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Week 2 Emergency Medicine > Toxicology > Flashcards

Toxicology Flashcards

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1
Q

Prompt Coma Treatment with Suspected Overdose

A

100 mg Thiamine IM/IV with suspected alcoholism

50 mL glucose with 50% IV solution

0.4-2.0 mg IV Narcan - 0.8 is stat

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2
Q

Toxicology Initial Keys

A

Maintain circulation, get IV access

Cardiac monitoring and pulse ox for all

Consider quick reversal methods

Collect as much history as possible and correlate with PE and clinical presentation

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3
Q

Decontamination

A

Emesis only occurs in patients with intact gag reflex

Emesis efficacy is decreased >1 hour ingestion

Ipecac syrup with water to induce vomiting - best with tylenol

Activated charcoal to bind toxins - effectiveness decreased by ipecac

  • only binds to positive ions, depends on the medication

Gastric Lavage - rarely used, not recommended; faster than ipecac

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4
Q

Poisons not bound by Activated Charcoal - PAIL

A

Potassium

Alcohols

Iron

Lithium

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5
Q

First-Order Kinetics

Zero-Order Kinetic

A

First-Order Kinetics: A fixed percentage of toxin removed per unit of time

Zero-Order Kinetics: A fixed amount of toxin is removed per unit of time

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6
Q

Hemodialysis vs Hemoperfusion

A

Hemodialysis: toxin must be water-soluble and not highly protein bound

Hemoperfusion: Drug/toxin is in direct contact with absorbent material - high MW, poor water solubility, and high binding are not limiting factors

  • Commonly associated with thrombocytopenia, will not correct electrolyte imbalance or pH
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7
Q

Antidotes:

Acetaminophen

Anticholinergics

Benzodiazepines

A

Acetaminophen: Acetylcysteine increases glutathione reserves

Anticholinergics: Physostigmine

Benzodiazepines: Flumazenil - GABA antagonist, may cause seizure w/ rapid infusion - rarely used

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8
Q

Antidotes:

Cyanide

Methanol/Polyethylene Glycol

Narcotics

A

Cyanide: Sodium nitrite and thiosulfate

Methanol/Polyethylene Glycol: Ethanol drip

Narcotics: Naloxone

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9
Q

MUD PILES

A

For anion gap metabolic acidosis

Methanol

Uremia

Diabetic Ketoacidosis

Paraldehyde

Infection

Lactic Acidosis

Ethylene Glycol

Salicylates

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10
Q

Osmolar Gap

A

Used to determine what intoxicant pt used

2(Na) + Glu/18 + BUN/2.8

Measured - calculated = osmolar gap (normal <10)

w/ gap >30 - think different forms of alcohol

Ethanol is the MC cause

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11
Q

Acetaminophen Overdose

A

Max dose is 3 grams; 6 grams is overdose

Hepatotoxic metabolite - accumulates in liver w/ delayed effect

>140 mg/kg is toxic dose; lower w/ chronic liver disease or alcoholism

Treat w/in 16 hours to reduce morbidity and mortality

Treatment: Activated charcoal with Acetylcysteine therapy (140 mg/kg) - binds metabolite

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12
Q

Cocaine/Amphetamine

A

CNS Stimulants - cause sympathetic hyperactivity

Significant vasoconstriction, HTN, bradycardia

-May result in ventricular arrhythmias, rhabdomyolysis, myoglobinuria

Peak effects w/in 1-2 hours

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13
Q

Cocaine/amphetamine Overdose Treatment

A

GI decontamination

Diazepam for agitation/psychosis and seizures

Do not acidify the urine

Nitroprusside for HTN - watch for cyanide buildup

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14
Q

Anticholinergics

A

Atropine, Scopolamine, Belladonna, antihistamines, TCAs, mushrooms

Block central and peripheral cholinergic receptors

“Hot as a hare, red as a beet, dry as a bone, blind as a bat, and mad as a hatter”

