Thalassaemia

Question 1

3 types of haemobglobin and constituents?

Answer 1

HbA - most common form (2 alpha and 2 beta chains)
HbF - predominant before birth (2 alpha and 2 gamma)
HbA2 - smaller amounts in adults (2 alpha and 2 delta)

Question 2

Inheritance for thalassaemia and patho?

Answer 2

Autosomal recessive

decreased or absence of synthesis of 1 of the 2 polypeptide chains

Question 3

3 types of B-thalassaemia and patho?

Answer 3

Major - no HbA produced
Intermedia - small amt of HbA with some HbF
Minor (trait)- asymptomatic, mild anaemia

Question 4

SSx of the three types of B-thalassaemia

Answer 4

Major - maxillary overgrowth, frontal bossing
Intermedia - bone and spine problems, DVT, gallstones
Trait - asymptomatic or nil anaemia

Question 5

4 types of a-thalassaemia and patho?

Answer 5

1 gene deleted - normal
2 genes deleted - asymptomatic carrier state (fall in MCV)
3 genes deleted - HbH disease (moderate anaemia, haemolysis, hepatosplenomegaly, leg ulcers, jaundice)
4 genes deleted - hydrops fetalis (death in utero, pericardial effusion, ascites, pleural effusion, skin edema)

Question 6

Tests?

Answer 6

High performance liquid chromatography (1st line)
Gel electrophoresis (2nd line)

Question 7

What might you see on blood film?

Answer 7

Codocytes

Question 8

Treatment

Answer 8

Blood transfusions (give chelating agents i.e deferipone, desferrioxamine

Question 9

Side effects of iron treatment?

Answer 9

Constipation
Liver Cirrhosis
Cardiomyopathy
Diabetes
Hypopituitarism
Skin hyperpigmentation

Question 10

What do you see on the blood film in patients with thalassaemia?

Answer 10

Basophilic stripping

Target cells