Overview
This lecture covered toxicology emergencies, focusing on common overdoses, their antidotes, critical symptoms, and environmental emergencies. Emphasis was on practical management, key exam points, and rapid identification.
Rapid Antidote Identification
- Acetaminophen (Tylenol) overdose: Antidote is acetylcysteine (Mucomyst).
- Benzodiazepine overdose: Antidote is flumazenil (Romazicon), but airway management comes first.
- Carbon monoxide poisoning: High-flow 100% oxygen; hyperbaric chamber in select cases.
- Cyanide exposure: Use the cyanide kit (amyl nitrite via inhalation, sodium nitrite IV, sodium thiosulfate IV).
- Iron overdose (common in children): Antidote is deferoxamine (Desferal); charcoal is contraindicated.
- Aspirin (salicylate) and tricyclic antidepressant overdose: Treat with sodium bicarbonate for metabolic acidosis.
- Digoxin toxicity: Antidote is digibind.
- Coumadin overdose: Antidote is vitamin K.
- Heparin overdose: Antidote is protamine sulfate.
- Calcium channel blocker overdose: Treat with calcium chloride (central line, emergencies) or calcium gluconate (peripheral, stable).
- Beta-blocker overdose: Treat with glucagon.
- Oral sulfonylurea overdose (e.g., metformin): Treat with octreotide or sandostatin.
- Ethylene glycol (antifreeze) poisoning: Use IV ethanol.
Overdose Symptoms & Management
- Acetaminophen: Check level ≥4 hours post-ingestion; liver failure if toxic, hypoglycemia, jaundice.
- Benzodiazepines: Respiratory depression; airway first, risk for seizures with reversal.
- Carbon Monoxide: Symptoms include headache, cherry red skin/mucosa (late); diagnose with carboxyhemoglobin.
- Cyanide: Bitter almond odor, rapid death; elevated lactate.
- Iron: Four phases—missed diagnosis, temporary recovery, sudden deterioration, long-term GI damage.
- Aspirin: Tinnitus, metabolic acidosis, tachypnea; elderly at higher risk.
- Stimulants (cocaine, meth): Mydriasis (dilated pupils), tachycardia, hypertension; no beta-blockers for cocaine—use benzos.
- Hallucinogens: Sedation, airway compromise, amnesia, legal/forensic concerns.
- Alcohol: Risk for aspiration, withdrawal seizures, Wernicke’s encephalopathy (give thiamine before glucose if malnourished).
Environmental Emergencies
- Hypothermia: Warm to at least 86°F before stopping resuscitation; start with least invasive warming.
- Frostbite: Affects distal areas (fingers, toes, nose, penis); aspirin may be used for clot prevention.
- Submersion injuries: Assess for C-spine/head trauma, hypothermia; treat like any respiratory arrest.
- Heat stroke/exhaustion: Both need cooling and fluids; difference is skin—wet in exhaustion, dry in stroke.
Special Toxic Syndromes
- Organophosphate poisoning (nerve agents): Salivation, lacrimation, urination, diarrhea, GI upset, emesis, miosis ("SLUDGEM" or "MUDDLES"); treat with atropine, pralidoxime (2-PAM), benzos for seizures.
- Petroleum distillates: Inhalation causes coughing, hypoxia; treat with high-flow oxygen.
- Radiation Exposure: GI symptoms first; decontaminate (remove clothing), limit exposure time/distance/shielding.
Key Terms & Definitions
- Antidote — substance that counteracts a specific poison.
- Myosis — constricted pupils (seen in opiates, organophosphates).
- Mydriasis — dilated pupils (seen in stimulant overdoses).
- Chelation — chemical process of binding/toxin removal (iron overdose treatment).
- Decontamination ("decon") — removal of contaminants (clothes, washing).
- Wernicke’s encephalopathy — brain swelling in alcoholics, prevented by thiamine.
- Delirium tremens (DTs) — severe alcohol withdrawal with autonomic/CNS symptoms.
Action Items / Next Steps
- Memorize key antidotes and associated exposures.
- Know the mnemonic phrases for organophosphate poisoning (MUDDLES, SLUDGEM).
- Remember the 4-hour acetaminophen level and 86°F hypothermia threshold.
- Review key signs for major overdoses (e.g., tinnitus in aspirin, cherry red in CO).
- Prepare for next lecture: environmental hazards and radiation specifics.