Red Cells Flashcards

1
Q

What is anaemia?

A

Reduction in red cells or their haemoglobin content

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2
Q

What substances are required for red cell production?

A

Iron, copper, cobalt, manganese
B12, folic acid, thiamine
Amino acids
Erythropoietin, androgens, thyroxine, SCF

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3
Q

What is the typically lifespan of red blood cells?

A

120 days

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4
Q

What are red blood cells broken down into?

A

Globin

Haem > bilirubin

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5
Q

What is the function of skeletal proteins?

A

Maintain red cell shape and deformability

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6
Q

What can occur if there are skeletal protein defects?

A

Increased cell destruction

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7
Q

What structural proteins are defected in hereditary spherocytosis?

A
Ankyrin
Alpha Spectrin
Beta Spectrin
Band 3
Protein 4.2
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8
Q

What is the clinical presentation of hereditary spherocytosis?

A

Anaemia
Jaundice (neonatal)
Splenomegaly
Pigment gallstones

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9
Q

What is the treatment for hereditary spherocytosis?

A

Folic acid
Transfusion
Splenectomy

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10
Q

What is the function of the pentose phosphate shunt?

A

Protects from oxidative damage

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11
Q

What is the function of glucose 6 phosphate dehydrogenase?

A

Protects red cell proteins from oxidative damage

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12
Q

If G6PD deficiency is X linked, who is affected?

A

Affects males

Female carriers

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13
Q

What is the clinical presentation of G6PD deficiency?

A

Neonatal jaundice
Drug, broad bean or infection precipitated jaundice or anaemia
Splenomegaly
Pigment gallstones

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14
Q

What drugs can cause G6PD deficiency?

A
Antimalarials 
Sulphonamides and sulphones 
Antibacterials 
Analgesics 
Antihelminthics 
Vitamin K analogues
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15
Q

What occurs in pyruvate kinase deficiency?

A

Reduced ATP
Increased 2,3-DPG
Cells rigid

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16
Q

What is the clinical presentation of pyruvate kinase deficiency?

A

Anaemia
Jaundice
Gallstones

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17
Q

What is the basic function of haemoglobin?

A

Oxygen to tissues

Carbon dioxide to lungs

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18
Q

What is the composition of haemoglobin?

A

Haem molecule
2 alpha chains
2 beta chains

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19
Q

What is the composition of sickle haemoglobin?

A

Haem molecule
2 alpha chains
2 beta (sickle) chains

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20
Q

What are the consequences of HbS polymerisation?

A

Haemolysis, endothelial activation, promotion of inflammation, coagulation activation, vaso occlusion

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21
Q

What are the complications of sickle cell disease?

A

Acute chest syndrome
Stroke
Pain episodes attributed to vasoocclusive tissue damage

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22
Q

What is the clinical presentation of sickle cell disease?

A

Painful bone and chest vaso-occlusive crises
Stroke
Hyposplenism
Chronic haemolytic anaemia (gallstones, aplastic crises)
Spleen and liver sequestration crises

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23
Q

What is the management of a chest crises?

A
Respiratory support 
Antibiotics 
IV fluids 
Analgesia 
Transfusion
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24
Q

What is the clinical presentation of chest crises?

A

Chest pain
Fever
Worsening hypoxia
Infiltrates on CXR

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25
Q

What is the life long prophylaxis for sickle cell disease?

A

Vaccination
Penicillin (and malarial) prophylaxis
Folic acid

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26
Q

What is the treatment for acute events due to sickle cell disease?

A
Hydration 
Oxygenation 
Prompt treatment of infection 
Analgesia (opiates, NSAIDs) 
Blood transfusion 
Disease modifying drugs (hydroxycarbimide) 
Bone marrow transplantation 
Gene therapy
27
Q

What are thalassaemias?

A

Reduced or absent globin chain production

Mutation or deletion of alpha or beta genes

28
Q

What are the clinical features of beta thalassaemia major?

A
Present at 3-6 months of age 
Expansion of ineffective bone marrow 
Bony deformities 
Splenomegaly 
Growth retardation
29
Q

What is the treatment for beta thalassaemia major?

A

Chronic transfusion support 4-6 weekly
Iron chelation therapy (desferrioxamine infusions, oral deferasirox)
Bone marrow transplantation (curative)

30
Q

What causes sideroblastic anaemia?

