Toxicology Review Christian La Rivière, MD, FRCPC

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

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

Ten Most Lethal Poisonings in Adults

Ten Most Lethal Poisons in Kids

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

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

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

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

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

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

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

Odors in the Overdose History Bitter almondsCyanide CarrotsWater Hemlock Fruity EtOH, acetone, isopropyl alc. GlueToluene, solvents Shoe polishNitrobenzine

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

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?

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

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

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

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

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.

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

Toxidromes Opioid Sympathomimetics Cholinergics Anticholinergics Other toxidromes

Opioids heroin, methadone, prescription meds CNS depression, respiratory depression, miosis

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

Sympathomimetics cocaine, amphetamines, MDMA HTN, tachycardia, dilated pupils, diaphoresis, agitation

Cholinergics organophosphatep esticides, etc. remember: “SLUDGE” and the “Killer B’s”

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

Cholinergics The “Killer B’s” Bradycardia Bronchorrhea Bronchospasm

Anticholinergics tricyclics, dimenhydrinate, diphenhydramine, muscle relaxants

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

Preventing Absorption

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

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

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

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

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

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

The End! Questions??