Approach to Suspected Poisoning Flashcards
1
Q
what are the types of poisonings
A
- drug overdose
- drug interactions
- adverse drug reactions
- true poisonings – usually accidental
2
Q
what is important when first assessing a suspected poisoning
A
impossible to know all possible toxins
history taking is vital
supportive care as essential as “antidote”
ask owner to bring product
3
Q
what are common poisonings (9)
A
- ethylene glycol
- metaldehyde
- rodenticide
- paracetamol
- xylitol
- chocolate
- raisins/grapes and lillies - renal
- permethrin - neurological
- ibuprofen - GI ulceration, renal, neuro
4
Q
what are the management goals of poisonings
A
- stabilize immediate clinical signs
- history
- prevent continual absorption
- antidote
- removal of toxin
supportive care and monitoring is key
5
Q
what is the general approach to a poisoning
A
if toxin confirmed by owner –> antidote if there is one
otherwise –> proceed with decontamination procedures while performing futher investigations
PCV/TP
urea/creatinine
ALT
glucose
electrolytes
urinalysis
ECG
6
Q
how do you prevent continual absorption from the GIT (5)
A
- emetics
- gastric lavage
- adsorbents
- enemas
- surgical removal
7
Q
how do you prevent further absorption topically (2)
A
- irrigation of eyes
- washing skin/clipping hair: prevent grooming (self and others), clip the coat and buster collar
8
Q
what patients should you not bathe
A
seizuring animals
9
Q
how is ocular decontamination done (4)
A
- irrigate the eye for at least 15 mins (water/saline)
- fluoroscein assessment
- corticosteroids only if no ulceration
- lubricants/topical antibiotics
10
Q
when are emetics contraindicated (5)
A
- neurological dysfunction: animals that are seizuring or likely to seizure
- corrosive ingestion: damage to esophagus (harder to treat than GI damage)
- predisposed to aspiration: megaesophagus, laryngeal paralysis, french bulldogs (prone to aspiration)
- time post ingestion (> 4hrs?): depends on what it is (paracetamol vs. raisins)
- prior vomiting
11
Q
what substances may prevent emesis
A
marijuana
codeine
12
Q
what are emetics used in cats and dogs
A
- apomorphine (dogs)
- xylazine/dexmedetomidine/medetomidine (cats)
- hydrogen peroxide (3%)
13
Q
how is apomorphine administered
A
IV, SC or via the conjunctiva
14
Q
how long does apomorphine take to have effect
A
5-10 mins
15
Q
is apomorphine a controlled drug
A
no
16
Q
what side effects can apomorphine cause
A
sedation –> reverse with naloxone if required
continued nausea
17
Q
what effects does xylazine/dexmedetomidine/medetomidine cause in cats
A
moderately effective
sedation and cardiorespiratory depression
18
Q
is apomorphine used in cats
A
no it isn’t effective
19
Q
what is the dose of hydrogen peroxide used to cause emesis
A
1-2 ml/kg P.O (max 50ml dogs)
20
Q
what are the adverse effects of hydrogen peroxide
A
mild gastric irritation
21
Q
can hydrogen peroxide be used in cats
A
yes but more side effects and its less effective
22
Q
what can be used to reverse side effects of xylazine/dexmedetomidine/medetomidine
A
atipamezole
23
Q
is repeat administration allowed in hydrogen peroxide
A
no more than once
24
Q
when is a gastric lavage used
A
neurological patients (metaldehyde)
seizure
25
how is a gastric lavage done
GA
stomach tube: 5-10 ml/kg of warm water and repeat until runs clear
26
what are the risks of a gastric lavage
aspiration --\> cuffed ET tube
27
what are contraindications of gastric lavage
1. corrosive substances
2. anesthetic risk too high
3. over 4 hours post ingestion
28
what absorbents are used
activated charcoal
29
how do activated charcoal work as absorbents
bind toxin and stop furhter absorption
30
which is better liquid and powder or tablets for activated charcoal
liquid and powder \> tablets
31
how is activated charcoal administered
give in food, via syringe/stomach tube
32
how often is activated charcoal repeated
q 4 hours --\> enterohepatic recycling
33
what needs to be considered when giving oral meds and activated charcoal
2 hours between charcoal and oral meds
34
what should you warn the owners when their pet is given activated charcoal
