Clinical meaning
Toxicology is the study of adverse effects of chemical, physical, or biological agents on living organisms, with clinical toxicology focusing on diagnosis and management of poisoning and drug overdose. The dose-response relationship (Paracelsus principle: 'the dose makes the poison') is fundamental — toxic effects depend on the agent's dose, route of exposure, duration of contact, and individual patient factors including age, weight, hepatic and renal function, and genetic polymorphisms. Toxidromes are characteristic constellations of signs and symptoms that help identify the class of toxic agent: anticholinergic (hot, dry, red, blind, mad), cholinergic (SLUDGE-M: salivation, lacrimation, urination, defecation, GI upset, emesis, miosis), sympathomimetic (hypertension, tachycardia, hyperthermia, diaphoresis, mydriasis), and opioid (respiratory depression, miosis, CNS depression). Initial management follows the ABCs with decontamination (activated charcoal within 1-2 hours for most ingestions), specific antidote administration when available, and enhanced elimination techniques.
Exam relevance
Risk factors: - Accidental ingestion (pediatric household chemicals) - Intentional overdose (medications, illicit substances) - Occupational chemical exposure - Carbon monoxide exposure from faulty heating - Food poisoning from bacterial contamination - Environmental lead exposure (old paint, contaminated water) - Asbestos exposure (construction, demolition, older buildings) - Pesticide and herbicide exposure (agricultural workers)