Alpha Thalassaemia - Microcytic Anaemia

Question 1

What is thalassaemia?

Answer 1

• Group of disorders characterised by reduced/ absent globin chain production

Question 2

What are the two types of Thalassaemia?

Answer 2

• Alpha (reduced/ absent globin chains)
• Beta (reduced/ absent globin chains)

Question 3

What are the 3 forms of severity for alpha- thalassaemia?

Answer 3

1. Alpha Thalassaemia Trait
2. Haemoglobin H (HbH) disease
3. Haemoglobin Barts

Question 4

What is Alpha Thalassaemia Trait?

Answer 4

• Patients are typically asymptomatic
• The condition is clinically relevant for offspring ( if two patients with alpha thalassaemia trait have a child = HbH or Hb Barts syndrome)

Question 5

What is Haemoglobin H (HBH) disease?

Answer 5

• Patients with HbH disease inherit three abnormal copies of the alpha globin chain
• HbH causes a reduced red cell survival causing a hypochromic microcytic anaemia
• These cells are removed from the circulation at a faster rate by the spleen
• HbH haemoglobin has a higher affinity for oxygen and is therefore ineffective as a an oxygen delivering molecule

Question 6

What is Haemoglobin Barts?

Answer 6

• Most severe form of alpha Thalassaemia
• Presents with 4 abnormal copies of the alpha globin chain
• This is incompatible with extrauterine life
• The Hb Bart’s is able to bind to oxygen with high affinity but is unable to release it into the tissues
• Hydrops Fetalis develops

Question 7

What is Hydrops Fetalis?

Answer 7

• Anaemia, High-output cardiac failure and generalised oedema

Question 8

What is the diagnosis/ Investigations for alpha thalassaemia?

Answer 8

• FBC (low haemoglobin and low MCV)
• Blood film ( hypochromic, microcytic red blood cells)
• LFTs
• Haemolysis ( LDH raised)
• Iron Studies ( Iron Deficiency anaemia)

Question 9

How will a newborn present?

Answer 9

-Pallor
- Anaemia
- Jaundice
-Aplastic Crisis

Question 10

What is the Diagnostic testing?

Answer 10

• Haemoglobin Analysis: completed using haemoglobin electrophoresis
• Genetic testing

Question 11

When is antenatal screening offered to women?

Answer 11

• offered to all women at 10 weeks gestation
• However alpha thalassaemia minima/ trait can only be detected via DNA testing

Question 12

What is the Management?

Answer 12

• Alpha thalassaemia or minima do not require treatment
• HbH disease: personalised treatment plan based on the severity of disease
• Transfusions when Hb <70g/L
• Iron Overload: regular transfusions are at risk of iron overload and secondary haemochromatosis - require iron chelation therapy (Desferasirox)
• Dietary Supplementation: Folic Acid
• Splenectomy: to reduced transfusion requirements and hypersplenism