beethoven

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If you transfuse RBCs, you're giving hemoglobin which contains iron. The body doesn't have that many mechanisms for getting rid of iron, so you can see how chronically transfused patients can get iron-overload.
 
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str8flexed

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If you transfuse RBCs, you're giving hemoglobin which contains iron. The body doesn't have that many mechanisms for getting rid of iron, so you can see how chronically transfused patients can get iron-overload.
I thought the patient needed RBC anyway, so after giving them a transfusion, now they have the normal amount, not an overload. Plus hemoglobin is in RBC's--is there some lysis of RBC associated with the transfusion? Mechanical trauma? Immune destruction?
 

512TA

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I thought the patient needed RBC anyway, so after giving them a transfusion, now they have the normal amount, not an overload. Plus hemoglobin is in RBC's--is there some lysis of RBC associated with the transfusion? Mechanical trauma? Immune destruction?
yes when you transfuse there ofcourse is hemolysis of RBCs. therefor on chronic transfusion one gets iron loaded.
 

Captopril

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Your iron levels are controlled by intestinal intake. If you are giving someone iron directly via IV (transfusions), their body loses the ability to maintain iron homeostasis...usually leading to iron overload. Remember that iron cannot be excreted.
 

beethoven

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I thought the patient needed RBC anyway, so after giving them a transfusion, now they have the normal amount, not an overload. Plus hemoglobin is in RBC's--is there some lysis of RBC associated with the transfusion? Mechanical trauma? Immune destruction?
I see what you mean. My understanding is that in a normal person, if an RBC lasts 120 days, at the end of its lifecycle it breaks down, and the Fe gets recycled and re-used. However, when you give a transfusion, you keep giving more and more Fe.

Your iron levels are controlled by intestinal intake. If you are giving someone iron directly via IV (transfusions), their body loses the ability to maintain iron homeostasis...usually leading to iron overload. Remember that iron cannot be excreted.
I thought that iron is excreted when cells lining the gut lumen shed?
 

McGillGrad

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Ask yourself how your body removes iron from your body. That's your answer.
 

pilottodoctor

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well another reason is that when pt. is on regular blood transfusion, he or she will increase in k+ levels, also when transfused red blood cells become senescent, they are degraded and their iron recycled by reticuloendothelial macrophages iron is then bound to transferrin and released into the circulation, where it is distributed to body tissues. When iron overload occurs, transferrin becomes saturated, resulting in the presence of non-transferrin bound iron in the plasma. Whereas tissue uptake of transferrin-bound iron is regulated by the expression of membrane-bound transferrin receptor which leads to pools of unbound iron within cells, which mediate toxicity by the formation of reactive oxygen species reactive oxygen species react with cellular components such as the plasma membrane, lysosomes, and organelle membranes, leading to cellular leakage, dysfunction, and ultimately cell death.

hope this helps
 
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Really? Could be true. RR Path says that we can't excrete iron.
it is true since small ammounts are stored there, but it's not a regulated process, meaning no -/+ feedback mechanism, so you can't turn it up if theres more iron since you need it for other stuff or turn it down and inadvertantly cause some kind of cancer.

under normal circumstances, you're reusing the iron from the dead RBCs everytime you make new RBCs. if you're transfusing, you're not reusing the iron to make new RBCs and when those die, you're not going to reuse that iron either so all that "old iron" builds up and is never reused and the cycle continues. since you're GI's epithelial tissue doesn't turnover fast enough to elliminate the "old iron" you're body is stuck with it and it and becomes a board question for test makers to salivate over.