Haematology Flashcards

1
Q

Foetal haemoglobin is comprised of what subunits?

A

2 alpha and 2 gamma subunits

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2
Q

Why is it important for foetal haemoglobin to have a higher affinity for oxygen than the maternal adult haemoglobin?

A

Foetal Haemoglobin needs to “steal” or displace oxygen from the mother’s Haemoglobin in the placenta

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3
Q

On an Oxygen dissociation curve, what is the x and y axis?

A

X axis: Partial pressure of O2

Y axis: Saturation of Hb with O2

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4
Q

What does it mean when the O2 dissociation curve of Foetal Hb is shifted to the left compared to Adult Hb?

A

It means Adult Hb requires a higher partial pressure of oxygen for molecule to bind to oxygen compared to Foetal Hb

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5
Q

When does HbF decrease in babies?

A

Production decreases from 32-36 weeks gestation, and at the same time HbA increases. By 6 months, very little HbF is produced

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6
Q

What is the mutation for SCD?

A

V600E mutation on position 6 of the beta-globin chain, of Adult Haemoglobin

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7
Q

Why does sickle cell disease not cause sickling of foetal Hb?

A

Because SCD affects the beta globin chain of Adult Hb, and in Foetal Hb there is only 2 alpha and 2 gamma chains

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8
Q

What medication can be used to increase production of Foetal Haemoglobin in patients with SCD?

A

Hydroxycarbamide

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9
Q

What factors cause the O2 dissociation curve to shift to the left?

A

Carbon monoxide

Foetal haemoglobin

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10
Q

What factors cause the O2 dissociation curve to shift to the right?

A

Increase in pCO2
Increase in temperature
Increase in 2,3 DPG
Decrease in pH (acidic)

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11
Q

What is Physiological Anaemia in Infancy?

When does it occur?

A
  • Caused by negative feedback to EPO and suppression of Hb production
  • Most common cause of anaemia in infancy
  • Normal dip of Hb at 6-9 weeks
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12
Q

Why might anaemia of Prematurity occur? Several reasons

A
  • Less time in utero
  • RBC creation cannot keep up with rapid growth
  • Reduced EPO levels
  • Blood tests may remove circulating volume
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13
Q

What are some causes of anaemia in young babies?

A
  • Physiologic anaemia of Infancy
  • Anaemia of Prematurity
  • Blood loss
  • Twin to twin transfusion
  • Haemolysis (HND, HS, G6PD deficiency)
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14
Q

What are two common causes of anaemia in older children?

A
  • Iron deficiency anaemia, 2ndary to dietary insufficiency

- Blood loss, most commonly in menstruating women

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15
Q

What is the most common cause of blood loss causing anaemia in developing countries for older children?

How is it treated?

A

Helminth infection, with roundworms, hookworms or whipworms

One off dose -> Albendazole, Mebendazole

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16
Q

Anaemias can be categorised based on RBC MCV. What are causes of Microcytic anaemia?

A

TAILS mnemonic

  • Thalassemia
  • Anaemia of chronic disease
  • Iron deficiency anaemia
  • Lead poisoning
  • Sideroblastic anaemia
17
Q

Anaemias can be categorised based on a RBC MCV. What are causes of Normocytic anaemia?

A

3 A’s and 2 H’s

  • Acute blood loss
  • Anaemia of chronic disease
  • Aplastic anaemia
  • Haemolytic anaemia
  • Hypothyroidism
18
Q

Anaemias can be categorised based on a RBC MCV. What are causes of Macrocytic anaemia?

A

Macrocytic Megaloblastic:

  • B12 deficiency
  • Folate deficiency

Macrocytic Normoblastic:

  • Alcohol
  • Reticulocytosis
  • Hypothyroidism
  • Liver disease
  • Drugs i.e. Azathioprine
19
Q

What is a sign specific to haemolytic anaemia?

A

Jaundice

20
Q

What are signs and symptoms specific to iron deficiency anaemia?

A

Signs:

  • Koilonychia
  • Angular cheilitis
  • Glossitis
  • Post cricoid webs
  • Brittle hair & nails

Symptoms

  • Pica
  • Hair loss
21
Q

Top 3 causes of iron deficiency anaemia?

A
  • Dietary insufficiency
  • Loss of iron (i.e. due to menstruation)
  • Chronic conditions (i.e. Crohn’s)
22
Q

Where is iron mainly absorbed in the gut?

A

In the duodenum and the jejunum

23
Q

Why might some medications interfere with iron absorption? Give an example of a medication?

What else can interfere with iron absorption?

A

Iron requires stomach acid to keep iron in the soluble Fe2+ form. If there is less acid, Fe2+ -> Fe3+. Some medications like PPIs reduce stomach acid and thus interfere with iron absorption

Diseases like Crohn’s Disease and Coeliacs may also interfere with iron absorption

24
Q

What is heme iron and non-heme iron?

A

Heme iron: Fe2+, aka ferrous

Non-heme iron: Fe3+, aka ferric

25
Q

Outline how iron is transported in duodenal cells and in the blood?

A

In duodenal cells, iron is transported as Fe2+, bound to Ferritin. When in blood being transported, iron is carried as Fe3+, bound to Transferrin. Once it is deposited into cells, it is deposited back as Fe2+ bound to Ferritin

26
Q

What is Total Iron Binding Capacity (TIBC)? Why is TIBC important?

A

TIBC refers to the total space on a transferrin molecule for iron to bind. TIBC is a good indicator for amount of Transferrin in blood

27
Q

What is the equation for Transferrin Saturation?

A

Serum Iron / Total Iron Binding Capacity

28
Q

What does:

  • Low Ferritin mean?
  • Normal Ferritin mean?
  • High Ferritin mean?
A
  • Low Ferritin: Iron deficiency anaemia
  • Normal Ferritin: May still be iron deficient
  • High Ferritin: Difficult to interpret, can be due to inflammation or iron overload
29
Q

What does:

  • High TIBC / Transferrin mean?
  • Low TIBC / Transferrin mean?
A
  • High: Iron deficiency

- Low: Iron overload

30
Q

In Iron deficiency, what will the values be for TIBC, Transferrin, Transferrin saturation, and Ferritin?

A

TIBC: High
Transferrin: High
Transferrin saturation: Low
Ferritin: Low

31
Q

What are the investigations for Iron deficiency anaemia?

A
  • Full Blood Count: Hypochromic, microcytic anaemia
  • Serum Ferritin: Low
  • TIBC / Transferrin: High
  • Blood film: Anisopolkiocytosis
  • Endoscopy: Rule out malignancy
32
Q

What is the management for Iron deficiency anaemia?

A
  • Treat underlying cause
  • Oral ferrous sulphate for 3 months
  • Iron rich diet
  • Transfusions (rare)