Haematology

Question 1

What is the haematocrit?

Answer 1

Volume % of RBCs in blood

Useful when looking for polycythaemia

Question 2

What is the mean corpuscular haemoglobin (MCH)?

Answer 2

Mean Hb quantity in RBCs - effects colour ‘chromic’

Question 3

Causes of microcytic anaemia?

Answer 3

Iron deficiency

Thalassemia

Question 4

Causes of normocytic anaemia?

Answer 4

Blood loss
Anaemia of chronic disease
Haemolytic anaemia
Sickle cell

Question 5

Causes of macrocytic anaemia?

Answer 5

B12/folate deficiency (megaloblastic)

Alcohol, pregnancy, liver disease, hydroxycarbamide, hypothyroidism

Question 6

What is haptoglobin?

Answer 6

Acute phase marker of RBC destruction. Normally binds to free Hb so may be severely reduced in haemolysis

Question 7

4 drugs that cause agranulocytosis

Answer 7

4 'c's 
Carbimazole
Carbemazepine
Colchicine
Clozapine

Question 8

What is a TIBC? (Total iron binding capacity)

Answer 8

Looks at how many binding sites are available on transferrin.
Low - seen in Fe overload
High - seen in anaemia

Question 9

What does TSAT show?

Answer 9

Should be about 30%
If high then Fe overload
If low then anaemia

Question 10

Features of haemolytic anaemia

Answer 10

Increased RBC breakdown (raised BR, raised LDH, raised urobilinogen, reduced haptoglobin, pigmented gallstones)

Increased RBC production (increased reticulocytes)

Question 11

3 reasons for abnormality in inherited haemolytic anaemia

Answer 11

Membrane defect
Enzyme abnormality
Hb abnormality

Question 12

Examples of membrane problems in HA

Answer 12

Hereditary spherocytosis

Heridatary elliptocytosis

Question 13

Examples of membrane problems in HA

Answer 13

G6PD deficiency

Pyruvate kinase deficiency

Question 14

Hereditary spherocytosis

Answer 14

Disorder of spectrin
RBCs lose shape in circulation, they become rounded so harder to carry o2 - destroyed by extravascular system
Variable anaemia + jaundice

Film: spherocytes with no central pallor and small

Question 15

Which condition do fava beans cause anaemia in?

Answer 15

G6PD deficiency

Question 16

G6PD deficiency

Answer 16

G6PD only source of NADPH in RBC so only protection from oxidative stress
When oxidative stress (infections, fava beans, drugs) - cause anaemia + a non-spherocytic anaemia

Question 17

Clinical features of G6PD deficiency

Answer 17

Anaemia
Reticulocyte count may be high
Urinalysis may show urobilinogen
Elevated UC BR 
High LDH
Low haptoglobin 

Smear shows - blister + ghost cells

Question 18

What are bite cells?

Answer 18

Seen in G6PD deficiency
Caused by the removal of Hb by the spleen

Evidence that a Heinz body has been formed then removed by the spleen

Question 19

What are Heinz bodies?

Answer 19

Precipitated, denatured Hb. Round towards the periphery.

Seen in: G6PD deficiency, unstable Hb disorder etc

Question 20

Types of acquired haemolytic anaemia

Answer 20

Auto-immune (warm or cold)
Allo-immune
Drug induced

Question 21

Warm haemolytic anaemia

Answer 21

IgG ABs against RBC with max activity at 37C

RBCs get opsonised in reticuloendothelial system

Question 22

Cold haemolytic anaemia

Answer 22

IgM ABs against RBC with max activity at 4C

IgM can bind more than 1 RBC as pentamic therefore causes clumping

Question 23

Which HA is associated with IgG ABs against RBCs?

Answer 23

Warm

Question 24

Which HA is associated with IgM ABs against RBCs?

Answer 24

Cold

Question 25

What do you give the mum to prevent haemolytic disease of the newborn?

Answer 25

Anti-RhD antibodies after 1st birth if mum rhesus -ve and baby rhesus +ve

Question 26

Examples of an allo-immune HA?

Answer 26

Haemolytic disease of the newborn | Following incompatible blood transfusion

Question 27

Features of a DVT?

Answer 27

``` Unilateral leg pain Asymmetrical leg swelling Increased temperature Dilatation/distension of superficial veins Red/discoloured skin ```

Question 28

Risk factors for a DVT

Answer 28

Pregnancy, cancer, COCP, major surgery, immobilisation

Question 29

Wells score for DVT

Answer 29

``` Cancer Calf swelling >3cm Swollen unilateral superficial veins Tenderness along deep system Unilateral pitting oedema Bedridden >3d or surgery >12w Paralysis, paresis or recent cast Previous DVT Swelling of entire leg Other diagnosis just as likely ```

Question 30

Investigation of a DVT

Answer 30

Do a wells score If <2 then D-dimer - if positive then USS Doppler If 2-9 - USS Doppler

Question 31

Treatment of DVT

Answer 31

Start LMWH (enoxaparin 1.5mg/kg SC) and start warfarin. When INR is 2-3 stop LMWH and continue warfarin for 3-6m

Question 32

What raises a D-dimer?

Answer 32

``` Liver disease Inflammation Malignancy Pregnancy Recent surgery ```

Question 33

Wells score for PE

Answer 33

``` Previous DVT/PE Cancer Clinical signs of DVT Immobilisation/recent surgery Haemoptysis HR >100 Alternative diagnosis less likely ``` ``` <4 = low risk - D-dimer >4 = high risk - CTPA + LMWH ```

Question 34

What do PT and INR look at?

Answer 34

The extrinsic path (Factor 7) Should be 12secs = INR of 1 Aim for INR of 2-3 if on warfarin

Question 35

What does APTT look at?

Answer 35

Intrinsic path Should be <40s

Question 36

What does bleeding time look at?

Answer 36

Platelet function

Question 37

What does thrombin time look at?

Answer 37

Fibrinogen test - time it takes to convert fibrinogen to fibrin. Tests the common path Should be <11secs

Question 38

Which is the intrinsic path?

Answer 38

Surface contact - 12 - 11 - 9

Question 39

Which is the extrinsic path?

Answer 39

Tissue factor - 7

Question 40

Which is the common path?

Answer 40

10 - (prothrombin - thrombin) - (fibrinogen - fibrin)

Question 41

What are platelet type bleeds?

Answer 41

Involve skin + mucous membranes

Question 42

What are factor type bleeds?

Answer 42

Involve deep tissue + joints