Haemolytic Anaemias Flashcards
What are the types of haemoglobinopathies?
Abnormal globin chain variants with altered stability/function e.g. sickle cell disease. A reduced or absent expression of normal globin chains e.g. thalassaemia.
What are the types of thalassaemia?
β thalassaemia (β globin gene expression affected) and α thalassaemia (α globin gene expression affected).
Where is thalassaemia more prevalent?
Typically more prevalent in South Asia, Mediterranean, Middle East and Far East.
What will a blood smear of thalassaemia show?
Hypochromic and microcytic red cells, anisopoikilocytes with frequent target cells, uncleared RBCs and Heinz bodies.
What does excess of the unaffected globin chain cause?
Contributes to the defective nature of red cells. Haemoglobin aggregates o get oxidised and can cause premature death of erythropoiesis precursors, also excessive destruction of mature red cells in spleen.
What are some consequences of thalassaemia?
Extramedullary haemopoiesis can cause classical skeletal abnormalities. Iron overload occurs due to excessive absorption of dietary iron and repeated blood transfusions. Reduced O2 delivery causes drive to make more defective red cells. Reduced life expectancy.
Treatments for thalassaemia.
Red cell transfusion from childhood, iron chelation, folic acid and immunisation.
What is sickle cell disease?
An autosomal recessive disease resulting from mutation of β-globin gene. GAG codon changed to GTG resulting in glutamic acid being substituted by valine at position 6.
Describe anaemia in sickle cell disease.
Usually mild as HbS readily gives up O2 in comparison to HbA. Problems occur in low oxygen state as deoxygenated HbS forms polymers that cause sickle shaped red cells.
What are the three types of sickle cell crises?
Vaso-occlusive, aplastic, haemolytic
What are some consequences of sickle cell disease?
Retinopathy, stroke, splenic atrophy, acute chest syndrome.
What is haemolytic anaemia?
An abnormal breakdown which reduces lifespan and can occur in blood vessels, spleen and wider RES.
What are some consequences of haemolytic anaemia?
Accumulation of bilirubin leading to jaundice and associated risk of complications such as pigment gallstones. Sudden, massive haemolytic can cause cardiac arrest due to lack of O2 delivery. Overworking red pulp can lead to splenomegaly.
