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Chapter 17: Toxicology
Toxicology: Poisoning: General
COL Clifford Cloonan, MC, USAIntroduction: Almost anything in sufficient quantity can be toxic, even substances that are essential to
life such as water and oxygen. A poison is any substance that even in small quantities produces harmful
physiologic or psychological effects. Poisonings are responsible for 10% of all emergency department visits,
9% of all ambulance patient transports, and 5%-10% of all medical admissions to hospitals. They are the
third leading cause of accidental death in the U.S. Risk Factors: Approximately 80% of all accidental poison-
ings occur in children ages 1-4, who typically ingest household products. Few of these incidents are fatal.
Adolescents and young adults are at highest risk for intentional poisonings (drug abuse/suicide). The majority
of poisoning deaths occur in individuals age 20-49, and are usually intentional. Geographic Associations:
Local health care providers can describe what toxins/drugs are commonly used in a specific culture for the
purpose of committing suicide and to achieve altered mental status.
Poisons enter the body through a variety of different routes - ingestion, inhalation, injection, and surface or
dermal absorption. The toxic effects of ingested poisons may be immediate when inhaled or injected, or
delayed when absorbed through the skin or ingested. Because most substances are absorbed through the
small intestine, it may take several hours for the poison to enter the bloodstream. Alcohol, which is absorbed
in the stomach, is a notable exception. Early management of ingested poisons focuses on removing the toxin
from the stomach and chemically binding the toxin to prevent absorption in the small intestine.
Alterations in mental status are common in poisonings but there are many other causes of altered mental
status that should ALWAYS be considered. In particular, do NOT assume that altered mental status is
due to alcohol or drug intoxication even when the patient has clearly been drinking. Use the mnemonic
AEIOUTIPS to recall other causes of altered mental status: A - Alcohol and other toxins/drugs, E - Endocrine
(hypothyroidism); I - Insulin, too much (hypoglycemia), or Insulin, too little (hyperglycemia); O - Opiates
(heroin, morphine, etc.) and Oxygen, too little (hypoxia); U - Uremia (kidney failure); T - Trauma (head injury,
shock)/Temperature (hyper/hypothermia); I - Infection (meningitis, encephalitis); P - Psychiatric
(pseudocoma); S - Space-occupying lesion (epidural/subdural hematoma), Stroke, Subarachnoid
hemorrhage, Shock.
When treating a poisoned/intoxicated patient, the medic should protect himself. If the patient has been
poisoned by a hazardous material, this substance may also pose a risk to the medic. Patients who are
intoxicated may behave irrationally or violently.
Subjective: Symptoms
An accurate history is the most important component of the workup. If poisoning was suicidal in nature or
involved the use of illicit drugs, history from patient is often inaccurate or intentionally misleading. Obtain
history from family members and obtain description of the scene from persons who initially found the patient.
Determine which drugs (legal and illicit) or toxins to which the patient may have had access. In the event
of ingestion, determine what was ingested, when it was ingested, and whether the patient vomited. In cases
of possible occupational exposure, identify the patient’s job and the types of toxins to which he/she may
have been exposed.
Symptoms: Acute (< 2 hr) Sub-acute (2-48 hr) Chronic (>48 hr)
Constitutional Nausea/vomiting Signs/symptoms of Death or recovery
are common organ failure +/- symptoms of chronic
organ system damage
Location: Three organ systems are most likely to produce immediate morbidity and mortality.
Respiratory Difculty breathing, Shortness of Recovery or chronic
shortness of breath breath on exertion shortness of breath,
chronic cough, etc...