RBC disorders

Question 1

blood composition

Answer 1

55% plasma, 40% cells,

Question 2

reticulocytes

Answer 2

newly formed red blood cells

Question 3

haemopoiesis

Answer 3

formation of new blood cells

Question 4

process of haemopoiesis

Answer 4

starts in yolk sac, then liver and spleen, then bone marrow

Question 5

extramedulla

Answer 5

outside of the bone marrow

Question 6

erythropoiesis

Answer 6

formation of red blood cells

Question 7

what is the earliest cell type in erythropoiesis to recognise?

Answer 7

normoblast

Question 8

essential dietary constituents of erythropoiesis

Answer 8

iron, vit B12, folic acid

Question 9

anaemia

Answer 9

deficiency of red blood cells

Question 10

what are the Three major types of anaemia

Answer 10

• hypochromic microcytic with a low MCV (Fe deficiency)
• normochromic normocytic with a normal MCV
• macrocytic with a high MCV (megaloblastic)

Question 11

Pathological consequences of anaemia

Answer 11

tissue hypoxia

Question 12

signs and symptoms of anaemia

Answer 12

fatigue
headaches
faintness
pallor (conjunctiva)

Question 13

Laboratory investigations for anaemia

Answer 13

decreased RBC count, haemoglobin and packed cell volume. abnormal blood film

Question 14

blood film features in anaemic samples

Answer 14

− Anisocytosis: variation in size
− Poikilocytosis: variation in shape
− Anisochromasia: variation in haemoglobinisation

Question 15

causes of anaemia

Answer 15

Suppressed proliferation
 e.g. aplastic bone marrow
Defective maturation
 e.g. haematinic deficiency
increased destruction
e.g. haemorrhage, haemolysis
increased reticulocytes

Question 16

Mechanisms of Fe deficiency

Answer 16

• Increased demands
• Chronic blood loss
• Poor diet
• Malabsorption

Question 17

megaloblasts

Answer 17

erythrocytes with delayed nucleus maturation

Question 18

how to detect Fe deficiency using microscopy

Answer 18

doesn’t stain as darkly

Question 19

howell-jolly bodies

Answer 19

nucleated RBCs

Question 20

causes of Megaloblastic Anaemia

Answer 20

Deficiency of B12 and folate
Abnormal metabolism of B12 and folate
Other defects of DNA synthesis

Question 21

why is vit B12 and folate importnat?

Answer 21

needed for methylation of uridine into thymine

Question 22

Associated chronic diseases of anaemia

Answer 22

− Chronic microbial infections (e.g. osteomyelitis)
− Chronic immune disorders (e.g. rheumatoid arthritis)
− Neoplasm (e.g. Hodgkin’s lymphoma, lung carcinoma)

Question 23

treatment of chronic anaemia

Answer 23

treat underlying condition and give erythropoietin

Question 24

Aplastic anaemia

Answer 24

pancytopenia with hypocellularity of bone marrow - lacks many other blood cells types as well

Question 25

Major causes of aplastic anaemia

Answer 25

idiopathic, chemical agents (used in chemotherapy, cytotoxic antibiotics), physical agents, viral infections

Question 26

signs of aplastic anaemia

Answer 26

− Bruising, bleeding gums and epistaxis | − Mouth infection

Question 27

Bone marrow examination of aplastic anaemia

Answer 27

hypocellular marrow with increased fat spaces

Question 28

causes of haemoglobin abnormalities

Answer 28

Mostly caused by single point mutation of subunit Abnormal globin chain structure Imbalanced globin chain production

Question 29

sickle cell disease cause

Answer 29

single base pair mutation (A becomes T meaning Glu becomes Val) that leads to abnormal beta globin chains - inherited HbS variant

Question 30

cause of Thalassaemias

Answer 30

abnormalities of globin chain (a or b) synthesis

Question 31

Thalassaemias diagnosed by...

Answer 31

haemoglobin electrophoresis

Question 32

Red cell enzyme

Answer 32

Glucose-6-phosphate dehydrogenase | G6PD

Question 33

Glucose-6-phosphate dehydrogenase importance

Answer 33

vital in hexose monophosphate shunt - maintains glutathione in a reduced state to protect against oxidant injury

Question 34

cause of Glucose-6-phosphate dehydrogenase deficiency

Answer 34

X linked condition that leads to a single amino acid substitution

Question 35

Glucose-6-phosphate dehydrogenase deficiency laboratory investigations

Answer 35

bite cells and blister cells in blood film, increased bilirubin

Question 36

bite cells vs blister cells

Answer 36

bite - oxidised, some parts taken away | blister - some parts beginning to repair