Suspected Animal Poisonings: Triage, History Taking, Decontamination, and Sample Collection

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Suspected Animal PoisoningsTriage, History
Taking, Decontamination, and Sample Collection

• Lisa A. Murphy, VMD, DABT
• VMAT-2
• University of Pennsylvania
• March 18, 2007

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Session Objectives

• Understand the basic principles of triage for an
  animal or group of animals
• Know specific historical questions to ask in
  cases of suspected animal poisoning
• Discuss appropriate decontamination methods for
  animals
• Know what biological and environmental samples to
  collect in cases of suspected animal poisoning

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Treat the Patient, Not the Poison

• Most intoxicated patients recover with close
  monitoring, appropriate symptomatic treatment,
  and good nursing care

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General Approach to Case Management

• Stabilization of vital signs
• Evaluation of the patient
• Decontamination
• Antidotes
• Enhanced elimination
• Symptomatic and supportive care
• Closely monitor the patient

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Stabilization of Vital Signs

• Maintain the airway and assure adequate
  ventilation
• Maintain cardiovascular function
• Maintain acid-base balance
• Control central nervous system signs such as
  seizures
• Maintain body temperature

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Obtaining a Good History

• If possible an investigation should include the
  animal, the owner, and the affected animals
  environment, with the primary goal of identifying
  possible sources of a toxicant
• Items to include
• Examination of the environment, including feed,
  water, and bedding
• Review management practices and recent animal
  movements
• Timeline of events may help match onset of signs
  with other environmental factors

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Obtaining a Good History

• Collect useful epidemiologic information
• Incidence rates, geographic location, animal
  movements
• Involvement of people in the area
• Signalment species, age, gender, breeds
• As able, review vaccination history, feeding,
  onset of signs and specificity of signs, severity
  and progression of signs, response to treatment,
  recent medications given

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Decontamination

• The goal of decontamination is to prevent
  continued absorption of the toxicant
• Factors to be considered
• Substance involved
• Amount involved
• Time since exposure
• Whether previous attempts at decontamination have
  already been made
• Species of animal involved
• Number of animals exposed
• Any known underlying organ dysfunction,
  especially of the liver or kidneys

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Toxicity

• A nontoxic substance or one with relatively low
  toxicity may not require extensive
  decontamination
• Always attempt to estimate the dose that may have
  been involved, then compare this with known
  toxicity information when available
• When information is not available, be
  conservative and begin decontamination as soon as
  possible

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Deciding to Decontaminate

• Information on toxic properties, concentrations,
  possibility of exposure, routes of exposure,
  type(s) of animal(s) involved, available
  resources, possibilities and probabilities will
  ultimately dictate the tactical decisions of the
  Incident Commander and determine subsequent
  mitigation efforts

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Possible Scenarios

• A terrorist attack with nerve agents, blister
  agents, lungdamaging agents, or other chemical,
  biological or pharmaceutical agents
• Any spill incidents of chemical agents such as a
  transportation accident or after a weather event
• Leaking of chemical agents from an industrial
  factory to water or soil

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Decontamination

• Protect human personnel
• Gloves
• Aprons
• Eye protection
• Ventilation

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Decontamination

• Avoid responder contaminant exposure
• Avoid responder injury from the animal
• Avoid animal self-trauma
• Limit animal handling time

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Decontamination

• Consider sedation or anesthesia
• Most toxin exposures will be ocular, dermal
  and/or oral

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Decontamination

• Bathe dermal exposures
• Eye washes for ocular exposures
• Emesis for witnessed oral exposures

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Dermal Exposures

• Some substances can be removed from birds by
  misting them with room temperature water in a
  warm environment

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Dermal Decontamination

• Liquid dish washing detergent is very effective
  for removing oily substances
• Do not use automatic dishwasher detergents
• Repeat as needed

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Dermal Exposures

• Thorough rinsing is especially important for
  aquatic birds and some marine mammals

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Dermal Decontamination

• Vacuuming for dry compounds
• Shaving or clipping may work well for dried
  paint, tar, etc.

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Dermal Decontamination

• Oily substances can help remove glue traps,
  asphalt, pine sap, etc.
• Do not use solvents!

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Ocular Exposures

• May cause irritation to corrosion depending on
  the substance, the concentration, the exposure
  time and the sensitivity of the patient

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Ocular Decontamination

• Flush with tepid water or saline solution
• Ideally for a minimum of 20-30 minutes
• Do not use Visine or similar products
• Dont forget to flush nostrils, too!

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Ocular Exposures

• Eyedropper can be used for smaller birds or
  reptiles
• With larger patients, fill a plastic cup and
  slowly pour over the ocular area

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Ocular Exposures

• Fluorescein staining should be performed after
  flushing if injury or significant exposure is
  suspected
• Repeat 12-24 hours later
• Treatment with lubricant ointments can follow
  staining

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Oral Exposures

• The purpose of oral decontamination is to prevent
  absorption

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Dilution

• Dilution makes compounds less irritating
• Milk
• Water
• Milk of Magnesia, Kaopectate, Mylanta, Maalox,
  etc.

