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Poisoning, Toxidromes, Emergency Medicine

Basics

Description

- Anticholinergic: Mnemonic: "Blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone, the bowel and bladder lose their tone, and the heart runs alone " ¯: - Hyperthermia ( "hot as a hare) - Dry, flushed skin ( "dry as a bone " ¯ and "red as a beet " ¯) - Dilated pupils ( "blind as a bat " ¯) - Delirium ( "mad as a hatter " ¯) - Tachycardia ( "the heart runs alone " ¯) - Hypertension - Hyperthermia - Urgency retention ( "bowel and bladder lose their tone " ¯) - Decreased bowel sounds ( "bowel and bladder lose their tone " ¯) - Seizures - Mental status changes - Somnolence

- Opiate: - Classic triad: - Miosis - Hypoventilation - Coma

- Sedative " “hypnotics and alcohol: - Sedation - Mental status changes (confusion, delirium, hallucinations) - Vision changes (blurred vision, diplopia) - Slurred speech - Ataxia - Nystagmus

- Bradycardia: - α2-adrenergic agonists (e.g., clonidine) - ˇ ²-blockers - Calcium-channel blockers - Digoxin and related substances - Cholinergics - Opioids

- Tachypnea: - Paraquat (and other drugs that cause pneumonitis) - Salicylates - Sympathomimetics - Dinitrophenol - Methylxanthines - Drugs that cause acidosis

- Mees lines: - Arsenic - Thallium - Chemotherapy agents - Radiation

  • A toxidrome is the constellation of signs and symptoms that result from the effects of a particular toxin (toxic syndrome)
  • Mechanism of action varies with each class of toxin to which the patient may be exposed and the target receptors.

Diagnosis

Signs and Symptoms

Toxidromes ‚

  • There are multiple toxidromes:AnticholinergicCholinergicSympathomimeticHallucinogenicOpiateSedative " “hypnoticWithdrawal syndromesSerotonin syndromeMalignant neuroleptic syndrome
  • Anticholinergic: Mnemonic: "Blind as a bat, mad as a hatter, red as a beet, hot as a hare, dry as a bone, the bowel and bladder lose their tone, and the heart runs alone " ¯:Hyperthermia ( "hot as a hare)Dry, flushed skin ( "dry as a bone " ¯ and "red as a beet " ¯)Dilated pupils ( "blind as a bat " ¯)Delirium ( "mad as a hatter " ¯)Tachycardia ( "the heart runs alone " ¯)HypertensionHyperthermiaUrgency retention ( "bowel and bladder lose their tone " ¯)Decreased bowel sounds ( "bowel and bladder lose their tone " ¯)SeizuresMental status changesSomnolence
  • Cholinergic: Mnemonic: DUMBELS for the muscarinic component:Muscarinic signs:Diarrhea, diaphoresisUrinationMiosisBradycardia, bronchorrhea, bronchospasm (the killer Bs)EmesisLacrimationSalivationNicotinic signs:MydriasisTachycardiaWeaknessHypertensionFasciculations
  • Sympathomimetic: Similar to anticholinergic presentation except for skin and bowel differences (diaphoresis and increased bowel sounds may be present in sympathomimetic presentations):DiaphoresisMydriasisTachycardiaHypertensionHyperthermiaSeizuresIncreased peristalsis
  • Hallucinogenic: May have significant overlap with sympathomimetic toxidrome as many sympathomimetic drugs have hallucinogenic properties (e.g., MDMA/ecstasy, cathinones, hallucinogenic amines). Other hallucinogens include LSD, psilocybin, peyote, mescaline:DisorientationHallucinationsAnxietyPanicSeizures
  • Opiate:Classic triad:MiosisHypoventilationComaMay also present with:BradycardiaHypotensionHypothermiaDecreased bowel sounds
  • Sedative " “hypnotics and alcohol:SedationMental status changes (confusion, delirium, hallucinations)Vision changes (blurred vision, diplopia)Slurred speechAtaxiaNystagmus
  • Withdrawal (alcohol, benzodiazepine, barbiturates):MydriasisTachycardiaHypertensionHyperthermiaIncreased respiratory rateDiaphoresisIncreased bowel soundsTremorAgitationAnxietyHallucinationsConfusionSeizures
  • Withdrawal (opioid):NauseaVomitingDiarrheaAbdominal crampsIncreased bowel soundsMydriasisPiloerectionTachycardiaLacrimationSalivationHypertensionYawning
  • Neuroleptic malignant syndrome:Recent treatment with typical and atypical antipsychotic medications:Generally occurs from hours to several weeks of starting or increasing the dose of a medication, but can occur at any time.HyperthermiaMuscular rigidityDiaphoresisMental status changesHypertension or hypotension may be seenSialorrheaTremorIncontinenceIncreased creatinine phosphokinaseLeukocytosisMetabolic acidosis
  • Serotonin syndrome:Occurs soon after the increase in dose or addition of serotonergic medications.Syndrome with variable presentationFollowing are most common, seen 25 " “57% of the time:Mental status changes (confusion, agitation, hypomania, lethargy)SeizuresMyoclonusHyperreflexiaMuscle rigidityTremorNystagmusHyperthermiaDiaphoresisTachycardiaHypertensionMydriasis