A

Defects in mitochondrial steps of harm synthesis

31
Q

What factors influence the normal range of Hb?

A
Age
Sex 
Ethnic origin 
Time of day sample taken
Time to analysis
32
Q

What is the Hb reference range for males under 70?

A

140-180

33
Q

What is the Hb reference range for males over 70?

A

116-156

34
Q

What is the Hb reference range for females under 70?

A

120-160

35
Q

What is the Hb reference range for females over 70?

A

108-143

36
Q

What are the general clinical features of anaemia?

A
Tiredness 
Breathlessness 
Swelling of ankles 
Dizziness 
Chest pain
37
Q

What are the symptoms of anaemia with an underlying cause of bleeding?

A

Menorrhagia

Dyspepsia, PR bleeding

38
Q

What are the symptoms of anaemia related to malabsorption?

A

Diarrhoea

Weight loss

39
Q

What measurement are used when investigating red cells?

A

Mean cell volume (MCV)

Mean cell haemoglobin (MCH)

40
Q

Where is hepcidin produced and what is its function?

A

Made in hepatocytes

Blocks ferroportin, reducing intestinal iron absorption

41
Q

What are the clinical features of iron deficiency?

A

Koilonychia
Angular cheilitis
Atrophic tongue

42
Q

What are the causes of iron deficiency?

A

GI blood loss (worms)
Menorrhagia
Malabsorption (gastrectomy, coeliac disease)

43
Q

What is the treatment for iron deficiency anaemia?

A
Diet 
Ulcer therapy 
Surgery if bleeding 
Oral iron supplements
Transfusion
44
Q

What is a positive direct antiglobin test an indicator of?

A

Immune mediated haemolytic anaemia

45
Q

What is a negative direct antiglobin test an indicator of?

A

Non-immune mediated haemolytic anaemia

46
Q

What is the management of haemolytic anaemia?

A

Folic acid
Immunosuppression if autoimmune
Remove site of red cell destruction (splenectomy)
Treat sepsis, leaky prosthetic valve, malignancy if intravascular

47
Q

What are the causes of B12 deficiency?

A

Pernicious anaemia

Gastric/ileal disease

48
Q

What are the causes of folate deficiency?

A
Dietary 
Increased requirements (haemolysis) 
GI pathology (coeliac disease)
49
Q

What is the treatment for megaloblastic anaemia?

A

Replace vitamin
B12 IM injection
Oral folate replacement

50
Q

What are the other causes of macrocytosis?

A
Alcohol 
Drugs (methotrexate, ART, hydroxycarbamide) 
Disordered liver function 
Hypothyroidism 
Myelodysplasia
51
Q

What does the “Bohr effect” on an oxygen dissociation curve take into account?

A

Acidosis
Hyperthermia
Hypercapnia

52
Q

What is sickle cell?

A

Mutations leading to structurally abnormal global chain

53
Q

What is homozygous alpha zero thalassaemia?

A

No alpha chains

Hydrops fettles incompatible with life

54
Q

What is thalassaemia major?

A

No beta chains

Transfusion dependent anaemia

55
Q

What are the possibly morphological descriptions of cells within anaemia?

A

Hypochromic microcytic (little and pale cells)
Normochromic normocytic
Microcytic (big cells)

56
Q

What does serum ferritin indicate?

A

Measurement of the body’s iron stores

57
Q

What would a low serum ferritin indicate?

A

Iron deficiency anaemia

58
Q

What would a normal or increased serum ferritin indicate?

A

Thalassaemia
Secondary anaemia
Sideroblastic anaemia

59
Q

Where is ferritin mostly found?

A

Liver

60
Q

What are the investigations for iron deficiency anaemia?

A

Endoscopy

Barium studies

61
Q

What are the causes of haemolytic anaemia?

A
Hereditary spherocytosis (HS)
Enzyme deficiency (G6PD deficiency)
Haemoglobinopathy (HbSS)
Auto-immune haemolytic anaemia 
Mechanical eg.artificial valve
Severe infection                 
Drugs
62
Q

How would you know if a patient is haemolysing?

A

FBC, reticulocyte count, blood film
Serum bilirubin high, LDH high
Serum haptoglobin low

63
Q

What are the features of pernicious anaemia?

A

Antibodies against intrinsic factor and gastric parietal cells
Malabsorption of dietary B12