Equine anaemia evaluation and management

Question 1

T/F Equine red cells have longer lifespan

Answer 1

True!

Question 2

T/F Immature red cells are released from bone marrow to circulation in the horse

Answer 2

False!

Question 3

T/F There are no equine reticulocytes even in regenerative anaemia

Answer 3

True!

Question 4

General clinical signs of anaemia in horses

Answer 4

Acute blood loss/haemolysis
Tachycardia
Tachypnoea & hyperpnoea indicative of significant hypovolaemia and hypoxaemia
Mucous membrane colour depends on severity of loss

Chronic blood loss/haemolysis
Exercise intolerance
Weight loss
Pallor of mucous membranes only clinically evident at <20-24 l/l
Adaptive tachycardia at <20 l/l
Haemic murmur due to decreased viscosity, increased turbulence

Question 5

What are the features of regeneration in horses

Answer 5

Howell jolly Bodies
Increased MCV in regeneration
Anisocytosis more marked

Question 6

Where to draw blood from a horse to test for anemia

Answer 6

Facial venous plexus

Question 7

Which blood tube should I use to collect blood in horses and why

Answer 7

Citrate. EDTA clumps blood in horses.

Question 8

How to calculate blood volume in a horse

Answer 8

80-100 ml/kg

Question 9

Describe horse blood groups

Answer 9

Horses have 7 blood groups (A,C,D,K,P,Q & U)
Each contains 1 (systems C,K & U) to 15 factors (D) composed of proteins of carbohydrates: countless blood types
80-90% general population do not have alloantibodies
AaCa +ve blood group = best donor

Question 10

What is the anticoagulant used in blood bags when collecting blood from horse for transfusion

Answer 10

Acid citrate dextrose

Question 11

How much blood to transfuse in horses?

Answer 11

Up to 15 ml/kg depending on blood volume lost
1 drop/5s for first 5 mins, monitoring heart rate & potential signs of anaphylaxis or severe transfusion reaction
Equation often academic, depends on severity

Question 12

Differentiate between primary IMHA and secondary IMHA in horses

Answer 12

Primary is less common
Primary means antibodies are produced against erythocytes
Primary shows positive coombs test
Secondary can have multiple causes, including drug interaction, respiratory infections, neoplasia
Secondary means disease alters RBC membrane

Question 13

How to treat Equine IMHA

Answer 13

Rate of blood loss is key factor
Identify & discontinue suspected medications
Dexamethasone if severe haemolysis
Change to prednisolone 1 mg/kg SID if longer term requirement
Blood transfusion from compatible donors

Question 14

What is neonatal isoerythrolysis and how does it occur

Answer 14

Immune-mediated haemolysis
Most often in multiparous mares when colostral antibody to foal’s rbc antigen causes a RBC ag incompatibility

Question 15

Clinical signs of neonatal isoerythrolysis

Answer 15

Anaemia, icterus, weakness
↑RR, HR, pale mm’s

Question 16

Diagnosis of neonatal isoerythrolysis

Answer 16

Signs, haematology
Exclusion diagnosis
Immunological testing
Foal RBCs + mare serum/colostrum

Question 17

How to prevent neonatal isoerythrolysis

Answer 17

Check compatibility of pairing, particularly if mare Aa/Qa negative
Prevent nursing for 24 h as no antibody passed transplacentally
Alternative source of colostrum

Question 18

Suggest reasons for inadequate erythropoiesis in the horse

Answer 18

Nutritional deficiencies
Myelophthisic anaemia (presence of immature erythrocytes in the peripheral blood due to infiltration of the bone marrow by abnormal tissue)
Bone marrow aplasia

Question 19

What are blood panel results for acute blood loss in horse

Answer 19

Low PCV, Hb and low TSP

Question 20

What are blood panel results/ significant finding for Haemolysis in horse

Answer 20

Low PCV, normal TSP, decreased unconj Bilirubin, Increased MCHC, haemoglobinuria

Question 21

What are blood panel results/ significant finding for Chronic anemia in horse

Answer 21

Low PCV, low Hb but relatively high TSP

Question 22

Clinical signs of acute piroplasmosis

Answer 22

Pyrexia, lethargy and haemolysis
PCV to 10%
Systemic signs depend on level of haemolysis
Tachycardia, tachypnoea, weakness
Petechiations & marked thrombocytopaenia
Concurrent disease exacerbates signs
Recurrent episodes of anaemia

Question 23

What is piroplasmosis and the cause of it

Answer 23

Blood-borne protozoal infection of horses caused by Theileria (Babesia) equi and/or Babesia caballi.

Question 24

Treatment of piroplasmosis

Answer 24

Imidocarb dipropionate
Preceded by glycopyrrolate (If acute)