Haemoglobinopathies

Question 1

1. There are three major types of Haemoglobin. HbA which has two alpha and two beta chains. HbA2 which has two alpha and two _____ chains. HbF which has two alpha and two _____ chains.
2. What are the two main types of Haemoglobinopathies?

Answer 1

1. delta, gamma

2. Thalassaemias and Structural Haemoglobin Variants.

Question 2

1. Thalassaemias are where normal haemoglobin is being produced at a _________ rate.
2. Structural Haemoglobin Variants are where _______ haemoglobin is being produced at a normal rate

Answer 2

1. Reduced

2. Abnormal

Question 3

1. What are the two types of Thalassaemia?

2. What is the main consequence of this disease?

Answer 3

1. Alpha and Beta- alpha where it effects the alpha chain synthesis and beta where it effects the beta chain synthesis.
2. Microcytic hypochromic Anaemia

Question 4

1. The classification of Alpha Thalassaemia is based on the number of _____ genes. There are normally four genes. If a patient has one or two missing they are a carrier if they have three missing they have _____ disease and shall present with anaemia. If they have no functional genes this is known as Hb Barts _____ ____ which is incompatible with life.

Answer 4

1. Alpha, HbH, Hydrops Fetalis.

Question 5

1. The classification of Beta Thalassaemia is based on ______ _______. Beta Thalassaemia trait is diagnosed by a raised ______. Beta Thalassaemia intermedia requires occasional ________. Beta Thalassaemia ______ entails lifelong ________ dependency.

Answer 5

Clinical severity, HbA2, Transfusions, major, transfusion

Question 6

1. What are the clinical features of Beta Thalassaemia major?
2. What is the main cause of side effects with blood transfusion dependency? How does this present?
3. How might iron overload be managed?

Answer 6

1. Presents aged 6-24 months, pallor, failure to thrive, Extramedullary haematopoiesis.
2. Iron Overload. This leads to endocrine dysfunction (diabetes and Osteoporosis), Cardiac disease (cardiomyopathies and arrythmias), Liver disease (Cirrhosis).
3. Iron Chelating drugs such as Desferrioxamine

Question 7

1. Sickle cell anaemia is caused by a ____ mutation of the _____ globin gene substituting Glutamine for Valine forming BetaS. The new Hb is called ____. When exposed to low oxygen the Sickle cells ________.
2. Sickle cell trait is where a person has one normal ______ globin and one abnormal ______ globin. Sicle cell anaemia is where the person has two abnormal _____ globins.

Answer 7

1. Point, Beta, HbS, Polymerise.

2. Beta, BetaS, BetaS

Question 8

1. What are the clinical features of sickle cell anaemia?
2. What is a sickle cell crises?
3. What can precipitate a sickle cell crises?
4. How is a crises treated?

Answer 8

1. Sickle cell crises (Episodes of tissue infarction due to vascular occlusion). Chronic Haemolysis and Hyposplenism.
2. sickle vaso-occulsion occurs (the sickle cells occlude the blood vessels) resulting in tissue ischaemia and pain.
3. Hypoxia, dehydration, infection, cold exposure, stress/fatigue
4. Hydration, opiate analgesia, rest, oxygen, blood transfusion if severe.

Question 9

1. How is sickle cell anaemia managed long term?

Answer 9

1. Prophylactic penicillin, vaccinations, (hyposplenism increases risk of infections) folic acid supplements, hydroxycarbamide, blood transfusions in selected cases.

Question 10

1. How are haemoglobinopathies diagnosed?

Answer 10

1. FBC, Blood film, HPLC (High Performance Liquid Chromatography)