Toxicology Flashcards
Mechanism of action of strychnine toxicity?
Inhibits glycine, which makes it easier for neurons to fire action potentials leading to tetanus
Signs of lead intoxication? Treatment?
Signs: Acute vomiting Tremoring Abdominal pain Mild anemia with nRBCs
Treatment:
CaEDTA (also treatment for mercury toxicity)
Mechanism of tetanus anti-toxin?
Neutralizes free toxin
Mechanism of botulism toxin?
Blocks ACh release from presynaptic receptors, resulting in flaccid paralysis
Treatment for acetaminophen toxicity?
N-acetylcysteine
Mechanism of cyanide toxicity?
Inhibits ATP production in the mitochondria (i.e. not responsive to oxygen supplementation)
Mechanism of carbon monoxide toxicity?
Binds Hgb with high affinity, preventing O2 from binding
Castor bean (ricin) toxicity – what body system?
Multiple organs but GI primarily
What toxicity is suspected in a dog with increased nRBC’s and tremors?
Lead toxicity
What toxin is most responsive to Silybin?
Amanita mushrooms (aka death cap mushroom)
What does blue-green algae toxicity cause? What is the treatment?
Depends on the strain ingested
Anabaena sp., Aphanizomenon sp., Oscillatoria sp.,, which produce the neurotoxins anatoxin-a (May present acutely with muscle tremors, rigidity, lethargy, respiratory distress, and convulsions.) and anatoxin a(s) (signs consistent with inhibition of AchE. Increased salivation, urination, lacrimation, defecation, as well as tremors, dyspnea, and convulsions)
Microcystis sp., which produces the hepatotoxin microsystin; or Nodularia sp., which produces the hepatotoxin nodularin
Environmental risk factors include warm weather and increased nutrients in water
No specific treatment/antidote, decontamination and supportive care
Prognosis is poor to grave
What is the mechanism of Organophosphates (OPs) & Carbamates (CMs) (pesticides) toxicity and what is the treatment?
AChE inhibitors
CS: SLUD (salivation, lacrimation, urination, defecation), muscle twitching, ataxia, depression
Tx: Atropine, 2-PAM (pralidoxime)
In which toxicoses are Intravenous lipid emulsion therapy indicated? What are the potential adverse effects
Any lipophilic drug in which other standard of care therapy has been exhausted (i.e. other antidotes administered where available, supportive care, and patient continues to show signs of circulatory collapse
Drugs: bupivacaine, clomipramine, verapamil, bupropion, mepivacaine, ropivacaine, haloperidol quetiapine, doxepin, carvedilol, carbamazepine, flecanide, hydrocloroquine, amlodipine, propanolol, moxidectin, ivermectin
Adverse effects: Thrombophlebitis due to contamination of solution, anaphylactoid-like reaction, fat-overload syndrome
What is the mechanism of Pyrethrins & Pyrethroids toxicity and what is the treatment?
Bind to Na+ channel, cause depolarization (insects much more sensitive to effects than mammals); most tox occurs when cats are treated with a product not intended for them
CS: hypersalivation, paw shaking, ear and skin on the back twitching, and flicking of the tail; Within 12-18 hours, cats exhibit agitation and tremors and can be seizing by 18-20 hours. Untreated cats may die within 24 hours.
Tx: Bathe with dish soap, methocarbamol, diazepam
What is the mechanism of Fipronil (pesticides) toxicity and what is the treatment?
Fipronil non-competitively inhibits the GABA-induced ion influx, causes hyperexcitation of CNS
Toxicity occurs due to ingestion/licking of Frontline
CS: tremors, convulsions, seizures and death
Tx: Bathe with dish soap, symptomatic care
