Paediatric Haematology Flashcards
What are some key points to remember when interpreting paediatric blood tests
Pre-pubertal children differ physiologically from adults
What is normal differs from the adult
There are no gender differences before puberty
Give a reason why the range of diseases seen in children differ from in adults
The first encounter with a pathogenic microorganism often occurs in childhood (whereas adults often have some degree of immunity)
What may rapid growth of children predispose them to?
Vitamin or mineral deficiency
Iron deficiency is common in childhood and during the adolescent growth spurt, particularly if diet is sup-optimal
In what way does a child respond to an infection differently to adults?
Children are more likely to develop lymphocytosis
‘Reactive’ lymphocytes are also common because of the frequent encounters with new microbial antigens
Give an example of a haematological disease that can cause endocrinological dysfunction and growth retardation in children?
Beta thalassaemia (and its treatments) result in iron overload
What is a key haematological difference in neonates?
Type of haemoglobin
gamma haemoglobin
What enzyme levels in red cells are different in neonates?
glucose-6-phosphate dehydrogenase (G6PD) concentration is 50% than in adults
What may cause polycythaemia in the foetus or neonate?
Twin-to-twin transfusion
Intrauterine hypoxia
Placental insufficiency
What may cause anaemia in the foetus or neonate?
Twin-to-twin transfusion
Foetal-to-maternal transfusion
Parvovirus infection (not cleared by immature immune system)
Haemorrhage from the cord or placenta
What else may affect the blood of the foetus?
Irradiation
Something crossing from the mother to the infant e.g.
Drugs - anticoagulant drugs can cause haemorrhage or foetal deformity
Antibodies can destroy red cells, white cells or platelets
With what genetic syndrome does congenital leukaemia occur?
Down’s Syndrome
What is another name for congenital leukaemia?
Transient abnormal myelopoiesis (TAM)
What are the features of congenital leukaemia?
Myeloid with major megakaryocyte lineage
Usually remits spontaneously and relapse one to two years later occurs in 25%
Analogies with other childhood tumours e.g. neuroblastoma
What are thalassaemias?
Genetic disorder resulting in reduced synthesis of globin chains
What are haemoglobinopathies?
Genetic disorder resulting in synthesis of a structurally abnormal globin chain
What globin chains are present in haemoglobin A and when is it present?
alpha2, beta2
Late foetus, infant, child and adult
What globin chains are present in A2 haemoglobin and when is it present?
alpha2, delta2
Infant, child and adult
What globin chains are present in F haemoglobin and when is it present?
alpha2, gamma2
Foetus and infant
What is sickle cell disease?
Generic term that describes homozygous and compound heterozygous states that are associated with the pathological effects of sickling
What is sickle cell anaemia?
SS
Homozygous for sickle cell
Why does sickle cell anaemia not clinically manifest at birth?
Clinical features become manifest as gamma chain production and haemoglobin F synthesis decrease and betaS and haemoglobin S production increase
How do we test for sickle cell disease in neonates?
Guthrie spot
Why does sickle cell anaemia in the infant and child differ from the same disease in adults?
Initially due to presence of haemoglobin F
The distribution of red bone marrow (susceptible to infarction) differs - extends right down the long bones into hands and feet
The infant still has a functioning spleen - splenic sequestration can occur