Ha - Paeds Haem Flashcards
how to response to infection differ in adults and kids
kids = lymphocytosis
adults = neutrophilia
how does neonate blood count differ from children
neonate has higher haem F, higher Hb, lymphocyte count, neutrophil count
why doesn’t beta thalassaemia major affect babies
they have more ham F not haem B so doesnt develop until switched to haem B
3 causes of polycythaemia in foetus / neonate
twin to twin transfusion
IU hypoxia
placental insufficiency
what is bad about polycythaemia
get hyperviscosity
4 causes of foetal / neonatal anaemia
twin to twin transfusion
foetal to maternal transfusion
parvovirus infection
haemorrhage from cord / placenta
when does the first leukaemia genetic hit occur
in utero
who gets congenital leukaemia (aka transient abnormal myelopoiesis)
downs syndrome
how is congential leukaemia different from normal leukaemia
it spontaneously remits
what cell type is involved in congential leukaemia
myeloid - megakaryocytes
newborn babies vs adults have got what different in their blood film ?
a higher Hb
what is thalassaemia
reduced rate of synthesis of one type of haemaglobin
what is haemaglobinopathy
synthesis of a structurally abnormal molecule of haemaglobin
or
can include thalassaemias too
why do defects in alpha / beta haemaglobinopathies occur at different ages?
alpha synthesis starts in utero so will show up then
beta synthesis starts after birth so newborn babies wont have it
what chromosome has beta hb encoded
11
what chromosome has alpha hb encoded
16
how does sickle cell cause blockage of BVs
regular haemaglobin is donut shaped
if it has the sickle cell gene, it will turn into sickle shape when exposed to HYPOXIA
these aggregate and block BVs
is sickle cell trait part of sickle cell disease
no - it causes subclinical sx if any
if both parents have sickle trait, what % of children will have:
- sickle trait
- sickle cell
- normality
50% trait
25% sickle cell
25% normal
how is sickle cell diagnosed at birth
guthrie spot
why do kids get sickle crises in hand / feet but adults dont
kids have extension of red marrow further into limbs - these are very vascular areas so more likely to get sickle occlusion –> leads to hand-foot syndrome where thrombosis in periperhies, which you don’t get in adults
how can sickle cell manifest differently in kids and adults
hand-foot syndrome in kids - longer red marrow
splenic sequestration - spleen is still functioning, so can get sickle cells sequestering
stroke - thinner BVs in kids
why doesn’t splenic sequestration happen in older children / adults
splenic infarction occurs so much that the spleen has become small and fibrotic
what risk increases as splenic sequestration risk decreases
hyposplenism - bacterial infections etc
what 2 infections are particularly bad in sickle babies
pneumococcal
parvovirus
why does folic acid matter more in a child with sickle cell than in a normal child / adult
hyperplastic erythropoiesis and growth spurts requires folic acid
what is the lifespan of a sickle red cell
20 days
how do you manage sickle cell and complications in infant / child
accurate diagnosis
educate parents - sickle cell crisis signs
vaccinate - pneumococcus
prescribe folic acid / penicillin
is stroke more common in sickle kids or adults
kids - smaller BVs in brain
siblings with sickle cell anaemia present together with severe anaemia, low reticulocyte count. Dx?
parvovirus b19 infection
6 year old afro caribean boy with chest / abdo pain. hb 63, mcv 85 and blood film shows sickle cells. is this trait/anaemia/sickle with beta thalassaemia ?
sickle cell anaemia
what blood film feature is seen in sickle cell with beta thalassaemia
microcytosis
what is beta thalassaemia
condition resulting from reduced synthesis of beta globin chain and therefore haemaglobin A
when does beta thalassaemia first present
3-6 months
what is prognosis of beta thalassaemia heterozygosity/trait
harmless but genetically important
what is prognosis of beta thalassaemia homozygosity
severe anaemia, that in the absence of transfusion, is fatal in first few years of life
what is the name for the intermediate forms of beta thalassaemia
beta thalassaemia intermedia
clinical effects of poorly treated thalassaemia
anaemia - HF, growth retardation
erythropoietic drive - bone expansion, hepatomegaly, splenomegaly
iron overload - HF, gonadal failure
Mx of infant / child with beta thalassaemia major
accurate diagnosis
family counselling
blood transfusion
chelation therapy once iron overload occurs
name 2 chelation therapies
desferioxamine
deferiprone
are all congenital haemolytic anaemias inherited? why?
no - can get transplacental passage of ABs causing haemolytic disease of newborn
what causes transplacental haemolytic anaemia
ABO or RH D ABs mismatch
what causes inhertied haemolytic anaemias in children
defects in:
red cell membrane (spherocytosis/elliptocytosis)
Hb molecule (sickle cell)
red cell enzymes - glycolytic pathway (pyruvate kinase def) / pentose shunt (G6PD def)
signs of haemolytic anaemia in newborn
jaundice
splenomegaly
increased unconjugated BR
why is high BR an issue in babies
can lead to conikterose
name 5 inherited haemolytic anaemias in children
hereditary spherocytosis
hereditary elliptocytosis
sickle cell
pyruvate kinase deficiency
G6PD deficiency
what should be avoided in G6PD deficiency
moth balls - naphthalene
fava beans (broad beans)
some drugs
infection
2 important acquired haemolytic anaemias in kids
autoimmune haemolytic anaemia
haemolytic uraemic syndrome
characteristics of AI HA
spherocytosis
positive coombs test
characteristics of hamolytic uraemic syndrome
haemolysis
uraemia (kidney impairment)
small angular fragments and microspherocytes –> schistocytes
what precipitates haemolytic uraemic syndrome in kids
a specific e coli
presentation of haemophilia in kids
boys
bleeding following minor ops eg circumcision
haemarthroses when starting to walk
bruises
Mx of haemophilia in kids
accurate Dx
counselling of family
Tx of bleeding episodes
use of prophylactic coagulation
involve school / family
mucosal bleeding, bruises and post traumatic bleeding. Dx?
von willebrand disease
Tx of von willebrand factor
lower purity factor Viii concentrates
1 year old boy presents with joint bleeding
hb, wcc, platelet normal
aptt long
pt, bleeding time normal
Dx?
haemophilia A
which is more likely of the haemophilias
A
petechiae, bruises and blood blisters in mouth. dx?
ITP
Dx of ITP
history
blood count and film
aspirate if needed
Mx of ITP
observation
steroids
high dose IV IG
IV anti Rh D (if positive)
what leukaemia is more common in kids
ALL
what leukaemia is more common in infants under 1
AML
Mx of hyposplenism
vaccinations
prophylactic penicillin
advice to parents re other risks - malaria, dog bites
