Week 1

Question 1

What are the 3 different mechanisms of action of Erythropoietin?

Answer 1

1. Early release of reticulocytes.
2. Inhibition of apoptosis
3. Reduce processing time of blood cells. (released faster)

Question 2

RBC’s consist of how many globin chains and how many pairs?

Answer 2

4 globin chains and 2 pairs.

Question 3

Each globin has how many heme groups?

Answer 3

1

Question 4

Does ferrous iron (Fe2+) combine irreversibly or reversibly with oxygen?

Answer 4

reversibly

Question 5

Majority of RBC natural death occurs in the ________.

Answer 5

Spleen - extravascular macrophage mediated haemolysis.

Question 6

When it comes to investigating haemolysis what are you looking for?

Answer 6

increased RBC destruction, increased RBC produciton, evidence of damaged RBC’s

Question 7

Where does Intravascular and extravascular haemolysis take place?

Answer 7

Intravascular - within blood vessels

Extravascular - outside the blood vessels

Question 8

Haemoglobinaemia (increased plasma Hb) decreased haptoglobin, increase plasma bilirubin (unconjugated, haemoglobinuria, haemosiderinuria (iron in renal tubules) are all evidence of extravascular RBC destruction or intravascular RBC destruction?

Answer 8

Intravascular

Question 9

What is the normal way of removing majority of senescent RBC’s?

Answer 9

macrophage mediated (extravascular) haemolysis

Question 10

Increased extravascular destruction can happen when RBC’s have abnormal markers and are removed. What are 3 examples of abnormal markers on RBC’s?

Answer 10

heinz bodies
intracellular parasites
immunoglobulins

Question 11

What would be seen on a blood film if a macrophage ingested only part of RBC membrane?

Answer 11

Spherocyte - Remainder membrane seals gap with ↓ content

Question 12

Is this evidence of intravascular or extravascular RBC destruction? increased urobilinogen (urine), increased plasma bilirubin, increased stercobilinogen (faecal) decreased haptoglobin.

Answer 12

Extravascular

Question 13

What do intrinsic and extrinsic RBC defects refer to.

Answer 13

Intrinsic - in the RBC itself

Extrinsic - the environment surrounding the RBC

Question 14

Give 3 examples of intrinsic defects.

Answer 14

Membrane abnormalities (eg. spherocytosis)
Enzymopathies( G6PD deficiency)
haemoglobinopathies (sickle cell, thalassemias)

Question 15

What are some laboratory findings for hereditary spherocytosis?

Answer 15

Anaemia = yes normally
Retic = normally increased
MCV & MCH = normal
MCHC = increased
Blood film = spherocytes 
RDW= increased

Question 16

List 3 other tests to determine hereditary spherocytosis

Answer 16

1. DAT
2. Osmotic fragility test
3. Autohaemolysis test

Question 17

What does a neg DAT mean?

Answer 17

No Antibody/s bound to RBC

Question 18

What DAT result would you expect in a patient with hereditary spherocytosis?

Answer 18

Neg

Question 19

What does the DAT determine?

Answer 19

If RBC’s have been sensitised in vivo. Is there an antibody bound to the RBC

Question 20

Describe the osmotic fragility test.

Answer 20

RBC’s are added to increasing hypotonic NaCl solutions. H2O enters cell until equilibrium is achieved. Cell swells until membrane cannot withhold the pressure

Question 21

In the osmotic fragility test what would you expect a patient with hereditary spherocytosis to have?

Answer 21

RBC lysis beginning earlier in lower concentrations of the hypotonic NaCl solutions.

Question 22

Describe an autohaemolysis test.

Answer 22

RBC are incubated in own plasma. RBC’s lyse gradually. (5% after 48 hours) more if glucose is added

Question 23

What would the result of an autohaemolysis test be in a patient with hereditary spherocytosis?

Answer 23

haemolysis is much greater after 48hr (10-50% lysis)

Question 24

Is eliptocytosis and ovalocytosis more common in malria endemic areas?

Answer 24

Yes

Question 25

What are 2 most common enzymopathies?

Answer 25

G6PD - deficiency | Pyruvate Kinase deficieny.

Question 26

List three triggers of oxidative stress?

Answer 26

1. Infection (most common) 2. Some drugs 3. Fava beans

Question 27

What are Heinz bodies and how do you visualise Heinz bodies?

Answer 27

Denatured Hb seen with a supravital stain eg. crystal violet

Question 28

Haemoglobinopathies are all due to mutations in what?

Answer 28

Gene mutation

Question 29

Haemoglobinopathy that has a structural defect is

Answer 29

Sickle cell disease = quality of Hb

Question 30

Haemoglobinopathy that has a reduced rate of synthesis

Answer 30

Thalassemia = defect in quantity

Question 31

Describe why a patient with sickle cell disease might experience joint pain

Answer 31

Sickle RBC's are less soluble & less deformable, more fragile, leads to haemolysis, leads to vessel occlusion leading to infarct. Increase susceptibility to infection.

Question 32

List other screening tests for sickle cell disease.

Answer 32

1. Hb electrophoresis | 2. Haemoglobin solubility test

Question 33

What would be the difference between sickle cell trait and sickle cell anemia on an electrophoresis test?

Answer 33

Sickle cell anemia would be all HbS. Sickle cell trait would HbS plus another Hb beta chain.

Question 34

What is the most severe form of Thalassemia?

Answer 34

Beta thal major

Question 35

Would the MCV be low or high in a patient with Thalassemia?

Answer 35

Low

Question 36

Blood film of a patient with thalassemia could include.

Answer 36

``` Target Cells Elliptocytes other poikilocytes basophilic stippling nucleated RBC (major thal) ```

Question 37

Alloantibodies means

Answer 37

Antibodies to foreign

Question 38

Autoantibodies means

Answer 38

Antibodies to self

Question 39

Besides malaria what are some other causes of non-immune RBC haemolysis?

Answer 39

Drugs, chemicals, venoms, burns

Question 40

What are the two types of Auto antibody?

Answer 40

``` Warm autoimmune (most common) Cold agglutinins ```

Question 41

WARM AUTOimmune Haemolytic Anaemia (WAIHA) is what Ig class?

Answer 41

IgG

Question 42

Normal age group for WARM AUTOimmune Haemolytic Anaemia (WAIHA) is

Answer 42

under 4 and over 40

Question 43

What is the Ig class for COLD Agglutinin Disease (CAD)

Answer 43

IgM (4 degrees optimal)

Question 44

What can be a source of foreign Ag to cause ALLO immune Haemolytic Anaemia?

Answer 44

Blood transfusions

Question 45

How is Drug-Induced Immune Haemolytic Anaemia different to drug-induced haemolytic Anaemia?

Answer 45

in DIIHA drug us absorb to the RBC = immune complex - Ab is porduce against it - DAT will be positive

Question 46

List 3 conditions with small RBC's and briefly discuss why the RBC's are smaller

Answer 46

Thalassemia minor - reduced synthesis of the globin chain of hemoglobin iron deficiency - disruption of iron supply Sideroblastic anemia

Question 47

List 3 conditions with large RBC's and briefly discuss why the RBC's are larger

Answer 47

Megaloblastic anaemia Alcoholism Pernicious anaemia

Question 48

What is the most common cause of microcytic anemia?

Answer 48

iron deficiency