Anaemia and microcytic anaemia Flashcards
Define anaemia
reduced total red cell mass
what are surrogate markers used to measure red cell mass
haemoglobin Hb
haematocrit Hct
For a male, at what levels are you anaemic
Hb < 130
Hct 0.38-0.52
For a female, at what levels are you anaemic
Hb < 120
Hct 0.37-0.47
Where does erythropoeisis occur
bone marrow
what is a macrophage also known as
histiocyte
how is Hb concentration measured
spectophotometric method
burst RBC to create Hb solution and measure optical density
how do you measure haematocrit
ratio/% of the whole blood fluid that is red if it was left to settle
are Hb and Hct always reliable markers of anaemia
no
what is the response to anaemia
reticulocytosis
sign of increased red cell production
what are reticulocytes
immediate precursors of red cells that have just left the bone marrow and entered the bloodstream
features of reticulocytes
no nucleus - RNA is present
larger than RBC
purple colour
polychromatic blood film
in terms of red cell parameters, what is measured and what is calculated
measured: Hb concentration, number and size of RBCs
calculated: Hct, mean cell Hb, mean cell Hb concentration
in anaemia:
decreased production will have a high/low reticulocyte count
low - since bone marrow is not working effectively
in anaemia:
increased destruction and loss of cells will have a high/low reticulocyte count
high - since marrow is working to compensate for loss
what are causes of a low reticulocyte count
hypoproliferative - decreased erythropoeisis
maturation abnormality - cytoplasmic or nuclear
what defect occurs if there is a cytoplasmic maturation abnormality
impaired haemoglobinisation
what defect occurs if there is a nuclear maturation abnormality
impaired cell division
what is MCV
mean cellular volume
what is MCV useful for
distinguishing between cytoplasmic and nuclear defects
what does a low MCV indicate
microcytic cells
cytoplasmic defect in haemoglobinisation
what does a high MCV indicate
macrocytic cells
nuclear defect in maturation
in which part of the cell is Hb synthesised
cytoplasm
what makes up Hb
Haem = Fe2+ and Porphyrin
Globin
deficiency of what causes small cells with low Hb content
low Fe, porphyrin, globin
what do microcytic hypochromic cells indicate
deficient Hb synthesis from cytoplasmic defect
what are causes of haem deficiency
iron deficiency
anaemia of chronic disease
abnormal porphyrin synthesis
congenital sideroblastic anaemia
what are causes of globin deficiency
thalassaemia
how can iron exist in the body
Fe2+ –> ferrous state
Fe3+ –> ferric state
what are the functions of iron
carry O2 in Hb and myoglobin
transport electrons in mitochondria
generate free radicals (dangerous)
In iron studies: what tests for functional iron
Hb levels
in iron studies: what tests for transported iron
serum iron
transferrin
transferrin saturation
in iron studies: what tests for storage iron
serum ferritin
what is transferrin
protein with 2 binding sites for iron atoms which transfers iron from donor tissue to cells expressing transferring receptors
what is % transferrin saturation with iron
measurement of iron supply
Iron deficiency and anaemia of chronic disease cause high/low %transferrin saturation
low
haemochromatosis causes high/low %transferrin saturation
high
what is ferritin
large intracellular storage protein that stores Fe3+
what happens to ferritin if there is an increase in iron levels
ferritin levels go up
low ferritin means there is iron deficiency, true or false
true
what is an indirect measure of storage iron
serum ferritin
what are causes of iron deficiency
insufficient dietary intake
haemorrhage - menorrhagia, GI, haematuria
malabsorption - coeliac, crohns
where is iron absorbed in the GI tract
proximal gut
what is needed to help iron absorption
acid
