Microcytic Anemia Flashcards
What does the CBC of someone with iron deficiency look like?
Decreased: RBC, Hgb, Hct, MCV, and Reticulocytes
Increased: RDW and Platelets
Dietary iron is of what charge?
Fe3+
To be taken in by gut enterocytes what charge must iron be?
Fe2+
What are the two transporters on either side of gut enterocytes?
DTM-1 (lumen side)
Ferroportin (basolateral surface)
To bind to transferrin, what charge must iron be?
Fe3+
Iron bound to transferrin has what 2 fates?
Use (transferrin binds to TfR on surface of bone marrow RBCs to make new RBCs)
Store (in macrophages in the liver, spleen, and bone marrow bound to ferritin)
What molecule controls ferroportin activity?
Hepcidin has a negative effect on ferroportin activity
If iron levels decrease, what happens to hepcidin?
it decreases (allows ferroportin to take in iron from gut enterocytes and release iron from stores)
How do you diagnose an iron deficiency?
Check serum ferritin (because serum ferritin is proportional to body stores of iron).
- Low ferritin
- Increased TIBC
- Decreased Serum Ferritin
What are two major reasons for iron deficiency?
- Malabsorption (duodenum)
- Blood loss (ex. menorrhagia, colon cancer)
- Hookworm
- Picca
What are the three main medications you use to treat iron deficiency?
1) Ferrous Sulfate (oral)
2) Ferrous gluconate (oral)
3) Iron dextran (parenteral–if patient’s problem is uptake)
What happens/what should you do if someone overdoses on iron?
- Necrotizing gastrointeritis, abdominal pain, bloody diarrhea, shock, lethargy, dyspnea
- Give Deferoxamine (iron chelator)
If you have an infection or chronic inflammation, what happens to hepcidin?
- levels of IL-1, IL-6, and TNF-alpha increase
- Liver makes acute phase reactants (including hepcidin)
- Hepcidin blocks ferroportin activity (so no intake of iron and no mobilizaiton of iron)
What is a ‘functional iron deficiency’?
Occurs in ACD, because you have enough iron, you just cannot take it up or mobilize it!
What diseases can lead to ACD?
RA, Lupus, Tb, cancer, sarcoidosis, AIIDS
What do iron studies show for ACD?
Ferritin normal or increased
Serum Fe is decreased
TIBC is decreased
What stain is diagnostic of ACD? What do you see?
Prussian blue stain of bone marrow shows lots of blue iron present in macrophages.
Thalassemias prevent the proper production of what component of Hgb?
alpha globin (ch. 16) beta globin (ch. 11)