L11: Nutritional Anaemias Flashcards
Define anaemia
→the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body’s physiologic needs
What is insufficient oxygen carrying capacity due to?
→reduced haemoglobin concentration as seen with insufficient RBC
How many chains are found in Hb?
→alpha=2
→beta=2
What are the basic requirements for normal erythropoeisis?
→Vitamin B12 & folic acid →Iron →vitamins →cytokines →healthy bone marrow environment
Why is VitB12 and folic acid needed for erythropoiesis?
→DNA synthesis
Why is iron needed for erythropoeisis?
→Hb synthesis
→Essential for O2 transport
→Most abundant trace element in body
What are the three mechanisms of action that leads to anaemia?
→hypoproliferation
Reticulocytopenic
→Ineffective Erythropoiesis
→Decreased Survival
Give three examples of microcytic anaemias
→Iron deficiency
→Thalassemia
→anaemia of chronic disease
What is thalassaemia due to?
→globin deficiency
Give examples of normocytic diseases
→anaemic chronic disease →aplastic anaemia →chronic renal failure →bone marrow infiltration →SCD
Give examples of macrocytic diseases
→b12 deficiency →folate deficiency →myelodysplasia →alcohol/drug induced →liver disease →myxoedema
What does reticulocyte count inform on?
→whether marrow can actually make cells
→adds further clue as to failure of production or increased losses
What is nutritional anaemia?
→Anaemia caused by lack of essential ingredients that the body acquires from food sources
What deficiencies are found in nutritional anaemias?
→Iron deficiency
→Vitamin B12 deficiency
→Folate deficiency
What are foods that are rich in iron?
→Meats
→seafood
→vegetables
→wheat
How does iron absorption differ between meat eaters and vegetarians?
→Non-heme iron absorption is lower for those consuming vegetarian diets, for whom iron requirement is approximately 2-fold greater.
How is excess iron dealt with?
→regulation is at absorption level, not excreted is an essential component of cytochromes, oxygen-binding molecules
Where is dietary iron absorbed?
→predominantly in the duodenum
How does iron circulate?
→bound to plasma transferrin and accumulate within cells in the form of ferritin
How is 2/3 of the iron in the body incorporated?
→incorporated into haemoglobin in developing erythroid precursors and mature red cells
Which other cells is iron found in?
→hepatocytes and reticuloendothelial macrophages
What do reticuloendothelial macrophages do?
→ingest senescent red cells,
→catabolise haemoglobin to scavenge iron,
→load the iron onto transferrin for reuse
How many states of iron are in the body?
→ferric states- 3+
→ferrous states- 2+
Where are ferrritin and haemosiderin found?
→liver
→spleen
→bone marrow
