Equine Intoxications

What causes Nigropallidal encephalomalacia?

Yellow star thistle and Russian knapweed

What is the most common C/S of Nigropallidal encephalomalacia?

Difficulty with prehension and weight loss

What is the toxic component of white snakeroot?

Tremetol

What are the C/S of white snakeroot?

Elevated CK, AST, pigmenturia, proteinuria, acidosis due to MUSCLE NECROSIS

Very cardiac toxic

Cardiac arrhythmias

How do foals get white snakeroot?

There will be toxic concentrates in milk, so do not give them white snakeroot

What is a very similar toxicant to white snakeroot?

Monensin (ionophores)

What are C/S of red maple tox?

Acute hemolysis and anemia

methemoglobinemia

Tachypnea and tachycardia

When do horeses get red maple tox?

In the fall from WILTED LEAVES after trimming or a storm

What is acer rubrum?

Red maple

What are your ddx for red maple?

Phenothiazine tox, wild onion, IMHA, EIA, drug hypersensitivity, ehrlichiosis, piroplasmosis, endotoxemia, hepatic failure

How do you manage red maple?

Stabilize with blood transfusions, anti-inflammatories, antibiotics, antibiotics, oxyen

What are the cardiac glycoside containing plants?

Digitalis purpurea (foxglove), also oleander or azaleas

What does foxglove cause?

GIT irritation and cardiac arrhythmias

How do you manage cardiac glycoside plants like foxglove?

Avoid Ca and K containing fluids

Supportive care with IV fluids, analgesia, antioxidants

What is primary photosensitization?

Plant directly causes photosensitization

What causes primary photosensitization?

Hypericum perforatum (St. John’s wort)

What is secondary photosensitization?

Plant causes hepatic disease which leads to photosensitization

What plants cause secondary photosensitization?

Senecio spp. (Ragwort)

What are sins of Pyrrolizidine alkaloid toxicity?

Poor BCS

Icterus

Primary hepatic disease signs

Megalocytosis

Bridging fibrosis

What are two examples of Pyrrolizidine alkaloid plants?

Senecio and Crotalaria

What mycotoxins can infect hay, forage, or grain?

Slobber toxin from Rhizoctonia leguminicola

Fescue tox from Neotyphodium coenphialum

Leukoencephalomalacia from Fusarium proliferatum

How do you manage fescue tox in pregnant mares?

Remove from pasture until foaling for last 60-90 days

Treat with domperidone

What mycotoxin causes leukoencephalomalacia?

Fumonisin B1 which interferes with sphingolipid metabolism disrupting endothelial cell walls

What is the lesions of leukoencephalomalacia?

Liquefactive necrosis and degeneration of the cerebral white matter if its a chronic lower dose

Liver tox if it is high dose

What are signs of ionophore intoxication?

Anorexia, colic, acute death, weakness, myocarditis

Horses that got into cattle feed

How do you diagnose ionophores?

History of getting into cattle feed

Liver and muscle enzyme elevation

Cardiac isoenzymes increased (troponin 1)

Cardiac evaluation with an ECG or echo

What is blister beetle tox?

Cantharidin is rapidly absorbed and excreted in urine

Causes uncoupling of ox phosphorylation and cell death

What are the C/S of blister beetle?

Ulcers, GIT and urinary system

Colic

Renal, hepatic, cardiac dysfunction

What does yellow star thistle cause?

Bilateral non-progressive focal necrosis of globus pallidus

What are C/S of yellowstar thistle?

Facial hypertonicity increases with food being offered but cannot prehend

How do you manage toxin ingestion?

Supportive care, evacuate GIT, give mineral oil or activated charcoal, diuresis

What is the MOA of cardiac glycoside tox?

Inhibition of Na/K ATPase that leads to increased calcium in the cell

How do you manage photosensitization?

First rule out significant hepatic disease

Then determine what plants are in pasture, remove from direct sunlight, SSD and antimicrobial

Lesions should heal in 2-3 weeks

What does pyrrolizidine alkaloid tox cause?

Hepatic disease

What is the MOA of pyrrolizidine alkaloid toxicity?

Reactive metabolites bind cell molecules and cross link DNA preventing mitosis

What is alsike clover?

Mycotoxin that causes anorexia, wt. loss, icterus, and secondary photosensitization

What is red clover?

Mycotoxin (slaframine)

How do you treat red clover?

Stop feedign contaminated hay

What do you need to rule out with red clover?

Oral trauma, ulcers, foreign bodyW

hat is Ergopeptine alkaloid toxicosis?

Fescue toxicosis from the endophyte

What are the effect of ergopeptine alkaloid toxicosis (fescue toxicosis)?

Depressed prolactin secretion

Depressed fetal cortisol secretion

Elevated circulating estradiol concentration

What are the C/S of equine fescue toxicosis?

Delayed gestation, thickened placenta, impaired lactogenesis, poor fetal maturity

How do you prevent fescue toxicosis?

Remove from pasture 90 days before foaling

Can treat with D2 agonist (domperidone)

What is the MOA of fescue toxicity?

Ergopeptine infeseted fescue enhances dopamine receptor binding which inhibits prolactin

What is the common source of fumonisin?

Moldy corn

What are the C/S of leukoencephalomalacia?

Blindness, hypermetria, depression, disorientation

How do you manage ionophore intoxication?

Remove feed, mineral oil or activated charcoal

What should not be given to horses with ionophore toxicity?

Digoxin or calcium

How can you determine the prognosis of ionophores?

ECG:

No abnormalities is good

Minimal change can be a breeding animal

Reduced fractional shortening is guarded for survival

What is the prognosis of ionohpore tox?

Poor

What tips you off to blister beetle?

Alfalfa hay

What does Cantharidin tox cause?

Pseudomembranous inflammation of GIT

Hemorrhagic cystitis

Myocarditis and necrosis

How do you diagnose Cantharadin tox?

ID toxin in urine

How do you manage Cantharidin?

Empty stomach

IV fluids to fix hypocalcemia

Plasma for hypoproteinemia

What are some common complications of cantharidin?

Cardiac, renal, laminitis