Lecture 6: Rodenticide intoxication

What are the steps for emergency treatment of rodenticide toxicity?

• Decontamination

• activated charcoal

• IV lipid emulsion

When should decontamination be considered?

Less than 4-6 hours after ingestion

-no risk aspiration

-not caustic/sharp

• +/- gastric lavage

Rodenticide decontamination in dogs: what is used

• 3% Hydrogen peroxide

  • oral burns

  • severe vomiting

  • hypersalivation

• apomorphine IV or intraocular

• clevor intraocular

Rodenticide decontamination in cats: what is used

• 3% Hydrogen peroxide

  • oral burns

  • severe vomiting

  • hypersalivation

• Xylazine or Dexmedetomidine IM

Why should syrup of ipecac not be used in rodenticide toxicity?

It is cardiotoxic (humans) and delays activated charcoal administration.

Clevor- what is it

• FDA approved

• Ropinirole

• intra-ocular administration only

• dogs only

How does ropinirole compare with apomorphine for inducing emesis in dogs?

It has similar efficacy.

How does activated charcoal work?

Its large surface area binds to toxins.

-administer within 1-2 hours

-best XR toxins

-enterohepatic recriculation toxins

What is the purpose of adding a cathartic to activated charcoal?

• To move material through the GI tract faster

• dehydration, electrolyte changes

• hypernatremia

when should activated charcoal not be used

• small molecules, alcohols, heavy metals

• > 1-2 hrs

• hypernatremia

• prior to GI endoscopy/surgery

• high risk aspiration

What is IV lipid emulsion typically made from?

Soybean oil

-creates lipid “sink” in bloodstream → binds to toxin

-few to no side effects

How does dialysis remove a toxin?

It filters the toxin from the blood

-ideally NOT highly protein bound

-smaller molecules

Anticoagulant rodenticides testing

• PT

  • prolonged sooner

  • Factor VII

• PTT

• both usually prolonged when bleeding

What is the antidote for anticoagulant rodenticide toxicity?

Vitamin K.

What blood product supplies clotting factors during anticoagulant rodenticide toxicity?

Plasma.

What should be done if rat bait was ingested less than 4-6 hours ago?

Induce emesis.

What should be done for an asymptomatic patient more than 4-6 hours after anticoagulant rodenticide ingestion?

Recheck PT in 48-72 hours.

When does bleeding commonly develop after anticoagulant rodenticide ingestion?

More than 7-10 days after ingestion.

Where can bleeding occur with anticoagulant rodenticide toxicity?

Large cavities, lungs, subcutaneous spaces, and joints.

What major abnormality is caused by cholecalciferol-containing rodenticides?

Hypercalcemia.

What can occur when the calcium-phosphorus product is high?

Calcification of tissues.

How much cholecalciferol bait can cause hypercalcemia in a 65-pound dog?

About 0.5 teaspoon of pellets.

how do you treat hypercalcemia?

• IV 0.9% saline diuresis

  • lose Ca loss through kidneys

  • Na enhances Ca in kidney

How does furosemide treat hypercalcemia?

It promotes calcium waste through the kidneys.

How does prednisone help treat hypercalcemia?

• decreases bone absorption

• decreases intestinal calcium resorption

• increases renal calcium excretion

How does calcitonin treat hypercalcemia?

It reduces osteoclast activity and formation.

How does pamidronate treat hypercalcemia?

It decreases osteoclast activity

-side effect is renal failure

What abnormalities should be monitored after cholecalciferol ingestion?

Azotemia and hypercalcemia.

What is the mechanism of bromethalin toxicity?

It interferes with oxidative phosphorylation in the brain.

How does bromethalin affect ATP production?

It decreases ATP production.

Why does bromethalin cause cerebral edema?

There is insufficient ATP to operate the sodium-potassium ATPase pumps.

When should decontamination be performed after bromethalin ingestion?

Within 4 hours.

How frequently may activated charcoal be administered for bromethalin toxicity?

Every 4 hours for up to 48 hours.

What is the prognosis for a patient that is asymptomatic after bromethalin ingestion?

Good.

What is the prognosis for a patient showing neurologic signs after bromethalin ingestion?

Poor.