Anaemia Flashcards
What is haemoglobin made up of?
Polyphyrin, haem + Fe atom and 4 polypeptide chains forming globin
What chains form HbA?
2 alpha and 2 beta
What chains form HbA2?
2 alpha and 2 delta - present in small amounts
What chains form HbF?
2 alpha and 2 gamma
What causes a left shift in the O2 dissociation curve?
An increase in pH or a decrease in temp, CO2, 2,3DPG
Causes HIGHER O2 affinity so less O2 delivery
What causes a right shift in O2 dissociation curve?
Decrease in pH or an increase in temp, CO2, 2,3DPG
Causes LOWER O2 affinity so high O2 delivery
Give an example of a Hb with a left shifted curve and conditions in which there is a right shifted curve.
Left = HbF
Right = Methaemoglobin - Fe3+ prevents O2 binding
Sickle cell HbS
Why don’t Sickle cell patients present as breathless?
O2 is more readily supplied due to the right shift allowing release of O2 more readily.
What is the function of 2,3DPG?
As O2 is released, beta chains pull apart and 2,3DPG binds within to further decrease the affinity of O2 and increase O2 delivery = right shift effect
Where is Hb synthesised?
Mitochondria
What is the definition and classification of anaemia?
A reduction in Hb concentration accompanied by reduced RBC count and packed cell volume/Haematocrit.
Males <130g.L
Females <115g.L
What is relative polycythemia and what may cause it?
A reduced plasma volume which elevates Hb concentration and masks anaemia e.g. Dehydration
What state may lead to apparent anaemia?
Pregnancy - Plasma volume increases and reduces the concentration of Hb
What happens to Hb at altitude?
Hb concentration increases to increase O2 transport due to the reduced availability in the atmosphere
What happens to O2 carrying capacity when Hb concentration changes?
Remains the same
What is the definition of O2 carrying capacity?
The amount of O2 that will bind to a Hb unit in blood.
What are the SYMPTOMS of anaemia?
Fatigue, SoB, palpitations, angina, drowsiness, headache
What are the SIGNS of anaemia?
Angular stomatitis (Mouth)
Koilonychia (nail spooning)
Conjunctiva pallor
=Iron deficiency
How can anaemia be classified?
Based on size of RBC and mean cell volume = Micro, normo, macro
Based on the cause = Reduced production, poor function, increased destruction
What type of conditions cause macrocytic anaemia?
DEFICIENCIES and DESTRUCTION
What type of conditions cause microcytic anaemia?
Conditions that directly affect Hb