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What are the basic classes of toxins?
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What is an organic toxin?
- derived from living things
- carbon based
- usually containing C-H bonds
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What is an inorganic toxin?
- not organic
- not containing C, C-H
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What are the three different types of treatments for toxicity?
- supportive care
- decontamination
- drugs and antidotes
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What are the different types of toxins?
- acetaminophen
- botulism
- carbon monoxide (CO)
- chocolate and caffeine
- ethylene glycol
- grapes and raisins
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Which toxin is the worst toxin?
acetaminophen
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What is acetaminophen?
Tylenol
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Is acetaminophen organic or inorganic?
organic
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What three enzyme systems can acetaminophen be metabolized?
- sulfatranferases
- glucuronyl transferase
- cytochrome P-450
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Are sulfatranferases toxic or non-toxic metabolites? Is this pathway significant in dogs and cats?
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Are glucuronyl transferase toxic or nontoxic metabolites? Is this pathway significant in dogs and cats?
- non-toxic metabolite
- cats lack this enzyme, making them more susceptible
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Are cytochrome P-450 toxic or non-toxic metabolites? What is the toxic metabolite called?
- toxic metabolite
- NAPQI (N-acetyl-para-benzequinoneimine)
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How does NAPQI work?
- partially binds with glutathione
- forms a non-toxic product that is eliminated in the urine
- when glutathione, an antioxidant, is used up, methemoglobin is formed - cats are more sensitive to metHg
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What are the clinical signs of acetaminophen toxicity?
- cyanosis or dark mucous membranes
- dyspnea
- facial edema
- anorexia
- depression
- hypothermia
- vomiting
- increased ALT
- weakness
- coma
- death
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What is the supportive treatment for acetaminophen toxicity?
- airway
- oxygen
- collect lab samples
- IV catheter
- fluids
- Oxyglobin
- plasma
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What is the decontaminate treatment for acetaminophen toxicity?
- emesis or gastric lavage
- cathartics
- activated charcoal
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What are the drugs and antidotes you can use to treat acetaminophen toxicity?
- acetylcysteine
- ascorbic acid
- cimetidine
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How is acetylcysteine given for acetaminophen toxicity?
PO or IV
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Why is by mouth administration preferred for treating acetaminophen with acetylcysteine?
reaches the liver quickly through portal circulation
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How is ascorbic acid given to treat acetaminophen toxicity?
IV
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What does ascorbic acid do for treating acetaminophen toxicity?
converts methemoglobin to oxyhemoglobin
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What is methemoglobin?
bad for of hemoglobin
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How does cimetidine (Tagamet) or ranitidine (Zantac) treat acetaminophen toxicity?
ties up the cytochrome P-450 enzyme system so less NAPQI is formed
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How can we prevent acetaminophen toxicity?
client education
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What is botulism?
toxins produced by Clostridium botuinum
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Where can Clostridium botuinum be found?
- in garbage and decaying animal carcasses
- also ingestion of spores, wound contamination by spores
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Is botulism organic or inorganic?
organic
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How does botulism cause toxicity?
- toxins bind to receptors in nerve endings
- this inhibits a release of acetylcholine - nusculoskeletal and parasympathetic neurotransmitter
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Where are the clinical signs usually seen with botulism toxicity?
seen 24 - 48 hours after ingestion
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What are the clinical signs of botulism toxicity?
- generalized weakness
- ascending paresis
- flaccid paralysis
- mydriasis
- poor jaw tone
- dysphagia
- failure to swallow causing salivation
- vomiting
- death due to respiratory paralysis
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What do we need to rule out before diagnosing botulism?
- tick paralysis
- rabies
- polyradiculoneuritis (coon hound paralysis)
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What is the supportive treatment for botulism toxicity?
- airway
- oxygen
- collect lab samples
- IV catheter
- fluids
- deep bedding
- physical therapy (to keep muscles from contracting)
- frequent turning
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What is the decontamination treatment for botulism toxicity?
- emesis
- gastric lavage
- activated charcoal
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What are the different drugs and antidotes to treat botulism toxicity?
- botulism antitoxin (available, but unsure how effective)
- penicillin or amoxicillin
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What is the prognosis for botulism toxicity?
- most pets recover good wtih nursing care
- can take several weeks
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What is carbon monoxide and where does it come from?
- CO is odorless and colorless
- it is a byproduct in incomplete combustion of hydrocarbon fuels
- fires, smoke inhalation, improperly ventilated vehicles and houses
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Is carbon monoxide organic or inorganic?
inorganic
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What are the clinical signs for carbon monoxide toxicity?
- cherry red blood
- red or dark pink mucous membranes
- tachypnea
- dyspnea
- ataxia
- deafness
- lethargy
- confusion
- shock
- collapse
- seizures
- coma
- death
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What kind of readings do we get on the pulse oximeter when there is carbon monoxide toxicity?
falsely normal
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What is the supportive treatment for carbon monoxide toxicity?
- airway
- ventilate
- oxygen
- collect lab samples
- IV catheter
- fluids
- control seizures
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What is the decontamination treatment for carbon monoxide toxicity?
remove patient from the source of the CO
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What are the drugs and antidotes used to treat carbon monoxide toxicity?
- Oxyglobin
- fresh blood transfusion
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What is the prognosis for carbon monoxide toxicity?
depends on the amount of exposure
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Which is more toxic, dark chocolate or milk chocolate?
dark chocolate
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What in chocolate makes it toxic?
theobromine and caffeine
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Is theobromine and caffeine organic or inorganic?
organic
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How does theobromine cause toxicity?
inhibits phosphodiesterase, resulting in the release of catecholamines (epinephrine, norepinephrine)
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How does caffine cause toxicity?
directly stimulates the myocardium and CNS
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What are the clinical signs of theobromine toxicity?
