Zinc Phosphide Flashcards

1
Q

Are zine phosphide rodenticides general or restricted use products?

A

Most are restricted use pesticides

Available as grain bait, past, tracking powder

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2
Q

T/F: Aluminum and magnesium phosphide have similar toxic effects as zinc phosphide

A

TRUE

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3
Q

How are pets exposed to zinc phosphide baits?

A

Accidental ingestion

Relay toxicosis has been observed

malicious poisoning

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4
Q

What are the properties of zinc phosphide poison?

A

Grey-black powder
Garlic or dead fish odor

***when exposed to acid - liberates phosphine gas (PH3) - gas is toxic, flammable, and an irritant

relatively insoluble in water

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5
Q

Acute zinc phosphide toxicosis is due to _______

A

Phosphine gas

When a patient ingests zinc phosphide - the acidic environment of the stomach/GI will liberate the toxic gas

pH below 7, and even more so pH below 4

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6
Q

T/F: Ingestion of zinc phosphide is more dangerous on an empty stomach

A

FALSE

when a patient has not eaten in hours the stomach will be more alkaline, so less gas will be liberated

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7
Q

What causes chronic zinc phosphide toxicosis?

A

both the zinc phosphide and phospine gas

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8
Q

Toxic effects of zinc phosphide can be seen in dogs at doses of _______ mg/kg

A

20 - 40 mg/kg

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9
Q

Hydrolysis and liberation of phosphine gas occurs at a pH of ____ or lower

A

4

  • *hydrolysis and liberation of gas**
  • vomiting or alkaline stomach pH will decrease toxicity
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10
Q

Where is zinc phosphide and phosphine gas absorbed?

A

GIT

Phosphine gas can also be absorbed through inhalation

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11
Q

Where is zinc phosphide and phosphine gas excreted?

A

Gas is excreted through the lungs

small amount zinc phos will be metabolized, inactivated, and excreted in the urine

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12
Q

What tissues are most greatly effected by zinc phosphide toxicosis?

A

Tissue with high O2 demand: brain, heart, kidney, liver, lung

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13
Q

What is the suspected MOA of phosphine gas?

A

Inhibition of oxidative phosphorylation –> decreased cellular energy production and cell death

increase in oxgen radicals resulting in peroxidation and cell damage

damage to RBCs, and blood vessels

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14
Q

What clinical signs are observed in a patient with zinc phosphide toxicosis?

A
Rapid onset (min - hrs)
Anorexia, vomiting, abdominal pain, bloat-cows, increased resp rate and effort

Dogs may show CNS excitation

death within 3-48 hours due to tissue anoxia

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15
Q

What lesions are associated with zine phosphide toxicosis?

A

Smell of the bait in vomitus
Gastroenteritis - may be hemorrhagic
Congestion of liver, kidney, and lungs

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16
Q

What lab abnormalities are expected in a patient with zinc phosphide poisoning?

A

Metabolic acidosis, dehydration, hypocalcemia, increase serum zinc

Hypo or hyper glycemia, hyperbilirubinemia, elevated liver enzymes, azotemia, thrombocytopenia, DIC

17
Q

When sending off specimens for zinc phosphide testing, what is important about the containers used?

A

Need to be air tight. Don’t want toxic gas leaking out

samples should be frozen immediately

18
Q

T/F: Phosphine gas is a potential health hazard for owners and animal hospital staff when dealing with a patient who’s ingested zine phosphide rodenticide

A

TRUE

if you’re smelling the gas.. you’ve been exposed to a high amount (~2ppm)
*EPA safe amount = 1-0.3ppm

proper ventilation needs to take place

19
Q

What decontamination protocol is recommended for zinc phosphide poisoing?

A

Emetics - have to way risk vs benefit.. should not induce emesis with a caustic agent.. but if you don’t it will continue to be absorbed

Gastric lavage with dilute potassium

Antacids to raise gastric pH

activated charcoal - efficacy isn’t really known

20
Q

What treatment is recommended for Zinc phosphide poisoning?

A

Supportive and symptomatic

IVF, O2. CV support, Analgesics, tx Sz, GI protectants.. etc

21
Q

What is the prognosis of zinc phosphide poisoning?

A

If not signs by 8-12hr post ingestion or 12-24hrs after vomiting = good prognosis

Severe signs of tissue damage - guarded to poor

22
Q

In all symptomatic survival patients, what should be monitored after 3-5 days?

A

Monitor liver and kidney values - there can be a rare delayed injury