Overdose/TCA toxicity Flashcards

1
Q

History questions to ask in a suspected overdose

A

what drugs were taken

how many pills

when was the OD taken

why was it taken

**ask for an empty bottle of available

any known or witnessed trauma details

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2
Q

PMHx or social history to ask in a suspected overdose

A

drug allergies

medical conditions–> DM, known seizure activity

prescription meds

concurrent ingestion of alcohol or recreational drugs

any previous attempts

previous depression or psychiatric history

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3
Q

how should you approach a patient with suspected overdose with a depressed level of consciousness

A

should be initially managed in a similar fashion

should always include particular attention to ABCs and necessary management done simultaneously with the initial exam to ensure secondary complications of ingestion are prevented

vitals with the inclusion of O2 sats and EKG monitoring–> watch for arrhythmias

when time permits, then do a full secondary assessment

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4
Q

what types of secondary complication from suspected overdose do you try and prevent during primary survey/treatment in a patient with depressed consciousness

A
hypoxia
aspiration
respiratory failure
cardiac arrest
shock
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5
Q

what initial investigations should be done in suspected overdose

A
CBC
lytes
BUN
Cr, eGFR
serum glucose 
baseline LFTs
ABGs
serum osmolality
blood screening for specific agents 
ECG
chest xray 
consider CT head if trauma
urine pregnancy test
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6
Q

what specific agents should be screened for in suspected overdose

A
ASA
acetaminophen
alcohol
toxic alcohols
digoxin
barbiturates
benzodiazepines 
amphetamines
cocaine
TCAs
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7
Q

what is the “coma cocktail”

A

if ingestion is unknown

involves administration of
naloxone 2 mg IV
thiamine 100 mg IV
50 cc of 50% dextrose

flumazenil is generally not included in this initial treatment unless there is a high suspicion of benzodiazepine or ethylene glycol overdose

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8
Q

describe a general approach to overdose management

A
ABCs
oxygen
IV access
monitor
vitals, with cardiac monitoring

administer coma cocktail if ingestion unknown

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9
Q

in what situation would you give flumazenil

A

suspected or confirmed benzodiazepine or ethylene glycol overdose

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10
Q

why do you avoid giving flumanzenil unless confidently indicated

A

because it makes seizure control difficult by rendering your primary anti-seizure meds, benzos, ineffective

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11
Q

what is the role of syrup of ipecac in the ER with suspected overdose

A

not usually useful in the emergency setting as the induction of vomiting may delay subsequent therapy–its use has fallen out of favour

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12
Q

what is the role of gastric lavage in the ER with suspected overdose

A

can be useful if initiated within 60-90 minutes of the ingestion

the airway however must be protected in patients with decreased or absent gag reflex

use 28-36 F (larger the better) with 200-300mL boluses of warm saline until the effluent is clear

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13
Q

what is the role of activated charcoal in the ER with suspected overdose

A

no controls trials demonstrating harm after using it

may be useful in almost ALL overdoses if given less than 2 hours after toxic ingestion

should NOT be used in patients with decreased LOC without proper airway management

first dose should be given as 50g diluted in sorbitol and the following doses should be in water, every hour

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14
Q

who should you not use activated charcoal in

A

should NOT be used in patients with decreased LOC without proper airway management

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15
Q

how do you administer activated charcoal

A

first dose should be given as 50g diluted in sorbitol and the following doses should be in water, every hour

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16
Q

in what situations related to suspected overdose should you consider peritoneal or hemodialysis

A

useful for low molecular weight, water soluble toxins that are minimally bound to plasma proteins

these include 
ethanol
ethylene glycol
methanol
lithium
salicylates 

consider if
clinical deteriorate despite intensive therapy
blood toxin levels reach potentially lethal concentrations
renal or hepatic failure impairs clearance of toxins

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17
Q

list 4 common classes of drugs you may often see in an OD situation

A

salicylates

opiates

anticholinergic

cholinergic

18
Q

symptoms of salicylate overdose

A

hyperthermia

tachycardia

tinnitus

respiratory alkalosis

AG metabolic acidosis or mixed A/B disturbance

19
Q

specific treatment for salicylate OD

A

supportive

glucose

charcoal

alkalinization

20
Q

symptoms of opiate overdose

A

CNS depression

respiratory depression

miosis (pinpoint)

hypotension

21
Q

specific treatment for opiate OD

A

maloxone 0.4-2mg IV and repeat PRN

22
Q

what types of common drugs are anticholinergic

A

TCA
antihistamines
atropine
gravol

23
Q

specific symptoms of anticholinergic overdose

A
dry as a bone
mad as a hatter
blind as a bat 
hot as hades 
red as a beet 
and the heart runs alone 
\+ grabbing invisible objects and shaking
dry skin, mouth, urinary retention
confused
blurred vision/mydriasis (big pupils)
hyperthermia 
flushed skin 
tachycardia
24
Q

specific treatment for TCA overdose

A

NAHCO3 1-2mmol/kg IV if having an arrhythmia

25
Q

specific treatment for anticholinergic overdose

A

lorazepam 2-3 mg IV q5 minutes

physostigmine

26
Q

what types of drugs would result in a cholinergic overdose

A

acetylcholine
organophosphates
wild mushrooms

27
Q

symptoms of a cholinergic overdose

A
hypersalivation
bronchorrhea
bronchospasm
urination/defecation
lacrimation
 neuromuscular failure
28
Q

treatment of cholinergic overdose

A

atropine 2 mg IV repeat q 5-30 minutes

29
Q

name the TCAs

A
amitriptyline 
imipramine
desipramine
nortriptyline
doxepine
30
Q

what are the leading cause of drug OD in the USA

A

TCAs

31
Q

what amount of TCA leads to overdose

A

greater than 20 mg/kg with 35mg/kg being the approximate median lethal dose

32
Q

what are the pharmacologic actions of TCAs that must be specifically addressed in TCA overdose

A

peripheral anticholinergic activity

myocardial depression

respiratory depression

slowing of atrioventricular conduction

33
Q

how do you treat TCA overdose and why is that used

A

alkalinization with IV sodium bicarbonate

sodium bicarbonate 1-2mEq/kg to maintain arterial pH of 7.45 to 7.55

this is done to prevent and treat hypotension, arrhythmias and conduction disturbances

34
Q

what arterial pH is targeted in the treatment of TCA overdose

A

7.45-7.55

35
Q

which patients with TCA overdose should be transferred to the ICU

A

respiratory depression
hypotension
cardiac arrhythmias

36
Q

how should you manage someone with a suspected TCA overdose who is asymptomatic

A

if have a NORMAL EKG, they can be observed in the emergency room with cardiac monitoring for 6 hours following ingestion, decontamination and REPEATED CHARCOAL

once medically stable, they should be evaluated by psychiatry

37
Q

what arrhythmia is associated with TCA overdose

A

*QRS duration above 100ms and rightward axis

prolonged PR, QRS and QT intervals (wide complex arrhythmia)

AV block

non specific ST segment and T wave changes

right axis deviation

Brugada pattern

  • sinus tachy is the most common abnormality due to anticholinergic activity and inhibition of norepinephrine uptake by TCAs
  • torsades occurs uncommonly
38
Q

what is the Brugada ECG pattern

A

downsloping ST segment elevation in leads V1-V3 in association with RBBB

39
Q

in what time period would you expect death to occur from TCA poisoning

A

life threatening arrhythmias and death due to TCA poisoning usually occurs within 24 hours of ingestion

rapid deterioration is common

40
Q

what is the most sensitive clinical predictor of serious complications in TCA poisoning

A

LOC at presentation