Management of poisoned small animal Flashcards
When to think about poisoning?
- sudden onset of illness or sudden death in otherwise healthy animal
2.illness following recent change in food, medications, environment
- animal left in environment for extended period with potential access to poisons (garage, farm)
- Vague, non-specific illness that has not responded to other treatments
- concerns for intentional poisoning
- if bloodwork findings unexpected
Approach to a poisoned animal
- stabilize patient
- history/research of toxin. Physical exam
- decontamination
- give antidote if possible
- minimum database (CBC, chem, UA)
- symptomatic and supportive therapy (include monitoring)
Evaluating the patient
Immediate poisoning is highest priority of triage
-check for airway, breathing, circulation, disability, external assessment)
-smell on fur, remnants on body
-TPR (hypo/hyperthermia, HR, pulse, MM colour, CRT, RR)
-neurological assessment
Taking a Toxicology history
-What? (name of product, name of drug, dose, all ingredients)
-How much? (estimate ingested amount, compare LD50 or minimum lethal dose)
-When?
-Other: current meds, other animals involved, significant health history, any other treatments tried?
Two important aspects of toxocological history
- ID and treat immediate life threatening problems
*do not wait for confirmation of poison to start supportive therapy - Always treat the patient, not the poison
Purpose of decontamination
To minimize absorption and/or promote elimination; to dilute or remove irritant or corrosive
**used when benefits of decontamination outweighs risks
What is involved with decontamination?
Depends on route of exposure: ocular, dermal, GI, inhalation
- most cares are ingested= GI
*can induce emesis, administer charcoal, and/or gastric lavage
Emesis
The action or process of vomiting (empty stomach and proximal duodenum)
**first line of defense for GI
Indications for emesis
- recent ingestion (<1-2hrs post ingestion, within 30-60mins)
- Effective for small, uncharged molecules and weak acids
- Asymptomatic patient- likely not reached target sight of action so can induce
- unknown ingestion
What should you do if animal you want to induce vomiting but animal has empty stomach?
Give a small meal before inducing vomiting
What is vomiting?
What is regurgitation?
What drugs are used to induce vomiting in dogs or cats?
Dogs: Apomorphine
Cats: Xylazine (on NAVLE), Dexmedetomidine, hydromorphine
Efficacy of emesis in dogs
- Apomorphine: 94% of dogs within 27mins
- 3% hydrogen peroxide: 90% of dogs vomited within 42mins
Efficacy of emesis in cats
- Dexmedetomidine: 81% cats
- Xylazine: 44%
- no cats vomited when given hydrogen peroxide
What are contraindications for inducing emesis?
- symptomatic patient
-neurological animal- very risky if they aspirate
-lack of pharyngeal reflexes, laryngeal paralysis, megaesophagus
-hypoxia, weakness
-agent type: corrosive or volatile materials, sharp materials, agents with rapid onset
-animal vomiting or has already vomited
-brachycephalic dogs
-animals that can’t vomit (rabbits, rodents, birds, horses)
What factors would you keep in mind when proceeding to vomit?
-brachycephalics
-history of seizures
-very young or very old
-recent GI surgery
-significant underlying disease
Risks of emesis?
-aspiration
-lack of efficacy
-sedation
-intussusception
After emesis?
-consider hydration status
-ensure animal cannot consume its vomit
-administer anti-emetic
Potential anti-emetics
-Maropitant (cerenia)
-Ondansetron (Zofran)
-Metoclopramide
Hydrogen peroxide use for emesis
-must be 3%
-only for dogs
-ensure fresh/unexpired= bubbly
Mechanism of hydrogen peroxide
Stimulates the pharyngeal receptors (CN IX) and local gastric irritation
Dose of hydrogen peroxide for emesis
1-2ml/kg (max 3 tablespoons)
Potential side effects of using hydrogen peroxide in dogs
-GI irritation and ulceration
-aspiration
-lack of efficacy
-GDV
What methods not to be used to induce emesis at home?