stains feces black
35
what substances does activated charcoal not work on
xylitol, onion, garlic, ethylene glycol
36
what facrtors are there to consider when using an antidote
cost and shelf life
necessity of antidote
37
what does tox box contain
activated charcoal
apomorphine
european adder activation
methocarbamol
acetylcysteine
vitamine K1
intralipid
38
how can the toxin be removed
1. IVFT
2. intravenous lipid emulsion
3. blood purification techniques (dailysis)
39
why are intravenous fluids helpful (3)
1. increase renal elimination: theobromine
2. support kidneys: lillies, raisins, nephrotoxins
3. GI loss, hypotension
40
what is the intravenous lipid emulsion
liquid sink for lipophilic toxins
41
what is the intravenous lipid emulsion used for
toxins with short half-life --\> ivermectin, permethrin, local anesthetics, ibuprofen, cannabis
42
what are adverse reactions associated with intravenous lipid emulsion (5)
1. pancreatitis
2. anaphylaxis
3. volume overload
4. coagulopathies
5. bacterial contamination
43
what can intravenous lipid emulsion interfere with
diazepam, phenobarbital
44
what are specific poisonings (7)
1. paracetamol/acetaminophen
2. metaldehyde (slug/snail pellets)
3. vitamin K antagonist (rodenticide)
4. ethylene glycol (anti-freeze)
5. theobromide (chocolate)
6. xylitol (chewing gum)
7. raisins/grapes
45
what does paracetamol toxicity cause
hepatic metabolism
- liver overwhelmed --\> accumulation of toxic metabolites and oxidative damage
- hepatocellular necrosis
- methemoglobin formation (chocolate blood)
heinz body anemia
dry eye
46
why are cats more susceptible to paracetamol
cats lack the glucuronide conjugation pathway
47
what is the absorption time of paracetamol
rapid
48
what are the clinical signs of paracetamol toxicity \<24 hrs (5)
1. cyanosis/muddy brown mucus membranes
2. tachycardia, tachypnea, lethargy
3. facial and paw edema
4. vomiting
5. anemia
49
what are the clinical signs of paracetamol \>24 hours (5)
1. liver failure
2. icterus (yellow mucous membranes)
3. seizures/coma
4. renal failure
5. hematuria/hemoglobinuria
50
when is paracetamol treatment recommended
\>10 mg/kg (cats) or \>100mg/kg (dogs)
51
what is the recommended treatment for paracetamol toxicity
emetics if \<1-2 hours post ingestion
absorbents
supportive care --\> IVFT, oxygen, blood products
antidotes
52
what are the antidotes for paracetamol toxicity
N-acetylcysteine --\> glutathione precursor
S-adenosylmethionine (S-AME)
ascorbic acid (vit C)
cimetidine (dogs) - inhibits conversion to toxic metabolite
53
what is metaldehyde
slug bait
pellets or solutions
54
what is the onset of metaldehyde
rapid
30-3 hours
55
what clinical signs does metaldehyde cause
hyperesthesia
tremors
seizures
hyperthermia
56
how does metaldehyde cause death
respiratory arrest/seizures
liver failure after 2-3 days
57
what is the treatment of metaldehyde toxicity
treat regardless of dose ingested
emetics if asymptomatic and observe
activated charcoal
if seizures: diazepam (propofol if non-responsive)
+/- gastric lavage
methocarbamol: muscle relaxer
IVFT and nursing care
58
what is the effects of rodenticides
blocks vitamin K activation
--\> depletion of clotting factors II, VII, IX, X
defect in secondary homeostasis
59
how are rodenticides absorbed
slowly absorbed from GIT
60
what are examples of rodenticides
first and second generation
warfarin, brodifacoum, bromodiolone
61
what is the plasma half life of rodenticides
long half life
varies for different compounds
62
what are the clinical signs of rodenticide ingestion (6)
coagulopathy
1. lethargy
2. body cavity hemorrhage (hemothorax dyspnea, hemoabdomen)
3. epitaxis
4. GI bleed - melena/hematemesis
5. joint pain
6. anemia
63
how are anticoagulant rodenticides diagnosed
1. prolonged prothrombin time (PT) occurs first (factor VII shortest half life, extrinsic pathway)
2. prolonged APTT
3. platelets: normal or decreased
4. PIVKA: proteins induced by vitamin K antagonism
5. anemia
64
how are asymptomatic anticoagulant rodenticide animals treated
emesis & activated charcoal
check coags 24, 48, 72 hours