Physical Exam

  • Bradycardia:α2-adrenergic agonists (e.g., clonidine) ˇ ²-blockersCalcium-channel blockersDigoxin and related substancesCholinergicsOpioids
  • Tachycardia:SympathomimeticsAnticholinergicsMethylxanthinesTricyclic antidepressantWithdrawalPhenothiazinesAtypical antipsychoticsα1-blockade with reflex tachycardiaPhosphodiesterase type 5 inhibitor (e.g., Sildenafil)
  • Hyperthermia:AnticholinergicsSympathomimeticsSerotonin syndromeNeuroleptic malignant syndromeMalignant hyperthermiaDinitrophenolSalicylatesWithdrawal
  • Hypothermia:Carbon monoxideOral hypoglycemicsOpiatesEthanolSedative " “hypnoticsα2-adrenergic agonists
  • Hypertension:SympathomimeticsAnticholinergicsNicotinePhencyclidine (PCP)Ergot alkaloids
  • Hypotension:α2-agonistsα1-antagonists ˇ ²-blockersCalcium-channel blockersAngiotensin converting " “enzyme inhibitorsMethylxanthinesNitratesOpioidsPhenothiazinesPhosphodiesterase type 5 inhibitorsSedative " “hypnoticsEthanolTricyclic antidepressantsAtypical antipsychotic medications
  • Miosis:CholinergicsClonidineReserpinePhenothiozinesAtypical antipsychotics
  • Mydriasis:AnticholinergicsSympathomimeticsWithdrawal (esp. opioids)Botulism
  • Seizures:Mnemonic with a limited list of causes for toxic seizures OTIS CAMPBELL:OrganophosphatesTricyclic antidepressantsIsoniazid, insulinSympathomimetics, salicylatesCamphor, cocaine, citalopramAmphetamines, anticholinergic agentsMethylxanthines (theophylline, caffeine), mushrooms (Gyromitra: monomethyl hydrazine group), meperidinePCP, propoxyphene, plants (nicotine, water hemlock)Benzodiazepine withdrawal, bupropionEthanol withdrawalLithium, lidocaineLead, lindane
  • Diaphoresis:SympathomimeticsCholinergicsSalicylatesWithdrawalSerotonin syndrome
  • Bradypnea:OpiatesSedative " “hypnoticsEthanol ˇ ³-hydroxybutyric acid and congenersBotulismMuscular receptor blockade
  • Tachypnea:Paraquat (and other drugs that cause pneumonitis)SalicylatesSympathomimeticsDinitrophenolMethylxanthinesDrugs that cause acidosis

