Anaemia (+ Iron) Flashcards
What is erythropoiesis and where does it occur?
Making of red blood cells
In the bone marrow
What removes the red blood cells?
Reticuloendothelial system (main organ=spleen)
What is dyserythropoiesis?
Abnormal/incorrect formation of RBCs
If there are problems with haemoglobin synthesis, anaemia can result. What two conditions involve a problem with haemoglobin synthesis?
Thalassaemia
Sickle cell disease
What is thalassaemia?
Reduced rate of synthesis of normal alpha/beta globin chains
What is sickle cell disease?
Synthesis of an abnormal haemoglobin
Caused by inheritance of the sickle beta globin chain
What is the exact mutation that causes sickle cell disease?
A point mutation causing the substitution of valine for glutamic acid in the beta chain (position six)
How is sickle cell disease inherited?
Usually autosomal recessive but there are cases where there is 1 sickle cell allele and then another abnormal Hb mutation allele which can have the same sickling effect.
Can be a carrier (and can protect against malaria)
What are the symptoms of sickle cell disease?
Symptoms of anaemia usually mild ie the anaemia is well tolerated as HbS readily gives up oxygen in comparison to HbA
**the clinical pattern of disease is very variable between individuals
What are the clinical problems associated with sickle cell disease?
Crises:
- vaso-occlusive = pain and organs effected (chest and spleen)
- aplastic
- Haemolytic
Other organ damage
Problems more likely to occur if it is cold, there are infections etc
What effect does thalassaemia have on the Hb levels and the size of RBCs?
Low Hb level
Thus microcytic red cells
What effect does thalassamia have on the breakdown of RBCs?
It increases it because the spleen and the rest of the reticuloendothelial system recognise the cells as faulty.
As a result the body must make more blood else where in the body
What is extramedullary haemopoeisis and why would it occur?
Making blood outside of the bone marrow (ie in the spleen, liver)
When the bone marrow isn’t making correct RBCs ie in thalassaemia
What issues does extramedullary haemopoeisis cause?
Splenomegaly
Hepatomegaly
Expansion of haemopoiesis into the bone cortex which impairs growth and causes skeletal abnormalities
How does the body try to cope with thalassaemia? What can this cause?
Extramedullary haemopoiesis
Stimulation of EPO
Iron overload
How is thalassaemia treated?
Transfusions, iron chelation (drugs to absorb iron), folic acid (stop secondary folate deficiency), immunisation, holistic care (cardiology, endocrine and psycholocal.) stem cell transplantation in some
What are the 3 classifications of beta-thalassaemia?
B-thalassaemia: Major and minor and intermedia
What are the 4 classifications of alpha thalassaemia?
Silent carrier state
Alpha thalassaemia trait
Haemoglobin H (HbH) disease
Hydrophobic fetalis
Explain how myelofibrosis can lead to anaemia
Heavilt fibrotic marrow-little space for haemopoiesis
Blood film shows cells looking like teardrops
Due to lack of erythropoiesis, extramedullary haemopoiesis occurs which causes splenomegaly
The increased size of the spleen also leads to the increased activity of the reticuloendothelial system and more red blood cells are broken down
Less produced + more broken down = anaemia
Explain how thalassaemia causes anaemia
Hb synthesis is effected
Those cells that are produced are defected
Which increase the removal of them
Extramedullary haemopoiesis also occurs so we get splenomegaly
Decreased production + increases removal = anaemia
Why might anaemia develop?
In Bone marrow:
1) abnormal erythropoiesis
2) abnormal haemoglobin synthesis
In peripheral red blood cells:
3) abnormal function
4) abnormal structure
5) abnormal metabolism
6) excessive blood loss
Removal:
7) abnormal function of RES
What is hypochromic anaemia?
Condition in which the red cells are paler than normal
What is rouleaux?
When cells stack together
What is anisocytosis?
When there are unequal sized RBCs
