Toxicology (main): Difference between revisions
 
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==Differential Diagnosis for Specific Signs==
==Differential Diagnosis for Specific Signs==
===Hyperthermia===
===[[Hyperthermia]]===
*Altered Metabolism
*Altered Metabolism
**[[Aspirin (Salicylate) Toxicity]]
**[[Aspirin (Salicylate) Toxicity]]
**withdrawal states
**Withdrawal states (e.g. [[baclofen withdrawal]]
**thyroid hormones
**[[Thyroid]] hormones
**dinitrophenols
**[[Dinitrophenol]]s
*Increased Muscle Activity
*Increased Muscle Activity
**withdrawal, sympathomimetics
**Withdrawal, [[sympathomimetics]]
**[[MAOI Toxicity]]
**[[MAOI Toxicity]]
**[[PCP]], LSD
**[[PCP]], [[LSD]]
**[[Lithium]]
**[[Lithium]]
**Amoxapine
**[[Serotonin Syndrome]]
**[[Serotonin Syndrome]]
*Impaired Heat Dissipation
*Impaired Heat Dissipation
**anticholinergics
**[[Anticholinergics]]
**antihistamines
**[[Antihistamines]]
**antipsychotics ([[TCAs]])
**[[Antipsychotics]], TCAs
**[[Phenothiazines]], [[Lithium]], LevoDopa
*[[Malignant Hyperthermia]]
*[[Malignant Hyperthermia]]
**anesthestics
**Anesthetics
*[[Neuroleptic Malignant Syndrome]]
*[[Neuroleptic Malignant Syndrome]]
**phenothiazines, [[Lithium]], LevoDopa


===Hypothermia===
===[[Hypothermia]]===
*Exposure
*Exposure
**[[Ethanol Toxicity]]
**[[Ethanol Toxicity]]
**Sedative hypnotics
**[[Sedative/Hypnotics]]
**[[Opioids]]
**[[Opioids]]
**[[TCAs]]
**[[TCAs]]
**Phenothiazines
**[[Phenothiazines]]
**[[Insulin]] ([[Hypoglycemia]])
**[[Insulin]] ([[Hypoglycemia]])
**[[Carbon monoxide]]
**[[Carbon monoxide]]


===Increased Respiratory Rate===
===Increased Respiratory Rate===
*Direct Stimulation
*Direct stimulation
**[[Aspirin (Salicylate) Toxicity]]
**[[Aspirin (Salicylate) Toxicity]]
**[[Metabolic Acidosis]]
**[[Metabolic Acidosis]]
**dintirophenol, pentachlorophenol
**[[Dinitrophenol]], pentachlorophenol
**hepatorenal failure
**[[Hepatic failure|hepatic]]/[[renal failure]]
**CNS stimulants (cocaine, amphet, theophylline)
**CNS stimulants ([[cocaine]], [[amphetamine]], [[theophylline]])
*Tissue [[Hypoxia]]
*Tissue [[Hypoxia]]
**[[CO]]
**[[CO]]
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**[[Methemoglobinemia]]
**[[Methemoglobinemia]]


===Respiratory Depression===
===[[Respiratory failure|Respiratory Depression]]===
*Central Depression
*Central Depression
**antipsychotics
**[[Antipsychotics]]
**Chlorinated hydrocarbons
**Chlorinated [[hydrocarbons]]
**[[Sedative/Hypnotics]] ([[Ethanol Toxicity]], glycols)
**[[Sedative/Hypnotics]] ([[Ethanol Toxicity]], glycols)
**[[Tricyclic (TCA) Toxicity]]
**[[Tricyclic (TCA) Toxicity]]
**Lomitil
**[[Lomotil toxicity]]
**Opioids
**[[Opioids]]
**Marijuana
**[[Marijuana]]
*Muscle Failure
*Muscle Failure
**[[Organophosphates]]
**[[Organophosphates]]
**[[Marine Toxins]]
**[[Marine Toxins]]
**[[Nicotine Poisoning|Nicotine]]
**[[Nicotine Poisoning|Nicotine]]
**strychnine
**[[Strychnine]]
**botulinis
**[[Botulism]]
**Mojave rattlesnake, Cobra
**Mojave [[rattlesnake]], Cobra


