Toxicology and Environmental Emergencies
Toxicology questions reward a toxidrome-based approach: recognize the syndrome, then identify likely agents and antidotes. Candidates must know the classic toxidromes (anticholinergic, cholinergic, sympathomimetic, opioid, sedative-hypnotic) and the antidotes for high-yield poisons such as acetaminophen, salicylates, iron, opioids, benzodiazepines, and organophosphates. Understand that children are vulnerable to small ingestions because of low body weight, and that many ingestions are unintentional in young children versus intentional in adolescents.
Environmental emergencies include heat illness, hypothermia, drowning, and envenomation. Know that drowning resuscitation focuses on oxygenation and ventilation, and that submersion duration and water temperature influence prognosis. Recognize that carbon monoxide poisoning can present with nonspecific symptoms and requires co-oximetry.
Traps: relying on a single symptom rather than the full toxidrome; forgetting that activated charcoal is contraindicated with altered mental status or caustic ingestion; and missing the delayed presentation of acetaminophen toxicity. Another trap is assuming a negative initial drug screen excludes ingestion.
Worked example: a toddler with miosis, respiratory depression, and decreased consciousness after finding a family member's medication should receive naloxone with supportive airway management, recognizing that the half-life of naloxone may be shorter than the opioid and repeat dosing or infusion may be required. Rule of thumb: stabilize airway and breathing first, identify the toxidrome, then give the antidote when indicated.