Paediatric Haematology

Question 1

Differences between neonates and adult FBC

Answer 1

Newborns have higher Hb, WCC, neutrophils, lymph, MCV and higher HbF

Question 2

Cause of polycytaemia in foetus

Answer 2

TTS, intrauterine hypoxia, placental insufficiency

Question 3

Causes of anaemia in foetus

Answer 3

 Twin-to-twin or Foetal-to-maternal (rare) transfusion
 Parvovirus infection (virus not cleared by immature immune system)
 Haemorrhage from cord or placenta

Question 4

Other Causes of damage to foetus

Answer 4

 Irradiation
 Damage by something crossing the placenta (e.g. drugs, chemicals, antibodies)
 Anticoagulants ( haemorrhage or foetal deformity (e.g. vitamin K if given in the first trimester))
 Antibodies can destroy red cells, white cells or platelets
 Substances in breast milk (e.g. G6PDD-baby may suffer from haemolysis if mother eats fava beans)

Question 5

What condition is congenital leukaemia common in and how does the disease course look

Answer 5

Down syndrome
 This disease tends to remit spontaneously within the first 2 months of life
 However, it tends to relapse 1-2 years later in about 25% of infants

Question 6

What is Thalassemia

Answer 6

Resulting from reduced rate of synthesis of ≥1 globin chain as a result of a genetic defect

Question 7

What is haemoglobinopathy

Answer 7

Structurally abnormal hb

Question 8

Do alpha or beta defects occur first in life and why

Answer 8

o Defects in alpha globin chain and beta globin chains occur at different times in life because alpha globin synthesis begins early in foetal life whereas beta globin synthesis begins late in gestation
Due to alpha being used in HbF until 16 weeks, where as both are used ini HbA

Question 9

Pathophysiology of sickle cell anaemia

Answer 9

Mutation in globin B chain-
Hypoxia  polymerisation of haemoglobin S  crescent shaped RBCs and blocked blood vessels
 Occurs in post-capillary venules (when passing through these venules, red cells tend to elongate)
 This is reversible if the hypoxic state is resolved (unless the cells are very sickled)
o (2) If circulation slows, the cells sickle and become adherent to the endothelium which causes obstruction
o (3) Retrograde capillary obstruction  arterial obstruction

Question 10

What feature can you see on a microscope in sickle cell anaemia

Answer 10

Howell-Jolly bodies can feature as a feature of hyposplenism

Question 11

Guthrie spot use?

Answer 11

Prick blood, to test for sickle cell disease

Question 12

Distribution of red bone marrow in children and adults and why this is relevant in sickle cell

Answer 12

 Adult haematopoietic BM = restricted to axial skeleton
 Child haematopoietic BM = axial skeleton + extends to bones of hands and feet
• Hence, why children can get the hand-foot syndrome in sickle cell(swollen hands and feet)

Question 13

Differences in spleens in adult and children in sickle cells

Answer 13

 Adult / older-child spleen – spleen is small and fibrotic from recurrent infarction
• Suffer from more chance of sequalae of hyposplenism (i.e. pneumococcal infection)

 Child spleen – still has a functioning spleen
• Children can undergo splenic sequestration which is the acute pooling of a large percentage of circulating red cells in the spleen  SEVERE ANAEMIA, SHOCK and DEATH

Question 14

What infections are children with sickle cell vulnerable to

Answer 14

 Parvovirus can cause aplastic anaemia in sickle cell anaemia
 Pneumococcal infection is often FATAL in babies with sickle cell anaemia, but this can be prevented with a combination of vaccination and penicillin

Question 15

Why do those with sickle cell have increased need for folic acid

Answer 15

 Hyperplastic erythropoiesis
 Growth spurts
 Red cell lifespan is shorted so anaemia can rapidly worsen

Question 16

Types of B thalassaemia

Answer 16

Thalassemia minor- Only one of β globin alleles bears a mutation. Individuals will suffer from microcytic anemia- β+/β
βo/β

Thalassemia intermedia- Affected individuals can often manage a normal life but may need occasional transfusions- β+/β+
βo/β+

Thalassemia major- Homozygous form: Occurs when both alleles have thalassemia mutations. This is a severe microcytic, hypochromic anemia- βo/βo

Question 17

Features of poorly treated Thal Major

Answer 17

o Anaemia  heart failure, growth retardation
o Erythropoietic drive  bone expansion, hepatomegaly, splenomegaly
o Iron overload  heart failure, gonadal failure- low hepcidin level and subsequently to an increase in the absorption of iron from the gastrointestinal tract

Question 18

Types of inherited haemolytic anaemia

Answer 18

o Red cell membrane hereditary spherocytosis/eliptocytosis
o Haemoglobin molecule sickle cell anaemia
o Glycolytic pathway enzymes pyruvate kinase deficiency (provide energy to cell)
o Pentose-phosphate shunt G6PD deficiency (protect cell from oxidant damage)

Question 19

Types of autoimmune haemolytic anaemia

Answer 19

	Autoimmune haemolytic anaemia 
•	Spherocytosis 
•	Positive DAT (Coombs' test)
	Haemolytic uraemic syndrome:
•	Haemolysis 
•	Uraemia

Question 20

Presentation of haemophilia A and B

Answer 20

o Bleeding following circumcision
o Haemarthroses when starting to walk
o Bruises
o Post-traumatic bleeding

Question 21

Presentation of vWD

Answer 21

o Mucosal bleeding
o Bruises
o Post-traumatic bleeding

Question 22

Presentation of Autoimmune Thrombocytopaenia Purpura

Answer 22

o Petechiae Bruises

o Blood blisters in the mouth