===Bradycardia===
===[[Bradycardia]]===
PACED
PACED
*Propranolol/ beta-blockers, poppies (opiates), propoxyphene,
*[[Propranolol]]/[[beta-blockers]], poppies ([[opiates]]), propoxyphene,
physostigmine
[[physostigmine]]
*Anticholinesterases, antiarrhythmics
*[[Acetylcholinesterase inhibitors|Anticholinesterases]], [[antiarrhythmics]]
*Clonidine, calcium channel blockers
*[[Clonidine]], [[calcium channel blockers]]
*Ethanol or other alcohols
*[[Ethanol]] or other [[toxic alcohols|alcohols]]
*Digoxin, digitalis
*[[Digoxin]], [[digitalis]]


===Tachycardia===
===[[Tachycardia]]===
FAST
FAST
*Free base or other forms of cocaine
*Free base or other forms of [[cocaine]]
*Anticholinergics, antihistamines, antipsychotics, amphetamines, alcohol withdrawal
*[[Anticholinergics]], [[antihistamines]], [[antipsychotics]], [[amphetamines]], [[alcohol withdrawal]]
*Sympathomimetics (cocaine, caffeine, amphetamines, PCP), solvent abuse, strychnine
*[[Sympathomimetics]] (cocaine, caffeine, amphetamines, PCP), solvent abuse, strychnine
*Theophylline, TCA, thyroid hormones
*[[Theophylline]], [[TCA]], [[thyroid]] hormones


===Hypotension===
===Hypotension===
CRASH
CRASH
*Clonidine, calcium channel blockers
*[[Clonidine]], [[calcium channel blockers]]
*Rodenticides (with arsenic, cyanide)
*Rodenticides (with [[arsenic]], [[cyanide]])
*Antidepressants, aminophyline, antihypertensives
*Antidepressants, [[aminophylline]], [[antihypertensives]]
*Sedative-hypnotics
*[[Sedative/Hypnotics]]
*Heroin or other opioids
*[[Heroin]] or other [[opioids]]


===Hypertension===
===[[Hypertension]]===
CT SCAN
CT SCAN
*Cocaine
*[[Cocaine]]
*Thyroid supplements
*[[Thyroid]] supplements
*Sympathomimetics
*[[Sympathomimetics]]
*Caffeine
*[[Caffeine]]
*Anticholinergics, amphetamines
*[[Anticholinergics]], [[amphetamines]]
*Nicotine
*[[nicotine toxicity|Nicotine]]


===Pupil size===
===Miosis===
MIOSIS (COPS)
COPS
*Cholinergics, clonidine, carbamates
*[[Cholinergic]]s, [[clonidine]], [[carbamates]]
*Opioids, organophosphates
*[[Opioids]], [[organophosphates]]
*Phenothiazines, pilocarpine, pontine hemorrhage
*[[Phenothiazines]], pilocarpine, pontine hemorrhage
*Sedative-hypnotics
*[[Sedative/Hypnotics]]


MYDRIASIS (SAW)
===Mydriasis===
*Sympathomimetics
SAW
*Anticholinergics
*[[Sympathomimetics]]
*[[Anticholinergics]]
*Withdrawal syndromes
*Withdrawal syndromes


===Coma===
===[[Coma]]===
LETHARGIC
LETHARGIC
*[[Lead]], [[lithium]]
*[[Lead]], [[lithium]]
*[[Ethanol]], ethylene glycol
*[[Ethanol]], [[Ethylene glycol toxicity|ethylene glycol]]
*[[TCA]], [[thallium]], [[toluene]]
*[[TCA]], [[thallium]], [[toluene]]
*[[Heroin]], hemlock, [[hepatic encephalopathy]], [[heavy metals]], [[hydrogen sulfide]], hypoglycemics
*[[Heroin]], hemlock, [[hepatic encephalopathy]], [[heavy metals]], [[hydrogen sulfide]], hypoglycemics
*[[Arsenic]], antidepressants, anticonvulsivants, antipsychotics, antihistamines
*[[Arsenic]], antidepressants, [[anticonvulsants]], [[antipsychotics]], [[antihistamines]]
*[[Rohypnol]], risperidone
*[[Rohypnol]], [[risperidone]]
*GHB
*[[GHB]]
*[[Isoniazid]], [[insulin]]
*[[Isoniazid]], [[insulin]]
*[[Carbon monoxide]], [[cyanide]], clonidine  
*[[Carbon monoxide]], [[cyanide]], [[clonidine]]


