Haemoglobinopathy - Thalassaemia Flashcards

1
Q

What is Thalassaemia?

A

A haemoglobinopathy due to a genetic autosomal recessive defect in the protein chains that make up Haemoglobin.

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2
Q

What is Alpha Thalassaemia caused by?

A

A defect in the alpha globin chain - the gene coding for this protein is on Chromosome 16.

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3
Q

Clinical Severity of Alpha Thalassaemia (3).

A
  1. 1/2 Alleles affected = Hypochromic and Microcytic but Normal Hb.
  2. 3 Alleles Affected = Hypochromic Microcytic Anaemia with Splenomegaly (Hb H Disease).
  3. 4 Alleles Affected = Death in Utero e.g. Hydrops Fetalis, Bart’s Hydrops.
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4
Q

What is Beta Thalassaemia caused by?

A

A defect in the beta globin chain - the gene coding for this protein is on Chromosome 11.

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5
Q

What are the 3 Types of Beta Thalassaemia?

A
  1. Thalassaemia Minor.
  2. Thalssaemia Intermedia.
  3. Thalassaemia Major.
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6
Q

What is Thalassaemia Minor characterised by (4)?

A
  1. Carrier of Abnormally-Functioning Beta-Globin Chain.
  2. 1 Abnormal and 1 Normal Gene.
  3. Mild Microcytic Anaemia.
  4. Monitoring + No Active Treatment.
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7
Q

What is Thalassaemia Intermedia characterised by (4)?

A
  1. 2 Abnormal Copies of the Beta Globin Gene.
  2. Either 2 Defective Genes or 1 Defective + 1 Deletion Gene.
  3. More Significant Microcytic Anaemia.
  4. Monitoring + Occasional Blood Transfusions (+ Iron Chelation?).
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8
Q

What is Thalassaemia Major characterised by?

A
  1. Homozygous for Deletion Genes.
  2. No Functioning Beta Globin Genes.
  3. Severe Anaemia and Failure to Thrive in Early Childhood.
  4. Regular Transfusions, Iron Chelation, Splenectomy (+ Bone Marrow Transplant).
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9
Q

Clinical Features of Thalassaemia.

A
  1. Splenomegaly.
  2. Susceptibility to Fractures.
  3. Prominent Features e.g. Pronounced Forehead and Malar (Cheek) Eminences.
  4. Gallstones.
  5. Poor Growth and Development.
  6. Jaundice.
  7. Anaemia, Fatigue, Pallor.
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10
Q

What causes the Splenomegaly?

A
  1. The RBCs are more fragile and are easily broken down.
  2. The spleen sieves the blood to remove damaged cells.
  3. It works harder and swells.
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11
Q

What causes the bone changes?

A

The Bone Marrow expands to produce extra RBCs to compensate for the chronic anaemia.

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12
Q

Investigations in Thalassaemia.

A
  1. FBC - Microcytic (Disproportionate) Hypochromic Anaemia and HbA2 raised.
  2. Diagnosis - Haemoglobin Electrophoresis and DNA Testing.
  3. Screening - Pregnancy at Booking.
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13
Q

Management of Alpha Thalassaemia (5).

A
  1. Monitoring FBC and Complications.
  2. Blood Transfusions.
  3. Splenectomy.
  4. Curative : Bone Marrow Transplant.
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14
Q

Why can Iron Overload happen in Thalassaemia?

A

Faulty creation of RBCs, recurrent transfusions, increased absorption of Iron in response to iron.

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15
Q

Management of Iron Overload.

A
  1. Monitor Serum Ferritin levels.
  2. Limiting transfusions.
  3. Iron Chelation - Desferrioxamine.
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16
Q

Clinical Features of Iron Overload in Thalassaemia (7).

A
  • similar to Haemochromatosis :
    1. Fatigue.
    2. Cirrhosis.
    3. Infertility and Impotence.
    4. Heart Failure.
    5. Arthritis.
    6. Diabetes.
    7. Osteoporosis.