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- 1 Thalassaemia
- 2 Anaemias
- 3 Purpura
- 4 Non Muco-Cutaneous
- 5 Muco-Cutaneous
- 6 Vitamin K deficiency
- 7 DIC
Defect in synthesis of either the alpha or beta globin chains in haemoglobin.
- Caused by gene mutations
- If heterozygous, usually asymptomatic.
- In homozygous, large amounts of HB A2 and Hb F. Not as good an normal Hb A, but can cope, though in severe cases regular 6 week transfusions will be required – can lead to iron overload.
- Caused by gene deletions
- If all four are deleted you get Hb Barts which isn't compatible with life. Children are stillborn or die shortly after birth.
- If three are deleted some Hb A is present, and usually transfusion are not necessary.
- If 2 or less are deleted. Often not noticeable.
Sickle cell anaemia
- A base mutation
- No Hb A, just Hb S and Hb F in homozygous
- Carriers (heterozygous) will have sickle cell trait, with some signs of illness.
- Often presents with acute pain in hands and feet, due to vaso-occlusion of small vessels.
- Pigment stones can occur due to rapid haemolysis.
- Anaemia is present since sickle cells are broken down quickly. This can present with jaundice, due to increased levels of bilirubin getting released.
- Non functioning bone marrow
- Dangerous but uncommon.
- Can be caused by some chemicals and drugs (especially anticancer ones), radiation, infections and pregnancy (where it has 90% mortality).
- Leads to pancytopenia – a reduced red, white and platelet cell count.
- Excessive rate of erythrocyte breakdown.
- Causes jaundice (due to excess bilirubin)
- Associated with blood transfusion mismatch.
- Haemolytic anaemia of the newborn (when the mother is Rhesus – and the baby Rhesus + sometimes there can be a sever complication)
- Increased young cells, reticulocytes due to high turnover.
- Maturation of the normoblast needs vitamin B12 and folate.
- Without this it leads to formation of abnormally large megaloblasts which become macrocytes.
- Number of red cells is greatly reduced and the rate of destruction increased.
- Folate defiency is usually related to poor diet, B12 is malabsorbtion
- B12 deficiency, with defective absortion in the ileum.
- Caused by diet, or autoimmune disease where antibodies attack gastric parietal cells, so intrinsic factor can't be made.
- Treatment by B12 intramuscular injections till sorted then every 3 months for life.
- A skin rash due to capillaries bleeding into the skin.
- Easy bruising
- Can be due to capillary defects, platelet deficiency or malabsorbtion (eg. Vitamin K)
(Haemophilias, with bleeding into joints and muscles)
- Level of factor VIII is reduced, but vWF is normal.
- Sex linked on the X chromosome.
- Rare 1 in 10000
- Same as A, except factor IX is reduced.
- Very rare, 1 in 50000
vWD and platelet disorders.
Von Willebrand's disease (vWD)
- Autosomnal dominant.
- There is defective platelet function as well as factor VIII:C deficiency.
- Leads to longer extrinsic pathway.
- Pretty rare.
- Drug effect more common.
Vitamin K deficiency
- Needed for factors II, VII, IX and C and proteins C and S.
- It is a fat soluble vitamin needing bile for absorption – so in obstructive jaundice you get malabsorbtion.
- PT is prolonged.
- Warfarin is a Vitamin K inhibitor
- Neonates tend to have deficiency due to lack of gut bacteria and low conc of K in milk.
(Disseminated Intravascular Coagulation)
- Widespread generation of fibrin within the blood.
- Caused by diffuse endothelial damage, generalised platelet aggregation.
- Causes 1 sepsis, 2 obstetric, 3 malignancy – assume sepsis and treat for this.
- Also, burns, liver disease, trauma, malignant disease, septicaemia, haemolytic transfusion errors.