Haemolymphatic

Question 1

Describe the common causes of blood loss anaemia.

Answer 1

Surgery - castrations especially
Improper technique for NG intubation
Bleeding GI lesions - parasites
Haematuria
Haemostatic disorders
Respiratory tract bleeds - especially guttural pouch mycosis
Haemorrhagic diarrhoea from viral or bacterial infections - Salmonellosis for example
Haemothorax or haemabdomen

Question 2

What is the most ideal signalment for a blood donor?

Answer 2

500kg adult Standardbred gelding
The mare is also a suitable donot for a foal with NI but you need to wash the blood cells
Need to be Aa and Qa negative as these are the most reactive antigens - so no TBs

Question 3

Describe the potential complications associated with giving a blood transfusion and how to mitigate them.

Answer 3

Immediate red cell destruction
Pyrexia
Spread of infections

Monitor HR, RR + temperature throughout the entire transfusion - get updated readings every minute, then every 5 minutes, then every 15 minutes etc. to check for reactions
Start the transfusion off very slowly
If you see signs reduce the rate and re-assess - if they are getting worse then stop and administer dexamethasone 0.05-0.1mg/kg IV

Question 4

Are a majority of equine anaemias non-regenerative or regenerative?

Answer 4

Regenerative

Question 5

How can you differentiate haemorrhage from transudate on ultrasound?

Answer 5

Haemorrhage = spontaneous contrast, will be white + swirling
Transudate = just looks black

Question 6

Which 2 clinicopathologic tests are done to help determine the severity of blood loss?

Answer 6

PCV + TS
Lactate

Question 7

You are seeing a horse after foaling who’s showing some colicky signs - the PCV/TS is normal but lactate is through the roof. What’s happening?

Answer 7

Shes bleeding from somewhere.

Question 8

How long does it take for PCV/TS to decrease in a case of acute external haemorrhage?

Answer 8

24 hours due to splenic contraction boosting circulating red cell levels early after the haemorrhage

Question 9

Describe the treatment of acute blood loss anaemia.

Answer 9

Limit the haemorrhage - try to ligate the vessel, pack the surgical site, apply a pressure bandage if distal limb wound, may even need to take them to surgery to identify the bleed
Conservative IV fluid resuscitation while maintaining MAP >60mmHg
Careful use of sedatives - xylazine is okay, ACP is not to be used as its a vasodilator only
Antifibrinolytic drugs - aminocaproic acid, tranexamic acid
+/- blood transfusion if indicated

Question 10

Describe how to identify when a blood transfusion is clinically indicated.

Answer 10

Physical indicators of shock suggestive of blood loss > 30% blood volume
PCV < 20% within the first 12 hours
PCV < 12% during the first 24 hours
Hb < 5g/dl
Blood lactate > 4mmol/L after judicious fluid therapy

Question 11

How do we calculate how much blood is required in a blood transfusion?

Answer 11

Bodyweight x blood volume (assume 8%) x (normal PCV - PCV observed/PCV of the donor) = L blood required

Question 12

What 2 drugs are commonly associated with secondary haemolytic anaemia?

Answer 12

Penicillin
TMPS

Question 13

What clinical findings are associated with haemolytic anaemia in horses?

Answer 13

Tachycardia, tachypnoea, cold extremities, pale MM, cardiac murmur, icterus, pyrexia

Lab findings - autoagglutination, anaemia, hyperbilirubinaemia, haemoglobinaemia, haemoglobinuria

Question 14

Describe the treatment of IMHA in horses.

Answer 14

Remove initiating factor if possible
Diuresis if haemoglobinaemia, haemoglobinuria
Corticosteroid therapy - dexamethasone 0.05-0.2mg/kg IV or IM q12-24h until PCV stops declining
Blood transfusion may be required

Question 15

Which 4 factors determine if neonatal isoerythrolysis develops?

Answer 15

Dam having a different blood type/antigen to the sire
Probability that the foal will inheret the sires blood type
Development of antibodies against the antigen by the dam
Foal needs to then drink enough colostrum for the antibodies to enter circulation

Question 16

You are called out to see a 3d old foal for being dull and lethargic, and just generally off the suck. When you get there you find that the HR is 160 and the gums are pale and have a slight yellow tinge. What is your main DDx?

Answer 16

Neonatal isoerythrolysis –> haemolytic anaemia

Question 17

What clinicopathologic abnormalities are expected in a foal with NI?

Answer 17

Dec. PCV, Hb and RCC
Hyperbilirubinaemia
Haemoglobinuria or haemoglobinaemia
Inc. lactate concentration
+/- azotaemia
+/- hepatopathy

Question 18

Outline how we can prevent neonatal isoerythrolysis from occurring.

Answer 18

Blood type stallions and broodmares
Jaundice foal agglutination test (JFAT)
Separation at birth for 12h + strip colostrum off the mare, make sure to supplement colostrum for the foal or risk failure of passive transfer, if IgG is a fail then give commercial plasma IV and re-measure

Question 19

What is equine infectious anaemia? How is it spread? How do we diagnose? Can we treat it?

Answer 19

Viral disease transmitted by biting insects
Dx by Coggins test +/- ELISA
No treatment, only management + control exposure to biting insects

Question 20

Name the 4 formsof lymphoma in horses.

Answer 20

Alimentary
Thymic/mediastinal
Multicentric/generalised
Cutaneous

Question 21

What treatment needs to be given to a foal with NI?

Answer 21

1-4L blood transfusion