Red Cells 1

Question 1

What is anaemia?

Answer 1

Reduction in red cells or their haemoglobin content

Question 2

Substances required for red cell production

Answer 2

Metals:IRON, copper, cobalt, manganese
Vitamins: B12, FOLIC ACID, thiamine, vit B6
Amino acids
Hormones: ERYTHROPOIETIN, androgens, thyroxine

Question 3

Describe red cell breakdown

Answer 3

Occurs in reticuloendothelial system

After 120 days rbc broke down into:

• Globin (amino acids reused)
• Haem (iron recycled into haemoglobin, haem converted into bilirubin)

Question 4

What are the main components of a mature red blood cells

Answer 4

Membrane filled with enzymes and haemoglobin

Question 5

Examples of congenital anaemia?

Answer 5

Hereditary Spherocytosis
G6PD deficiency
Thalassemia,
Sickle Cell disease

Question 6

What type of inheritance is hereditary spherpcytosis

Answer 6

Autosomal dominant

Question 7

What structural proteins in red cell membrane does hereditary spherocytosis affect

Answer 7

Ankyrin, 
Alpha spectrin, 
Beta specctrin, 
Band 3, 
Protein 4.2

Question 8

What shape are hereditary spherocytosis red blood cells

Answer 8

Spherical

Question 9

What is the reticuloendothelial system

Answer 9

removes immune complexes from the circulation

Includes:
monocytes of the blood,
macrophages in connective tissue, 
lymphoid organs, 
bone marrow, 
bone, 
liver, 
lung

Question 10

Clinical presentation of hereditary spherocytosis

Answer 10

Anaemia,
Jaundice,
Splenmegaly,
Pigment gallstones

Question 11

Treatment of hereditary spherocytosis

Answer 11

Folic acid,
Transfusion,
Splenectomy (if severe)

Question 12

Examples of some rare genetic anaemia membrane disorders

Answer 12

Hereditary elliptocytosis,
Hereditary pyropoikilocytosis,
South East Asian ovalocytosis

Question 13

What provides red cells with energy and protects from oxidative damage

Answer 13

Provides energy- glycolysis

Oxidative damage protection- pentose phosphate shunt (with G6PD enzyme)

Question 14

How does Glucose 6 phosphate dehydrogenase protect red cell proteins from oxidative damage

Answer 14

Produces NADPH

Which reduces glutathione (which scavenges and detoxifies reactive oxygen species)

Question 15

How is G6PD deficiency inherited

Answer 15

X-linked

Question 16

Pro and Con of G6PD deficiency

Answer 16

Pro- protects against malaria

Con- cells vulnerable to oxidative damage

Question 17

How do cells appear in G6PD deficiency

Answer 17

Blister cells

Bite cells

Question 18

Clinical presentation of G6PD deficiency

Answer 18

Variable degrees of anaemia
Neonatal jaundice
Splenomegaly
Pigment gallstones

Question 19

Triggers to haemolysis in G6PD deficiency

Answer 19

Infection,
Acute illness eg DKA
Broad (fava) beans
Drugs- antimalarials, sulphonamides and sulphones, antibacterials, analgesics (aspirin), antihelminthics (B-naphthol), miscellaneous (vitamin K analogues, probenecid, methylene blue)

Question 20

What is Pyruvate kinase deficiency

Answer 20

Reduced ATP and increased 2,3-DPG

Causes anaemia, jaundice, gallstones

Question 21

What is Haemoglobin made up of

Answer 21

2 alpha chains
2 beta chains
Iron,
Haem

Hb A (aaBB) 
Hb A2 (aadeltadelta)
Hb F (aayy)

Question 22

Function of haemoglobin function

Answer 22

Gas exchange:
-O2 to tissues,
CO2 to lungs

Oxygen dissociation curve:

• shifts as a compensatory mechanism
• “Bohr effects”
  
  • acidosis
  • hyperthermia
  • hypercapnia

Question 23

What are haemoglobinopathies

Answer 23

Inherited abnormalities of haemoglobin synthesis

Question 24

Examples of haemoglobinopathies

Answer 24

Thalassaemia

Sickle cell

Question 25

What is Thalassaemia

Answer 25

Reduced or absent globin chain production can be alpha thalassaemia (mutation/ deletion in alpha gene) Or beta thalassaemia (mutation/deletion in beta genes)

Question 26

What is sickle cell disease

Answer 26

Mutations leading to structurally abnormal globin chain Sickle haemoglobin composed of haem molecule and 2alpha chains, 2 beta (sickle) chains (due to point mutations)

Question 27

What kind of inheritance is thalassemia

Answer 27

Autosomal recessive

Question 28

Consequences of HbS polymerisation

Answer 28

Haemolysis leading to vaso-occlusion

Question 29

Sickle cell disease clinical presentation

Answer 29

``` Cerebral infarcts Retinopathy Cardiomegaly Congestive heart failure Cholelithiasis Renal infarcts- haematuria Pulmonary infarcts- pneumonia Splenomegaly Infarcts of extremities Vaso-occlusion Ulcer of leg Aseptic bone necrosis- osteomyelitis Bone marrow hyperplasia ```

Question 30

Complications of sickle cell disease

Answer 30

Painful vaso-occlusive crisis of bone Chest crisis Stroke Increased infection risk due to hyposplenism Chronic haemolytic anaemia (gallstones, aplastic crisis) Sequestration crisis

Question 31

Treatment of acute painful crisis

Answer 31

Opiates, Hydration, Oxygen, Consider antibiotics

Question 32

Management of sickle cell disease

Answer 32

Life long prophylaxis: - vaccination, - penicillin - folic acid Blood transfusion (alloimmunisation) Bone marrow transplantation Gene therapy

Question 33

Prognosis of homozygous alpha zero thalassaemia

Answer 33

Incomparable with life | Known as hydrops fetalis and there will be no alpha chains

Question 34

How severe is beta thalassaemia major

Answer 34

No beta chains present | Dependent on transfusion

Question 35

What is non-transfusion dependent thalassaemia

Answer 35

Range of genotypes | Unlike beta thalassaemia major there is no dependence on transfusion

Question 36

What is thalassaemia minor

Answer 36

“Trait” or carrier state | Hypochromic microcytic red cell indices

Question 37

What is beta thalassaemia major

Answer 37

``` Severe anaemia Presents at 3-6 months Expansion of ineffective bone marrow Bony deformities Splenomegaly Growth retardation ```

Question 38

What is the life expectancy of someone with beta thalassaemia major without regular transfusions

Answer 38

<10 years

Question 39

Beta thalassaemia major treatment

Answer 39

Chronic transfusion support every 4-6 weeks However this causes iron overloading so this needs treated - iron chelation therapy (s/c desferrioxamine or oral deferasirox) Bone marrow transplants

Question 40

What is monitored in someone with beta thalassaemia major

Answer 40

Ferritin levels MRI scans To ensure normal life expectancy