Diagnosis and Treatment of Toxicity

Question 1

5 things to look for and treat immediately

Answer 1

1. heart rate
2. respiratory rate
3. temperature
4. seizure and brain function
5. hemorrhage

Question 2

respiratory maintenance

Answer 2

• unconscious, paralyzed, and severe respiratory distress patients are candidates for intubation
• ventilation may be needed if there is:
  
  • hypoventilation and hypercapnia
  • metabolic acidosis
  • hypoxia (treat with 40% oxygen)

Question 3

control CNS activity

Answer 3

• control hyperactivity
  
  • diazepam, phenobarb, methocarbamol
• control depression
  
  • analeptics, doxapram

Question 4

control CV function

Answer 4

• tachycardia and arrythmias
  
  • correct acid/base, electrolyte or fluid disorders
  • lidocaine, propanolol
• hypertension
  
  • nitroprusside, hydralazine
• fluid therapy-balanced electrolyte solution for shock and dehydration, monitor urine output, inotropic drugs like dobutamine

Question 5

stabilize the patient

Answer 5

• priority in animals presenting with severe clinical signs (hyper/hypothermia)
• obtain venous access and draw for lab profile and potential diagnosis testing (3 cc EDTA, 2 serum)
• once stable, perform a more comprehensive physical exam

Question 6

obtain a complete history

Answer 6

• one of the most important and most overlooked parts of diagnosing toxicity
• once stable, question owner fully in attempt to narrow down possible causes

Question 7

4 major themes to question owner about

Answer 7

1. health status overall
2. clinical signs currently
3. environment at home
4. diet

Question 8

questions to ask about current clinical history?

Answer 8

• how long was problem present?
• when was animal observed sick?
• if animal was found dead-when were they last seen healthy?
• size of herd?

Question 9

systems to cover for clinical signs

Answer 9

CNS, GI, renal, hepatic, cardiac, hematopoietic

Question 10

what to learn about the environment?

Answer 10

type of environment where the animal lives

indoor only? fenced yard? roaming?

Question 11

what to ask about diet?

Answer 11

what are they eating?

method of feeding?

presence of moldy or spoiled food?

water source?

water supply changes

Question 12

general supportive care includes:

Answer 12

• ensuring adequate urine output
• monitor respiratory, cardiac and neurological status
• manage clinical signs as they develop
• manage secondary hepatic or renal injury
• administer GI protectants/anti-emetic

Question 13

what is involved in symptomatic care?

Answer 13

• maintain body temperature
  
  • hypothermia: balnkets, circulating warm water pads-avoid heat lamps!
• alleviate pain
• prevent irritation of skin and membranes with demulcents, milk, sucralfate

Question 14

when to decontaminate?

Answer 14

only after animal has been fully stabilized

Question 15

what are the 2 most common types of decontamination?

Answer 15

emesis and activated charcoal

cathartics also used

Question 16

emesis for decontamination

Answer 16

• potential in clincally normal animals with suspected oral exposure
• should be induced within 60 minutes of known toxic ingestion
• intubate, wash stomach 3 times with warm water until fluid is clear
• possibly save vomitus for possible analysis

Question 17

when do you induce emesis?

Answer 17

• toxic dose of substance ingested
• no vomiting has yet occurred
• activated charcoal is not an option

Question 18

activated charcoal

Answer 18

• prevents toxic absorption
• animal may eat, can be mixed with baby food
• earlier given = more effective
• give repeated doses ever 4-6 hours
• can give alone or after emesis
• caution: aspiration potential

Question 19

activated charcoal contraindications

Answer 19

corrosive agents

non-polar material

Question 20

4 reasons to give activated charcoal

Answer 20

1. substance is known/thought to be absorbed by it (excluded acids, alkalis, alcohols/glycols, metals, oils, petroleum distillates, detergents)
2. ingestion was very recent/undergoes eneterohepatic circulation/is sustained release
3. can tolerate it
4. no immediate need to administer oral meds (reasonable to wait at least 2 hours between charcoal admin and oral med)

Question 21

cathartics

Answer 21

• decrease GI transit time, increase movement of toxins, or charcoal-toxin complex, and decrease possible absorption of the toxin
• use as adjunct to activated charcoal therapy to reduce transit time
• ex: mineral oil, saline cathar

Question 22

how to prevent absorption for corrosives, strong acids and bases:

Answer 22

• use dilution instead of emesis
• can dilute with milk, water, or eggs
• (caution: using milk or water may enhance absorption)

Question 23

dermal exposures:

Answer 23

may bathe in liquid dish soap, rinse well

Question 24

lipid infusion

Answer 24

• relatively new treatment
• off label use of IV lipids
• case reports/case series demonstrates its efficacy and safety
• promising adjunct to conventional treatments

Question 25

primary use and limitations for activated charcoal

Answer 25

* use: **absorbent material with large surface area**, **bind most drugs** * limit: some toxins not absorbed

Question 26

primary use and limitations for apomorphine

Answer 26

* use: **emetic agent for dogs, pigs** * limit: may cause **prolonged vomiting**

Question 27

primary use and limitations for xylazine

Answer 27

* use: **emetic agent for cats** * limit: may cause **hypotension** and **bradycardia**

Question 28

primary use and limitations for gastric lavage

Answer 28

* use: **sustained release products, massive overdoses** * limit: **invasive**! risk of perforation or rupture

Question 29

primary use and limitation for salt water, H₂O₂

Answer 29

* use: for **at home emesis induction** * limit: might **delay treatment for vet**

Question 30

primary use and limitation for surgical removal

Answer 30

* use: **lead**, **pennies**, etc * limit: **invasive**!

Question 31

primary use and limitation for whole-bowel irrigation

Answer 31

* use: **removal of sustained-release pharmaceuticals**, for toxins **not absorbed by activated charcoal** * limit: primarily for **small animals**, may cause **prolonged diarrhea**, safer than gavage

Question 32

analytic testing

Answer 32

* no one test that will "screen" for all known toxicants * multiple test for specific agents can become costly * must **narrow down general type of agent involved** * test: blood, serum, urine, liver, vomitus, kidney, brain, fat

Question 33

common toxins associated with an increased anion gap

Answer 33

ethylene glycol, ethanol, iron, methanol, salicylates, strychnine

Question 34

normal anion gap

Answer 34

10-12 mEq/L

Question 35

clinically significant anion gap

Answer 35

\> 30 mEq/L suggests metabolic acidosis

Question 36

common toxins associated with CNS depression

Answer 36

* ivermectin * cholinesterase in inhibitors * organophosphate insecticides * carbamate insecticides * blue-green algae * slaframine * lead * locoweed * ethylene glycol

Question 37

common toxins associated with seizures

Answer 37

* bromethalin * chocolate * lead * organophosphate insecticides * pyrethrins/pyrethroids * strychnine * water deprevation/sodium ion toxicosis * water hemlock

Question 38

4 parts to accurately diagnose any toxicity

Answer 38

1. history (health, current clinical hx, environment, diet) 2. clinical signs 3. pathology/necropsy 4. chemical analysis

Question 39

how to prevent further exposure?

Answer 39

* change pasture, feed, water, etc * remove baits, old pesticides, etc * bathe or flush for cutaneous or ocular exposure * EDUCATE

Question 40

summary of how to manage a poisoned patient

Answer 40

1. assess ABC's 2. control seizures, cardiac 3. metabolic derangements 4. history 5. GI decontamination 6. supportive and symptomatic care