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Toxicology Review

Discover the study of chemicals affecting humans, lethal poisonings, dangerous medications, and approaches to poisoned patients. Learn about toxidromes, toxicology history, exams, and crucial interventions for poisoned patients.

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Toxicology Review

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  1. Toxicology Review • Christian La Rivière, MD, FRCPC

  2. Outline • Overview • Toxicologic history and physical exam • Common toxidromes • Management of the undifferentiated poisoned patient

  3. Toxicology • the study of chemicals and how they affect humans • nearly any substance has the ability to be poisonous if taken in great enough quantity

  4. Ten Most Lethal Poisonings in Adults

  5. Ten Most Lethal Poisons in Kids

  6. Medications Dangerous to Children in 1 or 2 doses • Beta blockers • Calcium channel blockers • Glyburide • Oil of Wintergreen (methyl salicylate) • TCA • Camphor • Clonidine and the imidazolines • Opioids • Lomotil • Toxic alcohols

  7. Approach to the Poisoned Patient • Supportive care is the cornerstone of treatment of poisoned patients • Your attention to this will do more good for your patient than any other single intervention

  8. Approach (cont’d) • ABC’s-stabilize as needed • Oxygen, monitor, IV, glucose level, narcan? • Hx-what, how much, when? • Px-general exam, toxidromes • Labs-drug levels, drug screen? • Charcoal within 1 hour • Antidote if available

  9. The Toxicology History • Gather information from all sources possible • pill bottles • time of ingestion (good luck!) • amount ingested • types of ingestions/co-ingestions

  10. History (cont’d) • environmental/occupational history • Past Medical History • Past Psychiatric History

  11. Physical Exam • useful at framing the “toxidrome” • Vital Signs: very important in determining severity and type of ingestion

  12. General Appearance • says a lot! • track marks? • smells of ___?

  13. Bitter almonds Cyanide Carrots Water Hemlock EtOH, acetone, isopropyl alc. Fruity Glue Toluene, solvents Shoe polish Nitrobenzine Odors in the Overdose History

  14. Skin, Mucous Membranes • dry mouth or lots of secretions? • skin warm and flushed or diaphoretic? • any rash? • cyanosis?

  15. Neuro Exam • GCS helpful at giving a global assessment of LOC, but can be misleading • always look at the pupils • any evidence of a post-ictal state?

  16. Miosis (small pupils) • opioids • clonidine • PCP • cholinergics (insecticides, certain mushrooms)

  17. Mydriasis (dilated pupils) • sympathomimetics (cocaine, speed, Ectacy, etc.) • anticholinergics • sedative-hypnotic withdrawal (EtOH, benzo withdrawal)

  18. Substances that can cause seizures • Tricyclics • Isoniazid • Cocaine, amphetamines • Salicylates (Aspirin) • Anticholinergics • Organophosphates (insecticides)

  19. Respiratory • crackles and wheezes may indicate organophosphate poisoning! • stridor and immediate respiratory distress may point to a caustic ingestion

  20. Radiology • Radiopaque items • “C” chloral hydrate • “H” heavy metals • “I” iron • “P” phenothiazines • “S” slow release(enteric coated) • X-ray affect TX only in iron O.D.

  21. Toxidrome • a constellation of signs or symptoms that are associated with a toxin • most patients will not exhibit all aspects of the toxidrome • mixed ingestions complicate the picture

  22. Toxidromes • Opioid • Sympathomimetics • Cholinergics • Anticholinergics • Other toxidromes

  23. Opioids • heroin, methadone, prescription meds • CNS depression, respiratory depression, miosis

  24. Other Effects of Opioids • hypotension • bradycardia • hypothermia • non-cardiogenic pulmonary edema

  25. Sympathomimetics • cocaine, amphetamines, MDMA • HTN, tachycardia, dilated pupils, diaphoresis, agitation

  26. Cholinergics • organophosphatepesticides, etc. • remember: “SLUDGE” and the “Killer B’s”

  27. Cholinergics • Salivation • Lacrimation • Urination • Defecation • Gastrointestinal upset (nausea, abdo pain) • Emesis

  28. Cholinergics • The “Killer B’s” • Bradycardia • Bronchorrhea • Bronchospasm

  29. Anticholinergics • tricyclics, dimenhydrinate, diphenhydramine, muscle relaxants

  30. Anticholinergics • hot as hell • dry as a bone • mad as a hatter • red as a beet • blind as a bat

  31. Preventing Absorption

  32. Ipecac • There are really no indications for the use of ipecac syrup to induce vomiting

  33. Gastric Lavage • Questionable effectiveness • No evidence of improved patient outcome • Risk of serious complications ~3%

  34. Activated Charcoal • Binds toxins to its surface and being non-absorbable allows charcoal-toxin complex to be excreted via the GI tract • Toxic if aspirated • do not give if decreased LOC or greater than 1 hour from ingestion • Not bound by charcoal: • Iron, lithium, cyanide, strong acids and bases, ethanol, methanol, ethylene glycol • Ions/Acids/Bases/Alcohols

  35. Whole Bowel Irrigation • Polyethylene glycol electrolyte solution (PEG, GoLytely) • Useful for large ingestions of substances: • Not bound by charcoal • Late presentation after overdose • Extended release preparations • Need a nasogastric tube • 1-2 L/hr for adults and 0.5 L/hr for peds

  36. Antidotes • Carbon monoxide • Opiates • Acetominophen • Methanol • Ethylene glycol • Iron • Cyanide • Organophosphates • Oxygen • Naloxone • N-acetylcysteine • Ethanol/Fomepizole • Ethanol/Fomepizole • Deferoxamine • Nitrites/Thiosulfate • Atropine/2-PAM

  37. Antidotes • Isoniazid • Beta-Blockers • Sulfonylureas • Digoxin • Methemoglobinemia • Benzodiazepines • Pyridoxine • Glucagon • Diazoxide • Digibind • Methylene blue • Flumazenil

  38. The End!Questions??

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