Thalassaemia Flashcards

1
Q

Definition

A

A group of genetic disorders characterised by reduced globin chain synthesis

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2
Q

Aetiology

A
  • Autosomal recessive
  • Result in an imbalance of globin chain production and deposition in erythroblasts and erythrocytes
• This leads to:
o Ineffective erythropoiesis 
o Haemolysis
o Anaemia
o Extramedullary haematopoiesis
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3
Q

Types (alpha)

A

o ALPHA THALASSEMIA - reduction in alpha-globin chain synthesis. There are
FOUR alpha-globin genes on the chromosome.

• 4 gene deletion = Haemoglobin Barts Hydrops Fetalis (intrauterine death)
• 3 gene deletion = Haemoglobin H –> microcytic hypochromic anaemia and
splenomegaly
• 2 gene deletion = Alpha 0 thalassemia –> microcytic hypochromic red cells, NO ANAEMIA
• 1 gene deletion = Alpha+ thalassemia –> microcytic hypochromic red cells, NO ANAEMIA

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4
Q

Types (beta)

A

o BETA THALASSEMIA

• Beta Thalassemia Major (homozygous beta thalassemia) –> little or no
beta-chain synthesis

• Beta Thalassemia Intermedia - mild defect in beta-chain synthesis leads to:
▪ Microcytic anaemia
▪ Reduced alpha-chain synthesis
▪ Increased gamma-chain synthesis

• Beta Thalassemia Trait (heterozygous carrier state)
▪ ASYMPTOMATIC
▪ Mild microcytic anaemia
▪ Increased red cell count

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5
Q

Epidemiology

A
  • WORLDWIDE

* Most common in the MEDITERRANEAN and areas of the Middle-East

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6
Q

Presenting symptoms

A
• Beta Thalassemia Major
o Anaemia
o Presenting at 3-6 months
• This is when the change from HbF to HbA takes place
• Failure to thrive
• Prone to infection

• Alpha or Beta Thalassemia Trait
o May be ASYMPTOMATIC
o Detected during routine blood tests or due to family history

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7
Q

Signs on physical examination

A

Beta Thalassemia Major

o Pallor
o Malaise
o Dyspnoea
o Mild jaundice
o Frontal bossing
o Thalassaemia facies (facial features caused by marrow hyperplasia)
o Hepatosplenomegaly (due to erythrocyte pooling and extramedullary
haematopoiesis)
o Patients with beta-thalassemia intermedia may also have these signs

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8
Q

Investigations (bloods)

A

o FBC

  • Low Hb
  • Low MCV (microcytic anaemia)
  • Low MCH
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9
Q

Investigations (blood film)

A

o Hypochromic microcytic anaemia
o Target cells
o Nucleated red cells
o High reticulocyte count

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10
Q

Investigations (other)

A

• Hb Electrophoresis
o Absent or reduced HbA
o High HbF

• Bone Marrow
o Hypercellular
o Erythroid hyperplasia

• Genetic Testing (rarely used)

• Skull X-Ray
o ‘Hair on end’ appearance in beta thalassemia major
• This is caused by expansion of marrow into the cortex

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