L2: Diagnosis and Treatment of Toxicity (Martyniuk) Flashcards
In a patient with intoxication, what should you do first?
assess patient, evaluating for immediate life-threatening problems. Assess:
-Cardiac (brady/tachycardia)
-Respiratory (apnea, shallow breathing)
-Seizures
-Hemorrhage
-Temperature (hypothermia)
Then obtain brief history including duration of signs, initial signs, age, prior health status, environment, diet
3 most lethal compounds for small animal
rodenticide
ethylene glycol
organophosphates (pesticides)
Respiratory maintenance
- unconscious, paralyzed, paretic, or severe resp. distress patients are candidates for intubation
- intubation required if no voluntary breathing effort or if you plan to do gastric lavage
- prevent aspiration of vomitus by placing head lower than body
Control of breathing
- if animal hypoventilating (hypercapnic PCO2 >45mmHg, acidotic pH 7.35), ventilation with room air may be required
- if hypoxemia present (PO2 < 65mmHg), treat with 40% oxygen. May need assisted ventilation
Control of CNS activity
Hyperactivity (seizures):
- Diazepam (tx of choice if etiology unknown)
- Phenobarbital (or pentobarbital)
- Methocarbamol (causes skeletal m. relaxation and may be useful in controlling seizures)
- most are GABA agonists (GABA is inhibitory for seizures)
Depression:
-Analeptics such as Doxapram (can make stabilization difficult)
Things to do while stabilizing the patient
- obtain venous access and draw for laboratory profile and potential diagnostic testing (ideally pre-medicating)
- once stable, perform thorough PE
- fluid therapy (balance electrolyte solution for shock/dehydration)
- monitor urine output
less than what percent of poisonings are intentional?
1%
health history should include:
- illness in past few months
- recent animal exposure
- vax current
- medications, sprays, dips, antihelmintics, etc. in past few months
current clinical history should include:
- how long problem present
- when observed sick
- when animal last seen healthy (if dead)
- size of herd
- morbidity/mortality numbers
CNS CS ex.
head-pressing, circling, ataxia, seizures, depression,etc.
GI CS ex.
vomiting, diarrhea, painful abdomen, painful constipation, etc.
Renal CS ex.
PU, proteinuria, anuria, kidney enzyme abnormalities, etc.
Hepatic CS ex.
jaundice, elevated liver enzymes
Cardiac CS ex.
arrythmias, brady/tachycardia, BP changes
Hematopoietic CS ex.
anemia, hemoglobinemia, MetHb, petechia, etc.
Diet History
- what diet
- changes in diet
- method of feeding
- presence of moldy/spoiled food
- drinking water osurce
- water supply changes
1 priority pollutant for human consumption concerns
arsenic
blood gas can rule out:
hypoxia
ancillary support
- maintain hydration
- monitor urine output
- monitor resp, cardiac, neuro status
- manage CS as they develop
- manage 2ary hepatic or renal injury
- admin. GI protectants/anti-emetic
symptomatic care
maintain body temp
alleviate pain
prevent irritation of skin and membranes (ie. demulcents, sucralfate, kaolin-pectin)
when to induce emesis
- only after animal fully stabilized
- within 60 minutes of known toxic ingestion (can be effective 3-4 hours later depending on toxin)
- save vomitus!
contraindications to inducing emesis
- corrosives, volatile hydrocarbons, petroleum distillates
- seizures/convulsions
- horses, ruminants, rodents, rabbits
- unconscious, no gag reflex, coma
activated charcoal
- administer early to prevent toxicant absorption
- works well for pesticides, pharmaceuticals
- repeated doses q4-6hours
- contra: corrosive agents, ethylene glycol, Fe
vomiting removes what percent of stomach contents?
40-50%
cathartics
- factors that help move things through GIT and decrease possible adsorption of the toxin
- adjunct to activated charcoal therapy
- Ex: mineral oil (DON’T use with act. charc.), Saline cathartic such as MgSO4 or Na2SO4
apomorphine
emetic for dogs, pigs
-may cause prolonged vomiting
xylazine
emetic for cats
-my cause hypotension and bradycardia
gastric lavage
- removal of concretions (bezoars), sustained-release products, or w/ massive overdoses
- INVASIVE; risk of perf/rupture: don’t use with toxicants that weaken gastric wall
salt water, hydrogen peroxide
commonly used at-home emesis inducers
-may delay vet. tx
sx removal
FB
-invasive
whole-bowel irrigation
removal of sustained-release pharmaceuticals
- for toxins not adsorbed by act. charc.
- mainly for SA
- causes d
- safer than lavage
if toxic agent has been identified, what antidote should be used?
specific antagonist (after p stable). Otherwise, tx is supportive and symptomatic
rodenticide antidote
vitamin K
pro/cons of analytic testing
pro: human hospitals can test for human meds
cons: no one test will screen for all toxicants. Multiple tests become costly.
blood sample tests for:
heavy metal anticoags antifreeze cholinesterase cyanide chlorinated pesticides
serum sample tests for:
Cu,Zn
nitrate/nitrite
ammonia
liver sample tests for:
metals
aflatoxin
alkaloids
vomitus sample tests for:
heavy metals anticoags antifreeze pesticides various poisons
kidney sample tests for
As, Pb
phenolic compounds
oxalates
brain sample tests for
chlorinated pesticides
pyrethrins
cholinesterase
metals
fat sample tests fo
chlorinated pesticides
dioxins
% =
parts per hundred
1% = 100 ppt = 10,000 ppm
0.25% gossypol is what ppm?
2500 ppm
Q: before beginning tx, dog starts seizing. How change tx plan?
tx with diazepam, phenobarbital (receptor-acting compounds). Don’t use charcoal or induce vomiting
4 parts to accurately diagnosing any toxicity:
1) History (health, current clinical, env., diet)
2) Clinical signs
3) Pathology/necropsy
4) Chemical analysis
Main things to remember when managing a poisoned patient
ABCs (airway, breathing, circulation) Control seizures metabolic derangements GI decon Supportive care
Future Prevention methods
- change pasture, feed, water, etc.
- remove baits, old pesticides
- bathe/flush for cutaneous or ocular exp.
- educate clients!
common toxins assoc. with increased anion gap
ethylene glycol ethanol iron methanol salicylates (aspirin) strychnine
anion gap
ratio b/w cations (Ca,K) and anions (bicarb, Cl)
(high anion gap = acidosis (>30mEq/L))
Normal = 10-12
