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  1. #1
    YuQX is offline Junior Member 510 points
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    Microcytic anemia and Beta-thalassemia

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    Can you help me differentiate microcytic anemia and Beta-thalassemia?
    Thank you!

  2. #2
    wcb22 is offline Elite Member
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    several things can cause a RBC to be microcytic, the most common being iron deficiency. on microscopy the RBCs will be small and pale in color. the difference is... microcytic anemia can be described by several pathologies. usually when you are working up an anemia, you want to first determine the MCV (mean corpuscular volume)... microcytic (<80), normocytic (80-100), and macrocytic (>100).

    whereas B-thal is a specific disease (major and minor). you have an absense, or shortage of b-globin chains, necessary for oxygen transport. the molecular biology (which you need to know for boards) is that there is a defect in the promoter sequence, introns or exons, so that the spliceosomes aren't splicing in the correct areas (so the mRNA it produces has some introns in it, which should NOT be there, only the exons).

    now in b-thal, you may have microcytic cells, but does that mean that all microcytic RBCs are a result of b-thal?

    no way, most common cause of microcytic anemia in the US is because of iron deficiency. so what happens if you mistake a b-thal for iron deficiency anemia, and treat this person with iron? you get sued, because you are iron-overloading this person (remember, your body has no way of ridding itself of iron, minus bleeding out). once someone is diagnosed with b-thal (major), they will need transfusions throughout life, and they will become iron overloaded anyway. these people die in the 30s, if they even make it there. hopefully the lawsuit goes through quickly so he can spend the money, as he travels back to the mediterranian, which is where he is from. (just kidding, i hope no one here ever gets sued).

    on microscopy, you can tell the difference between just microcytic anemia (MCC = iron def anemia) and b-thal major. there are some screwed up cells in b-thal.
    Last edited by wcb22; 06-25-2006 at 12:15 AM.
    M.D., PGY-3 Internal Medicine

  3. #3
    homedale9 is offline Newbie 510 points
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    Yes this is true. Although technically B-thal can be considered a microcytic anemia, the most definig characteristic is not the microcytic cells itself, but the presence of target cells and occasionally teardrop cells. Hope this helps.

  4. #4
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    IMG SURVIVOR is offline Moderator 536 points
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    Beta thalasemia can be DX with electroforesis
    Moderator: USMLE AND Residency Forums.

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    why even bother with the obvious. Just know where you are need it and where you can help the most.

  5. #5
    2Good2BMD is offline Junior Member
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    Answer

    Regarding your question:
    To differentiate thallasemia from Fe deficiency it will be helpful to look at the iron studies:
    Fe deficiency: Ferritin low + TIBC high
    Thallasemia: Ferritin normal or high + TIBC normal or low.
    Hope it was helpful.
    We are born naked, wet and hungry. Then things get worse....

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