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Flashcards in Nutritional Anaemia Deck (52)
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1

What is the definition of Anaemia? 

  • Reduced O2 carrying capacity 
  • Conditions where the number of red blood cells is insufficient to meet the bodies physiological needs 

 

 

2

What are the formed elements in the blood? 

  • Red blood cells 
  • Platelets 
  • Monocyte 
  • Lymphocyte 
  • Eosinophil 
  • Basophil 
  • Neutrophil 

3

Describe normal erythropoesis 

  • Starts in the bone marrow 
    • Stimulated by cytokine EPO released from the kidney 
  • Undergoes multiple round of maturation from Megakaryocyte Erythroid Progenitor (MEP) to Late Erythroblast 
  • Nucleus is extruded and forms a reticulocyte 
  • Which then forms a mature RBC 
    •  Requires vitamin B12 = co factor for methylation in DNA + cell metabolism 
      • Intracellular conversion of 2 active enzymes necessary for homeostasis methylmalonic acid + homocysteine 
    • Requires folate = necessary for DNA synthesis -> adenosine, thymine and guanine synthesis 
    • Requires iron = necessary for Hb synthesis 

4

What are the three main mechanisms of action which cause anaemia? 

  1. Failure of Production - not producing enough RBCs - hypoproliferation, reticulocytopenic (low reticulocyte count) = shows the bone marrow isnt able to catch up - hence failed production 
  2. Decreased survival -  can be due to stabbing leading to blood loss, haemolysis, reticulocytosis - increased reticulocyte cound due to bone marrow stimulating further erythropoesis 
  3. Ineffective Erythropoesis - main cause of microcytic (iron deficiency ) and macrocytic (B12 and folate) 

5

  1. What is used to assess anaemia clinically in the UK? 
  2. What is used to assess the underlying CAUSE of anaemia? 

  1. Haemoglobin concentration 
  2. Red blood cell SIZE 
  • Reticulocyte count will then add further clue to increased loss (reticulocytosis) or failure of production (reticulocytopenia) 

6

What are causes of microcytic anaemia? 

  • Iron deficiency 
  • Thalassaemia 
  • Anaemia of chronic disease 

7

What are causes of normocytic anaemia? 

  • Anaemia of chronic disease 
  • Sickle cell disease 
  • Chronic renal failure 
  • Aplastic Anaemia 

8

What are causes of macrocytic anaemia? 

 

 

 

(Macrocytic can further be split into megaloblastic and non-megaloblastic) 

  • Vitamin B12 and Folate deficiency 
  • Myelodysplasia (cancer where immature blood cells in bone marrow do not mature and become healthy blood cells) 
  • Alcohol induced 
  • Drug induced 
  • Liver disease 
  • Myoxedema 

9

What can a mixture of iron deficiency and vitamin B12 and Folate deficiency lead to? 

Normocytic Anaemia 

 

Because macrocytic anaemia (due to Folate and vitamin B12) and microcytic anaemia (due to iron deficiency) 

10

Aswell as looking at MCV (size = normocytic, macrocytic and microcytic) what else can you look for to discover the type of anaemia? 

Reticulocyte count adds further clue as to failure of production (reticulocytopenia) or increased losses (reticulocytosis) 

11

Briefly describe the structure of  haemoglobin 

  • Iron containing oxygen transport metalloprotein 
  • Composed of 2 alpha and 2 beta globin chains 
  • 4 iron containing haem groups 
    • Reduced HB leads to anaemia as it reduces the O2 carrying capacity 

12

Define nutritional anaemia and list the main ones  

Nutritional anaemia = Anaemia due to lack of essential ingredients that the body acquires from food sources 

3 Types 

  • Iron deficiency 
  • Vitamin B12 deficiency 
  • Folate deficiency 

13

Why is iron important for the body? 

  • Essential for O2 transport 
    • Most abundant trace element in the body 
  • We cant keep a big store of iron therefore we need our daily requirement needed for EPO 
  • We cant naturally excrete iron from the body its uptake is regulated by hepcidin 

14

Which gender needs more iron? 

  • Women need more daily iron than men (due to menstruation) 
  • When pregnant, a lot more iron is needed 
  • Women reach male iron levels post-menopause 

15

Where do we get our iron from? 

Which form of iron is easily absorbed? 

