Nutritional Anaemia Flashcards
What is the definition of anaemia?
WHO definition: Anaemia is a condition in which the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body’s physiologic needs.
In real life/ practice: Insufficient oxygen carrying capacity due to reduced haemoglobin concentration as seen with insufficient RBC.
What is Haemoglobin?
Iron containing oxygen transport metalloprotein within RBCs, essential for oxygen carrying properties of red blood cells and is where iron lives in RBCS.
What three main types of cells does blood contain?
- Red blood cells, normal blood film has round cells with pale centre in the middle. Ring around it should be about 1/3 of the diameter. Redness is the Hb.
- White blood cells – neutrophils, monocytes, lymphocytes, eosinophil, basophil
- Platelets
What does normal erythropoiesis (maturation of RBC) require?
- Vitamin B12 and folic acid – helps in DNA synthesis
- Iron for Haemoglobin synthesis
- Other vitamins
- Cytokines (erythropoietin)
- Healthy bone marrow environment needs to be working healthily
Why might anaemia occur?
Failure of production: hypoproliferation reticulocytopenia.
Ineffective erythropoiesis
- You’ve got ingredients but not right instructions, seen in red cell disorders like thalassemia
- Bone marrow can’t use ingredients – B12, folate etc, and so doesn’t make enough red blood cells
Decreased survival – blood loss, haemolysis, reticulocytosis
Why might you see increased reticulocytes in anameia? Why might you have reticulotyopenia (decreased)?
- If there isn’t enough Hb the bone marrow goes into overdrive to try to catch up, causing lots of reticulocytes. - reticulocytosis (seen in decreased survival)
- If BM can’t make enough RBC due to lack of right ingredits/instructions, peripheral blood lacks reticulocytes too.
Reticulocytes tell you if its failure of production or decreased survival of RBC.
What can cause microcytic anaemia?
- Iron deficiency (heme deficiency)
- Thalassaemia (Globin deficiency)
- Anameia of chronic disease
What causes macrocytic anaemia?
- B12 deficiency
- Folate deficiency
- Myelodysplasia
- Alcohol induced
- Drug induced
- Liver disease
- Myxoedma
What causes normocytic anaemia?
- Anaemia Chronic Disease
- Aplastic anaemia
- Chronic Renal Failure
- Bone Marrow infiltration
- Sickle cell disease
What is nutritional anaemia?
Anaemia caused by a lack of essential ingredients that the body acquires from food sources
- Iron deficiency
- Vitamin B12 deficiency
- Folate deficiency
What is iron important for?
- Essential for O2 transport
- Most abundant trace element in body
- Daily requirement for iron for erythropoiesis
- Varies depending on gender and physiological needs e.g are you pregnant, a child, menstruating
At 14 years old why is there a difference in iron requirements between males and females?
Why is iron from meat more readily available?
- Because females menstruate, so need more iron. Iron levels equal after menstration, 51+
- Meat sources contain blood, better absorption of iron. Non-heme iron absorption lower, need twice as much.
Where is iron absorbed? How is the iron transported in the body?
From duodenum, 1-2mg per day.
Body produces transferrin, transports iron to where it’s needed.
- Most iron sits in RBC and BM in reticular endothelial system, macrophages and spleen
- Iron in liver and muscles too
Iron lost by sloughed mucosal cells in GIT, menstruction and blood loss.
What are the stable forms of iron? What are the storage proteins?
More than 1 stable form of iron:
- Ferric states (3+) and ferrous states (2+)
- Most iron is in the body as circulating Hb
Hb: 4 haem groups, 4 globin chains able to bind to 4 O2
Storage proteins:
- Ferritin and haemosiderin
- Found in cells of liver, spleen and bone marrow
How is iron absorption regulated? How does iron absorption happen?
- Regulated by GI mucosal cells and hepcidin (negative feedback)
- Duodenum and proximal jejunum
- Via ferroportin receptors on enterocytes
- Transferred into the plasma, iron binds to plasma and then plasma with iron binds to transferrin , taking iron to where it is needed
What does hepcidin, its receptor and the iron channel ferroportin control?
Controls dietary absorption, storage and tissue distribution of iron.
- Hepcidin causes ferroportin internalisation and degradation, decreasing iron transfer into blood plasma from duodenum
- from macrophages recycling senescent erhtrocytes
- and from iron-storing hepatocytes.
What regulates hepcidin feedback?
Iron concentrations in plasma and liver, and by erthropoietic demand for iron.
As you become more iron replete and there is enough iron, hepcidin falls.
What are sources of B12 and folate?
What is the difference between megaloblast and non-megaloblast?
Megaloblastic changes of RBC seen in B12 and folic acid deficiency.
Megaloblasts:
- RBC big and oval, more uniform
- Changes in neutrophils, are segmented. Nucleus of neutrophil has lots of lobes
- macroovalocytes and hypersegmented
Non megaloblast:
- RBC big but not the same
- In this picture myelodysplastic, bone marrow is producing abnormal red blood cells
What are some causes of b12 deficiency?
