Anaemia

Question 1

Blood components

Answer 1

Plasma = 55% 
Cells = 45%

Cells found in blood include erythrocytes, leukocytes and platelets

Question 2

Erythrocytes

Answer 2

7 microns in diameter

Biconcave discs with good plasticity

Question 3

Haemopoiesis

Answer 3

Haemopoiesis is the production of RBCs

It begins in the foetus in the yolk sac before moving to the liver and spleen

After birth, it occurs in the bone marrow

Question 4

Erythrocyte differentiation

Answer 4

RBCs differentiate from the myeloid lineage

They develop into an erythroblast and then eventually an erythocyte

Question 5

Erythropoiesis

Answer 5

Erythropoiesis is stimulated by erythropoietin, which is released from the liver

Iron, vitamin B12 and folic acid are also required

Question 6

Anaemia

Answer 6

Anaemia is characterised by a haemoglobin level lower than the reference range and a reduction in red cell mass

Question 7

Clinical features of anaemia

Answer 7

• Fatigue
• Headaches
• Faintness
• Tissue hypoxia

Question 8

Lab investigation of anaemia

Answer 8

A blood film can show anisocytosis (cell size variation), poikilocytosis (cell shape variation) and anisochromasis (haemoglobinisation variation)

A reduced erythrocyte count can also be seen

Question 9

Iron deficiency

Answer 9

The most common cause of anaemia

Cells will be microcytic and hypochromic

Causes = increased demand, blood loss, poor diet, malabsorption

Question 10

Iron deficiency treatment

Answer 10

Oral iron supplements

Question 11

Megaloblastic anaemia

Answer 11

Characterised by enlarged megaloblasts

Results in Howell-Jolly bodies

Causes = B12 deficiency, folate deficiency, DNA synthesis defects

Question 12

Anaemia of chronic diseases

Answer 12

Anaemia can also occur as a complication of chronic diseases such as microbial infections of immune disorders

Chronic inflammation causes release of hepcidin which limits iron release and erythropoietin production

Question 13

Treating anaemia of chronic diseases

Answer 13

Treating the underlying disease is the only cure

Patients may benefit from erythropoietin supplements

Question 14

Aplastic anaemia

Answer 14

Hypocellularity of the bone marrow

Causes = inherited disease, suppression of pluripotent stem cells (due to chemotherapy)

Question 15

Symptoms of aplastic anaemia

Answer 15

• Bruising
• Bleeding gums
• Epistaxis
• Mouth infections

Question 16

Treatment of aplastic anaemia

Answer 16

Withdrawal of causative agent

Infection control

Bone marrow transplant

Question 17

Sickle cell anaemia

Answer 17

Caused by a point mutation in the B-globin gene

The mutated haemoglobin is unstable and becomes crystalline leading to chronic haemolysis

Question 18

Treatment of sickle cell anaemia

Answer 18

Supportive therapies such as folic acid supplements can be helpful

Antibiotics and vaccines are important to prevent infections

Question 19

Thalassaemia

Answer 19

Caused by abnormalities in globin chain synthesis

Results in ineffective erythropoiesis leading to haemolysis

Question 20

G6P dehydrogenase deficiency

Answer 20

Affects the rate-controlling step of the pentose-phosphate pathway

Silent until a trigger is encountered (e.g. oxidant drugs)

Leads to haemolysis