treating immune mediated haematological conditions

Question 1

What is the usual cause of mortality in IMHA cases

Answer 1

Thromboemolic disease i.e DIC or pulmonary thromboembolism

Question 2

Main treatment for IMHA

Answer 2

Immunosuppression
+ DO thromboprophylaxis to reduce risk of thromboembolic disease (all anti-thrombic drugs off licence)
Can also give anticoagulants; heparin, rivaroxaban

Question 3

Are most cases of IMHA primary or secondary

Answer 3

Primary i.e idiopathic

Question 4

Immunosuppressive therapy for IMHA

Answer 4

Glucocorticoids is 1st line: mainly prednisolone (oral) and dexamethasone

• Could also use cyclosporine but expensive; other things not licensed

Question 5

Side effects of glucocorticoid theraoy

Answer 5

Hyperadrenocorticism (i.e PU/PD, polyphagia, muscle wastage, poor hair growth, ALP elevation)

GI ulceration

Question 6

Immunosuppressive rate of glucocorticoids /day for dogs

Answer 6

2mg/kg/day (or use surface area calculation for large dogs)

Question 7

Which anticoagulant drugs may be used in treating IMHA

Answer 7

Heparin = activates antithrombin III
Rivaroxaban = inhibits factor Xa

Question 8

Tapering glucocorticoids in IMHA therapy

Answer 8

Reduce by 25% every 3-4 weeks
Must check PCV and haematology every few days and before any dose reduction

Question 9

How do we treat IMTP

Answer 9

Similarly to IMHA; use glucocorticoids at immunosuppressive doses

May use vincristine

Question 10

How do we treat vWD

Answer 10

Just avoid invasive procedures or platelet inhibiting drugs
- If doing procedures give desmopressin before to increase vWF conc pre-suergy
Can also do transfusion before surgery of frozen plasma or cryoprecipitate

Question 11

Treating rodenticide toxicity

Answer 11

Give parenteral vitK1 therapy for 3-4 weeks
In emergency with significant bleeding; give frozen plasma transfusion to replace coagulatino factors

Question 12

Treating angiostrongylus vasorum

Answer 12

Moxidectin
Praziquantel
Fenbendazole

Question 13

At what PCV would we consider transfusino

Answer 13

If <15-20% (dogs)
Will very likely do it if <12%

Question 14

How much platelet concentrate (new product for dogs) do we need to give in acute haemorrhage cases for thrombocytopenic dogs

Answer 14

1 unit/10kg

Each unit platelets comes from 1 unit of whole blood

Question 15

Requirements for dog being a blood donor

Answer 15

Healthy, vaccinated, no travel
>25kg; between 1-8 years old
Normal PCV ideally >40%
Ideally DEA 1.1 -ve

Question 16

Requirements for cat being blood donor

Answer 16

NB: no cat blood bank
- Healthy, vaccinated, normal PCV (ideally >40)
>4 kg; 1-8 years old

Question 17

When might we do xenotransfusion

Answer 17

From dog to cat
BUT can only do once; will develop antibodies

Question 18

Storing different blood products

Answer 18

Red cells: 4 weeks in fridge; 24 hours once open - agitate every few days
Plasma: at -20 degrees
Platelets: room temp; just 72 hours

Question 19

What does cross matching mean

Answer 19

Checking that donor and recipient blood are compatible via mixing blood cells/plasma in vitro and looking for agglutination/haemolysis

Question 20

When do we need to cross match blood

Answer 20

With unknown transfusion history or previous transfusion
Any female that has had a litter
Cats whenever possible

Question 21

Rough guide for how we increase PCV by 1% during transfusion

Answer 21

Need 1ml/kg of packed red cells
Or 2ml/kg of whole blood

Question 22

Care taken with blood transfusion delivery

Answer 22

Give at slow rate with monitoring over first half hour i.e just 0.5ml/kg/hr

THEN give quickly; want to give whole transfusion within 4 hours to avoid contaminatino

Question 23

What is an acute haemolytic transfusion reaction

Answer 23

= type II hypersensitivity reaction of recipient plasma to donor blood
Causes intravascular haemolysis
> See fever, vomiting, tachycardia, hypotension, haemoglobinuria/aemia

Common in DEA1.1 sensitised dogs given DEA1.1 blood

Question 24

What is an acute allergic or anaphylactic non-haemolytic transfusion reaction

Answer 24

= type 1 hypersensivit reaction

Either stop transfusion or slow depending on severity
+ give corticosteroids and antihistamines

Question 25

What is febrile non-haemolytic transfusion reaction

Answer 25

When transfusion patient has rise in body temp by >1 degree
Need to rule out bacterial contamination
> Relates to white cells and platelets usually (may use leukodepletion filter)

Question 26

What is delayed haemolytic transfusion reaction

Answer 26

One over few days after transfusion due to alloimmunisation (PREVIOUS exposure)
- See jaundice and anaemia

Question 27

When do we need to cross match plasma before transfusion

Answer 27

Only if lots of transfusion before or transfusion reaction seen in the past

Ideally match DEA1.1 type as there will be some red cell contamination

Question 28

Difference between fresh frozen plasma and frozen plasma

Answer 28

FFP : contains all clotting factors, immunoglobulins, albumins etc
FP = FFP that is 1-5 years old; now has lower concentrations of factor V, VIII, vWF

Question 29

What does frozen plasma still contain good concentratinos of

Answer 29

Vit K dependent factors; so useful in rodenticide poisoning

Question 30

WHat is cryoprecipitate

Answer 30

Fresh frozen plasma which has been centrifuged to concetrate clotting factors so can deliver fibrinogen, factor VIII and vWF via much smaller volumes

Question 31

What is draw back in platelet transfusions

Answer 31

Only very short lived; so helps acutely but short half life