Tox- Small animal tox part 2- common encounters 2

wilsbach's version from 2016-04-28 20:14


Question Answer
anticholinesterase toxicity: what product is this toxin in? how does it work?in insecticides, Inhibition of acetylcholinesterase (AchE) in synapse, ACh builds up, over excitement at NM junction etc. OVERSTIM OF THE POSTSYNAPTIC NEURON.
which is worse- organophosphates or carbamates? what is the MOA?Organophosphates are WAY worse. they are way more effective, can cause irreversible buildup, are quicker/more severe/ longer lasting. Both OPs and carbamates are anticholinesterases.
what is timing important with organophosphates?they permanently bind at 12-24hr
3 major areas ACh works in, and therefore, the 3 major areas affected by anticholinesterases? (OPs, carbamates)(1) MUSCARINIC: (postganglionic parasymp) see SLUDGE signs: salivation, lacrimation, urination, defecation, GI signs. also miosis and bronchoconstriction. (2) NICOTINIC: (preganglionic, parasymp, incld NM junction) MM tremors, twitching, weakness, paralysis. (3) CNS: seizures, convulsions, obtundation, coma
what do you do a atropine test dose for? what does it tell you?Do atropine test in antiACh tox: If its truly a OP/carb tox, the signs might get a little better but wont totally go away. This is bc atropine only works on muscarinic receptors, and OPs work on muscarinic, nicotinic, AND CNS. (so if you give atropine and theyre totally better, its not OP)
antidotes for treating OP/carbamate (antiAChase) tox?If you give both ATROPINE (for muscarinic) AND 2-PAM (Pralidoxime) (for nicotinic) THEN all the he CSs can go away. Also consider diazepam (anticonvulsant, sedative.). Obv early tx includes decontamination too (emesis, gastric lavage, charcoal)
WHO are you most likely to see pyrethrin tox in?CATS
pyrethrins: what products do you see these in?these are INSECTICIDES, used as flea control products (spot ons)
Pyrethrins: MOA?not toxic for mammals until INGESTED. It is rapidly absorbed from the GIT (high bioavailability), and causes a NEUROTOXICITY--> PNS, CNS, and other organ impact. Works by: Disrupts voltage sensitive Na+ channels--> slow channel activation and opening.
CSs of pyrethrin tox? (remember Disrupts voltage sensitive Na+ channels in nerves and stuff) Hypersalivation, Hyperexcitability, tremors, GI signs (v/d), Paraesthesia of area where applied, Disorientation, Hyperthermia (bc of convulsions), Seizures, depression.
tx and px of pyrethrin tox?(1) DERMAL DECONTAMINATION (bath them! if they call from home, have them bathe them before they even come in) (2) Supportive care: activated charcoal (unsure if it works), Diazepam to make them relax, Methocarbamol (mm relaxor), Cooling, fluids, monitoring
hepato-toxic mushrooms: what species?Amanita
when do you start to see signs of Amanita poisoning? what are the various signs you will see?6-12h NO symptoms, then suddenly SEVERE GI signs, 12-24hrs Hepatotoxicity/Fulminant liver failure: Hypoglycemia, Hypoalbuminemia, Coagulopathy!, Icterus, Abdominal pain, Hypovolemic shock.
how do you tx hepatotoxic mushroom tox (Aminita)?SUPPORTIVE, maybe biliary aspiration? bile reuptake inhibitors, antioxidants (Silbinin, SAM-E), maybe dialysis? Basically this is the worst, if showing CSs probably gonna die. Euthanasia is a very real option.
Xylitol: what are the 2 major problems xylitol tox causes?(1) HYPOGLYCEMIA: xylitol stims pancreas to excessively release insulin-->Weakness, disorientation, tremors, seizures. (2) Hepatic necrosis: unknown MOA, seen with higher doses 8-12hr post ingestion.
tx for xylitol tox? supportive, dextrose (taper before discharge to see if they still need it or not), IVF, monitor chemistry, hepatic antioxidants (SAMe, silymarin)
pathophys of methylxanthine (caffeine, theophyline, theobromine) tox↑iCa2+, catecholamine release (vasopressors, epi, adrenaline, tcachy, restless, anxiety) (from werners: bind to adenosine receptors and antagonize it, --> excitation. ALSO inc INTRACELLULAR Ca++ which inc contractility of the heart and inc NT release)
CSs of methylxanthine tox? Tx?Initially GI – v/d, Tachyarrhythmia, Hypertension.. TX: GI decontamination, fluid diuresis, Symptomatic, supportive
most toxic methylxanthine to worry about?theobromine
severity of chocolate (methylxanthine) tox depends on?depends on type of chocolate. baking chocolate>milk.
explain CSs of a low(20mg/kg), med(40mg/kg), and high(60mg/kg) dose of chocolate/theobromineLOW: general signs: agitation, hyperactive, GI signs. MED: carciac signs (hypertension, tachy). HIGH: Neuro signs: tremor, twitch, seizure
which things doesnt charcoal work for again?alcohol, xylitol
tx for choco tox?start with emesis/charcoal, then supportive (IV fluid, anxiolytics, antiarrythmic, anti hypertensive) be sure to monitor mentation, TPR, BP, ECG
blue-green algae/cyanobact: what IS this?microscopic bacteria that “bloom” or colonize in bodies of fresh & brackish (warm weather). blooms= hundreds to millions of algae. Turn water green (or red, or orange...)
when is seasonally highest risk of seeing cyanobact tox? Levels increase during summer (swimming, lots of sun)
if every cyanobact toxic?no, about 80/2000 sp are toxic, but 80 is still a lot.
what are the two major types of toxins found in cyanobacteria? 2 major things they do?Microcystins (hepatotoxins) & anatoxins (anatoxin –a and anatoxin-as), powerful neurotoxins*****
microcystins are from what/ what do they do?HEPATOtoxin from cyanobacteria
anatoxins are from what/do what?POWERFUL NEUROTOXINS from cyanobacteria
how do dogs/animals/humans get intoxicated with cyanobacteria?A few mouthfuls of contaminated water can cause fatal signs. Suggested absorption thru respiratory & skin possible
what are the CSs from cyanobact tox?(1) From the MICROCYSTINS: HEPATIC signs within 30 mins: Anorexia, lethargy, vomiting, diarrhea, weakness, and pale mucous membranes, shock, death. Restlessness, recumbency, and seizures prior to death (hepatic encephalopathy). (2) Anatoxin-a: signs within minutes to hours. NEURO toxin, so see cyanosis, respiratory failure, stiffness, muscle tremors, Paralysis and death in minutes to a few hours. +/- salivation, lacrimation, excess urination, and diarrhea
tx/px for cyanobact toxRinse exposed animals thoroughly, No specific antidote. Survival might be possible with EARLY AGGRESSIVE supportive care. IF showing CSs, prog is poor. **CAUTION OWNERS TO PROTECT THEMSELVES