Toxicology and Environmental Health

Toxicology asks two linked questions: what has entered the body, and what is that exposure doing to physiology? Toxic effects depend on dose, route, duration, formulation, age, body size, pregnancy, and hepatic or renal function. A small amount inhaled into the lungs may be more dangerous than a larger amount swallowed because absorption is rapid and the airway is directly threatened. The experienced nurse notices the pattern of injury before trying to name the product. Toxidromes are useful pattern clusters, not substitutes for an exposure history: - Opioid toxicity: reduced level of consciousness, slow or absent breathing, and often small pupils. Severe hypoxia may produce bradycardia or cardiac arrest. Dilated pupils do not exclude opioid poisoning, particularly with hypoxia or mixed ingestion. - Anticholinergic toxicity: delirium, tachycardia, urinary retention, reduced bowel sounds, flushed skin, mydriasis, and dry mucous membranes. The patient is often hot and dry. - Sympathomimetic toxicity: agitation, tachycardia, hypertension, mydriasis, hyperthermia, and diaphoresis. Sweating helps distinguish it from anticholinergic toxicity. - Cholinergic toxicity: salivation, lacrimation, urination, diarrhoea, abdominal cramping, vomiting, miosis, bronchorrhoea, bronchospasm, bradycardia, and weakness. Secretions...