Haem 10 - Paediatric Haematology

Question 1

How do haematological parameters differ in a child vs in an adult?

Answer 1

o Neonates have high WCC, neutrophils, lymphocytes, Hb and MCV

Question 2

What is TAM (transient abnormal myelopoiesis)?

Answer 2

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

Question 3

Which chromosome is responsible for

alpha chain production
beta chain production

In Hb

Answer 3

alpha chain - Chr 16

Beta chain - Chr 11

Question 4

Which Hb chain is defective in sickle cell disease?

Answer 4

Beta chain

Question 5

When does sickle cell disease usually manifest?

Answer 5

o Sickle cell anaemia manifests around 6 months of age as
 Gamma chain production and HbF synthesis decrease
 HbS production increase

Question 6

Explain one complication of sickle cell disease in children that is absent in adults

Answer 6

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

Question 7

When does hand and foot syndrome usually occur in children with SCD?

Answer 7

o Hand-foot syndrome tends to occur in the first 2 years of life

Question 8

Why does folic acid matter more in a child with sickle cell disease than in a normal child or an adult?

Answer 8

Hyperplastic erythropoiesis requires folic acid

Growth spurts require folic acid

Red cell life span is shorter so anaemia can rapidly worsen

Question 9

Complications of sickle cell anaemia that are more common in adults than children include

Answer 9

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)

Question 10

Heinz bodies vs Howell Jolly bodies

Answer 10

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

Question 11

Inheritance pattern of blood coagulation disorders

o Haemophilia A
o Haemophilia B
o Von Willebrand disease

Answer 11

o Haemophilia A (F8 deficiency) – X-linked recessive
o Haemophilia B (F9 deficiency) – X linked recessive
o Von Willebrand disease – AD

Question 12

• Key aspects of the diagnosis in a child with a suspected inherited defect of coagulation

Answer 12

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

Question 13

main differential of Von Willebrand disease

Answer 13

Haemophilia A

bc factor 8 is low in both conditions

haemophilia
- haemarthroses

VBD
- mucosal bleeding

both
bruises
post traumatic bleeding

Question 14

Von Willebrand disease mx

Answer 14

Lower purity factor 8 concentrates

Question 15

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

Answer 15

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

Question 16

Autoimmune thrombocytopenic purpura mx

Answer 16

o	Observation (most common)
o	Corticosteroids 
o	High dose IVIG 
o	Anti-D IV (in RhD +ve with spleen) – the anti-D coats the RBCs and is preferentially removed by the reticuloendothelial system in preference to the AB-covered platelets, thus conserving platelet levels

Question 17

Commonest childhood leukaemia

Answer 17

ALL

AML is more common in those <1y (i.e. TAM in DS is an AML)

Question 18

Child presenting with pneumoccoal infection important ix

Answer 18

Examine blood film for features of hyposplenism (Howell Jolly bodies)

Question 19

Hyposplenism mx

Answer 19

o	Appropriate vaccinations 
     Neisseria Meningitidis
     Haemophilus influenzae 
     Streptococcus pneumoniae
o	Prophylactic penicillin
o	Advice to parents regarding other risks
	Malaria 
	Dog bites