5.1 - Haemolytic Anaemias And Haemoglobinopathies Flashcards
Why would someone with thalassaemia have hypochromic RBC?
Lack of haemoglobin in RBC
What are the types of alpha thalassaemia?
In its silent carrier state
- deletion of a single alpha globin gene
- asymptomatic
If you have the trait
- deletion of 2 alpha globin genes
- minimal/ no anaemia and no physical signs
Haemoglobin H disease
- deletion of 3 alpha chains
- tetramers of B globin called HbH form
- moderately severe anaemia, resembling B thalassaemia intermedia
Hydrops fetalis
- deletion of 4 alpha genes
- usually foetus dies
What are the types of B thalassaemia?
Major
- severe transfusion dependent anaemia, apparent 6-9 months after birth as synthesis switches from HbF to HbA
- either type B or type Bo
- homozygous
Minor/trait
- asymptomatic with mild anaemia
- heterozygous
B thalassaemia intermedia
- severe but not enough to need transfusions
- heterozygous
What are the consequences of thalassaemia?
1) extramedullary haemopoiesis to compensate but results in splenomegaly and haemopoiesis in bone cortex = impairs growth = skeletal abnormalities .
2) reduced oxygen delivery = more EPO = more defective reticulocytes
3) iron overload causes premature death due to excessive absorption as as result of ineffective haemopoiesis and repeated blood transfusions to treat anaemia
What’s the treatment of thalassaemia?
- transfusion of RBC
- iron chelation
- folic acid
- immunisation
- holistic care
- stem cel transplant
- pre conception counselling for couples at risk
What is sickle cell disease?
- inheritance of sickle B globin chain
- point mutation of valine for glutamic acid
- HbSS = homozygous, v bad
- HbS = heterozygous, sickling disorder and causes mild anaemia. Found in W African people as it confers protection against malaria
What are the symptoms of sickle cell anaemia like?
Usually mild as HbS readily gives up O2 in comparison to HbA
Problem comes in low oxygen state where HbS forms polymers and The RBC form a sickle shape
Sickle RBC are less deformable and can cause conclusions in small vessels = sticky
What is a sickle cell crisis and what are the symptoms?
Crisis = pain that begins suddenly when occlusion occur in small blood vessels that carry blood to bones
Symptoms include
- fatigue
- pain
What are the three subtypes of crises?
1) vaso- occlusive - bone organ chest and spleen
2) aplastic
3) haemolytic
What are the results of haemolytic anaemia?
- symptoms of anaemia
- accumulation of bilirubin = jaundice and other risks e.g gallstones
- overworking of red pulp = splenomegaly
- massive sudden haemolysis (e.g as in blood transfusions) can lead to cardiac arrest due to lack of o2 to tissues and hyperkalaemia as a result of intracellular contents
What is autoimmune haemolytic anaemia?
- autoantibodies bind to RBC membrane
- classified as warm or cold autoimmune haemolytic anaemia
- the spleen recognises the red cel and as abnormal and removes it
What is haemolytic anaemias key lab features?
Increased reticulocytes as marrow tries to compensate
Raised bilirubin
Raised LDH (RBC rich in this enzyme)
