Thalassaemia

Question 1

What is beta-thalassaemia.

Answer 1

Most common autosomal recessive inherited haematological disorder.

Question 2

Where is beta-thalassaemia most common. (3)

Answer 2

Mediterranean.
Middle East.
Asia.

Question 3

What is the pathogenesis of beta-thalassaemia.

Answer 3

Decreased beta-globin production, leading to chronic anaemia.

Question 4

What does beta-thalassaemia lead to.

Answer 4

Chronic anaemia.

Question 5

What sort of anaemia is present in beta-thalassaemia.

Answer 5

Microcytic anaemia.

Question 6

What is seen in patients who are homozygous for beta-thalassaemia. (4)

Answer 6

Failure to thrive.
Severe anaemia (from 3 to 6 months).
Splenomegaly.
Bone hypertrophy (secondary to extramedullary haemopoiesis).

Question 7

What is seen in patients who are heterozygous for beta-thalassaemia. (3)

Answer 7

Usually asymptomatic.
Mildly anaemic.
Decreased MCV.

Question 8

What are the complications of beta-thalassaemia. (2)

Answer 8

Secondary haemosiderosis (from repeated blood transfusions). 
Endocrine disease.

Question 9

What are the clinical divisions of beta-thalassaemia. (3)

Answer 9

Thalassaemia minor.
Thalassaemia intermedia.
Thalassaemia major.

Question 10

What characterises thalassaemia minor.

Answer 10

A symptomless heterozygous carrier state.
May have mild manageable anaemia.
The anaemia may worsen during pregnancy.

Question 11

What characterises thalassaemia intermedia. (2)

Answer 11

A moderate anaemia.

Not requiring regular transfusions.

Question 12

What characterises thalassaemia major.

Answer 12

Severe anaemia requiring regular transfusions.

Question 13

What distinguishes thalassaemia minor from iron deficiency anaemia on blood tests. (2)

Answer 13

Serum ferritin and iron stores are normal.

Question 14

What is another name for thalassaemia major.

Answer 14

Cooley’s anaemia.

Question 15

What are some physical signs seen in thalassaemia intermedia. (6)

Answer 15

Splenomegaly.
Bone deformities.
Recurrent leg ulcers, gallstones and infections.
They may be iron overloaded despite the lack of regular blood transfusions.

Question 16

What are some physical signs seen in thalassaemia major. (4)

Answer 16

Most children affected by homozygous Beta-thalassaemia present during the first year of life with:
Failure to thrive.
Recurrent bacterial infections.
Severe anaemia from 3-6months.
Extramedullary haemopoiesis that leads to hepatosplenomegaly and bone expansion - giving a classic thalassaemic face.

Question 17

What is seen on the skull Xrays of a child with thalassaemia major.

Answer 17

The characterisitc ‘hair on end’ appearance of bony trabeculation, as a result of the expansion of the bone marrow into cortical bone.

Question 18

What is the cause of beta-thalassaemia.

Answer 18

Usually caused by point mutation in beta-globin genes on Chromosome 11.

Question 19

What is absent or abnormal in beta-thalassaemia.

Answer 19

There is either decreased beta chain production, or its absence.

Question 20

What is MRI used for in beta-thalassaemia.

Answer 20

To monitor myocardial siderosis from iron overload.

Question 21

When does thalassaemia major usually present.

Answer 21

In the first year of life.

Question 22

What is necessary in thalassaemia major.

Answer 22

Lifelong blood transfusions.

Question 23

What is a complication with the treatment for thalassaemia major.

Answer 23

Transfusions result in iron overload/deposition.

This is seen after approximately 10 years and presents as endocrine failure, liver disease and cardiac toxicity.

Question 24

What is seen on the blood film of a patient with thalassaemia major. (3)

Answer 24

Very hyperchromic, microcytic cells.
Target cells.
Nucleated RBCs.

Question 25

How many alpha thalassaemia genes are there.

Answer 25

There are two separate alpha globin genes on each chromosome 16.
Ie, there are 4 genes.

Question 26

What is the predominant mechanism for alpha thalassaemia.

Answer 26

Gene deletions.

Question 27

What occurs if there is deletion of all four alpha genes.

Answer 27

Bart’s hydrops - death in utero.

Question 28

What occurs if there is deletion of three alpha genes.

Answer 28

HbH disease.

Question 29

What are the characteristics of HbH disease. (2)

Answer 29

There may be moderate anemia.

Features of haemolysis (hepatosplenomegaly, jaundice, leg ulcers).

Question 30

What is seen on the blood film of a patient with HbH.

Answer 30

There is formation of Beta4 tetramers due to excess beta chains.

Question 31

What are the characteristics of HbA. (2)

Answer 31

Asymptomatic carrier state.

Low MCV.

Question 32

What occurs if there is deletion of one alpha globin gene.

Answer 32

There is a normal clinical pictures.

Question 33

What is the difference between alpha and beta thalassaemias. (2)

Answer 33

In alpha thalassaemia there are excess beta chains.

In beta thalassaemia, there are excess alpha chains.