===Seizures===
===[[Seizures]]===
OTIS CAMPBELL
OTIS CAMPBELL
*[[Organophosphates]], oral hypoglycemics
*[[Organophosphates]], oral hypoglycemics (e.g. [[sulfonylurea]])
*[[TCA]], [[theophylline]], tramadol  
*[[TCA]], [[theophylline]], [[tramadol]]
*Isoniazid, Insulin
*[[Isoniazid]], [[Insulin]]
*[[Sympathomimetics]], [[salicylates]], strychnine
*[[Sympathomimetics]], [[salicylates]], [[strychnine]]
*Camphor, [[carbon monoxide]], [[cyanide]], chlorinated hydrocarbons, [[cocaine]]
*[[Camphor toxicity|Camphor]], [[carbon monoxide]], [[cyanide]], chlorinated [[hydrocarbons]], [[cocaine]]
*[[Anticholinergics]] (antihistamines), amphetamines, antidepressants (citalopram, TCAs, buproprion)
*[[Anticholinergics]] (antihistamines), [[amphetamines]], antidepressants (citalopram, [[Tricyclic antidepressant toxicity|TCAs]], [[bupropion]])
*[[Methanol]], Methylxanthines (theophylline, caffeine), [[MAOI]]  
*[[Methanol]], Methylxanthines ([[theophylline]], [[caffeine]]), [[MAOI Toxicity|MAOI]]  
*[[PCP]], propranolol
*[[PCP]], [[propranolol]]
*Benzo withdrawal, buproprion, botanicals (hemlock, nicotine), GHB
*[[Benzodiazepine withdrawal]], [[bupropion]], botanicals (hemlock, [[nicotine toxicity|nicotine]]), [[GHB]]
*EtOH withdrawal, ethylene glycol
*[[ETOH withdrawal]], [[ethylene glycol]]
*[[Lead]], [[lithium]]
*[[Lead]], [[lithium]]
*Lidocaine, lindane (pesticide, scabies)
*[[Lidocaine]], [[lindane]] (pesticide, scabies)


===Skin findings===
===Skin findings===
DIAPHORETIC SKIN (SOAP)
====Diaphoresis====
*Sympathomimetics
SOAP
*Organophosphates
*[[Sympathomimetics]]
*Acetylsalicylic acid and other salicylates
*[[Organophosphates]]
*PCP
*[[Acetylsalicylic acid]] and other salicylates
 
*[[Phencyclidine toxicity|PCP]]
DRY SKIN
====Dry skin====
*Antihistamines, anticholinergics
*[[Antihistamines]], [[anticholinergics]]
 
====Bullous lesions/blisters====
BULLOUS LESIONS/BLISTERS
*[[Barbiturates]]
*Barbiturates
*[[Mustard agent (vesicants|Mustard gas]]
*Mustard gas
*[[Snake bites|Snakes]] and [[spider bites|spiders]]
*Snakes and spiders
====Flushed/red appearance====
 
*[[Anticholinergics]]
FLUSHED/RED APPEARANCE
*[[Niacin]]
*Anticholinergics, niacin
*Boric acid
*Boric acid
*Carbon monoxide
*[[Carbon monoxide]]
*Cyanide
*[[Cyanide]]
 
====Cyanosis====
CYANOSIS
*[[Benzocaine]] and other local anesthetics
*[[Cyanokit]], nitrites, nitrates, well water (nitrates)
*[[Antimalarials]]
*[[Quinolones]]
*[[Dapsone]] (used to treat leprosy, PCP pneumonia, toxoplasmosis, dermatitis herpetiformis, brown recluse bite)
*Aniline dyes
*Aniline dyes
*Dapsone
*Phenazopyridine<ref>Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.</ref>
*Ergotamine
*Nitrates, nitrites
*Nitrates
*Ergotamine toxicity|Ergotamine]]
*Nitrites
====Acneiform [[rash]]====
*Phenazopyridine
 
ACNEIFORM RASH
*Bromides
*Bromides
*Chlorinated aromatic hydrocarbons
*Chlorinated aromatic [[hydrocarbons]]


==Evaluation==
==Evaluation==
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*[[Antidote]]
*[[Antidote]]
*[[Camphor toxicity]]
*[[Camphor toxicity]]
*[[In-Training Exam Review]]


==References==
==References==

Latest revision as of 19:18, 20 February 2021

Background

Epidemiology

  • In 2014, ~2.2million human exposures reported to US poison control centers
  • Top 5 substance classes:
    • analgesics (11%)
    • cosmetics/personal care products (8%)
    • household cleaning substances (8%)
    • sedatives/hypnotics/antipsychotics (6%)
    • antidepressants (4%)
  • 1,835 human exposures resulted in death

Autonomic Nervous System Receptors and Their Effects

  • Parasympathetic - ACh is transm
    • Muscarinic
      • receptors in heart, eye, lung, GI, skin and sweat glands
      • Bradycardia
      • Miosis
      • Bronchorrhea / Bronchospasm
      • Hyperperistalsis (SLUDGE)
      • Sweating
      • Vasodilation
    • Nicotinic
  • Sympathetic
    • Alpha effects (vessels, eye, skin)
    • Beta effects (heart, lungs)

