Haematology - Thalassaemia

Question 1

What is thalassaemia?

Answer 1

Genetic defect in protein chains that make up Hb

Question 2

What protein chains is normal Hb made of?

Answer 2

2 alpha and 2 beta globin chains

Question 3

What is an alpha vs beta thalassaemia?

Answer 3

Alpha - defect in alpha globin chains

Beta - defect in beta globin chains

Both are autosomal recessive conditions

Question 4

What happens to RBCs in patients with thalassaemia?

Answer 4

More fragile and break down more easily

Question 5

Why do patients with thalassaemia get splenomegaly?

Answer 5

Spleen collects all the destroyed RBCs

Question 6

How does is chronic anaemia due to thalassaemia compensated for?

Answer 6

Bone marrow expands to produce extra RBCs

Question 7

What does bone marrow expansion lead to?

Answer 7

Increased susceptibility to fractures
Pronounced forehead
Pronounced malar eminences

Question 8

What are the potential signs of thalassaemia?

Answer 8

Microcytic anaemia
Pallor
Jaundice
Gallstones
Splenomegaly
Poor growth and development
Pronounced forehead and malar eminences
Fatigue

Question 9

How is thalassaemia diagnosed?

Answer 9

• FBC - shows microcytic anaemia
• Haemoglobin electrophoresis - diagnose globin abnormalities
• DNA testing - genetic abnormality

Pregnant women offered screening test for thalassaemia at booking

Question 10

Why does iron overload occur in thalassaemia?

Answer 10

• Faulty RBC synthesis
• Recurrent transfusions
• Increased iron absorption in gut in response to anaemia

Question 11

How are patients with thalassaemia monitored?

Answer 11

Serum ferritin levels to check for iron overload

Question 12

How is iron overload managed?

Answer 12

Limit transfusions
Iron chelation

Question 13

What does iron overload cause?

Answer 13

Fatigue
Liver cirrhosis
Infertility
Impotence
Heart failure
Arthritis
Diabetes
Osteoporosis and joint pain

Question 14

What is alpha-thalassaemia caused by?

Answer 14

Autosomal recessive gene mutation on chromosome 16 which codes for alpha globin chains

Question 15

How is alpha thalassaemia managed?

Answer 15

• Monitor FBC
• Monitor complications
• Blood transfusions
• Splenectomy
• Bone marrow transplant - may be curative

Question 16

What is beta-thalassaemia caused by?

Answer 16

Autosomal recessive gene mutation on chromosome 11 which codes for beta globin chains

Gene defect can have abnormal copies that retain some function or deletion genes where there is no function in the beta globin protein at all

Question 17

How is beta-thalassaemia split?

Answer 17

Thalassaemia minor
Thalassaemia intermedia
Thalassaemia major

Question 18

What is thalassaemia minor?

Answer 18

Abnormally functioning beta globin gene

One abnormal and one normal gene

Causes mild microcytic anaemia, patient only needs monitoring and no treatment

Question 19

What is thalassaemia intermedia?

Answer 19

Two abnormal beta globin gene copies

Two defective
or
One defective and one deletion gene

Causes significant microcytic anaemia
Require monitoring and occasional blood transfusions

May need iron chelation to prevent iron overload when giving blood transfusions

Question 20

What is thalassaemia major?

Answer 20

Homozygous for deletion genes

No functioning beta globin genes at all

Most severe form

Question 21

How does thalassaemia major present?

Answer 21

Severe anaemia
Failure to thrive

Question 22

What does thalassaemia major cause?

Answer 22

Severe microcytic anaemia
Splenomegaly
Bone deformities

Question 23

How is thalassaemia major managed?

Answer 23

Regular transfusions
Iron chelation
Splenectomy

Bone marrow transplant can be curative