Derek James
Flashcards by Derek James, updated more than 1 year ago
Derek James
Created by Derek James over 5 years ago



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Question Answer
What is Toxicology? science and study of poisons (toxicants) and their effects on living organisms
What is a toxicant? toxicant- solid, liquid or gas that interferes with life processes (molecular, organism, population levels); can be organic, inorganic, metallic, biological and natural or synthetic agents
What is a dose? The amount of the toxin to which the animal is exposed.
Threshold Dose Highest dose of a toxicant that effects are not observed
Dosage rate amount of toxicant÷weight or mass of animal÷time
Therapeutic Index The ratio of the dose known to produce a toxic effect in 50% of a population vs the dose known to produce an efficacious effect in 50% of the population. Larger ratio = safer AKA Safety Margin
Sources of variance in toxic response regarding the animal 1. Species Differences 2. Genetic Polymorphisms 3. Age 4. Concurrent Disease
Sources of variance in toxic response regarding the exposure 1. Route or site of exposure (IV vs ingestion) 2. Duration of exposure 3. Frequency of exposure 4. Magnitude of Exposure
TD50 Toxic Dose for 50% of animals in the pop'n
LD50 Lethal Does for 50% of animals in the pop'n
toxicokinetics What the body does to the chemical (determines organs/tissues affected). ADME- absorption, distribution, metabolism and excretion.
toxicodynamics what the chemical/metabolite does to the body (physiologically, biochemically, molecularly); depends on the mechanism of action of the chemical; basis for most toxicants is cellular damage (by altering pH, occupying receptors, free-radical production, lipid peroxidation)
Stabilize CAB in that order Circulation, airway breathing
POISONED PATIENT.... ZOMG what do I do? -On the phone -This is your chance to TRIAGE. -How serious (see it or no?)? Manage conservatively? Can they bring sample, vomit, feces? -Who (animal questions)? What (source, route, container)? When (timeline)? Where (outdoor animal?)?
POISONED PATIENT.... ZOMG what do I do? -At the hospital •You need to quickly assess the respiratory system, CV system, renal system and neuro •You should have the meds you need ready for the patient - •STABILIZATION OF THE PATIENT COMES FIRST - stabilize CAB in THAT ORDER first - circulation, airway, breathing
Stabilizing/Supportive Care •Respiratory Cause of resp distress? May need to intubate? Hypoventilation hypercapnia or hypoxemia may need to be treated, assess oxygenation of patient, be cautious of using respiratory stimulants due to CNS hyperactivity
Stabilizing/Supportive Care •Circulatory (BV and O2 content of blood, heart function, integrity of BVs, may need to stabilize the circulatory system by ECG/BP monitoring, etc, hypovolemic shock treatment with crystalloids or colloids, interstitial fluid losses, altered cardiac performance can result in reduced BP and tissue perfusion, altered BP can require use of vasoactive agents: hypotension= <60 vasoconstrictors, hyper=>140 vasodilators
Stabilizing/Supportive Care •CNS may need to treat animals who are experiencing seizures/trembling, tremors in ABSENCE of seizures with diazepam and methocarbamol, seizures with diazepam and then phenobarbital
Stabilizing/Supportive Care •Body Temp •monitored continuously with rectal probes if patient is unconscious, •hyperthermia=>42C can cause cellular damage/organ failure-->use surface cooling, •hypothermia=<32-34C causes CNS depression-->use blankets etc
POISONED PATIENT.... ZOMG what do I do? -At the hospital decontamination •remove the source of the poison to prevent further absorption ASAP •includes PEOPLE involved like the vet, staff, owner, etc. •when source is unknown - change location of animal, change feed/water
Induction of emesis at home •If the trip to the clinic is greater the 1h •Hydrogen Peroxide 2ml/kg (large dog), 10 ml (cats •Ipecac 3ml/kg in cats, 1-2ml/kg dogs (less effective). Gastric lavage if emesis fails. •Repeat after 15 min if needed
induction of emesis at the clinic in cats •xylazine in cats (can reverse if necessary) - 0.44mg/kg IM •Reversible with yohimbine/atipemazole •Adverse effects are sedation and bradycardia (this is a sedative remember!)
Induction of emesis at the clinic in dogs apomorphine for dogs (put in conjunctival sac), Don’t use in cats 6mg tabs to dissolve in water or saline, or injectable SQ 0.3mg/kg, or can give in conjunctival sac and then wash out after Activates dopamine receptors in the CNS Too much = CNS or respiratory depression - reverse with naloxone
Gastric lavage •When evac req'd but emesis doesn't work •Req's anesthesia, protect airwary (inf cuff) •Tepid water/saline, low pressure, tilt head •Initial lavage for lab, kink tube at removal •Poor recovery >60m post ingestion •Precautions to prevent aspiration
Activated Charcoal Treatment •1-2g/kg premeals with follow up of.25-.5g/kg does for 1-6h up to 3d •Different forms, aqueous slurry, powder, tablets •Makes poo black... tell owner
When is activated charcoal a good call? When are they a really good idea? When large amount of toxins are ingested, when the toxicant has a delayed or prolonged dissolution or release phase, and when the toxicant undergoes extensive enterohepatic recycling . When you don't know what the toxicant is.
When does activated charcoal perform poorly? Toxicants of these classes: •small, polar (hydrophilic) agents like alcohols, strong acids, strong alkalis, •metals like iron, lead, and lithium
Cathartics •hasten GI transit time via the stool (e.g. Metamucil and pumpkin) •Saline or saccharides, mineral oil •Don't use in dehydrated animals •One use, don't give 2nd dose if 1st fails •Caution in young or old patients.
