General Anemia and Iron Deficiency anemia Flashcards
What is the technical definition of an anemia? Defn in terms of Hb?
Reduction of circulating RBC mass. Hb less than 13.5 g/dl in males and 12.5 g/dl in females is anemia.
What are some signs and symptoms of anemia?
Headaches, weakness, dyspnea, PALE CONJUNCTIVA AND SKIN. Also can cause angina in patients with pre existing coronary issues.
What lab value is used to distinguish anemias from microcytic, normocytic or macrocytic, and what are the cut off values?
MCV (Mean corpuscular volume) is used to distinguish this, MCV below 80 is microcytic, between 80-100 is normocytic, and greater than 100 is macrocytic.
Why do microcytic anemias occur? What is it in general?
Microcytic anemia is when the MCV is less than 80, meaning that the RBC’s are smaller than they should be. Normally RBC’s come from erythroblasts, their progenitor cells, and then slowly they will divide into smaller fragments to form RBCs. In microcytic anemia, there is DECREASED PRODUCTION OF HEMOGLOBIN and as a result, one extra division occurs with the RBC moreso than normal, resulting in RBC’s that are smaller than they should be.
What is hemoglobin made of?
Heme + globin. Heme is made of iron (Fe) and the protein protoporforin. Globin is a protein.
What are the 4 major causes of microcytic anemia and why do they present?
Iron deficiency anemia, due to not enough Fe intake. Anemia of chronic disease, in which the Fe in the body cannot be used because they are being stored in macrophages due to some chronic inflam process. Sideroblastic anemia is when there is decreased production of protoporferin. And Thalassemia is when there is a problem in production of globin.
Which is the most common anemia in the world?
Iron deficiency anemia, due to inadequate nutrition which results in decreased Fe in blood.
How can iron be obtained from the diet and where and how is it absorbed?
Can be heme derived (from meat) and non-heme (from vegetables). The meat derived form is more readily absorbed. Absorbed IN THE DUODENUM. Enterocytes uptake Fe from the gut and transfers it across to the blood vessels through “FERROPORTIN.”
What is the transporter that allows for the absorption of iron and what’s the point?
Ferroportin is used by the enterocytes to transfer Fe into the blood vessels. We do not have a way to get rid of iron from our body efficiently, so by regulating iron absorption we regulate our iron concentration.
Whats the difference between Ferroportin, Transferrin and Ferritin?
Ferroportin transports iron from gut to blood, once in the blood the Fe gets shuttled into the liver and bone marrow macrophages and it does so via being bound to transferrin. Once in the tissue iron is stored in the form of ferritin. The reason for all these conversions is because of iron’s ability to induce oxidative stress so it ALWAYS needs to be bound to something.
What is the difference between “serum iron” “TIBC (Total Iron Binding Capacity), % saturation, and Serum Ferritin?
Serum iron tells you how much Fe is in the blood, TIBC tells you how much TOTAL transferrin molecules are there in the blood whether bound or not. For every 3 transferrin molecule there should be 1 bound iron. % saturation is a calculation of how much iron is bound to transferrin. Serum Ferratin is a measure of how much stored iron is in the liver and bone marrow macrophages.
Why would infants, children, adults (males and females) and the elderly present with iron deficiency?
Infants due to breast feeding (breast milk has very little iron), infants due to poor diet, male adults due to PUD, female adults due to menorrhagia or preggo. Elderly due to colon polyps or carcinoma in the west, hookworms in developing countries. Also of note, celiac disease, stuff that messes with absorption and gastrectomy are other examples.
Why is gastrectomy associated with iron deficiency?
Stomach acid helps maintain iron in the Fe 2+ form, which is more readily absorbed. The Fe 3+ state is harder to absorb. In a patient with gastrectomy a part of the stomach is lost so acid production decreases somewhat, resulting in less Fe 2+ and higher incidence of malabsorption.
How is serum ferratin and TIBC related?
When serum ferratin goes down the TIBC goes up and vice versa, the logic is that when the liver senses that serum ferratin is down it notes that it needs more iron. Thus it sends out more transferrin into the blood to try to catch more iron.
What happens to % sat if serum iron goes down?
If one Fe is available for every 3 transferrin molecule and there is loss of iron (hence serum iron decreases), it would mean then that the % sat of iron will also decrease.
