worsens the neuropsychiatric manifestations of the B12 deificiency
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Where is folic acid stored?
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Liver
We've got a 2-4 month reserve |
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Who needs more folic acid?
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Women who are pregnant, lactatin
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What's the source of folic acid?
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Leafy greens
Fruits |
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Where is folic acid absorbed?
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Small intestine
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What is the mechanism of distributing folic acid to the body from the liver?
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Bile.
If you're draining bile because there's a blockage, you can become folic acid deficient |
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What's the function of folate in the body?
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Tetrahydrofolate is an active coenzyme that donates a methyl group in the conversion of dUMP to dTMP
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What are causes of folatedefiency?
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Intake problems
Increased requirements Intestinal malabsorption Drugs |
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What are labs that you should take for folate deficiency?
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Measurement of serum foate levels
RBC folic acid levels Homocysteine levels (should be elevated) Methylmalonic acid (normal) |
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What's the treatment for folate deficieny?
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Give people folate!
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Who should we give folate prophylactically to?
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Women who are pregnant or who are thinking about being pregnant
It prevents neural tube defects |