Cathartics- Mineral Oil •Often used in horses-careful of aspiration •In small animals, elim'n of oil based toxins
Gastrototomy/Endoscopy •Physical Removal of foreign bodies •such as zinc containing pennies, button batteries, galvanized metal, lead
Topical Toxins •Treat by mild shampoo baths, wear PPC •Act'd Charc' if grooming suspected •Rinse eyes w saline (sedation maybe) • Chemical burns treated with saline or warm water lavage.
Detoxification Goal to hasten elimination of abs'd toxicant Methods: Diuresis/dialysis, ion trapping, antidotes
Forced Dialysis/Diuresis •risk-benefit is important, IV admin of Na solutions +/- diuretic can assist in hastening elimination of toxin via kidney •bromide, lithium, salicylates and amphetamines are things you’d force dieresis for •need to weigh out electrolyte concerns vs. risk of volume overload
ion trapping •trap in urine exc'd by kidneys, toxicant needs to be exc'd unchanged by kidneys •alkalization of pee =pH>7 w NaHCO3 traps weak acid (ethylene glycol & salicylates) •acidification=pH5.5-6.5 w NH4Cl - enhances elim'n of weak bases of strychnine and amphetamines
Antidotes therapeutic agents that have specific action against toxicant/effects, interact with toxicant to neutralize it, antagonize the effects of toxicants at R site or through inhibition of pathways that make metabolites or by restoring altered body functions
SLUDGE(M) Salivation, Lacrimation, Urination, Diaphoresis, GI upset, Emesis, Miosis
Acid Burns cause coagulation necrosis (by coagulation of proteins) acts as a barrier to further penetration
Alkali Burns •cause liquefactive necrosis, facilitates rapid, deep dissolution of tissue (much more severe)- this causes deeper and severe burns; does not form a barrier to further penetration therefore damage is much more severe and can form perforations and ulcers
General concepts about soaps, detergents, cleaning agents • detergents contain inorganic--> non-ionic, anionic or cationic compounds • clinical signs= GIT V/D can cause electrolyte imbalances for CNS/heart •Hemolysis if metabolite exc'n impaired •Treat by decont'n and support
Soaps •soaps= salts of FAs (rxn of fat w alkalis) •may cause GI signs (vomiting, diarrhea) • Alkali may cause caustic burns, (homemade soap, washer detergents may contain free alkali- NO EMESIS) •low tox common, ingestion rare d/t taste •Tx, emesis (non alkali), Dilution (oral milk or water, Fluids if dehydrated.
Non-ionic detergents •Generally low tox •e.g. many hand dishwashing detergents, shampoos, baby soaps, mild soaps   Usually GI signs (vomiting), mild corneal damage, Ingestion uncommon •Tx: Decontamination, Dilution, Fluids if dehyd'd
Anionic Detergents •Mild to mod tox (usually not fatal) • E.g. Sulfates, sulfonates in laundry and dishwasher detergents •Esophageal 1º concern, non-phosphate containing cause most damage •Well abs'd in GI and metab'd in liver (IV hemolysis), can cause corneal opacity and erosions. Main signs V/D, nausau Ocular lesions more severe
Anionic Detergents Tx •Ingestion uncommon but very harmful •Treatment: -Decontamination (flush skin/eyes) -Dilution (oral milk/water) -Activated charcoal? -Fluids if vomiting/diarrhea severe
Cationic Detergents General •Toxicity high to extreme because they are Quaternary ammonium compounds • e.g. some detergents, fabric softeners, sanitizers, germicides •1% formulas cause mucosal damage, and 7.5%+ cause severe caustic damage Alcohols often added- increases absorption from GI
Cationic Detergents Symptoms • Severe oral & esophageal caustic burns, severe ocular damage - MUCOSAL DAMAGE •Profuse salivation, hematemesis, CNS depression, weakness/muscle fasciculations, respiratory depression, seizures, coma
Cationic Detergents Tx Decontamination (flush skin/eyes) , Dilution/deactivation (milk, egg whites) - this inactivates the compounds, Activated charcoal? Fluids to correct electrolyte imbalances ***DO NOT INDUCE VOMITING *** ***Do not give acids***
Should you give acids to treat cationic detergent toxicity? if you give acids to neutralize it, it produces a ton of heat which is way too risky
Acidic corrosive/caustic cleaning products toilet bowl cleaners, anti-rust compounds, swimming pool cleaners, automotive batteries acids produce coagulation necrosis that prevents deep penetration of mucosa, pain limits ingestion
Alkali corrosive/caustic cleaning products general •many cleaners (drain/toilet bowl cleaners/homemade soap containing lye) •immediate liquefactive necrosis which can penetrate deeply (esophageal perforation--> can cause strictures with scarring) - may obliterate the esophagus or cause gastric perforation
Alkali corrosive/caustic cleaning products treatments •treat with dilution by milk/water, do not lavage due to perforation risk, AC doesn’t work, may need supportive care such as fluids or intubation, steroids can prevent stricture formation, may need pain meds - they will be in SEVERE pain
Alkali corrosive/caustic cleaning products symptoms •effects similar to cationic detergents, or worse •involve rapid onset of severe pain, inability to swallow, hematemesis, respiratory distress, abdominal pain, shock
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