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80 Cards in this Set
- Front
- Back
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What is Iron a component of?
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Cytochromes, and O2 binding molecules.
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How can it damage tissues?
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By producing free radicals that attack cellular membranes, Proteins, and DNA.
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What are the proteins of Iron transport, uptake and storage?
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Transferrin, Transferrin Receptor, and ferritin.
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What is Transferrin?
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It is a transport protein which carries iron in the plasma and and ECF to supply tissue needs.
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What is the tarnsferrin receptor?
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It is a glycoprotein that sits of the surface of the cell membrane, binds to the transferrin-iron complex and is internalized as a vesicle.
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What is ferritin?
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Ferritin is the iron storage protein.
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Why is the level of ferritin important?
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To determine the amount of iron that is stored in the body.
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What are the proteins of Iron regulation?
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Iron Regulatory Proteins (IRP's) are mRNA binding proteins that coordinate expression of tranferrin, transferrin receptor and ferritin.
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How many IRPs are there?
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Two; IRP-1 and IRP-2.
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What happens if there is low iron?
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The iron regulatory protein will block the translation of ferritin.
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What are the storage amounts of iron in an adult male?
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35-45mg/kg
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How much is it in women?
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A bit less.
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Where is this iron located?
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2/3 of the body iron is in hemaglobin in erythron.
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Where is the remaining 1/3 iron located?
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It can be found in the hepatocytes and the reticuloendothelial cells that act as depots.
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Where is the dietary iron absorbed?
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It is absorbed in the duodenum.
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Where does it go then?
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It goes into the blood where it is bound to transferrin. It can then be transported to the bone marrow.
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What happens in the bone marrow?
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It is incorporated into RBC's.
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Where else can it go?
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It can go to the liver.
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What happens once it is incorporated into the RBC?
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It stays there for 60-120 days after which it is phagocytosed by macrophages.
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What is another storage protein other than ferritin?
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Hemosiderin.
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Where is the third largest store of iron in the body located?
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In Myoglobin.
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Why is regulation of iron absorption so crucial?
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Because humans have no way of excreting the iron and too much of it leads to toxicity.
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Where does absorption occur?
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In the gastro-duodenal junction in acid environment.
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What is the role of transferrin in the intestinal absorption of iron?
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It has no role in the intestinal absorption of iron.
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What is meant by dietary regulation?
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When you take too much iron in your diet the enterocytes become resistant to iron.
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What is meant by stores regulator?
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It means the the body responds to total body iron. It will stop accumulating when the stores are full.
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What is meant by erythropoietic regulator?
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There is modulation in iron absorption in response to requirements for erythropoiesis.
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What is Hepcidin? Not function...just what is it?
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It is a 25 AA polypeptide produced by the liver cells. It is an acute phase protein.
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What is its function?
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It is the major hormonal regulator of iron homeostasis.
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How does it do what it does?
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It inhibits Fe release from the macrophages, intestinal epithelial cells, and from placenta. Also it interacts with the transmembrane Fe transporter ferroprotein and decreases Fe transport.
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Why do people who suffer from inflammatory diseases also suffer from anemia?
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Because it induces Hepcidin.
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What inflammatory cytokines specifically induce Hepcidin?
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IL-6 and TNF.
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What does hepcidin levels decrease?
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In 3 cases...In Iron deficiency, hypoxia, and ineffective erythropoesis.
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How many people worldwide have adverse effects as a result of iron deficiency?
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More than 1/2 a Billion.
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What is the most common cause of anemia worldwide?
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Iron deficiency.
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What is anemia of iron deficiency caused by?
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Defective synthesis of hemaglobin resulting in RBC's that are smaller than normal (microcytic) and contain reduced number of hemoglobin.
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What is called when they have a reduced number of hemoglobin?
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It is called hypochromatic.
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What do we see in iron deficiency anemia other than a smaller and paler RBCs?
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We also see poikilocytes which are are abnormal small, not alike, cells. Normally RBC's look alike.
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What are the two major causes of iron deficiency anemia?
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Inadequate absorption and Increase loss or requirement.
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What is included in inadequate absorption?
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There are 7 entries here:
1) Antacid or high gastric pH 2) Excess branphytates. 3) Loss of erythrocytes. 4) Bowel resection. 5) Celiac disease. 6) IBD 7) Intrinsic RBC defect. |
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What is branphytates?
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It is the principle storage form of phosphorus in plant tissue, especially bran and seeds.
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What are the causes of increased loss or requirement of iron?
