Microcytic Anaemais And Iron Metabolism Flashcards
What is microcytic anaemia?
A reduced rate of haemoglobin synthesis where the erythrocytes are smaller than normal. The cells are also often paler than normal (hypochromic).
What does TAILS stand for?
Thalassaemia, Anaemia of chronic disease, Iron deficiency, Lead poisoning, Sideroblastic anaemia
Ferrous vs Ferric Iron.
Ferrous iron (2+) is the reduced form, ferric iron (3+) is the oxidised form. Ferric needs to be reduced to ferrous before it can be absorbed into the diet.
Factors affecting absorption of non-Haem iron from food.
Negative influence: tannins, phytates, fibre and antacids. Positive influence: vitamin C helps to reduce ferric to ferrous iron, prevents the formation of insoluble iron compounds.
What are examples of food sources that are haem/non-haem?
Haem: liver, kidney, steak, chicken, salmon/tuna. Non-haem: raisins, beans, oat, barley, rice
What’s the function of hepcidin?
It inhibits ferroportin, so that iron can’t exit enterocyte into the blood.
Describe cellular iron uptake.
Fe3+ bound transferrin binds to transferrin receptor, entering cytosol receptor-mediated endocytosis. Fe3+ is reduced to 2+ and is transported to the cytosol via DMT1. Here, Fe2+ can be stored as ferritin, exported as ferroportin or taken up by the mitochondria.
How is hepcidin synthesis affected?
An increase in iron overload and it is decreased by high erythropoietic activity.
What are some causes of iron deficiency?
Insufficient iron in diet, malabsorption of iron, bleeding, increased requirement (pregnancy), anaemia of chronic disease.
Treatment of iron deficiency.
Dietary advice, oral iron supplements, intramuscular iron injections, intravenous iron, blood transfusion.
Why is iron excess dangerous?
Can exceed the binding capacity of transferrin, this excess iron can be stored in organs as haemosiderin. Iron promotes free radical formation and organ damage.
What is hereditary haemochromatosis and how is it treated?
It is an autosomal recessive disease, cause by a mutation in HFE gene, this causes too much iron to enter cells and accumulate in end organs causing damage. It is treated with a venesection.
