Haematology

Question 1

Sickle Cell Disease Key Points (8)

Answer 1

• MDT approach with obstetrics and haematology
• Complications of SCD (including crises) are more common in pregnancy
• Perinatal and maternal morbidity and mortality rates are higher
• Risks for the baby include miscarriage, FGR, preterm delivery
• Risks for the mother include thrombosis, severe PET, infection, transfusion reactions
• Folic acid 5mg/day and prophylactic penicillin V 250mg BD should be given to all women
• Infection, hypoxia, acidosis and dehydration should be prevent/treated aggressively
• Prophylactic exchange transfusion is not recommended

Question 2

Anaemia Key Points (8)

Answer 2

• Plasma volume increases by 50% and there is a fall in Hb concentration
• Pregnancy causes a 2-3x increase in the requirement of iron
• Pregnancy causes a 10-20x increase in the folic acid requirement
• Many women develop IDA because they enter pregnancy with depleted iron stores
• May be iron deficient with a normal Hb and MCV
• Prevent iron and folate deficiencies with PO supplements if at risk
• Folic acid 400mcg/day should be taken peri-conception as prophylaxis against NTD
• Maximum rise in Hb achievable with PO/IV iron is 8g/L per week

Question 3

Pathogenesis of Thalassaemia (5)

Answer 3

• Defective production of a-globin (a-thal) or ß-globin (ß-thal)
• Ineffective erythropoeisis: normal globin chains form tetramers that precipitate within red blood cell precursors in bone marrow
  → damaged RBC and erythroid precursors into peripheral circulation
  → extravascular haemolysis via red cell sequestration and destruction
  → Hypochromic anaemia

Question 4

ITP Key Points (6)

Answer 4

• ITP is a diagnosis of exclusion
• Bleeding is unlikely if platelets are >50
• Risk of serious neonatal thrombocytopenia and haemorrhage from transplacental IgG is low
• Caesarean is only required for obstetric indications
• Neuraxial analgesia is safe with stable platelets >75-80
• Treatment should be with steroids or IVIg

Question 5

Thalassaemia Pathogenesis (5)

Answer 5

• Defective production of A-globin or B-globin, resulting in excess of other chain
• Normal globin chains form tetramers which precipitate within red blood cell precursors in the bone marrow
  → damaged RBC and erythroid precursors are released into peripheral circulation
  → extravascular haemolysis via sequestration and destruction
  → hypochromic anaemia

Question 6

A-thalassaemia pathogenesis (4)

Answer 6

A-thal trait/minor
- a+: 1/4 genes absent
- a0: 2/4 genes absent

• haemoglobin H (ß4): 3/4 absent
• haemoglobin barts (a-thal major): 4/4 genes absent

Question 7

A-thalassaemia effects on mother (2)

Answer 7

• a0: may become anaemic
• haemoglobin H: anaemia worsened in pregnancy

Question 8

A-thalassaemia effects on fetus (2)

Answer 8

• May be carriers
• Haemoglobin barts incompatible with life (severe anaemia, fetal hydrops, IUFD)

Question 9

A-thalassaemia minor management (3)

Answer 9

• Iron and folate supplementation in pregnancy
• Should not receive parenteral iron
• Transfusion may be required

Question 10

B-thalassaemia pathogenesis (3)

Answer 10

• B-thalassaemia minor: heterozygous state

Homozygous state:
- B-thalassaemia intermedia: 0-6 transfusio n episodes per year
- B-thalassaemia major: ≥7 transfusion episodes per year

Question 11

B-thalassaemia effects on mother (12)

Answer 11

• Anaemia
• Folate deficiency

Iron overload causing:
- Hepatic dysfunction
- Diabetes
- Hypothyroidism
- Hypogonadotrophic hypogonadism
- Cardiac dysfunction/arrhythmias
- Gall stones
- Bone disease/osteoporosis

• Red cell antibodies/transfusion reactions
• VTE
• PPH

Question 12

B-thalassaemia effects on fetus (6)

Answer 12

• Early pregnancy loss
• FGR
• IUGR
• Fetal hypoxia
• Affected fetus
• HDFN from antibodies