Toxicology Flashcards
How should we go about treating toxicity cases?
Treat the ptx not the toxin
major body assessment: what can kill our ptx first and how can we get that under control?
What is there to consider when dealing with a toxin?
What?
When?
How much (toxic dose, volume)
Clinical signs?
Recumbent/seizure/gag reflex
Pharmacokinetics (enterohepatic, renal, charcoal binding, antidote)
Risk of treatment?
What are the potential treatments for toxins?
emesis
gastric lavage
enema
activated charcoal
sorbitol (cathartic)
IVF
dermal decontamination
antidotes
intralipid
dialysis
What are the categories for ddx?
VITAMIN D
- vascular
- inflammatory/infectious/immune mediated
- toxin/trauma
- anomalies
- idiopathic/iatrogenic
- neoplasia/nutritional
- degenerative
What is considered a toxic dose?
lethal dose in 50% of animals
What are the indications for emesis as tx for toxins?
ingestion under 4h
this depends on what is ingested as well
What are the contraindications for emesis as tx for toxins?
neurological changes: recumbent, unconscious, no gag, seizure
caustic (acid/alkali/bleach)
petroleums
detergents
What are the complications possible with emesis as tx for toxins?
aspiration pneumonia
How do we induce emesis?
apomorphine for dogs
xylazine, medetomidine, dexmedetomidine for cats
What are the indications for gastric/colonic lavage as tx for toxins?
ingestion under 4h
emesis contraindicated
ingested large amounts
What are the contraindications for gastric/colonic lavage as tx for toxins?
caustic
What are the possible complications for gastric/colonic lavage as tx for toxins?
aspiration pneumonia
cuffed et tube
hypothermia
How do we do a gastric lavage?
general anaesthesia, cuffed et tube (length from muzzle to last rib)
water, slosh in abdomen, tube below animal to empty and repeat until no contents left
kink tube so contents dont link in oesophagus when removing
What are the indications for activated charcoal as a tx for toxins?
toxins which can bind to charcoal
enterohepatic metabolism
What are the contraindications for activated charcoal as a tx for toxins?
recumbent, unconscious, no gag, seizure
what DOES NOT bind to it
What are examples of toxins that do not bind to activated charcoal?
ethylene glycol
alcohol
alkali
petroleum
heavy metals
xylitol
What are the possible complications for activated charcoal as a tx for toxins?
aspiration pneumonia
if containing sorbitol: dehydration
ONLY USE ONCE
What are the indications for diuresis as tx for toxins?
renal excretion of toxins
nephrotoxic
What are the contraindications for diuresis as tx for toxins?
risk of fluid overload
-anuric/oliguric
-cardiac dz
-pulmonary dz
How do we use diuresis as tx for toxins?
6+ml/kg/h IVF for 48-72h
if anuric/oliguric use furosemide
What are the indications for dermal decontamination as tx for toxins?
dermal toxins ex: permethrin, engine oil, oil on birds
What are considerations to think about when using dermal decontamination as tx for toxins?
hypothermia
sedation
How do we use dermal decontamination as tx for toxins?
clip contaminated area
wash with vegetable oil + dish washing liquid
What are the indications for intralipids as tx for toxins?
lipophilic toxins
What are examples of lipophilic toxins
local anaesthetics
ivermectin
permethrin
naproxen
baclofen
marijuana
mycotoxin
tca, b-blocker, ca channel blocker
What are the adverse affects of intralipids?
lipaemia
pancreatitis
hypersensitivity
What is the antidote for opioids?
naloxone (antagonist)
what is the antidote for alpha 2 agonists
atipamezole (antagonist)
What is the antidote for benzodiazepine?
flumazenil (antagonist)
What is the antidote for ethylene glycol?
ethanol
4-methylpyrazole
What is the antidote for paracetamol/acetaminophen?
