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22 Cards in this Set
- Front
- Back
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What are microcytic anemais due to? |
decreased hemoglobin production secondary to either decreased heme prodution and/or decreased globin production
is this iron deficiency or anemia of inflammation/chronic disease? |
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What regulates iron metabolism |
iron can be excreted and toxic
due to the absence of an active iron excretory mehcnaism the iron balance is maintained by limiting its uptake at the level of the intestines
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What is ferritin |
main source of stored iron |
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What is transferrin |
plasma carrier that transports iron to tissues that have transferrin receptors |
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Hemosiderin |
insoluble protein/iron complex derived from partially digested ferritin molecules |
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Hepcidin |
major hormonal regulator of iron homeostatiss |
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Ferroportin |
transmembrane iron exporter exrpressed highly on the surface of duodenal enterocytes |
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What regulates the Fe conc at the systemic level |
hepcidin by binding and degrading the sole cellular iron exporter ferroportin |
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What happens when there is an iron overload |
hepcidin is up regulated and degrades ferroportin, when the cells need iron hepcidin is down regulated and ferroportin releases iron to tissues |
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What are the key pts? |
iton cannot be naturally secreted from the body
too much iron is toxic to cells and is tightly controlled at the level of absorption
DMT1 is the major control of absorption ferroportin controls release, hepcidin controls ferroportin, transferring carries it to plasma and ferritin stores it in the cell |
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What can cause iron def? |
poor diet increased need poor absorption acute of chronic blood loss intravascular hemolysis |
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What happens during inflammation to iron |
hepcidin is up regulated and iron is sequestered in the cell
it is a protective mechanism gone bad, dont wnat to lose to much blood and give iron to pathogens |
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What can stimulate hepcidin action |
pro inflammatory cytokines can stimulate iron retention in macrophages via,
macrophafe erythrophago iron uptake via DMT1 increased lived produciton of hepcidin increases autocrine hepcidin of macros |
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What are the classic findings of anemia of inflammation |
low serum, low transferring, low sTr, low saturation, high ferritin
iron is sequesterd |
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What are the causes of macrocytic anemai |
MCV>100
Megaloblastic anemia is the term reserved for those macrocytic anemis showing abnormalities in the nucleus and DNA
Megaloblastic is usualy caused by folic acid or B12 def. |
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What are the non-megaloblastic macrocytic anemias |
hemolysis (elevated retics which are large) alcoholism due to more cholesterol hypothyroidism liver disease pregnancy myelodysplastic syndrome some drugs |
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What is the role of B12 defi |
B12 is released from food and combines with IF which complexes then binds to specific receptors in the ileum
major cofactor in homocyteine to methionin and methlymalonyl mutase
can cause progressive neuropathy, peripheral sensory nerves and posterior lateral columns
most likely secondary to defectice methylaiton of myelin |
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What can cause a B12 deficiency |
pure vegan diet
gastrectomy loss of IF
malabsorption at the level of the small intestines, celiac disease IBD bacterial overgrowth, tapeworm
pernicious anemia |
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What is pernicious anemia |
autoimmune disorder affecting the gastric mucosa leading to atrophic gastritis
results in acholhydria, lack of gastric acidity
90% show antibodies to parietal cells or to intrinsic factors
may present with other autoimmune disease
consequence: increased risk of gastric cancer, need acid medium |
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What are the causes of folate deficiency |
poor diet, we dont store folate
malabsoroption
excess utilization
liver disease
alcoholism |
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What are the presentations to B12/folate deficiency in the smear |
elevated MCV greater then 115 target cells macroovalocytes = oval cells hypersegmentation low retic counts = no pushing out megaloblasts as retics WBC and platelets are often reduced pan cytopenia elevated bilirubin and LDH because of chronic hemolysis of poorly made red blood cells bone marrow: megaloblasts in high conc. |
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How do we treat the b12/folate def |
cant use oral in pernicious because it cant be absorbed without the IF. oral folic acid is easily absorved and given daily
b12 stores can be replaced and last a long time |