-salt
-mustard powder
-syrup of ipecac
-liquid dishwashing fluid
-your finger
-no spinning animal
Ropinirole (clevor)
-new emetic
-full DA-receptor agonist= highly selective for D2 receptors. No D1 receptor activity or opioid receptor activity
-ophthalmic solution
-effective but not superior to apomorphine
*side effects: protracted vomiting, ocular signs
What is activated charcoal?
-high heat and temperature processed wood
*very porous
Activated charcoal
Used to absorb compounds in GIT to decrease absorption
-give at recent ingestion; asymptomatic stable patients
Contraindications of activated charcoal
-Does not bind to alcohols, xylitol, hydrocarbons, metals, nitrates/nitrites, caustic/corrosive agents, salt, chlorates
-severe dehydration- need to give them fluids
-potential for GI surgery
Risk of administration of activated charcoal
-hypernatremia
-poor visibility during endoscopy
-aspiration
Dosing activated charcoal
-give immediately after pet has vomited
-first dose should contain a cathartic
-only really need to give once
-can be given in food, through OG tube or syringing
-keep head level to avoid aspiration
Risk factors for hypernatremia
- dehydration
- vomiting, fasting, incapable of drinking
- Predisposition for electrolyte imbalances (CKI, endocrine diseases, psychogenic polydipsia)
- Poisons that cause hypernatremia (chocolate, bromethalin, salt, playdough)
What is the function of cathartics?
Reduces GI transit time= enhanced fecal expulsion
Options for cathartics
- Ingredient in ToxiBan
- Sodium sulfate (Glauber’s salt)
- Magnesium sulfate (epsom salt)
Contraindications for cathartics
-GI stasis
-ingestion of a caustic substance
-patient is hypotensive and/or volume depleted
-Patient has diarrhea or has been given a laxative
-Renal insufficiency, electrolyte imbalance
What is gastric lavage?
Flushing the stomach with water through an OG/NG tube to remove stomach contents
*performed under sedation or GA with endotracheal intubation
*better than emesis, but labour intensive
Indications for gastric lavage use
-animal cannot vomit
-emesis has been unsuccessful
-large volume of stomach contents present
-symptomatic patient
-potentially lethal exposure
eg. chocolate, bread dough, specific drugs
Contraindications for gastric lavage
- Hydrocarbons or corrosives
-liquid toxicants
-patient is unstable
-patient has a high risk of bleeding/injury
-recent surgery
-too long post-ingestion (ie. not in the stomach anymore)
What volume and number of cycles are needed for gastric lavage?
-5-15 cycles
-approx 20ml/kg water
-need large tube that allows contents to actually evacuate
-kink tube to avoid aspiration
Other than induced vomiting, and gastric lavage, what other methods of GI decontamination are there?
-dilution (eg. milk for corrosive substances)
-endoscopy )batteries, coins)
-whole bowel irrigation
-surgical removal (ex lap)
-enemas
Purpose of dermal decontamination
-prevent transdermal absorption or prevent secondary exposure through self grooming
Methods of dermal decontamination
**proper PPE for staff, watch temperature, put cone on them
-wash with gentle degreasing liquid dish soap
-be gentle with caustic materials
-clip hair if needed
What to avoid when undergoing dermal decontamination?
-high temperatures
-high pressure sprays
-aggressive scrubbing
-soaps with essential oils
Ocular decontamination
Used to prevent corneal damage or damage to deeper structures of the globe
**corrosive and irritant agents
Examine eyes afterwards to check for damage
How to perform ocular decontamination?
Rinse eye medial to lateral with tepid water (tap, saline, distilled) for 20-30mins
**owner can start at home but sedation may be needed
Inhalational decontamination
-use if signs of irritation, increased secretions, pulmonary edema, aspiration
-move them to fresh air/ ensure ventilation in area because otherwise it is an occupational hazard
Ion trapping
Alter the ionization status of the agent to prevent reabsorption and enhance elimination
*acidification for weak bases, alkalization for weak acids
Dialysis
Blood is filtered externally and returned to the patient
*rare in clinics
Forced diuresis
Promote excretion of renally-eliminated toxic agents
*risk of fluid overload and result in increased nephrotoxicities
Antidotes
Most toxins do not have an antidote and some that do only work within a small window
-can have side effects, be costly, hard to get, and not guarantee success
Antidotes
