Topic 18 - Anaemias and Blood Transfusion

Question 1

Why is it important to know and recognise anaemia in dentistry?

Answer 1

• Can recognise oral symptoms of anaemia and contribute to diagnosis
• If patient has low platelets as part of their anaemia, can give them some platelets before MOS or extraction to minimise risk of blood loss.

Question 2

Where are blood cells made?

Answer 2

Bone marrow

Question 3

Define anaemia

Answer 3

Reduction in Haemoglobin concentration in the blood

Question 4

What demographic information does Hb levels depend on?

Why should you have this info to hand?

Answer 4

Gender and ethnicity

Should know it when analysing lab results to see what the normal range is

Question 5

What is the normal conc. of Hb in males and females?

Answer 5

135-180g/L for males, and 115-155g/L for females

Question 6

Is it normal for Hb levels to ever drop?

Answer 6

Yes, when patients become elderly but this is normal - as long as pt isn’t symptomatic you don’t need to treat it at the end of life

Question 7

What is the structure of a haemoglobin molecule?

Answer 7

It consists of the Haem or iron group, and also proteins called globins. It can bind to oxygen or CO2 in the blood.

Question 8

Why is it important to find out the cause of anaemia before treating it?

Answer 8

Have to identify the cause. If you just supplement with iron but actually the patient is anaemic because they were losing blood in their faeces occulty due to bowel cancer, you’d miss the fact that they had cancer.

Question 9

What are the main causes of anaemia?

Answer 9

• Blood loss. Could be because of occult bleeding (bowel cancer) or trauma, injury leading to blood loss and therefore anaemia. In acute setting, just treat the anaemia. If chronic, investigate to find out the cause.
• Iron deficiency - either nutritional deficiency or females with heavy menstrual losses.
• Impaired synthesis - the bone marrow doesn’t produce enough blood cells which can result in aplastic anaemia which can be fatal.
• Increased destruction or haemolysis. This can be intravascular or extravascular.

Question 10

What investigations can we carry out for anaemia?

Answer 10

FBC - full blood count. Looks at no. of Hb, platelet cells, RBC, and WBC differential (proportion of each type of WBC in the peripheral blood).

Peripheral blood film - not done in all anaemias unless required. They take a smear of blood and look down the microscope at the actual morphology of the cells.

Question 11

What does ‘cytic’ mean?

Answer 11

Size of the RBC. Can be too small, normal, or too large.

Question 12

What does ‘chromic’ mean and what does it indicate?

What does a pale colour mean?

Answer 12

Colouration - how dense a RBC is so how much Hb it has.
Pale (hypochromic) suggests there’s not a low Hb count.
Normochromic suggests Hb unaffected.

Question 13

What are the three classes of anaemia?

Answer 13

1. Hypochromic microcytic
2. Macrocytic
3. Normochromic microcytic

Question 14

Which is the most common type of anaemia?

Answer 14

Hypochromic microcytic - where there’s a reduction in Hb count and also in size of RBC.

Question 15

What is the cause of hypochromic microcytic anaemia and how is this cause caused?

Answer 15

Iron deficiency or thalassemia.

Iron is a rate limiting step for production of RBC - without it, not enough will be made in the bone marrow.

Causes of iron deficiency:

• Not obtaining enough from diet. Iron is obtained from diet like offal, yolks, legumes, fortified cereals etc. It’s more readily absorbed from meat diets - with plant based diets, add vitamin C.
• Drinking tea prevents absorption of iron.
• Menstrual losses and pregnancy. These women need more iron.
• Those who are bleeding and therefore losing iron, like PUD, bowel cancer.
• Bowel may not absorb iron due to the disease going on in the gut wall during Coeliac disease and Chron’s disease.

Question 16

How does hypochromic microcytic anaemia present?

Answer 16

Breathlessness on exertion, fatigue, pallor, angular cheilitis, glossitis.

Question 17

What treatment options are there for hypochromic microcytic anaemia?

Answer 17

• Firstly rule out cancer. Then prescribe oral iron tablets. These are not always well tolerated and can cause constipation.
• If so, i.v. iron administered
• Blood transfusions not typically administered for this stage of diagnosis - only when pt is rapidly bleeding.

Question 18

What is the cause of macrocytic anaemia?

Answer 18

B12, folate deficiency or chronic alcohol dependency.

Folate is a requirement for the synthesis of DNA bases purine and pyrimidine, and B12 is required for folate utilisation. With lower numbers of these, there’s an impairment in DNA synthesis which results in altered morphology of RBC.

Alcohol causes macrocytic anaemia as diet is replaced by alcohol.

Question 19

Where is folate and b12 found?

Answer 19

Folate is found in green leafy vegetables, fruit, fortified cereals, alternative milks etc.

b12 is found in animal sources only as it’s produced by bacteria on the surfaces of animals.

Question 20

How does macrocytic anaemia present?

Answer 20

Dizziness, breathlessness on exertion, pallor, fatigue
angular cheilitis and glossitis,
and especially here, where there’s burning mouth syndrome, oral aphthous stomatitis, dysphasia etc.

Question 21

What treatment is there for macrocytic anaemia?

Answer 21

Supplementation for at least 3 months and diet modification

Question 22

What are the RBCs like in normochromic normocytic anaemia?

What causes it?

Answer 22

They’re normal but there’s not enough of them.

Caused by mixed b12, folate and iron deficiency.

Question 23

How can you diagnose normochromic normocytic anaemia?

Answer 23

Don’t just ask for FBC, get haematinics too so that you can see levels of iron, b12 and folate in the blood.

Question 24

Who can typically get normochromic normocytic anaemia?

Answer 24

It’s termed the anaemia of chronic diseases. E.g. in rheumatology this is the anaemia that those with rheumatoid arthritis typically get

Question 25

Can you list two positives and four negatives of blood transfusion?

Answer 25

PROS:

• Allowed many surgical procedures to be done
• Can treat sequelae of anaemia

CONS:

• Donor pool falling
• Expensive
• Justified safety concerns
• Poorly evidence based

Question 26

What can you harvest from a blood donation?

Answer 26

The blood is fractionated into diff components e.g. RBC, platelets, plasma. These can all be used in diff patients.

Question 27

There are many blood types. Which classification system do we concern ourselves with?

Answer 27

ABO and Rhesus systems

Question 28

Why is it important to match ABO in patients (donor and recipient)?

Answer 28

To prevent haemolytic transfusion reactions from occurring which can be fatal.

Question 29

What problem can a pregnant woman have if given a transfusion?

Answer 29

If there’s mismatched Resus classification, then while delivering there can be haemolytic transfusion which is problematic.

Question 30

What safety concerns are there with transfusions?

Answer 30

HIV hepatitis transmission etc - isn’t much of a risk at all.

Haemolytic transfusion reaction due to mismatching of blood group is more of a safety concern. Transfusions shouldn’t be done unless required and it should be done in hospital where there’s resus equipment is patient does have a haemolytic transfusion reaction.

Question 31

How can you prevent haemolytic transfusions occurring?

Answer 31

They’re normally caused by human error. Stringent safety check are used. Don’t do transfusions unless necessary.

Question 32

What dental consideration can be given to chronic anaemic patients?

Answer 32

If they need extraction or XLA or something, refer to hospital where they can be treated with haematology team too. This can prevent blood loss or bleeding after XLA and for patient to remain safe