- vomiting
- diarrhea
- PU
- urinary incontinence
- mild hypertension
- bradycardia/tachycardia
- dysrhythmias
- nervousness
- excitement
- hyperthermia
- seizures
- panting
- coma
- death
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What are the clinical signs of caffeine toxicity?
- tachycardia
- tachypnea
- vomiting
- restlessness
- hyperexcitability
- hyperthermia
- tremors
- seizures
- cyanosis
- dysrhythmias
- generalized congestion or hemorrhage
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What is the supportive treatment for theobromine and caffeine toxicity?
- airway
- oxygen
- collect lab samples
- IV catheter
- fluids
- control seizures
- treat hyperthermia
- monitor EKG - treat dysrhythmias
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What is the decontamination treatment for theobromine and caffeine toxicity?
- emesis
- gastric lavage with warm water
- activated charcoal
- saline cathartic
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What drugs and antidotes can we use to treat theobromine and caffeine toxicity?
- no specific antidote
- cardiac drugs
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How do we enhance elimination of theobromine and caffeine from the system?
- fluid diuresis
- urinary catheter
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What is the prognosis for theobromine and caffeine toxicity?
depends on the amount of exposure
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What is ethylene glycol?
antifreeze
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What does antifreeze taste like?
tastes sweet
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How does ethylene glycol cause toxicity?
- partially eliminated unchanged through the kidneys and does not do damage
- the rest of the ethylene glycol is eliminated through the liver, broken down by alcohol dehydrogenase, and toxic metabolites are formed
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What are the toxic metabolites with ethylene glycol?
- glycoaldehyde
- glycolate
- oxalate
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Is ethylene glycol organic or inorganic?
organic
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How does glycoalhyde cause problems?
causes CNS and respiratory depression
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How does glycolate cause problems?
causes metabolic acidosis
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How does oxalate cause problems?
combines with calcium to corm calcium oxalate crystals which precipitate in renal tubules causing kidney damage
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How many clinical sign stages are there for ethylene glycol toxicity?
3
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How long does it take for ethylene glycol to get to stage 1?
30 minutes to 12 hours after ingestion
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What are the clinical signs in stage 1 of ethylene glycol toxicity?
- PU/PD
- nausea
- vomiting
- depression
- ataxia
- seizures
- low urine specific gravity
- calcium oxalate crystals may be present in urine
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How long does it take for ethylene glycol to get to stage 2?
12 to 24 hours after ingestion
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What are the clinical signs of stage 2 in ethylene glycol toxicity?
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How long does it take for ethylene glycol to reach stage 3?
- 24 to 72 hours after ingestion in dogs
- 12 to 24 hours after ingestion in cats
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What are the clinical signs of stage 3 in ethylene glycol toxicity?
oliguric renal failure: severe depression, vomiting, diarrhea, dehydration, azotemia, oliguria, painful kidneys, hypothermia
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What kind of supportive care can we do for ethylene gylcol toxicity?
- airway
- oxygen
- collect lab samples
- IV catheter
- fluids
- monitor urine output
- control seizures
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What are the decontamination treatments for ethylene gylcol toxicity?
- emesis
- gastric lavage (only if ingestion occurred within the last 15-30 minutes and the patient is showing no clincial signs)
- repeated doses of activated charcoal unless the patient is to receive oral ethanol
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Which types of drugs and antidotes can we use for ethylene glycol toxicity?
- fomepizole
- ethanol
- sodium bicarbonate
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What is fomepizole?
alcohol dehydrogenase inhibitor
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How does fomepizole work?
prevents ethylene glycol from being broken down to toxic metabolites
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How do we administer ethanol and when should we administer ethanol?
- IV
- very effective if started within 1 hour of ingestion
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How does ethanol work to treat ethylene glycol toxicity?
ethanol competes with ethylene glycol for alcohol dehydrogenase and alcohol dehydrogenase has a much higher affinity for ethanol than ethylene glycol
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What is ethanol?
alcohol (like what we drink)
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Can we use ethanol and fomepizole together?
no
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How do we administer sodium bicarbonate to treat ethylene glycol?
IV
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When do we use sodium bicarbonate to treat ethylene glycol toxicity?
for severe metabolic acidosis
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How do we enhance the elimination of ethylene glycol?
- hemodialysis
- peritoneal dialysis
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What is the prognosis for ethylene glycol toxicity?
good if treatment starts soon after exposure
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When is the prognosis for ethylene glycol poor?
once azotemia occurs (24 - 48 hours after ingestion)
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How do we prevent ethylene glycol toxicity?
- owner education
- use propylene glycol-based antifreeze
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What happens to a dog if they ingest a large amount of grapes or raisins?
develop kidney failure
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Are grapes and raisins organic or inorganic?
organic
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Do we know how grapes and raisins create a toxicity in animals?
no, still under investigation
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What are the clinical signs of an animal with grape or raisin toxicity?
- vomiting
- lethargy
- anorexia
- abdominal pain
- diarrhea
- polyuria
- oliguria
- anuria
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What is the supportive treatment for grape and raisin toxicity?
- collect lab samples
- IV catheter
- fluids
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What are the decontamination treatments for grapes and raisin toxicity?
- emesis
- gastric lavage
- activated charcoal
- saline cathartic
- peritoneal dialysis
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What are the drugs and antidotes to treat grapes and raisin toxicity?
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