Haem: Paeds Haem Flashcards
(53 cards)
Why are reactive lymphocytes more common in children?
Because of frequent encounters with new antigens
Why are disorders of B globin genes more likely to present later in children?
As there is a high percentage of HbF in neonates
What are some causes of Polycythaemia in neonates?
Twin-to-twin transfusion
Intrauterine hypoxia
Placental insufficiency (oxygen is not getting to the foetus so there is increased EPO production and the Hb rises)
What are some causes of anaemia in neonates?
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
What condition is Congenital leukaemia usually associated with?
Down’s syndrome
What can Congenital leukaemia also be called?
Transient abnormal myelopoiesis
What cells does Congenital leukaemia involve?
This leukaemia is myeloid with major involvement of the megakaryocyte lineage
How does congenital leukaemia progress?
It remits spontaneously, similar to neuroblastoma
What is thalassemia?
a condition resulting from a reduced rate of synthesis of ≥ 1 of the globin chains as a result of a genetic defect
Problems with which chain (a or b) present at birth?
a present at birth as it is part of HbF and HbA
b chain defect present at first year of life
Which 2 Cr control globin chains?
11 and 16
Around which week of gestation does HbA production rapidly increase?
HbA
What is sickle cell anaemia?
Sickle cell anaemia refers to homozygosity of the HbS gene (HbSS)
What is the pathophysiology of sickle cell anemia?
Hypoxia leads to polymerisation of HbS, leading to crescent shaped RBCs and blocked small blood vessels
This tends to occur in post-capillary venules
When passing through these venules, RBCs tend to elongate
If the circulation slows, the cells will begin to sickle and become adherent to the endothelium, which causes obstruction
Retrograde capillary obstruction results in arterial obstruction
At the beginning of the hypoxic stimulus, the cell may start to become distorted.
However, this is reversible once the hypoxic state resolves.
What are Howell Jolly bodies?
feature of hyposplenism (e.g. due to splenic infarction)
What is the sickle cell trait and what are the symptoms?
BBs The Bs is inherited from only one parent
Totally asymptomatic
How does the BsBc sickle cell trait present?
Causes a sickling disorder that is slightly milder than HbSS
When does BsBs (sickle cell) present?
Clinical features manifest as the γ globin chain and HbF synthesis DECREASE and HbS production INCREASES
This occurs around 6 months of age
How does the HbS/ B thalassemia trait present?
The severity of this is variable
It is dependent on whether it is a:
β0 gene- no β-globin production
β+ gene- a little bit of β-globin production (reduced rate of synthesis)- MILDER
How and why is Sickle cell anaemia (SCA) different in adults and children?
This is because the distribution of red bone marrow differs
Adults- red bone marrow restricted to the axial skeleton
Infants- red bone marrow goes right down the long bones and bones of hands and feet - Hand foot syndrome
What is the commonest cause of stroke in childhood
SCA blocking the cerebral arteries?
What does the infraction of ribs and lungs due to SCA cause?
Acute chest syndrome
What is splenic sequestration and how does it present and how is it treated?
This means that the child can undergo splenic sequestration which is the acute pooling of a large percentage of circulating RBCs in the spleen, leading to acute enlargement
This can also lead to SEVERE ANAEMIA, SHOCK and DEATH
To treat splenic sequestration, the patient should receive a blood transfusion
What are 2 organisms SCA kids are prone to?
Pneumococcus and parvovirus
