Red blood cells Flashcards

1
Q

What is anaemia?

A

Reduction in red cell count or haemoglobin content of red cell count

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2
Q

What are general aetiologies to anaemia?

A

Bloof loss
Decreased production
Defective production
Increased destruction

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3
Q

What is a reticulocyte?

A

Immature red blood cell - not fully haemoglobinised

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4
Q

What metals are required for blood production?

A

Iron
Copper
Cobalt
Manganese

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5
Q

What vitamins are required for red cell production?

A
B12 
Folic acid
Thiamine
B6
C
E
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6
Q

What hormones are required to produce red cells?

A

Erythropoietin
GM-CSF
Androgens
Thyroxine

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7
Q

What is a normal red cell lifespan?

A

120 days

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8
Q

Where does red cell breakdown occur?

A

Spleen

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9
Q

What are red cells broken down to?

A

Globin - amino acids

Haem - iron - recycled into haemoglobin, haem - billirubin

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10
Q

What happens to billirubin after red cell breakdown?

A

Binds to albumin in the plasma

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11
Q

Where can genetic effects cause congenital anaemia?

A

Red cell membrane
Metabolic pathways - enzymes
In haemoglobin

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12
Q

What maintains the shape of red cells?

A

Skeletal proteins in the membrane

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13
Q

What is the commonest red cell membrane disorder?

A

Hereditary spherocytosis

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14
Q

Is hereditary spherocytosis autosomal dominant or recessive?

A

Dominant

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15
Q

What is clinical presentation of congenital anaemias?

A

Anaemia
Jaundice (neonatal)
Spenomegaly
Pigment gallstones

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16
Q

How do we treat hereditary spherocytosis?

A

Folic acid
Transfusion
Spenectomy if severe anaemia

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17
Q

What are rarer membrane disorders?

A

Hereditary elliptocytosis
Hereditary pyropoikilocytosis
South east asian ovalocytosis

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18
Q

What pathways are important in red cells?

A

Glycolytic pathway

Pentose phosphate shunt

19
Q

What is the purpose of the pentose phosphate shunt?

A

Protection from oxidative damage

20
Q

What enzymes can be affected in red cells leading to anaemia?

A

Glucose-6-phosphate dehydrogenase

Pyruvate kinase

21
Q

What happens to the cell in the absence of glucose-6-phosphate dehydrogenase?

A

Cell is vulnerable to oxidative damage

22
Q

Why is G6PD deficiency common in malarial areas?

A

Provides protection from malaria

23
Q

How does G6PD deficiency present?

A

Variable degrees of anaemia
Neonatal jaundice
Splenomegaly
Pigment gallstones

24
Q

Does illness affect red cell production?

A

Yes

25
Q

What are triggers to haemolysis in G6PD deficiency?

A

Infection
Acute illness
Broad beans
Drugs

26
Q

What shifts the oxygen dissociation curve to the left?

A

Decrease pH
Increase in 2,3-diphosphoglycerate
Increase in temperature

27
Q

How many alpha and beta chains are in haemoglobin?

A

2 alpha

2 beta

28
Q

What happens to haemoglobin in the first year of life?

A

It is shifted from foetal haemoglobin to haemoglobin A by switching off gamma chains and switching on beta chains

29
Q

What is haemoglobinopathy?

A

Abnormality of haemoglobin synthesis

30
Q

What is reduced or absent globin chain prouction called?

A

Thalassaemia alpha or beta depending which chain is affected

31
Q

What is sickle cell disease?

A

Point mutation of the beta globin chain

32
Q

Is sickle cell disease autosomal recessive or dominant?

A

Recessive

33
Q

What will be seen under the microscope in a patient with sickle cell?

A

Some normal cells

Some sickle cells

34
Q

When do red cells sickle?

A

After deoxygenation

35
Q

What happens to blood vessels in sickle cell patients?

A

Vaso-occlusion

36
Q

What happens after haemolysis in sickle cell?

A

Endothelial activation
Promotion of inflammation
Coagulation activation
Dysregulation of vasomotor tone by vasodilator mediatiors

37
Q

What are systemic presentations of sickle cell?

A

Chest crisis
Stroke
Hyposplenism
Gallstones

38
Q

How is sickle cell managed?

A

Life long prophylaxis:
Vaccination
Penicillin and malarial prophylaxis
Folic acid

39
Q

How is acute event of sickle cell managed?

A
Hydration
Oxygenation
Prompt treatment of infection
Analgesia
Blood transfusion
40
Q

What are clinical features of beta thalassaemia major?

A
Severe anaemia
Present at 3-6 months of age
Expansion of ineffective marrow
Bony deformities
Splenomegaly
Growth retardation
41
Q

What is life expectancy for untreated beta thalassaemia major?

A

<10 years

42
Q

What are different types of thalassaemia?

A

Homozygous alpha zero thalassaemia
Beta thalassaemia major
Non-transfusion dependent thalassaemia
Thalassasaemia minor

43
Q

How is beta thalassaemia major treated?

A

Chronic transfusion 4-6 weekly
Watch for iron overload - will kill if untreated
Iron chelated - iron excreted

44
Q

What drugs can be used for iron chelation therapy?

A

Desferal

Exjade