Haematology Flashcards Preview

MED 2042 Wks 1-5 > Haematology > Flashcards

Flashcards in Haematology Deck (36)
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1

red cell structure and function:
haemaglobin breakdown

broken into haem and globin
haem becomes bilinogen and excreted in faeces/urine
globin becomes aa
the iron from haem gets transported via transferrin and stored in bone marrow/recycled

2

haemophillia A

deficiency of F8

3

haemophillia B

deficiency of F9

4

universal recipient

AB+ (cos it has the antigen of everything)

5

universal donor

O- (cos it does not have the antigen of anything)

6

O type RBCS

universal donor for giving cells

7

AB type plasma

universal donor for giving serum- in an emergency if need to give plasma, give AB plasma

8

AB type blood

universal recipient

9

What happens when antibodies meet the antigen?

IgM antibodies fix complement -> permeabilises RBC membrane -> intravascular haemolysis.

10

ABO blood system

Body naturally makes antibodies against antigens it doesn’t have
Antibodies are type IgM
A, B, O antigen is an oligosaccharide (sugar)
Anti A, B, O antibodies cant cross the placenta

11

Rhesus blood system

Body doesn’t naturally make antibodies against antigen it doesn’t have- must need exposure eg a wrong transfusion-befor body makes antibodies
Antibodies are type IgG
D antigen is a PROTEIN
Anti-D antibody can cross the placenta and cause HDN

12

blood grouping:
forward group

• pt’s red cells are tested with antibodies.

• If pt has either A, B or D antigen, the antibodies will bind to the antigens –causing agglutination

13

blood grouping:
In the Backward group:

• Mix pts serum with A, B and AB cells

• If pt has either A antibody, B antibody or both, it will bind to the A, B or AB cells and cause agglutination.

14

Indications for Red cell transfusion

If pts haemoglobin level was less than 70 g

But if no symptoms then u might not need transfuion

70-100 appropriate with ongoing blood loss
100- unlikely to be appropriate

15

FFP

contains all coagulation factors

16

when to give platelet transfusion

u normally want platelet count mroe than 50
so if less than that, give platelet transufison

17

wat bac contamination common for blood transfusion

gram neg organism- yersinia enterocolita

18

wat do we screen for in blood?

Syphilis antibodies
􀁹 Hepatitis B Surface Antigen
􀁹 Hepatitis C antibody
􀁹 HIV antibody
􀁹 HTLVI and II antibody
HIV Nucleic acid testing
HCV Nucleic acid testing

19

indications for blood transfusion

acute major blood loss: surgery, post part
marrow problems: ALL, AML
haemoglobinopathies: thalassaemia major
chronic disae; malignancy

20

direct coombs test

to detect antibodies already on cell

get pts cells (with antibodies on them) and add anti-human antibodies. everything sticks together
agglutination=positive result

21

indirect coombs test

to detect antibodies in recipeints serum

take pt's serum (with antibodies in it) , add donor rbcs, add anti-human antibodies. if donors rbcs had the antigen, everything will agglutinate= positive result

22

conditions that cause a right shift:

increase in temperature, 2,3-DPG, or PCO2, H+
a decrease in pH

these conditions REDUCES haemoglobin's affinity for oxy
hence need high PO2 for same O2 saturation

23

foetal hb and hb dissociation curve

Foetal haemoglobin (HbF) is left shifted compared to adult Hb.
It is not sensitive to 2,3DPG (so can’t move the curve to the right).

24

haemophillia

X-linked recessive, women asymptomatic
haemathrosis, haemartoma,
prolonged aPTT

25

forming a platelet plug

platelets bind to collagen via glycoprotein IIa/Ia
vWF helps platelets bind to collagen (forms extra links bw platelet’s glycoprotein Ib and collagen)

activated platelets release granules like ADP and thromboxane A2 to call more platelets to come

26

PT tests for factors

7, 10, 5, 2, 1

27

PTT or aPTT test for factors

12, 11, 9, 8, 10, 5, 2, 1

28

thrombin time TT test for factor

1

29

Target INR in anticoagulation therapy

2-3

30

prolonged Prothrombin time (PT)

vitamin K deficiency
DIC
warfarin use
liver disease