Clinical Features

Toxidrome Chart

Finding Cholinergic Anticholinergic Sympathomimetic Sympatholytic^ Sedative/Hypnotic
Example Organophosphates TCAs Cocaine Clonidine ETOH
Temp Nl Nl / ↑ Nl / ↑ Nl / ↓ Nl / ↓
RR Variable Nl / ↓ Variable Nl / ↓ Nl / ↓
HR Variable ↑ ↑ (sig) Nl / ↓ Nl / ↓
BP ↑ ↑ ↑ Nl / ↓ Nl / ↓
LOC Nl / Lethargic Nl, agitated, psychotic, comatose Nl, agitated, psychotic Nl, Lethargic, or Comatose Nl, Lethargic, or Comatose
Pupils Variable Mydriatic Mydriatic Nl / Miotic
Motor Fasciculations, Flacid Paralysis  Nl Nl / Agitated Nl
Skin Sweating (sig) Hot, dry Sweating Dry
Lungs Bronchospasm / rhinorrhea Nl Nl Nl
Bowel Sounds Hyperactive (SLUDGE) ↓ / Absent Nl / ↓ Nl / ↓
^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan
Withdrawal from substances have the opposite effect

Differential Diagnosis for Specific Signs

Hyperthermia

Hypothermia

Increased Respiratory Rate

Respiratory Depression

Bradycardia

PACED

physostigmine

Tachycardia

FAST

Hypotension

CRASH

Hypertension

CT SCAN

Miosis

COPS

Mydriasis

SAW

Coma

LETHARGIC

Seizures

OTIS CAMPBELL

Skin findings

Diaphoresis

SOAP

Dry skin

Bullous lesions/blisters

Flushed/red appearance

Cyanosis

  • Benzocaine and other local anesthetics
  • Cyanokit, nitrites, nitrates, well water (nitrates)
  • Antimalarials
  • Quinolones
  • Dapsone (used to treat leprosy, PCP pneumonia, toxoplasmosis, dermatitis herpetiformis, brown recluse bite)
  • Aniline dyes
  • Phenazopyridine[1]
  • Nitrates, nitrites
  • Ergotamine toxicity|Ergotamine]]

Acneiform rash

Evaluation

Toxicological Exam

  • All vital signs (Temp, RR, HR, BP) + bedside glucose
  • Neurologic exam
    • Level of consciousness
    • Pupillary exam
    • Motor response
    • DTRs
  • Skin Exam - moisture, temp, evidence of injection drug abuse
  • Lung Exam
  • Bowel Sounds
  • ECG (ie. look for QT prolongation, QRS prolongation, etc)
  • Consider CBC, BMP, urinalysis (with ẞ-HCG if appropriate), urine toxicology screen, serum alcohol concentration, VBG
    • The urine screen is a qualitative test -> positivity ≠ acute toxicity
    • It can be falsely positive due to cross-reactivity
    • It can be falsely negative if the substance ingested does not cross-react with the tested analyte
    • The diagnosis of intoxication is clinical!!!

Management

  • Depends on agent
  • See antidotes
  • "Coma cocktail" when suspecting toxic ingestion (mnemonic = "DONT")
    1. Dextrose (50mg IV)
    2. Oxygen
    3. Naloxone (0.2-0.4mg IV/IM, repeat dose 1-2mg)
      • Empiric opioid ingestion treatment
    4. Thiamine (50-100mg)
      • Treat or avoid Wernicke encephalopathy
      • Though some suggest giving thiamine prior to dextrose, do NOT let this delay treatment of hypoglycemia!
      • Case reports of dextrose precipitating Wernicke's involved thiamine-deficient patients receiving prolonged course of IV glucose, NOT with single bolus[2][3]

Disposition

  • Depends on agent

See Also

References

  1. ↑ Jeffery WH, Zelicoff AP, Hardy WR. Acquired methemoglobinemia and hemolytic anemia after usual doses of phenazopyridine. Drug Intell Clin Pharm. 1982 Feb;16(2):157-9.
  2. ↑ Donnino MW, Vega J, Miller J, Walsh M. Myths and misconceptions of Wernicke's encephalopathy: what every emergency physician should know. Ann Emerg Med. 2007;50(6):715-21.
  3. ↑ Gussow, L. Myths of Toxicology: Thiamine Before Dextrose. Emergency medicine news. 2007;29(4):3-11.
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