Haematology 2 - Paediatric haematology Flashcards
How should congenital leukaemia in Down’s syndrome be managed?
It will resolve spontaneously so it’s okay
Why may there be Howel-Jolly bodies on the blood film in sickle cell disease?
They are produced when there is splenic infarction
If not identified in a Guthrie spot, at what age does sickle cell disease tend to present?
6 months
In what age group might the hand-foot syndrome of sickle cell disease present?
<2 years
Why is there no risk of splenic sequestration in sickle cell disease once Howel-Jolly bodies have been identified on blood film?
Once there has been a splenic infarction (which will cause Howel Jolly bodies) you will get hyposplenism but there is no risk of sequestration
Recall 2 drugs that are required lifelong in all sickle cell disease patients?
Folic acid
Penicillin (for protection against encapsulated bacteria because of hyposplenism)
In sickle cell disease, when is the highest risk of stroke?
In childhood (actually less common in adults with sickle cell)
What is the main risk of blood transfusions in treating thalassaemia?
Iron overload
Recall some inherited causes of haemolytic anaemia
Spherocytosis
Elliptocytosis
PKU deficiency
G6PD deficiency
Sickle cell
What is the most common cause of acquired haemolytic anaemia in children?
E coli causing haemolytic uraemic syndrome
Which inherited defect of coagulation often presents with mucosal bleeding?
Von willebrand disease
How can you test for von willebrand disease?
Factor VIII assay
What is the treatment for von willebrand disease?
desmopressin
recombinant vWF - severe disease, usually type 3
Low purity factor VIII (rarely used)
In which haemoglobinopathy is there benefit to carotid doppler monitoring?
Sickle cell
Do doppler monitoring alongside exchange transfusion if there is turbulent carotid flow
How do cell counts in children differ to adults?
In neonates?
- Higher Hb
- Higher WCC
- higher neutrophil count
- higher MCV
Neonates
- Higher Hb
- Higher WCC
- Higher Lymphocyte count
- higher neutrophil count
- higher MCV
How do enzymes in bloodd cells differ between neonates and adults?
Children have higher levels of G6PD in RBC
How does TTTS affect blood cell counts of foetus?
One will be anaemic, the other polycythaemic
When do Beta-globin disorders manifest in children?
3-6 months
Because of higher proportion of HbF - 2 alpha and 2 gamma
HbA: globin chains
2 alpha
2 beta
HbA2: globin chains
2 alpha
2 delta
Which genes are encoded on Chr 11?
- beta: found in HbA and HbA2
- delta: found in HbA2
- gamma: found in HbF
- Episolon…
Which genes are encoded on Chr16?
Alpha genes
α2 gene
α1 gene
ζ (zeta)
Which are the embryonic globin genes?
Episolon and zeta
(EZ!!!)
NORMAL FORMS OF HAEMOGLOBIN
What percentage of normal human haemoglobin should HbA2 comprise?
<3.5%
How do the haemoglobins in utero change over time?
- first 16 weeks: Haemoglobin Gower and Portland, comprise epsilon and zeta chains
- HbF predominates throughout foetal life
- HbA increases 32 weeks onwards
- At birth- HbA comprises 1/3 of Hb. Increases steadily with age
- prematurity- v low HbA levels
Causes of polycythaemia in the foetus
Twin-to-twin transfusion (twin bleeding into another twin)
Intrauterine hypoxia
Placental insufficiency- oxygen not getting to foetus → increased EPO production → Hb rises
Causes of anaemia in the foetus
Twin-to-twin transfusion
Foetal-to-maternal transfusion (baby bleeds into the mother’s circulation)
Parvovirus B19 infection (virus not cleared by immature immune system)
Haemorrhage from the cord or placenta
When do most mutations for leukamiea occur?
In utero
Leukamiea in down’s syndrome
Sometimes called transient abnormal myelopoiesis - as it is transient and spontaneously resolves within a few weeks, especially if they survive the first 4-6 weeks
*only invovles myeloid cells
*does not need treatment at this stage
NB: it can recur 1-2 years later in 25% of children so will need treatment then
Inherited haemolytic anaemias in children
Defects in:
- Red cell membrane
- Hereditary spherocytosis- defects in vertical interaction
- hereditary elliptocytosis- defects in spectrin protein (horizontal interaction)
- Haemoglobin molecule
- Haemoglobinopathy- abnormal structure of haemoglobin - SICKLE CELL DISEASE
- Haemoglobin quantity reduction - alpha and beta thalassamiea
- metabolic deficiencies
- G6PD deficiency
- Pyruvate kinase deficiency- rare
Difference in timing of presentation of defects in alpha vs beta globin genes vs gamma globin genes
- alpha- manifests early on as it’s part of HbF
- beta- only manifests in first year of life as HbF does not rely on beta
- gamma- only manifests in neonatal period as it’s only found in HbF
What infection can trigger G6PD deficiency?
Urinary tract infection
*infections in general can cause oxidative damage
Characteristic features of autoimmune haemolytic anaemia in children
- spherocytosis
- positive DAT test