Chapter 76: Toxic and Environmental Exposures

Poisoning remains the leading cause of injury-related death in the United States, with incidence patterns differing between unintentional pediatric exposures and intentional adult ingestions. Understanding poisoning requires knowledge of dose-dependent pathophysiologic mechanisms, such as how carbon monoxide displaces oxygen binding on hemoglobin or how sedatives enhance inhibitory neurotransmission through GABA receptors. Clinical assessment relies heavily on identifying toxidromes, which are constellation patterns of symptoms characteristic of specific drug classes including sympathomimetic, anticholinergic, cholinergic, sedative-hypnotic, and opioid categories. Management incorporates decontamination strategies such as activated charcoal administration within the first hour, gastric lavage for protected airways, and whole bowel irrigation for sustained-release formulations, alongside specific antidotal reversals like naloxone for opioid toxicity. Heat-related illnesses form a clinical continuum from minor conditions to life-threatening emergencies, with pathophysiology centered on the failure of radiation and conduction mechanisms above 95°F, leaving evaporation as the sole thermoregulatory pathway. Heat exhaustion presents with profuse diaphoresis and elevated core temperatures, whereas heat stroke represents a medical emergency characterized by core temperatures exceeding 104°F accompanied by neurologic dysfunction and potential multisystem organ failure. Rapid cooling through evaporative and conductive methods forms the cornerstone of heat illness treatment. Cold-related injuries similarly span a spectrum from hypothermia, defined as core temperatures below 95°F with progressive stages of severity and characteristic electrocardiographic findings, to frostbite involving tissue freezing with varying degrees of structural damage. Management of hypothermia emphasizes gradual passive and active rewarming to prevent afterdrop, while frostbite treatment involves controlled rewarming in warm water followed by judicious blister management. Throughout all toxic and environmental exposures, prevention through patient education regarding toxin storage, environmental acclimatization, and appropriate protective clothing remains paramount, with psychiatric evaluation required for intentional exposures.