Haematology 16: Paediatric Haematology Flashcards
What is Transient abnormal myelopoiesis ?
- Congenital form of leukaemia commonly affecting children with Down syndrome.
- Tends to remit within the first 2 months of life
- Mainly affecting megakaryocyte lineage
On which chromosome is the ß cluster ?
Chromosome 11
On which chromosome is the å cluster ?
Chromosome 16
Which Globin chains make up HbA ?
å2ß2
Which Globin chains make up HbA2 ?
å2∂2 (alpha and delta)
Which Globin chains make up HbF ?
alpha 2 gamma 2
Why does Sickle cell disease not present in the first 6 months of life ?
HbF is still in high concentration and is able to compensate
Name the test used to diagnose sickle cell anaemia at birth ?
The Guthrie spot test
Why do children with sickle cell experience hand-foot syndrome whereas adults get bone pain in the central skeleton?
- Red bone marrow (where red blood cells and leukocytes are produced) is only present in the central skeleton in adults but in all bones in children.
- Sickle cells cause infarction of the vessels that supply the bone marrow causing pain
What happens if a child with sickle cell anaemia gets a parvovirus b19 infection ?
Aplastic anaemia
What are some of the clinical features of thalassaemia Major ?
Bossing of facial bones
Hepatosplenomegaly
Iron overload- heart/liver failure
Growth retardation
What is the main treatment for vWD ?
Factor 8 concentrates
What is the most common leukaemia of childhood ?
ALL
differences in neonatal bloods
high WCC, neutrophils, lymphocytes, Hb and MCV, higher percentage HbF, lower G6PD concentration
causes of fetal polycythaemia
twin-to-twin transfusion
intrauterine hypoxia
placental insufficiency
causes of fetal anaemia
twin-to-twin transfusion
foetal-to-maternal transfusion
parovirus infection
haemorrhage from cord or placenta
features of leukaemia in utero
congenital leukaemia common in DS = TAM (transient abnormal myelopoiesis remits spontaneously within the first 2 months of life relapses 1-2 yrs myeloid leukaemia
what is thalassamia
condition resulting from a reduced rate of synthesis of one or more of the globin genes
what is a haemoglobiopathy
structurally abnormal haemoglobin
what chromosomes are the globin chains controlled by
chromosomes 11 and 16 chr 11: - beta gene - delta gene - gamma gene - LCR (locus control region)
chr 16:
- 2 x alpha genes
- zeta gene
list the different forms of Hb
A - a2b2
A2 - a2d2 (<3.5% of total adult Hb)
F - a2y2
describe Hb in utero
HbF predominated
until 32 weeks - rapid increase in Hb A
at birth 1/3 haemoglobin is HbA
features of SCA
SCA = homozygous HbS gene SCD = homozygous and heterozygous states
hypoxia leads to poymerisation of HbS - crescent RBC and blocked blood vessels
post-capillary venules
what are howell-jolly bodies a feature of
hyposplenism
what is the difference between adult and child in splenic sequestration
infant still has a functioning spleen
splenic sequestration - acute pooling of circulating rec cells in the spleen
leads to anaemia, shock, death
describe vaso-occlusion in the first decade of life in SCA
hand-foot syndrome - 1st 2 yrs
acute chest syndrome - infarction in the ribs and lungs
painful crises
stroke
describe spleen problems and bacteraemia in the first decade of life with SCA
splenomegaly
hyposplenism
acute splenic sequestration
bacteraemia
what infections are children with SCA especially vulnerable to
pneumococcus
parovirus - aplastic anameia
prevent with vaccination and penecillin
why do children with SCA have increased folic acid demands
hyperplastic erythropoiesis
growth spurts
red cell lifespan is shortened so anaemia can rapidly worsen
treatments for SCA
establish a diagnosis
educate parents
vaccinate
folic acid and penecillin
features of childhood beta thalassaemia
manifests after first 6m guthrie spot test trait = harmless homozygosity - severe anaemia fatal in 1st few years without blood transfusion
poorly treated - anaemia (HF, growth retardation), erythropoietin drive (bone expansion, hepatomegaly, spleno), iron overload (HF, gonadal failure)
list 4 triggers of haemolysis in G6PD deficiency
infections
drugs
napthalene
fava beans
(X linked)
what parts of the history are important with suspected inherited defect of coagulation
child history - umbilical cord bleeding / on guthrie test, hematoma after it K injection, bleeding after circumscision family history coagulation screen platelet count assays of coagulation factor
presentation of VWD
mucosal bleeding
bruises
post-traumatic bleeding
DDx - haemophilia A
presentation of haemophilia A and B
bleeding following circumscision
haemarthroses
bruises
post-traumatic bleeding
presentation of AITP
petechiae
bruises
blood blisters in mouth
how is hyposplenism managed
vaccinations
prophylactic penecillin
