Flashcards in Anaemia Deck (43)
What is anaemia?
Reduced red blood cells
State the parameters for defining anaemia in an adult male (Hb and haematocrit levels)
Hb less than 130g/L
State the parameters for defining anaemia in an adult female (Hb and haematocrit levels)
Hb less than 120g/L
What is haematocrit?
Ratio/percentage of whole blood that is made up of red cells if the sample was left to settle
What cells represent circulatory red cells that have just left the bone marrow?
How does the blood film of reticulocytes appear?
How is anaemia classified by pathophysiology?
Decreased production of red cells (reduced or ineffective erythropoiesis) [low reticulocyte count]
Increased destruction of red cells (haemolysis, bleeding) [high reticulocyte count)
What morphological characteristic can be used to classify anaemia?
Mean cell volume
How can mean cell volume be used to distinguish between cytoplasmic and nuclear defects in erythropoiesis?
Low MCV suggests problems with haemoglobinisation in the cytoplasm
High MCV suggests problems with red cell maturation
Deficiency in haemoglobin production results in what type of anaemia?
Microcytic anaemia - cells are small (low MCV) and hypochromic (lack colour)
List some causes of microcytic anaemia
Haem deficiency (lack of iron, problem with porphyrin synthesis)
Globin deficiency (thalassaemia)
Circulating iron is bound to what?
Iron is stored as ferritin where in the body?
How can iron deficiency be confirmed?
Anaemia (less functional iron)
Low ferritin (less stored iron)
List some causes of iron deficiency
High mean cell volume is associated with which type of anaemia?
Macrocytic anaemia - cells are big
What is the difference between macrocytosis and macrocytic anaemia?
Macrocytosis: raised MCV, normal RBC count
Macrocytic anaemia: raised MCV, low RBC count
How many binding sites are there on a transferrin molecule?
What unit is MCV measured in?
(1 femtolitre = 10^-15 litres)
What is the range for a normal MCV?
What is a megaloblast?
Abnormally large red cell precursor with an immature nucleus
Macrocytic anaemia can be caused by megaloblastic cells. What is the characteristic microscopic appearance of these red cells?
What is the consequence of a megaloblastic cell?
Cytoplasm and haem synthesis is fully developed even though nucleus is immature; cell senses it has enough Hb and doesn't divide anymore, leading to macrocytosis
List some causes of megaloblastic anaemia
Why does lack of B12 and folate cause megaloblastic anaemia?
B12 and folate are essential cofactors for nuclear maturation - enable reactions for DNA synthesis
Thus deficiency leads to DNA defects
Which 2 biochemical cycles involving folate and B12 are involved in DNA synthesis?
Where in the body does B12 bind to intrinsic factor?
List some causes of B12 deficiency
Dietary insufficiency (vegetarians)
Small bowel resection
Malabsorption (Coeliac, IBD)
Where in the body is dietary folate absorbed?
Duodenum and jejunum