L4. Blood and Anaemia Flashcards Preview

02. Cardiovascular > L4. Blood and Anaemia > Flashcards

Flashcards in L4. Blood and Anaemia Deck (24):

What is blood made out of?

Cells (WBCs, RBCs, and platelets)
Fluid (plasma) and proteins


What are the different problems with RBCs?
Not enough, too much, dysfunctional

Not enough: anaemia
Too much: polycythemia
Dysfunctional: dyserythropoiesis


What are the different problems with WBCs?

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


What are the different problems with platelets?

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


What is anaemia?

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.


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

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

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


What are the causes of anaemia?

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


What are the clinical signs of anaemia?

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


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

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.


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

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


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

Morphology of cells and their size, shape and colour


What are the classifications of anaemia?

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


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

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)


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

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


Where does haemopoiesis occur?

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.


How does the bone marrow change over life?

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


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

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


How is the bone marrow stroma important to haemoapoesis?

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.


What is a left shift?

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


What are some haemopoetic growth factors?

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


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

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


How do haemopoetic growth factors mediate their effects?

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


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

Vitamin B12


What are each of the haematinics important for?

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