L7 - Intro To Anaemia

Question 1

What is anaemia?

Answer 1

Haemoglobin below the reference range for the normal population

CORRECT ANSWER

Question 2

What are some symptoms of anaemia the patient may recognise

Answer 2

Shortness of breath/fatigue/palpitations/headache/cardiac failure

Question 3

Upon examination of an anaemia patients what signs may we see suggesting anaemia

Answer 3

Pallor , tachycardia, breathlessness, hypotension

Question 4

One way in which anaemia can ensure is through reduced erythropoiesis (dyserythropoiesis). eryhtropoiesis (production of RBC’s) is stimulated by what hormone?

Answer 4

Erythropoietin

Question 5

How is erythropoiesis stimulated in detail?

Answer 5

Reduced pO2 senses by the kidney -> increase in erythropoietin production by kidney -> hormone stimulates red marrow to increase no of red cells -> increases oxygen delivery -> feedback loop causes erythropoietin levels to fall

Question 6

Name three problems which can cause reduced erythropoiesis

Answer 6

1) Kidney stops making erythropoietin - chronic kidney disease
2) ‘empty bone marrow’ - lack of haemopoietic cells in the marrow to respond to EPO - aplastic anaemia
3) marrow infiltrated by cancer cells or fibrous tissue thus reducing the normal amount of haemopoietic cells - myelofibrosis

Question 7

What clinical tests point to dyserythropoiesis (defective development of RBC’s)?

Answer 7

Increased CRP and ferritin/marrow shows no response to EPO

Question 8

What is happening in anaemia of chronic disease (ACD)

Answer 8

1) iron is not being released by recycling macrophages for use by the bone marrow
2) RBC life span is reduced
3) marrow shows a lack of response to EPO

Question 9

Defects in haemoglobin synthesis can also cause anaemia. What anaemia involves

a) a functional lack of iron
b) lack of folate (B12)
c) mutations in proteins encoding the globin chains

Answer 9

a) anaemia of chronic disease
b) megaloblastic anaemia
c) thalassaemia/sickle cell disease

Question 10

How can defects in RBC membranes cause anaemia (haemolytic anaemias - reduced RBC lifespan)?

Answer 10

The cells are more flexible and are damaged more easily -> they break up in the circulation and are then removed by the RES in the spleen

Question 11

Give a hereditary and an acquire cause of damage to RBC membrane structure

Answer 11

Hereditary - hereditary spherocytosis/eliptocytosis/pyropoikilocytosis

Acquired - heart valves/DIC/burns/vascular is

Question 12

Also anaemia can be the result of defects in the enzymes of RBC metabolism. Give an example

Answer 12

Glucose-6-phosphate dehydrogenase

Pyruvate kinase deficiency

Question 13

In haemolytic anaemias RBC’s are destroyed more quickly than they are absorbed because they are damaged or defective. What disease do cells in the RES recognise autoantibodies on the bodies RBC membranes?

Answer 13

Autoimmune haemolytic anaemia

Question 14

In anaemia a reticulocytosis suggests what is working adequately?

Answer 14

The bone marrow

Question 15

If there is a reticulocytosis in an anaemic patient we then must see if there is evidence of haemolysis and then work out the cause of that. If there is not haemolysis, what is the likely cause of the problem?

Answer 15

A bleed

Question 16

If see a low reticulocytosis count in a potentially anaemic patient, The next step is to evaluate the Mean cell volume - low = microcytic/ normal = normocytic and high = macrocyclic. What are the 5 diseases associated with a microcytic anaemia with a low retic count

Answer 16

Thalasseamia trait
Anaemia of chronic disease (though this is normally normocytic)
Iron deficiency 
Lead poisoning
Sideroblastic anaemia 

TAILS mnemonic

Question 17

Give an example of some of the important diseases associated with

a) macrocytic anaemia with low retic count
b) normocytic anemia with low retic count

Answer 17

a) vitamin b12 deficiency/ folate deficiency/alcoholism/myelodysplasia
b) anaemia of chronic disease/HIV/aplastic anaemia

Question 18

Vitamin B12 and/or folate deficiency cause a deficiency in the building blocks for DNA, what kind of anaemia does this cause and what class of anaemia would this be?

Answer 18

Megaloblastic anaemia - macrocytic anaemia

Question 19

What are deficiencies in iron/b12 or folate called?

Answer 19

Haematinic deficiencies

Question 20

What does B12 bind in the small intestine that is necessary for its absorption in the terminal ileum?

Answer 20

Intrinsic factor

Question 21

List two causes of low vitamin B12 (B12 is rich in animal products)

Answer 21

Dietary deficiency - commonly vegans or poor diet
pernicious anaemia - Lack of intrinsic factor
Ileum diseases e.g. crohns disease
Congenital deficiency of transcobalamin

Question 22

Give two example of how a patient would get a folate deficiency

Answer 22

Poor diet (leafy greens are a good source of folate)
Pregnancy/haemolytic anaemia (increased use of folate)
Crohns

Question 23

Why are vb12 and folate dependent on one another?

Answer 23

Folate requires b12 to be in its active form

Question 24

Megaloblastic anaemia is characterised by macrocytic red cells with abnormally large nuclei and open chromatin. Explain the pathogenesis behind this

Answer 24

B12 and folate are necessary for thymine production this a deficiency cause a thymine deficiency. Uracil is incorporated instead, detected as error and DNA destroyed -> normal cytoplasm, no loss of nucleus and large nucleus forms

Question 25

Name three features on a megaloblastic anaemic blood film

Answer 25

Macrocytic RBC’s
Anisopoikilocytosis with tear drops
Hypersegmented neutrophils
Can see white cell precursors

Eventually causes a pancytopenia

Question 26

What would we see clinically in a FBC of a megaloblastic anaemic patient?

Answer 26

Low Hb
High MCV (macrocytic)
High bilirubin and LDH (both increased in increased cell destruction)
Low B12/folate 
Blood film has megaloblastic features

Question 27

What is the treatment for
a) folate deficiency
b) b12 deficiency
What

Answer 27

A) oral folic acid

B) Intramuscular b12 in pernicious anaemia (autoantibodies)

Question 28

Patients with vitamin b12 deficiency get it over a long time cos we have big stores of it. Thus transfusion of b12 in those patients we need to be careful of why?

Answer 28

Cos it can cause cardiac failures

Question 29

what triggers the release of eryhtropoietin?

Answer 29

Reduced pO2 detected at the kidney -> release of EPO -> stimulates the bone marrow to increase production of RBC’s -> more oxygen delivered -> feedback loop turns off EPO.

Question 30

When might we see tear drop RBC’s?

Answer 30

Vitamin B12/folate deficiency or myelofibrosis (fibrotic marrow)

Question 31

Vitamin B12 is required for folic acid to be converted to its active form in the body. Vitamin B12 binds haptocorrin in the salivary glands. This complex then travels to the terminal ileum where it binds intrinsic factor -> haptocorrin released. Complex internalised T/F

Answer 31

`T

Question 32

Be able to recognise a megaloblastic anaemia on a blood film. B12 and folate deficienct cause a defect in DNA development. The red cells have very large nucleia and open chromatin, is this a microcytic, normocytic or macrocytic anaemia? What other features might we see on a megaloblastic anaemia blood iflm

Answer 32

Macrocytic

tear drop cells/hypersegmented neutrophils/presence of white cell precursors/

Question 33

What are some problems with a) long term untreated b12 deficiency b) long term untreated B12/folate deficiency
c) folate deficiency in pregnancy

Answer 33

a) demyelination
b) neurological disease
c) neural tube defects