Anaemia Intro Flashcards
What is anaemia defined as?
reduced total red cell mass
What is the normal response to anaemia?
reticulocytosis
How long does up regulation of reticulocyte production by the bone marrow in reponse to anaemia take?
a few days
What does polychromasia in reticulocytes result from?
residual RNA in the cell
What do automated machines measure?
Hb conc.; no. of RBCs; size of RBCs
What does the automated machines calculate?
haematocrit; mean cell haemoglobin and mean cell haemoglobin conc.
Waht is the purpose of calculating mean cell haemoglobin concentration?
mainly as a lab QC
What are the 2 causes of decreased production of RBCs?
hypoproliferative or maturation abnormality
What are the 2 types of maturation abnormality?
cytoplasmic or nuclear
What is seen with cytoplasmic defects?
impaired haemoglobinisation
Waht is seen with nuclear defects ?
impaired cell division
What are the causes of anaemia with a high reticulocyte count?
bleeding and haemolysis
What is the main difference between bleeding and haemolysis?
in haemolysis waste products are recycled
How can cytoplasmic and nuclear defects be distinguished?
mean cell volume
What type of defect is macrocytic?
maturation
What type of defect is microcytis?
haemoglobinisation
Where does haemoglobin synthesis occur?
in the cytoplasm
What is the main cause of hypochromic microcytic anaemia?
iron deficiency
What are the causes of haem deficiency?
iron deficiency; anaemia of chronic disease
What are the causes of problems with porphyrin synthesis?
lead poisoning; pyridoxine responsive anaemias
What disease is associated with globin deficiency?
thalassaemia
Why is iron potentially toxic?
generates free radicals
Where is most of the iron in the body?
haemoglobin
How is Hb loss calculated from blood loss?
half blood loss
How is iron stored?
as ferritin mainly in the liver
How are bone marrow macrophages invovled in iron metabolism?
feed it to red cell precursors
What is circulating iron bound to?
transferrin
How many bidning sites for iron atoms does transferrin have?
2
What is the function of transferrin?
transports iron from donor tissues (macrophages; enterocytes and hepatocytes)to tissue expressing transferrin receptors
What does % sat of transferring with iron measure?
iron supply
What is heavy menstrual loss defined as?
> 60ml
What is the average menstrual blood loss?
30-40ml/month
