Lecture 7- Anaemia

Question 1

What are the two general causes of anaemia?

Answer 1

Problems with RBC production and loss or premature removal of RBCs

Question 2

What is anaemia?

Answer 2

Haemoglobin below the reference range for the normal population

Question 3

What are the sins and symptoms of anaemia?

Answer 3

Tachycardia, hypotension, tachypnoea, pallor (paleness), shortness of breath and tiredness, headache and cardiac failure

Question 4

What removes red blood cells?

Answer 4

The reticuloendothelial system

Question 5

Why might anaemia develop?

Answer 5

Enzymes for cellular metabolism may be absent which leads to deformed cells and increased removal rates. This can cause the spleen to enlarge and cells can subsequently pool in the spleen and more are removed.

Reduced erythropoiesis

Bleeding etc

Question 6

How is erythropoeisis controlled?

Answer 6

Low levels of O2 detected in interstitial peritubular cells of the kidney. erythropoietin production is increased and so RBCs are matured and released from the bone marrow. Increased O2 concentration means erythropoietin production will cease. Negative feedback loop

Question 7

What can cause reduced erythropoiesis?

Answer 7

Chronic kidney disease

Empty bone marrow eg after chemo or aplastic anaemia

Marrow infiltrated with cancer cells or fibrous tissue (myelofibrosis)

Question 8

What is aplastic anaemia?

Answer 8

A rare condition where bone marrow and haematopoeitic stem cells are damaged

Question 9

What is dyserythropoeisis?

Answer 9

Defective development of RBCs, not enough getting produced

Question 10

What causes dyserythropoiesis?

Answer 10

Myelodysplastic syndrome where genetic changes in. Cells means marrow will not allow them into circulation

Anaemia of inflammation or chronic disease where iron not made available to bone marrow, RBC lifespan reduction and marrow doesnt respond to erythropoeitin. Often indicated by raised ferritin and CRP

Question 11

What is megaloblastic anaemia?

Answer 11

Anaemia caused by inhibition of the production of DNA during RBC synthesis

Question 12

What defects in Hb synthesis are there?

Answer 12

Lack of iron due to chronic disease or iron deficiency

Lack of B12 or folate

Mutations in proteins encoding globin chains eg thalassaemia and sickle cell

Question 13

What are the effects of defects in RBC membrane structure?

Answer 13

Spherocytosis, eliptocytosisand pyropoikilocytosis

Cells more easily damaged and so removed by spleen

Question 14

How can RBC membranes get damaged?

Answer 14

Mechanical (heart valves, vasculitis, DIC etc)

Heat

Osmotic

Question 15

What is vasculitis?

Answer 15

Group of disorders that destroys blood vessels by inflammation

Question 16

What is DIC?

Answer 16

Disseminated intravascular coagulopathy where small blood clots form in vessels and use up clotting factors and platelets which can lead to excessive bleeding

Question 17

Effects of defects in cell metabolism?

Answer 17

No energy to maintain membrane and keep iron in reduced state

Question 18

What is autoimmune haemolytic anaemia?

Answer 18

Autoantibodies produced against RBC which attach and remove cell from circulation

Question 19

What is myelofibrosis?

Answer 19

Bone marrow becomes fibrotic which reduces erythropoeisis. It occurs in spleen and so it enlarges and cells pool in it

Question 20

What blood tests can you use to evaluate anaemia?

Answer 20

Reticulocyte count and MCV

Question 21

How is anaemia evaluated?

Answer 21

Mechanism of anaemia

By size- microcytic, microcytic, normacytic

By presence or absence of reticulocytosis

Question 22

What is hypochromic anaemia?

Answer 22

One in which RBCs are paler and have less haemoglobin

Question 23

What causes microcytic anaemia with low reticulocytes?

Answer 23

Iron deficiency

Gi/ mentrual bleeding

Question 24

Normacytic anaemia with low reticulocyte count?

Answer 24

Kidney disease

anaemia of chronic disease

Rheumatoid arthritis

Combined lack of iron and B12 which leaves big and small cells which balance to give average MCV

Question 25

What causes macrocytic anaemia with low reticulocyte count?

Answer 25

Can be megaloblastic where deficiency in vitamin B12 and folate is the cause

Can be caused by chronic liver disease and hypothyroidism

Question 26

What indicators are there of haemolysis?

Answer 26

High LDH (lactate dehydrogenase) and high bilirubin

Question 27

What causes anaemia with reticulocytosis?

Answer 27

Bone marrow not affected

Acute blood loss
Sequestration of cells in spleen

Haemolysis which can be immune or can be mechanical eg heart valves

Question 28

Anaemia with low reticulocyte count?

Answer 28

TAILS

Thalassaemia
Anaemia of chronic disease 
Iron deficiency 
Lead poisoning 
Sideroblastic anaemia

Question 29

What is megaloblastic anaemia?

Answer 29

Most common cause of microcytic anaemia with low reticulocytes. Caused by deficiency in B12 and folate

Question 30

What to look out for with megaloblastic anaemia?

Answer 30

It can occur very slowly as body stores of B12 normally insufficient for a few years. Heart will speed up and compensate over time for the anaemia.

Folate stores last a few months so deficiency will occur first .

B12 is required to convert folate to its active form

Question 31

What is pernicious anaemia?

Answer 31

Autoimmune form of anaemia where not enough parietal cells and so B12 not absorbed properly due to lack of intrinsic factor

Question 32

What can cause folate deficiency?

Answer 32

Dietary

Disease of duodenum and jejunum

Increased use in pregnancy and haemolytic anaemia

Certain drugs

Question 33

How to investigate megaloblastic anaemia?

Answer 33

Will get low Hb
High MCV
High LDH and Bilirubin due to haemolysis
Check for B12 and folate levels
Check for anti intrinsic factor antibodies

Question 34

How to treat B12 and folate deficiency?

Answer 34

Give oral supplements

If pernicious anaemia is the cause then inject B12 every 3 months.

With treatment anaemia should resolve itself after two months