N-acetylcysteine
What is the antidote for NSAIDs
misoprostol
What is the antidote for anticoagulant rodenticide?
vitamin k
Which toxins can you use dialysis as a tx against?
ethylene glycol
baclofen
paracetamol
ibuprofen
ivermectin
aminoglycosides
ethanol
mushroom
Where is metaldehyde found and what are the CS?
substance found in common slug/ snail pellet
toxin causes neuroexcitation
- increased monoamine oxidase activity
- decreased gaba activity
- decreased noradrenalin/serotonin
neurological, heat stroke, V+
30min-4h onset
Where can mycotoxins be found and what are the CS?
alfatoxin and mouldy food
vomiting, tremors, hepatopathy
increased liver enzyme activity
What is the moa and tx for mycotoxins?
moa: liver necrosis, cross bbb to cerebellum
lipid soluble
control tremors: methocarbamol, diazepam
GI decontamination
activated charcoal
intralipid
Where are methylanthines found and what are the CS?
chocolate, coffee, theophylline
antagonises adenosie receptors: CNS stim (seizure, tremor), tachycardia (SVT, VT), vasoconstriction
phosphodiesterase inhib: increase intracellular Ca+: increase cardiac contractility, muscle contractions
What is the toxic dose of methylanthines?
20mg/kg
What is the tx for methylanthines?
GI decontamination
activated charcoal
beta-blockers
urinary catheter vs absorbed by bladder
Where is permethrin found and what are the CS?
spot on flea for dogs toxic to cats
cats lack of glucuronide stimulation
bind to na+ channel: repeated stimulation: hyperexcitability, tremors
What is the tx for permethrin?
wash with dishwashing liquid
intralipid
methocarbamol, midazolam, propofol
What causes anticoagulant rodenticide to be toxic?
vitamin k antagonism
and vitamin k is required for many coagulation factors
What are the CS for anticoagulant rodenticide?
hx
increase PT within 48h
increase APTT later
haemorrhage (incl. pulmonary) if under 48h
What is the tx for anticoagulant rodenticide?
recent ingestion: emesis + activated charcoal
test PT at 48h: if prolonged also give Vit K PO w/ fatty foods for 1-6 weeks
if clincial (active bleeding): fresh frozen plasma, start vit k.
if half-life of rodenticide unknown repeat PT 48h after stopping vit K
What are the toxic doses of paracetamol/acetaminophen?
cats: under 20mg/kg
dogs: high doses 200mg/kg
What is the moa/CS of paracetamol/acetaminophen toxicity?
oxidative damage to RBC: methaemoglobinaemia, haemolysis, hepatocellular damage
anaemia: ahemolytic, heinz body
increased Tbil and ALT
What is the tx for paracetamol/acetaminophen?
activated charcoal
n-acetylcysteine
vit C (reduces methaemoglobin to haemoglobin)
cimetidine
What are the CS of NSAID toxicity?
GIT ulcer, renal failure
What is the tx for NSAID toxicity?
emesis
activated charcoal
misoprostal (dogs)
omeprazole
IVF
What are the clinical signs for ethylene glycol toxicity?
stage 1 under 6h
- git, cns, pu/pd, acidosis
stage 2 12-48h
- potentially transient recovery
stage 3 24-72h
- oliguric/anuric renal failure
high mortality
azotaemia, isosthemuria
calcium oxalate crystaluria
high anion gap metabolic acidosis
hallow sign on kidneys
woods lamp on urine
What is the tx for ethylene glycol?
inhibit it: fomepizole
compete for binding: sterile ethanol or vodka IV
IVF
supportive care
What are the CS of lily toxicity in cats?
git, pu or oliguria
azotaemia, isosthenuria
What is the tx for lily toxicity?
emesis
activated charcoal
IVF
What are the moa/ CS of Xylitol?
increase insulin levels= hypoglycaemia
hepatic necrosis
increase ALT, ALKP, Tbil
increase PT/APTT
decrease alb, chol, urea, glucose
What are the tx for xylitol toxicity?
glucose bolus + CRI
liver protectants
supportive care
What are the CS of marijuana toxicity?
variable
lethargy
ataxia
vomiting
urinary incontinence
agitated/irritable
mydriasis
twitching
lateral recumbency
etc.
What are the toxins that cause seizures/tremors?
metaldehyde
mycotoxin
theobromine
permethrin
lead
organophosphate
recreational drugs
What are the toxins that cause anaemia due to coagulation issues?
rodenticide
hepatotoxin
What are the toxins that cause anaemia due to haemolysis issues?
paracetamol (cats)
onion/garlic
heavy metals
What are the toxins that affect the renal system?
ethylene glycol
NSAIDs
Aminoglycosides
lilies (cats)
raisins/grapes (dogs)
What are the toxins that affect the hepatic system?
xylitol (also hypoglycaemia)
cycad
mushroom
paracetamol
