Paediatric haematology Flashcards
what is different about children?
Different physiology
Developing organs
Fetal blood production and changes at birth
Maternal factors influencing neonates
describe the difference between adult and foetal Hb
Adult Hb is mainly made up of HbA- alpha and beta chains
Foetal Hb is made up of alpha and delta chains until after birth- haemoglobin switching occurs after birth
when is platelet level in foetus
end of 1st trimester
describe normal RBC/Hb changes in 3rd trimester
Rising Hb and MCV
Transfer maternal iron stores (late)
HbF – relative hypoxia in utero
Until end of 3rd trimester mother gives iron to the baby, which leads to apparent polycythaemia and high MCV
The HbF in utero causes relative hypoxia- which is fine in a foetus bc the mother is providing the oxygen, however at birth more oxygen is needed so the BM changes and switches to production of HbA
describe normal RBC/Hb changes at birth
More oxygen to tissues Air not placenta HbA production Switch off HbF production Initially after birth, there is low Hb because the bone marrow needs time to adjust, but gradually as the bone marrow picks up, so does the Hb concentration
describe normal RBC/Hb changes from 8-12 weeks
Reach Hb nadir 8-12 weeks
Hb 90-110g/L
Start making RBC again
how are prem babies physiologically different in general?
Small spleens
Red cells are resistant to osmotic lysis
Red cells have altered shape
how are prem babies born at 28 weeks or less physiologically different?
Marked macrocytosis
Plentiful nucleated red cells- less efficient at carrying oxygen
Can see oxidative haemolysis 4-6 weeks of age
Short-lived acquired deficiency of red cell enzymes e.g. G6PD
causes of anaemia of prematurity (5)
lower baseline Hb
shortened RBC
survival- BM cant keep up
lower iron stores–Don’t get the maternal transfer of iron
rapid weight gain- increased RBC mass
iatrogenic blood sampling
ways to treat anaemia of prematurity
iron supplements
delayed cord clamping to allow as much maternal blood to reach the baby and deposit iron as possible
rationalise blood tests
causes of non-physiological anaemia
haemolysis: COMMONEST Immune Congenital: Enzyme Membrane Sepsis
blood loss: In utero During delivery Birth trauma Blood sampling
decreased production: Rare Pavrovirus DBA – usually presents later Occ other infections
how to evaluate anaemia
Baby: Gestational age & time of onset Jaundice Hepatosplenomegaly Cephalohaematoma O2 req/ tachycardia
Mum: Blood group + RBC alloantibody status FH of (mum/dad) Neonatal jaundice Splenectomy RBC transfusion
Laboratory Investigations
FBC, retic, DAT, film, blood group
Maternal Ab screen
Kleihauer: unexpected severe anaemia without jaundice
Cranial USS if blood loss w/o cause
Parvovirus PCR + maternal serology if reticulocytopaenia
prevention and management of HDN
Prevention of alloimmunisation
Early identification of alloimmunisation
Maternal Antibody screening
Threshold for FMU: anti-D >4IU/dL, anti-c >7.5 IU/dL, any Kell
Management of fetal complications Risk of baby being affected Monitoring for anaemia – MCA peak systolic velocity >1.5N Intrauterine transfusion Timing of delivery
Management of neonatal complications
Counselling regarding future pregnancies & transfusions
3 types of RBC membrane disorder
Hereditary spherocytosis
Hereditary elliptocytosis
Hereditary pyropoikilocytosis
describe G6PD deficiency
G6PD protects red cells from damage by oxidative substances
No symptoms unless oxidative stress
Medications, Fava beans
Affects about 400 million people worldwide
X-linked recessive inheritance
Africans
Mediterranean Groups
May present with neonatal jaundice
