Haematology 1

Question 1

What is the site of haematopoiesis?

Answer 1

Mainly liver in fetal life.

Bone-marrow in post-natal life.

Question 2

When are stores of iron, folic acid and Vitamin B12 low?

Answer 2

In preterm infants - depleted quickly in the first few months of life.

Question 3

What is anaemia in different age groups

Answer 3

Neonate Hb < 14
1-12 months Hb <10
1-12 years Hb <11

Question 4

What is the platelet count in children compared to adults?

Answer 4

Similar to that of an adult:
150-450x10^9

It increase to 270-570 (1-6months)

Question 5

What is the pattern of normal WCC in children

Answer 5

Highest in newborn to 2 years.

Slowly declines until adulthood

Question 6

Change in Haemoglobin from fetal to neonatal life?

Answer 6

Most important difference.

Foetal Hb is made of 2 alpha + 2 gamma units (higher affinity for oxygen)

Adult Hb is made of 2 alpha + 2 beta units

HbF is gradually replaced by HbA in the first year of life

Question 7

What are the changes in Hb concentration in a newborn

Answer 7

At birth, Hb is HIGH (14-21.5g/dl)
-to compensate for the low O2 concentration in the fetus

Hb falls over the first few weeks because of RBC production.

10g/dl at 2 months of age

Question 8

What are the general causes of IDA

Answer 8

Inadequate intake
Malabsorption
Blood loss (rare)

Question 9

Why is IDA common in infants?

Answer 9

Additional iron is required for the increase in blood volume accompanying growth and also to build up iron stores

Question 10

The role of diet in maintaining normal iron

Answer 10

Breast milk, formula or cow’s. Later solids!
Delay in weaning beyond 6 months can lead to IDA

Best absorbed with Vitamin C.
Tannin from tea reduces absorption.

Question 11

Diagnosis of IDA in infants

Answer 11

Clinical features present < 6-7g/dl

Easily fatigued
Feed more slowly
Pale (confirm on conjunctiva, tongue, palmar crease)

Microcytic, hypochromic anaemia (low MCV and MCH) and low serum ferritin

Question 12

Management of IDA

Answer 12

Dietary advice!
Oral supplementation if needed

If still no gain, investigate malabsorption

Foods to avoid in excess for toddlers:
cow’s milk, tea (tannin), high fibre foods (phytates inhibit)

Average iron:
pulses, beans, peas
fortified breakfast cereal with added Vit C
Wholemeal products
Dark green vegetables (broccoli, spinach)
Raisins, sultanas
Nuts and seeds (cashew/peanut butter)

HIGH in iron:
Red meat
Liver/kidney
Oily fish

Question 13

What are the effects of folate and vit B12 deficiency on blood cells?

Answer 13

Folate provides constituents to produce red cells.
Without them the body cannot make enough cells:
Macrocytic megaloblastic anaemia

B12 vital for DNA synthesis so similar effect

Question 14

Neutrophil and lymphocyte count changes with age

Answer 14

Slight drop with age

Question 15

Effect of malignant disorder of the blood on WCC

Answer 15

Can be both high or low

Generally a drop in WCC

Question 16

What is haemolytic anaemia

Answer 16

Lifespan of normal red cell is 120 days. Reduced in haemolysis (either intravascular or extravascular haemolysis)

If it is reduced to the point where bone marrow cannot compensate (production can increase about 8fold)

Question 17

Main causes of haemolysis in neonates and children

Answer 17

Neonates - immune haemolytic anaemia is common

In children, uncommon: mainly caused by intrinsic abnormalities of RBC

• RBC membrance disorders (eg. hereditary spherocytosis)
• Red cell enzyme disorders (G6PD deficiency)
• Haemoglobinopathies (abnormal haemoglobins eg. ß-thalassaemia major, sickle cell disease)

Question 18

Symptoms and signs of haemolysis

Answer 18

Anaemia
Hepatomegaly and splenomegaly
Increased serum unconjugated bilirubin
Excess urinary urobilinogen

Question 19

Diagnostic markers for haemolysis

Answer 19

Raised reticulocyte count (polychromasia - lilac)
Unconjugated bilirubinaemia and increased urinary urobilinogen

Abnormal appearance of RBC on blood film - eg. spherocytes, sickle shaped or very hypochromic

Positive direct antiglobulin test (identified antibody coated RBCs)

Increased RBC precursors in bone marrow

Question 20

What is hereditary spherocytosis (pathophysiology)

Answer 20

Usually autosomal dominant inheritance. In 25% it is a new mutation

Mutations in genes for protein in RBC membrane. (spectrin, ankyrin)

Reduces survace to volume ratio - become spheroidal. Less deformable and thus destroyed in the microvasculature of the spleen.

Question 21

Clinical features of hereditary spherocytosis

Answer 21

Jaundice - usually during childhood. May be severe in first few days of life

Anaemia - mild anaemia, but Hb level may transiently fall during infections

Mild to moderate hepatosplenomegaly

Gallstones (due to increased bilirubin excretion)

Aplastic crisis (uncommon transient)

Question 22

Diagnostic test for spherocytosis

Answer 22

Blood film

Spherocytes may also occur in autoimmune haemolysis: exclude with direct antibody test if no FHx

Question 23

What is G6PD deficiency

Answer 23

Glucose 6 phosphate dehydrogenase deficiency

It is a rate-limiting enzyme in preventing oxidative damage to RBCs

X-linked: predominantly affects males

Question 24

Presentation of G6PD

Answer 24

Neonatal jaundice - usually first 3 days of life

Acute haemolysis, precipitated by:

• infection (most commonly)
• fava beans
• certain drugs

Predominantly intravascular haemolysis leading to an acute picture:
jaundice
pallor
fever, malaise, passage of dark urine (Hb+urobilinogen)

Intermittent haemolytic crises

Ethnically, most affected are central Africa, Mediterranean, middle East, far East

Question 25

Diagnosis of G6PD deiciency

Answer 25

measure G6PD activity in RBC

However, may be elevated in a haemolytic crisis, so repeat assay in the steady state is required

Question 26

What are haemoglobinopathies?

Answer 26

RBC disorders which cause haemolytic anaemia because of reduced/absent production of HbA (alpha and beta thalassaemia) or because of the production of abnormal Hb (sickle cell)

Question 27

What are thalassaemias

Answer 27

Alpha is caused by deletions in the alpha-globin gene

Beta and sickle cell disease are caused by mutation in the beta globin gene

Question 28

When do haemoglobinopathies present

Answer 28

Alpha thalassaemia from newborn period (maybe even fetus?)

Beta thalassaemia and Sickle cell only after 6 months after birth - most HbF replaced by adult HbA