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Dilution

• Juicy fruits or vegetables may work well with
  birds and reptiles

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Emesis

• Most useful within 30-90 minutes
• DO NOT INDUCE EMESIS
• In species that cannot vomit
• Rodents, rabbits, birds, horses, ruminants
• In symptomatic animals

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Other Contraindications

• DO NOT INDUCE VOMITING IF
• Caustic substances or petroleum distillates have
  been ingested
• The animal has known underlying health problems

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3 Hydrogen Peroxide

• Acts by local GI irritation
• 1 tbsp per 10 lbs, with a maximum dose of 3-4
  tbsp
• Can repeat once
• Works best if given after a small amount of food

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Other Emetics

• Apomorphine is a centrally-acting opioid emetic
  used orally, intravenously, and subconjunctivally
• Use in cats is controversial
• Can use xylazine in cats
• Reversible with yohimbine
• Salt, liquid dishwashing liquid, syrup of ipecac,
  and powdered mustard are NOT recommended

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• But what if Im not sure what the animal may have
  ingested?

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• Or what do I do if I induce vomiting and nothing
  comes up?
• Diluents
• Adsorbants
• Cathartics

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AdsorbantsActivated Charcoal

• Binds most organic compounds and facilitates
  their excretion in the feces
• Powder, gel, or liquid formulations
• Recommended dose is 1-3 grams per kg body weight

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Activated Charcoal

• Can be given orally with a large syringe or a
  stomach tube
• Repeated doses may be useful when enterohepatic
  recirculation is known to occur

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Adsorbents

• Substances that are not well-adsorbed to AC
• Sodium chloride
• Alcohols
• Strong acids
• Alkalis
• Bromide
• Lead
• Iron
• Lithium

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Adsorbents

• Multiple doses of AC can be effective in
  interrupting enterohepatic recycling of numerous
  toxicants
• Digitoxin, phenobarbital, carbamazepine,
  phenylbutazone, dapsone, methotrexate, nadolol,
  theophylline, salicylate, cyclosporine,
  propoxyphene, nortriptylline, amitriptylline
• Multiple doses of AC are also beneficial when
• Large amounts of toxicant are ingested
• Dissolution of the toxicant is delayed
• The toxicant has a delayed or prolonged release
  phase

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Cathartics

• Enhance elimination of substances, including
  activated charcoal, by moving them through the GI
  tract
• Saline cathartics
• Osmotic cathartics
• Bulk cathartics

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Bulk Cathartics

• Use high fiber content to retain water and
  produce bulkier stools
• Metamucil (psyllium)
• Canned pumpkin
• Whole-grain breads

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Other Cathartics

• Osmotic cathartics
• Pull electrolyte-free water into the GI tract
• 70 sorbitol used most frequently
• Often combined with activated charcoal products

• Saline cathartics
• Stimulate GI motility
• Sodium sulfate (Glaubers salts)
• Magnesium sulfate (Epsom salts)

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Other Decontamination Techniques

• Enemas
• Helpful in eliminating toxicants from the lower
  gastrointestinal tract
• Warm water, warm soapy water, DSS

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Cheek Pouches

• May need to be emptied manually or with cotton
  swabs

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Other Decontamination Techniques

• Gastric Lavage
• Should not be used to remove caustic substances
  or hydrocarbons
• Requires general anesthesia and cuffed
  endotracheal tube

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Gastric Lavage

• Instill 5-10 mL/kg tepid water, then evacuate via
  aspiration or gravity flow
• Repeat until washings are clear
• Activated charcoal can be administered via the
  tube before it is removed
• Save the initial lavage sample for possible
  analysis

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Other Decontamination Techniques

• Endoscopy
• Useful for coins, batteries, toys, etc.

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Questions so far?
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Sample Collection and Storage

• With exposures to unknown toxicants, samples are
  often best collected and held until other testing
  can be completed because other test results may
  yield information about not only the organ(s)
  affected, but also the poison itself

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Sample Collection and Storage

• All samples should be labeled regarding the date,
  case, source, description, and a responsible
  partys name
• Samples should not be pooled unless they are from
  the same lot or bunk of feed
• When in doubt, samples for toxicology should be
  frozen
• Exceptions
• Keep hay or grain cool and dry
• Refrigerate whole blood
• Serum and plasma should be spun and removed from
  the clot, then frozen

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Sample Collection and Storage

• Most toxicants cannot be detected in tissues,
  making environmental samples critical to
  obtaining a diagnosis
• Water samples should be obtained at
• The source well, canal, pond
• In transit piping, tankers
• In storage tanks
• The site of exposure

