Equine Toxicities

Question 1

Ability to transport ions across biological membranes

Answer 1

Ionophores

Question 2

What are ionophores?

Answer 2

Lasalocoid, monensis, salinmycin

Question 3

What are ionophores used for in ruminants?

Answer 3

Growth promotion, coccidostats

Question 4

Which species are ionophores toxic to?

Answer 4

Horses

Question 5

What is the MoA of ionophore tox in horses?

Answer 5

Distrubtion of mitochondria causes loss of aerobic energy production

Question 6

What tissues are affected most by ionophore tox?

Answer 6

Muscular and neuro tissue

Question 7

How soon after ionophore exposure do acute clinical signs develop?

Answer 7

Within 24h

Question 8

What are acute clinical signs of ionophore toxicity?

Answer 8

Ataxia, anorexia, tremors, tachycardia, recumbency, death

Question 9

What are long-term effects of ionophore toxicity?

Answer 9

Poor performance, exercise intolerance, arrhythmias

Question 10

How does ionophore toxicity cause long-term effects?

Answer 10

Damage to the heart

Question 11

How do you treat ionophore tox?

Answer 11

Check diet and remove source, no specific therapy

Question 12

Used in insecticides

Answer 12

Organophosphates

Question 13

What is the MoA of organophosphates?

Answer 13

Inhibits ACh-ase = accumulation of ACh @ post-synaptic receptors = excessive neurotransmitter activity

Question 14

What are clinical signs of organophosphate toxicity in horses?

Answer 14

SLUDD signs, bradycardia, miosis

Question 15

What other toxicity causes clinical signs similar to organophosphate tox and works via the same mechanism?

Answer 15

Carbamates

Question 16

How do you treat carbamate tox?

Answer 16

Atropine and pralidoxime chloride (2-PAM)

Question 17

What fungus is assoc. w/fescue?

Answer 17

Neotyphodium

Question 18

What toxin does Neotyphodium produce?

Answer 18

Eropeptine alkaloids

Question 19

What is the MoA of eropeptine alkaloids?

Answer 19

Dopamine agonist

Question 20

What are clinical signs of fescue tox?

Answer 20

Prolonged gestation, placental thickening, agalactia

Question 21

How do you dx fescue tox?

Answer 21

Empiric

Question 22

How do you tx fescue tox?

Answer 22

Remove fescue + Domperidone

Question 23

What plant causes acute hemolytic anemia in horses?

Answer 23

Wilted red maple

Question 24

Are fresh red maple leaves toxic to horses?

Answer 24

No, just wilted ones

Question 25

What does the wilted red maple toxin cause?

Answer 25

Oxidative damage to erythrocyte membranes (RBC lysis)

Question 26

What are clinical signs of red maple tox?

Answer 26

Lethargy, dyspnea, dark-colored urine, acute renal failure

Question 27

How do you treat red maple tox?

Answer 27

IVFT, blood transfusion, Vit C

Question 28

What do blister beetles contain that is toxic to horses?

Answer 28

Cantharidin

Question 29

Where do blister beetles live?

Answer 29

Alfalfa hay

Question 30

What is the MoA of cantharidin?

Answer 30

GIT and kidney irritation

Question 31

What samples can you take to ID catharidin?

Answer 31

Stomach or urine contents

Question 32

How do you tx blister beetle toxicity?

Answer 32

Supportive care

Question 33

What does moldy corn toxicity cause?

Answer 33

Leukoencephalomalacia

Question 34

What toxin does moldy corn contain?

Answer 34

Mycotoxin fumonisin

Question 35

What type of clinical signs does moldy corn tox produce?

Answer 35

Neuro more than liver-related

Question 36

What are clinical signs of moldy corn tox?

Answer 36

Incoordination, blondness, head pressing, sweating, anorexia, lethargy

Question 37

What toes moldy corn toxin cause in the brain?

Answer 37

Liquefactive necrosis and cerebral degeneration

Question 38

How can you empty ionophores from the GIT of a horse?

Answer 38

Mineral oil, activated charcoal, IVFT

Question 39

How does fescue cause reproductive failure in mares?

Answer 39

Prolactin suppression

Question 40

Will GI or neuro signs appear first in horses affected by cantharidin (blister beetle tox)?

Answer 40

GI (colicking)

Question 41

How do you treat organophosphate toxicity in dogs and cats?

Answer 41

Atropine or 2-PAM