We get our iron from our food 

  • Haem (meat, chicken and fish) - easily absorbed 
  • Non-haem iron absorption is lower for those consuming vegetarian diets, for whom the iron requirement is 2 fold greater 

 

16

Where is dietary iron predominantly absorbed? 

Predominantly in the duodenum and proximal jejunum via ferroportin transporters on enterocytes 

17

What are the two forms of iron? 

  • More than one stable form of iron 
    • Ferric state (3+) and Ferrous state (2+)  

18

Describe iron absorption 

 

  • Regulated by GI mucosal cells and hepcidin 
  • Occurs in the duodenum and the proximal jejunum via ferroportin transporters on the enterocytes 
  • Transferred into plasma and bound to transferrin 

The amount absorbed depends on the type ingested!!

  • Haem iron (ferrous) sources (from meats and seafood) higher absorption
  • Non haem (ferric)  (from vegetarian diets) - need to eat more to acquire the same level of iron 

19

What factors can affect iron absorption in our body? 

  • Haem iron (ferrous) absorbed more than non haem iron (ferric) 
  • GI acidity 
  • State of iron storage levels 
  • Bone marrow activity 

20

How are iron levels regulated? 

Via HEPICIDIN (iron regulatory hormone) and FERROPORTIN (iron channel) 

  • Hepicidin causes ferroportin internalisation and degradation decreasing iron transfer into blood plasma from 
    • Duodenum 
    • Macrophages (recycle senescent erthyrocytes) 
    • Iron-storing hepatocytes 
  • Feedback is regulated by iron concentrations in plasma adn liver and by erythropoeitic demand for iron 

21

From what areas does hepcidin cause degradation and internalisation of ferroportin channels? 

  • Duodenum 
  • Macrophages involved in recycling senescent erthythrocytes 
  • Iron-storing hepatocytes 

This will decrease iron transfer from these into blood 

22

What happens after iron is absorbed? 

  • Iron will be transferred into plasma and binds to transferrin (iron transporting circulating plasma protein) 
  •  
  • This will then be transported to bone marrow and binds to transferrin receptors on RBC precursors 

23

What will the transferrin levels and ferritin stores look like in iron deficiency? 

IRON DEFICIENCY - will see reduced ferritin stores and increased transferrin 

24

What are the ways in which iron can be lost from the body? 

  • Desquamation of sloughed mucosal cells 
  • Menstruation/ blood loss 

The iron metabolism is controlled by absorption rather than excretion as we do not have a method of excreting iron 

25

What is the main distribution of iron in the body? 

  • Mostly incorporated into haemoglobin in developing erythroid precursors and mature red blood cells 
  • Remaining iron is found in storage and transport proteins found in hepatocytes, reticuloendothelial macrophages in liver, spleen and bone marrow 

26

What are the two storage proteins of iron? 

Haemosiderin and ferritin 

27

What is the role of reticuloendothelial macrophages? 

Ingest senescent red blood cells, catabolise haemoglobin to scavenge iron and load the iron onto transferrin for reuse

This process will be regulated by hepcidin which can downregulate ferroportin transporters preventing iron recycling 

 

28

What are the laboratory studies which determine someone's blood iron levels? 

  • Serum Fe (not used as much) 
  • Ferritin  - most commonly used 
  • Transferrin saturation - ratio of serum iron and total iron binding capacity - reveals percentage of binding sites that have been occupied by iron 
  • Transferrin 
  • Total iron binding capacity = measure of capacity of transferrin to bind iron, indirect measurement of transferrin 

29

What are the lab results in iron deficiency anaemia? 

  • Ferritin = LOW 
  • Transferrin Saturation = LOW 
  • Total Iron binding capacity = HIGH 
  • Serum Iron = LOW/ NORMAL 
  • Reticulocyte = low 
    • This is low because although bone marrow is capable of making RBC it cant because it doesnt have enough iron, therefore when patients are given iron it rises drastically 

30

What are the causes of iron deficiency? 

  • Either you dont get enough due to 
    • Poor diet, malabsorption or increased physiological needs 
  • Or you're losing too much due to 
    • Blood loss (menstruation), GI tract loss, parasites 

 

Excessive menstrual loss = first cause of iron deficiency in premenopausal women 

Blood loss from GI = second cause of iron deficiency in postmenopausal women and men 

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