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Sample Collection and Storage

• Fresh plants (flower, greenery, and roots) can be
  wrapped in wet newspaper or pressed in folds of
  dry newspaper for shipping
• Diagnosis of a plant poisoning also requires
  evidence of consumption by the animal
• Abundance of the plant in the area
• Indications of grazing
• Plant material in gut contents

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Sample Collection and Storage

• Serum chemistry and CBC are critical to help
  identify affected organ systems
• Postmortem tissue samples should ideally be
• Formalin fixed for histology
• Appropriately sampled and preserved for
  microbiology
• Frozen fresh in separate containers for
  toxicology testing

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Sample Collection and Storage

• Formalin-fixed tissue is generally useless for
  toxicology testing, though histology can
  sometimes be diagnostic for specific poisonings
• Pyrrolizidine alkaloid poisoning (megalocytosis,
  biliary hyperplasia, periportal fibrosis)
• Aflatoxicosis
• When in doubt, a veterinary toxicologist and the
  diagnostic laboratory should be consulted about
  proper sampling before beginning an investigation
• Samples should always be saved despite any
  initial findings

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Environmental Samples
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Antemortem Samples
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Postmortem Samplessmaller samples OK for
smaller patients
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Questions? Dr. Lisa Murphy murphylp_at_vet.upenn.
edu 610-925-6217
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CASE REPORT

• Tyler
• 6 year-old, male neutered Basset hound
• weighs 38lbs (17.3kg)
• previously in good health
• currently vaccinated

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Presenting Signs

• 30 minutes ago, owners found Tyler disoriented
  and shaking uncontrollably

• On presentation, the dog is seizuring and
  drooling profusely

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Initial Treatment

• 10mg (0.58mg/kg) diazepam given slowly
  intravenously in two 5mg boluses
• Little effect seen
• Additional treatment 60mg (3.47mg/kg)
  pentobarbital given slowly intravenously
• Seizures have stopped, but mild tremor activity
  still present
• T 105.0F

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• DIFFERENTIALS????????

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Possible Differentials

• Strychnine
• Metaldehyde
• Ethylene glycol
• Tremorgenic mycotoxins
• Amphetamines

• Cholinesterase inhibitors
• Methylxanthines
• Pseudoephedrine
• Cocaine

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Additional History

• Owners are in the process of moving back into
  their home after being evacuated for a hurricane
• It is a week later and they have been cleaning up
  their water-damaged home
• The dog was left alone in the house for 3 hours
  today and the owners returned home to find him
  symptomatic
• Tyler was found surrounded by the scattered
  contents of several trash bags

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Trash Contents

• Mayonnaise
• Old bottle of toilet bowl cleaner
• Mustard
• Pickles

• Pasta
• Peanut butter
• Nail polish
• Raisins
• Expired amoxicillin

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And by the way

• The power has been out since the hurricane hit
  one week ago

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So you bravely open the tupperware of pasta

• MOLD!!!!!!!!!!!!!!!

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Tremorgenic Mycotoxins

• At least 20 mycotoxins have been identified as
  tremorgens
• Most commonly associated with Penicillium species
• Most common toxins penitrem A and roquefortine C
• Intoxications demonstrated in dogs, cattle,
  sheep, rabbits, rodents, poultry

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Mechanism of Action

• Several proposed
• May vary both between specific toxins and
  individual susceptible species
• Penitrem-A inhibits the inhibitory
  neurotransmitter glycine in mice
• Another tremorgen, verruculogen, reduces
  concentrations of GABA in the brain

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Treatment

• Diazepam alone may not control severe
  mycotoxin-induced tremors and seizures
• For severe tremors methocarbamol at 55-220mg/kg
  slow IV to effect
• For severe seizure activity not responding well
  to diazepam barbituate such as pentobarbital at
  3-15mg/kg slow IV to effect

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Decontamination in an Asymptomatic Patient

• Consider gastric lavage in patients that have not
  already vomited
• Activated charcoal and a cathartic may limit
  further absorption

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General Treatment Recommendations

• Thermoregulation
• Treat for shock
• Intravenous fluid support
• Prognosis good with early and aggressive
  treatment
• No long-term sequelae expected

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Patient Update

• To ease the persistent tremor activity, 1000 mg
  methocarbamol was given slowly intravenously with
  good effects seen
• 20 grams of activated charcoal with sorbitol
  added was administered
• Lactated Ringers solution was given IV at a
  maintenance rate for 12 hours
• Body temperature was checked hourly

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• 10 hours after admission, Tyler was alert and
  ambulatory with a normal body temperature of
  101.6F
• At the owners request, 500 mg methocarbamol
  tablets were sent home with Tyler to be given as
  1/2-1 tablet (14.5-28.9mg/kg) by mouth as needed
  for any residual tremor activity

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Final Questions?