Flashcards in Paediatric haematology Deck (16):
How do paediatric RBCs differ from adult?
Site of haematopoeisis varies
At birth 55-65% is HbF
Difference in red cell structure and metabolism
Larger red blood cells
Rapidly reach similar values to adults
How are WBCs different in children vs adults?
Similar numbers - higher lymphocyte count
IgG crosses the placenta
Breast milk has IgA, IgD, IgE, IgG, IgM
Start producing antibodies at 2-3m
Can make satisfactory immune responses by 6m
How do platelets differ in children vs adults?
Reach adult numbers by 18w gestation
Initially larger, by birth slim down to adult size
Functionally different at birth
Hyporesponsive to certain agonists
Hyperresponsive to vWF
Differences balance out
How does haemostasis differ in children va adults?
Present but imperfect at birth
Coagulation proteins do not cross placenta effectively
Only fibrinogen, FV(5), FVIII(8), FXIII(13) are normal at birth
Most haemostatic parameters reach adult values by 6 months
Yet, see few problems clinically...unless ill or preterm
What is haemmorrhagic disease of the newborn?
The placental gradient means fetal vitamin K is 10% mother
FII(2), FVII(7), FIX(9), FX(10), protein C, protein S are vitamin K dependent
Exacerbated if on anti-convulsants - mother needs oral vitamin K
Warfarin is teratogenic
What routine treatment prevents haemmorrhagic disease of the newborn?
Routine neonatal Vit K
Which coagulation inhibitors exist at a reduced concentration in neonates?
Heparin cofactor 2
Which coagulation proteins exist in unique forms in neonates?
Are D dimers and vWF increased or decreased?
What are the possible congenital causes of anaemia in childhood?
Haemoglobin synthesis problem: haemoglobinopathy
Bone marrow failure syndromes
Bone marrow infiltration
What versions of Hb exist at the gestational age of 4-14 weeks?
ζ2e2 = Hb Gower-1
ζ2γ2 = Hb Portland
α2e2 = Hb Gower-2
What are the possible causes of peripheral destruction?
Rh / ABO or other incompatibility
Membrane defect: hereditary spherocytosis
Enzyme defect: G6PD deficiency, PK deficiency
What is hereditary spererocytosis?
Autosomal dominant abnormality of erythrocytes.
Caused by mutations in genes relating to membrane proteins that allow for the erythrocytes to change shape.
Abnormal erythrocytes are sphere-shaped (spherocytosis).
Dysfunctional membrane proteins interfere with the cell's ability to be flexible to travel from the arteries to the smaller capillaries.
This difference in shape also makes the red blood cells more prone to rupture
Cells with these dysfunctional proteins are taken for degradation at the spleen. This shortage of erythrocytes results in haemolytic anemia.
What might be the cause of acquired childhood anaemia?
Nutritional deficiency: iron, B12, folate
Bone marrow failure
Bone marrow infiltration
Peripheral destruction: haemolysis
What are the possible congenital causes of bleeding and bruising in children?
Clotting factor problem
Connective tissue disorder