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15
Q

Anticholinergic Overdose Treatment

A

Physostigmine reserved for severe symptoms

-Never w/ TCA overdose, asthma, or bowel/bladder obstruction

GI decontamination - sx may last awhile due to anticholinergic effect on bowel function

Supportive - may need external pacing

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16
Q

Arsenic Toxicity

A

Insecticides, rodenticides, wood preservatives, Shellfish, Gas

Arsenic is well absorbed, binds to tissue proteins and accumulates

Lethal dose in adult = 100-200 mg

Present with peripheral neuropathy, skin manifestations, and garlicky odor on breath, periorbital edema, with GI upset

17
Q

Arsenic Treatment

A

24 hour arsenic levels to monitor chelation therapy response

-may be false positives w/ shellfish ingestion

Treatment: Chelation therapy w/ chronic, GI decontamination with chelation for acute

Gas inhalation: transfusion with hydration to prevent renal hemoglobin deposition

-Chelation has no value w/ inhalation

18
Q

Digitalis Toxicity

A

Cardiac glycoside - enhance contractility, slow AV conduction, enhance automaticity

Anorexia, N/V/D, abdominal pain, blurred vision and color vision disturbance

EKG shows 3rd degree AV block, bradycardia, ventricular ectopy, paroxysmal A-tach with AV block

Acute ingestions associated w/ hyperkalemia

19
Q

Digitalis Toxicity Treatment

A

Glucose + insulin w/ severe hyperkalemia (>7) - do not use CaCl - will kill pt

Bradycardia/AV block - atropine, transcutaneous pacing

Ventricular ectopy - lidocaine drip

Dialysis or hemoperfusion is not effective

Digibind (Fab fragment antibodies) - bound dig is not active

20
Q

Mushroom Toxicology

A

Severe GI, muscarinic sx, hallucinations, anticholinergic effects - depends on mushroom type and toxin

Treatment is mainly supportive and targeted at whatever effects toxin has

Psilocybin mushrooms are MC seen poisoning - hallucinogens

21
Q

Clonidine Overdose

A

Mimics an opioid overdose - pinpoint pupils, respiratory depression

Do not respond to naloxone

Propoxyphene overdose is also resistant to naloxone

22
Q

Organophosphate Toxicity

A

Cholinesterase inhibitors - bug sprays, chemical warfare

Inhibit cholinesterase - allow ACh accumulation at muscarinic and nicotinic neuromuscular junction

Rapidly absorbed through skin, GI, respiratory

DUMBELS for symptoms

May have profound bradycardia (muscarinic) or tachycardia (nicotinic)

23
Q

DUMBELS

A

Diarrhea

Urination

Miosis

Bronchospasms

Excitation

Lacrimation

Salivation

24
Q

Organophosphate Toxicity Treatment

A

Decontamination

Aggressive airway management - secretions and bronchospasm

Atropine IV - large doses

Pralidoxime - competitive binder to ACh

25
Q

Phencyclidine (PCP)

A

Sympathomimetic, hallucinogenic, dissociative agent

Rapid onset of action - serious overdose w/ snorting or smoking

20-25 mg is severe intoxication; large volume distribution w/ half-life

Severe, paranoid, bizarre violent behaviour to quite stupor

Multi-directional nystagmus, seizures

Treatment is supportive - seizure and violence - diazepam and haloperidol

26
Q

TCA Toxicity

A

Anticholinergic, alpha-adrenergic receptor blocking, quinidine-like activity on the heart

Eliminated by hepatic metabolism

Anticholinergic effects; rapid onset of coma, refractory seizures

Cardiovascular manifestations are most difficult to manage - prolonged QT, PR intervals, varying blocks, torsades de pointes, HOTN

27
Q

3 C’s of TCA Toxicity

A

Cardiac abnormalities

Convulsions

coma

Week 2 Emergency Medicine (9 decks)

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