Dermatologic ‚

  • Mees lines:ArsenicThalliumChemotherapy agentsRadiation
  • Bullae:BarbituratesCarbon monoxideCaptopril
  • Flushed or red appearance:AnticholinergicsDisulfiram reactionsNiacinBoric acidScombroid poisoningMonosodium glutamateCarbon monoxide (frequently postmortem)Cyanide (rare)Vancomycin
  • Blue skin:ErgotaminesMethemoglobinemia from:NitriteNitrateDapsoneAniline dyePhenazopyridineBenzocaineChloroquinePseudocyanosis from:ChlorpromazineAmiodaroneMinocyclineSilver (argyria)Gold (chrysiasis)

Essential Workup

Depends on ingested substance: ‚

  • CBC
  • Electrolytes, BUN, creatinine, glucose
  • Urinalysis
  • Arterial blood gas, venous blood gas
  • Carboxyhemoglobin, methemoglobin levels
  • Toxicology screen
  • Aspirin and Acetaminophen level
  • Prothrombin time
  • Liver function tests

Diagnosis Tests & Interpretation

  • Anion gap acidosis: Mnemonic: A CAT MUD PILES (encompasses a limited number of common causes):Alcohol ketoacidosisCO/cyanideAcetaminophen in fulminant hepatic failureTolueneMethanolUremiaDiabetic ketoacidosisParaldehyde, phenformin/metforminIron, isoniazidLactic acidosisEthylene glycolSalicylates, sodium azide, hydrogen sulfide
  • Increased osmolar gap:MethanolEthylene glycolIsopropyl alcoholEthanolAcetoneGlycerolMannitolGlycine

Treatment

Initial Stabilization/Therapy

ABCs ‚

Ed Treatment/Procedures

Depends on ingested substance (see Poisoning; Poisoning, Gastric Decontamination) ‚

Pearls and Pitfalls

  • Obtain appropriate lab tests.
  • Recognize signs and symptoms and lab clues to the toxidromes.

Additional Reading

  • Boyer ‚ EW, Shannon ‚ M. The serotonin syndrome. N Engl J Med. 2005;352:1112 " “1120.
  • Nelson ‚ L, Lewin ‚ N, Howland ‚ MA, et al. Goldfranks Toxicologic Emergencies. 9th ed. New York, NY: McGraw-Hill; 2010.
  • Weatherald ‚ J, Marrie ‚ TJ. Pseudocyanosis: Drug-induced skin hyperpigmentation can mimic cyanosis. Am J Med. 2008;121(5):385 " “386.

See Also (Topic, Algorithm, Electronic Media Element)

  • Poisoning
  • Poisoning, Gastric Decontamination

Codes

ICD9

  • 971.0 Poisoning by parasympathomimetics (cholinergics)
  • 971.1 Poisoning by parasympatholytics (anticholinergics and antimuscarinics) and spasmolytics
  • 971.2 Poisoning by sympathomimetics [adrenergics]
  • 969.6 Poisoning by psychodysleptics (hallucinogens)
  • 965.00 Poisoning by opium (alkaloids), unspecified

ICD10

  • T44.1X1A Poisoning by oth parasympath, accidental, init
  • T44.3X1A Poisoning by oth parasympath and spasmolytics, acc, init
  • T44.901A Poisn by unsp drugs aff the autonm nervous sys, acc, init
  • T40.901A Poisoning by unsp psychodyslept, accidental, init
  • T40.601A Poisoning by unsp narcotics, accidental, init

SNOMED

  • 216593002 Accidental poisoning by anticholinergics (disorder)
  • 61356009 Poisoning by parasympathomimetic drug (disorder)
  • 45536007 poisoning by sympathomimetic drug (disorder)
  • 85975005 Poisoning by psychodysleptic (disorder)
  • 11196001 Poisoning by opiate AND/OR related narcotic (disorder)