L4. Blood and Anaemia

Question 1

What is blood made out of?

Answer 1

Cells (WBCs, RBCs, and platelets)

Fluid (plasma) and proteins

Question 2

What are the different problems with RBCs?

Not enough, too much, dysfunctional

Answer 2

Not enough: anaemia
Too much: polycythemia
Dysfunctional: dyserythropoiesis

Question 3

What are the different problems with WBCs?

Answer 3

Not enough: leukopenia, neutropenia, lymphopenia
Too Much: Leukocytosis
Dysfunction: White cell defect

Question 4

What are the different problems with platelets?

Answer 4

Not enough: Thrombocytopenia
Too Many: Thrombocytosis
Dysfunctional: Platelet function defect

Question 5

What is anaemia?

Answer 5

Anaemia is the Hb level below what is required/normal for an age or gender. It can be due to a reduced RBCs, reduced Hb saturation.

Question 6

What is the equation/relationship that determines how much oxygen gets delivered to the tissue?

Answer 6

O2 delivery = CO x [Hb] x %O2 saturation x 1.34

Depends on the CO, the concentration of Hb and the saturation of Hb

Question 7

What are the causes of anaemia?

Answer 7

Failure of RBC production
Increased destruction or loss of RBCs and their function
Inappropriate production of RBCs

Question 8

What are the clinical signs of anaemia?

Answer 8

Pale, lethargic, failure to thrive, hypoxia (confusion and disorientation), ischemia (especially in focal areas) and tachycardia

Question 9

What is the difference in tachycardia for acute vs. chronic anaemic patients?

Answer 9

Acute anaemia/hypoxia patients (hypovolemia, haemorrhage) are likely to have high tachycardia to compensate for the loss of oxygen delivery/

Chronic anaemic patients are likely to have a compensated for tachycardia.

Question 10

What are the important components of FBE to look at when diagnosing anaemia? [9]

Answer 10

1. Hb: how much Hb is present in each L of blood (Normal = 120-140 g/L in adults)
2. RCC (4.5-5 x 10^12 per L)
3. Haematocrit (Hct): what proportion of blood is cellular and what is plasma
4. MCV: mean corpuscular volume (size of each cell)
   - microcytic vs. macrocytic
5. MCH: Hb/RCC whether normal cells are made or not
6. MCHC: quality control
7. RDW: Red cell distribution width (variation around the mean)
8. WCC: differential white cell counts

Question 11

What information can be obtained in a blood film for anaemia?

Answer 11

Morphology of cells and their size, shape and colour

Question 12

What are the classifications of anaemia?

Answer 12

Regenerative: blood loss or blood destruction (haemolysis)
Agenerative (RBCs not being made properly)

Micro, Normo or Macrocytic anaemia is a further breakdown of these classifications

Question 13

What are some signs for an increase in destruction of RBCs?

Answer 13

Jaundice: increased serum bilirubin by the breakdown of Hb
Increased haptoglobins
Increased LDH
Can also look for signs of increased production (compensatory): high reticulocytes and polychromasia (blue tinge of Hb production)

Question 14

What is the normal production of blood cells (and their turnover)?

Answer 14

RBCs: 3-5 x 10^12 /L of blood and are replaced very 120 days
WBCs: 2-6 x 10^9/L of blood replaced every 3-5 days
Platelets: 150-400 x10^9 /L and is replaced every 10 days

Question 15

Where does haemopoiesis occur?

Answer 15

Age dependent:
In development it occurs primarily in the yolk sac, after 6 weeks the primary site is in the liver and spleen utnil about 7 months where the bone marrow becomes the main source. With increasing age, the process condenses down to the axial skeleton (Sternum, skull, vertebrae and pelvis only].

In some situations, the liver and spleen can be re-recruited as a site for haemopoeisis.

Question 16

How does the bone marrow change over life?

Answer 16

It become progressively more fatty through life accumulating more fat cells and spaces and less capable of haemopoesis.

Question 17

What is the pluripotent stem cell and how is it involved in haemopoesis?

Answer 17

The pluripotent stem cell is capable of self renewal and differentiation into ALL haemopoetic cell lines.

They exist only in very small numbers in the bone marrow

Question 18

How is the bone marrow stroma important to haemoapoesis?

Answer 18

The stroma is the supportive cells of the bone marrow and provide as specific microenvironment for growth.
Attachment of the cells to the stroma provides certain markers and signals for the cell to progress onto different lineages and maturities.

Question 19

What is a left shift?

Answer 19

When premature cells are released into the peripheral blood suggesting some kind of challenge to the blood contents (eg. infection)

Question 20

What are some haemopoetic growth factors?

Answer 20

A variety of circulating factors that mediate through receptors that affect stages of cell maturation processes occur and when.

Question 21

What is meant by there is a redundancy between the haemopoetic growth factors?

Answer 21

Growth factors are involved in multiple effects on multiple different stages and these effects have great overlap.

Question 22

How do haemopoetic growth factors mediate their effects?

Answer 22

Through activation of transcription factors (Second messenger activity and signalling)

Question 23

What are the three major Haematinics that are required for the adequate production of RBCs?

Answer 23

Iron
Vitamin B12
Folate

Question 24

What are each of the haematinics important for?

Answer 24

Iron: The Iron Moeity is what carries the O2 in Hb
B12: Blood cell production (deficiency from poor diet, absorption and metabolism)
Folate: cell production