Haem 10 - Paediatric Haematology Flashcards
How do haematological parameters differ in a child vs in an adult?
o Neonates have high WCC, neutrophils, lymphocytes, Hb and MCV
What is TAM (transient abnormal myelopoiesis)?
o Congenital leukaemia that is particularly common in Down syndrome
TAM is a myeloid leukaemia (it’s a type of AML) with major involvement of the megakaryocyte lineage
This disease tends to remit spontaneously within the first 2 months of life
However, it tends to relapse 1-2 years later in about 25% of infants
Different from leukaemia in older infants or children
Which chromosome is responsible for
alpha chain production
beta chain production
In Hb
alpha chain - Chr 16
Beta chain - Chr 11
Which Hb chain is defective in sickle cell disease?
Beta chain
When does sickle cell disease usually manifest?
o Sickle cell anaemia manifests around 6 months of age as
Gamma chain production and HbF synthesis decrease
HbS production increase
Explain one complication of sickle cell disease in children that is absent in adults
Children still have a functioning spleen –> splenic sequestration
acute pooling of a large percentage of circulating red cells in the spleen spleen enlarges acutely severe anaemia, shock and death
When does hand and foot syndrome usually occur in children with SCD?
o Hand-foot syndrome tends to occur in the first 2 years of life
Why does folic acid matter more in a child with sickle cell disease than in a normal child or an adult?
Hyperplastic erythropoiesis requires folic acid
Growth spurts require folic acid
Red cell life span is shorter so anaemia can rapidly worsen
Complications of sickle cell anaemia that are more common in adults than children include
Hyposplenism
Adult / older-child spleen – spleen is small and fibrotic from recurrent infarction
• No longer suffering from splenic sequestration
• Spleen filters bacteria + parasites -> Suffer from more chance of sequalae of hyposplenism (i.e. pneumococcal infection)
Heinz bodies vs Howell Jolly bodies
Heinz bodies
Inclusions within red blood cells composed of denatured hemoglobin
They are formed as a result of oxidative damage or mutations (i.e G6PD)
Macrophages in the spleen remove the denatured hemoglobin giving rise to the classic “bite cells” (see below)
Dot almost outside the cell
present with bite cells
Howell Jolly bodies
Nuclear (basophilic) inclusions within RBCs
Normally: During maturation, after leaving the bone marrow, erythroblasts’ nuclei are expelled within the spleen
HOWEVER, in patients without a spleen (asplenia) secondary to (i.e surgery, radiation or sickle cell disease) will retain these remnants (see below)
Dot inside the cell
https://medicinespecifics.com/heinz-bodies-vs-howell-jolly-bodies/
Heinz
https://explore.medstudy.com/hubfs/1556205366519_18_i_p6c_Heinz_bodies_in_G6PD.jpeg
Howell Jolly Body
https://stanfordmedicine25.stanford.edu/blog/archive/2016/Diagnose-the-cause-of-sepsis-from-one-cell-in-the-blood/_jcr_content/main/panel_builder/panel_0/panel_builder/panel_0/image.img.476.high.png/HJ-Body.png
Inheritance pattern of blood coagulation disorders
o Haemophilia A
o Haemophilia B
o Von Willebrand disease
o Haemophilia A (F8 deficiency) – X-linked recessive
o Haemophilia B (F9 deficiency) – X linked recessive
o Von Willebrand disease – AD
• Key aspects of the diagnosis in a child with a suspected inherited defect of coagulation
o History of the child
Was there umbilical cord bleeding or bleeding when the Guthrie test was performed?
Was there haematoma formation after vitamin K injection or vaccinations?
Was there bleeding after circumcision?
o Family history
o Coagulation screen
o Assays of specific coagulation factors
o Platelet count
o Platelet aggregation studies
main differential of Von Willebrand disease
Haemophilia A
bc factor 8 is low in both conditions
haemophilia
- haemarthroses
VBD
- mucosal bleeding
both
bruises
post traumatic bleeding
Von Willebrand disease mx
Lower purity factor 8 concentrates
A 1-year-old boy presents with joint bleeding, Hb, WBC and platelet count are normal, aPTT is prolonged, PT is normal, bleeding time normal—most likely diagnosis?
Haemophilia A Haemophilia B Von Willebrand disease Thrombotic thrombocytopenia purpura Has taken mother’s warfarin tablets
Haemophilia A
- APTT measures intrinsic, PT measures extrinsic
- Prolonged APTT suggests that it’s either haemophilia A, B or VWD(deficiencies in clotting factors of the intrinsic pathway)
- Normal bleeding time suggests that it’s not VWD
- Haemophilia A is 4x more common than B
Intrinsic pathway - twelvE, EleveN, NinE, EighT, Ten