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There are 5 subcategories here:
1) Growth, pregnancy, lactation. 2) GIT loss 3) Genitourinary loss. 4) Pulmonary loss. 5) Other- trauma- excessive phlebotomy, large vascular malfunction. |
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What is a very important point that needs to be remembered in terms of iron absorption?
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It happens only in an acidic environment.
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Which age group suffers the most from iron deficiency?
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Young kids.
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What do you have to check in a woman who comes into clinic and says that she is anemic?
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You have to check to see whether she has underlying cancer or not.
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What are some of the other causes of iron deficiency in women?
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Hematuria, menopause, autoimmune diseases, vascular malformations....major taruma.
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What are the stages of iron deficiency?
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There are three stages:
1) Iron depletion 2) Iron deficient Erythropoiesis 3) Frank Iron deficiency anemia. |
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What is meant by iron depletion?
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Decrease of iron stores but no decline in functional iron compound.
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What is meant by iron deficient erythropoiesis?
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it occurs when iron stores are exhausted and are lacking
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What are the clinical presentations associated with iron deficient anemia?
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They could be asymptomatic, or they could have signs and symptoms of underlying disorders. They could have manifestations common to anemias from all causes...such as pallor, wakness, shortness of breath...
Or they could present with findings specific to iron deficiency such as cognitive abnormalities. |
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What are some of the other clinical presentations specific to iron deficiency?
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Pica, Koilonychia, blue sclera, plumer-vinsen syndrome.
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What is pica?
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It is a perverted apetite for substances not fit as food or of no nutritional value such as paint.
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What do children with iron deficiency usually have?
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cognitive abnormalities.
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What is Koilonychia?
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A malformation of the nails in which the outer surface is concave; often associated with iron deficiency or softening by occupational contact with oils.
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What is Plummer-Vinson syndrome?
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It is a syndrome that presents as a clinical triad of dysphagia, glossitis, and iron deficiency anemia.
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What is the DD for microcytic anemias?
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It depends...is it with decreased iron stores or with normal or increased iron stores.
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What is the DD of microctic anemia with decreased iron stores?
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Iron deficiency anemia.
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What is the DD of microcytic anemia with increased or normal iron stores?
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4...
1) Impaired iron metabolism 2) Anemia of chronic disease 3) Disorders of globin synthesis- thalassemia 4) Disorders of Heme synthesis- sideroblastic anemia. |
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How do you treat iron deficiency anemia?
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Give therapeutic iron and it confirms the diagnosis if you see the following;
1) reticulocyte starts 3-5 days from therapy. 2) Rise of Hb 10-21 days from therapy. |
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What do you have to do for the treatment to work?
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You have to ensure compliance. You have to stop the blood loss and treat the coexistant disease.
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What are the two major oral ways that you can give iron treatment?
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Ferrous iron salt and ferrous sulfate.
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When would you give parenteral iron therapy?
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When there will be malabsorption, intolerance to treatment, chronic uncontrolled bleeding.
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What are the risks of parenteral iron therapy?
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Anaphylaxis, severe serum sickness,
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How is it given?
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IM
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Where does the dietary iron come from?
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Mostly in meat.
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So who is susceptible to iron deficiency anemia?
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Vegeterians...but not only they.
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Why are the elderly susceptible to iron deficiency anemia?
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Because they are on a tea and toast diet.
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What is iron overload?
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Accumulation of iron that occurs in disorders with excessive absorption or chronic blood transfusion.
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What is hereditary hemachromatosis?
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AR disorder that results in excessive absorption of Fe from the GI tract.
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What gene is involved?
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HFE on chromosome 6.
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What is the consequence of this mutation?
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HFE is not expressed on duodenal crypt cells...and it doesn't incorporate iron and seems iron deficienct and absorbs more iron.
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What happens to the levels of Hepcidin?
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It is downregulated.
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What are the clinical features of iron overload?
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1) Skin hyperpigmentation
2) Endocrine abnormalities. 3) Liver fibrosis, cirrhosis, hepatocellular carcinoma. 4) Cardiomyopathy 5) Arthropathy. |
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What are the endocrine abnormalities?
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Diabetes Mellitus, gonadal, thyroid, pituitary, and parathyroid dysfuction.
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how do you treat hemachromatosis without anemia?
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Regular venesection.
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What is removed with each unit of blood?
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200-250mg of iron.
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How do you treat tranfusional iron overload?
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With iron chelators that cause the excretion of iron in the urine or feces.
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What are 3 iron chelators? How are they administered?
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1) Deferoxamine- Parenteral
2) Deferiprone- Oral 3) Deferasirox- Oral |
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Which one has the least amount of side effects?
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Deferasirox.
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Which one is better in treating cardiac iron deposition?
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Deferiprone.
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