if PT prolonged treat with vitamin K1 for up to 6 weeks
repeat coags after finish treatment
1st dose S/C
oral bioavailability imrpoved with a fatty meal
clotting factors improve within 6 hours
65
how are symptomatic rodenticide animals treated
immediate support --\> oxygen +/- transfusion (plasma and red cells)
vitamin K1
66
how is ethylene glycol (anti-freeze) absorped
very rapid absorption
GI decontamination only effective in first 2 hours
67
what is the prognosis of ethylene glycol ingestion
poor prognosis
\>90% mortality in cats
68
at what dose of ethylene glycol are fatalities seen
\> 1ml/kg in cats
\> 4.4 ml/kg in dogs
69
when is treatment effective in animals that have ingested ethylene glycol
within 3-4 hours
70
what is the pathway of ethylene glycol that causes damage to the kidneys
71
when is euthanasia recommended after ethylene glycol ingestion
if the animal is azotemic
72
what are the clinical signs of ethylene glycol in the first 12 hours
1. neurological signs (ataxia, twitching, seizures)
2. GI signs
3. acidosis
73
what are the clinical signs of ethylene glycol in the first 12-24 hours
1. cardiac/respiratory system affected
74
what are the clinical signs of ethylene glycol in 24-72 hours
renal:
azotemia
anuria
hyperkalemia
75
how is ethylene glycol diagnosed (8)
1. history/clinical signs
2. metabolic acidosis
3. hypocalcemia
4. azotemia (from 12hours) --\> hyperkalemia, hyperphosphatemia
5. calcium oxalate crystals in urine
6. glycosuria, proteinuria, urine casts
7. medullary rim sign on US
8. in house tests
76
what is shown here
medullary rim signs from ethylene glycol toxicity
77
how is ethylene glycol treated
emetics not useful unless early on
diazepam for seizures
correct acidosis
IVFT - monitor urine output and electrolyte
78
what is the antidote for ethylene glycol
block alcohol dehydrogenase
20% ethanol (vodka): dilute it to 20% --\> stomach tube or IV
4-methylpyrazole (fomepizole): less side effects, limited availability
79
what are the doses of theobromine that cause GI signs, hyperactivity, panting, shaking
~20mg/kg
80
what are the doses of theobromine that cause cardiotoxicity (arrhythmias)
~50mg/kg
81
what are the doses of theobromine that cause seizures
~60mg/kg
82
what is the theobromine content in white chocolate
negligible
83
what is the theobromine content in milk chocolate
~1.4mg/mg
84
what is the theobromine content of dark chocolate
~5.3mg/g
85
what is the theobromine content of cocoa powder
38 mg/g
86
what amount of milk chocolate ingestion should you treat
\>14g/kg
87
what amount of dark chocolate ingestion should you treat
if \>3.5g/kg
88
what are the treatments for theobromine toxicity
1. emesis, activated charcoal
2. IVFT: diruresis, consider urinary cathertization
3. continuous ECG and seizure monitoring
4. supraventricular tachycardia --\> beta blocker
5. ventricular tachycardia --\> lidocaine
6. symptomatic treatment of seizures and GI signs
89
what effects does xylitol have
stimulates insulin release --\> hypoglycemia, hypokalemia, hypophosphatemia
90
what is the toxic dose of xylitol
\> 50mg/kg (1 piece of extra gum in a 20kg dog)
amounts of xylitol in gum brands differs
91
at what dose of xylitol can hypoglycemia be seen
\>100mg/kg see from 30 mins
92
at what dose of xylitol can hepatic necrosis be seen
\>500 mg/kg
delayed up to 72 hours
coagulopathy
93
how is xylitol toxicity treated
decontamination
rapid absorption --\> emesis?
charcoal of questionable use
monitoring: glucose (minimum of 12 hours), ALT, total bilirubin, potassium, phosphorus, clotting times
supportive care: fluids/dextrose
liver protectants: S-AME
94
what occurs in raisin ingestion
idiosyncratic reaction
some are fine but some are severely affected
not dose dependent
95
when is treatment recommended for raisin ingestion
recommended at any ingestion
96
what can raisins cause
GI signs: vomiting, diarrhea
acute renal failure
97
how is raisin toxicity treated
decontamination: emesis, charcoal
monitoring: urea, creatinine, electrolytes, phosphorus, calcium --\> baseline and after 48 hours, +/- after stopping fluids
supportive care: IVFT for 48-72 hours
