Toxicological Emergencies: Paramedic Briefing

Executive Summary:

This briefing document summarizes key themes and critical information from the provided toxicology resource, intended for paramedics and other prehospital care providers. The document covers various aspects of toxicological emergencies, including common causes, routes of exposure, the concept of toxidromes, substance abuse (with a focus on alcohol and stimulants), and the assessment and management of poisoned patients. It also details specific information regarding a wide range of toxic substances, from over-the-counter medications and household items to environmental toxins and biological agents. The overarching message emphasizes the importance of scene safety, thorough assessment, supportive care, utilization of poison control centers, and timely transport.

Main Themes and Important Ideas/Facts:

1. Scope of Toxicological Emergencies:

•Paramedics frequently encounter patients who have ingested or been exposed to a wide array of substances, including medications, over-the-counter products, supplements, and drugs used for recreational purposes.

•These exposures can lead to morbidity through interactions, inherent toxicity, excessive dosing, and addiction.

•Toxicological emergencies can be unintentional (e.g., medication errors, childhood poisonings, workplace hazards, simple neglect) or intentional (e.g., bioterrorism, "date rape" drugs, use of pharmacologic agents in homicide).

•The increasing variety of illicit drugs and the growth of licit drugs (highlighted by the "opioid pandemic") make it challenging to stay current, emphasizing the indispensable role of Poison Centres in Canada as resources for information. Paramedics are encouraged to "never hesitate to use this resource" and understand that their calls help the center collect valuable data.

2. Routes of Absorption:

•The document outlines several routes of poisoning:

◦Ingestion: Factors include the rate of effects, what and why it was ingested, assessment clues, and the time frame for treatment.

◦Inhalation: Poison present in the surrounding atmosphere (accidental or intentional). Scene safety is the first management consideration.

◦Injection: Includes stings, bites, and intravenous drug abuse, with potential for local, allergic, or occult systemic effects.

3. Understanding and Using Toxidromes:

•The concept of toxidromes is introduced, noting that "many drugs result in similar signs and symptoms," forming "syndrome-like symptoms of a poisonous agent," such as with narcotics. This highlights the importance of recognizing patterns of signs and symptoms to guide assessment and management.

4. Substance Abuse:

•History: Human beings have a "long history of abusing drugs and alcohol," including the emergence of "designer drugs."

•Definition: Substance abuse is defined as the "self-administration of licit or illicit substances in a manner not in accord with approved medical or social practice," emphasizing the cultural aspect of this definition, which may have "little relation to the potential harm from the abused substance."

•Basic Terms: The document defines key terms related to substance abuse, including drug abuse, habituation, physical and psychological dependence, tolerance, withdrawal syndrome, drug addiction, antagonist, potentiation, and synergism.

•Alcoholism: Alcohol is identified as the "most widely abused drug in Canada," with a significant portion of the population reporting past-year use and a notable percentage indicating alcoholism. Alcohol abuse decreases lifespan and progresses through phases of problem drinking to true addiction, affecting all social strata. Red flags for alcoholism include drinking early in the day, drinking alone or in secret, periodic binges, blackouts, tremulousness, anxiety, and a chronically flushed face and palms.

•Medical Consequences of Alcohol Abuse: Include toxic effects leading to serious illnesses and injuries, damage to the CNS (deterioration of mental functions, balance problems, decreased sensation), digestive system (gastritis), and liver (coagulopathies, hypoglycemia, cirrhosis, increased risk of pancreatitis, pneumonia, and cardiomyopathy).

•Alcohol-Related Emergencies:

◦Acute Alcohol Intoxication: Severe intoxication is a form of poisoning. Death can occur at high blood alcohol levels, with the "most immediate danger is respiratory depression and/or aspiration."

◦Alcohol Withdrawal Seizures: Typically occur within 12 to 48 hours after cessation.

◦Delirium Tremens: A "most serious and lethal complication" starting 48 to 72 hours after the last drink, with signs and symptoms including confusion, tremors, restlessness, fever, diaphoresis, hallucinations, and hypotension.

5. Assessment and Management of Poisoned Patients:

•Approach (Responsive Patient): Obtain history (what, how much, when, last meal, alcohol, vomiting, intentions?), take vital signs, SAMPLE history, and perform a focused physical examination.

•Approach (Unresponsive Patient): Focus on LOC, ABCs, obtain vital signs, and complete a rapid medical assessment.

•Specific Information Needed: Agent, time of exposure, amount, other substances taken, vomiting/aspiration, and reason for taking the substance.

•Scene Assessment: Overdose patients may be dangerous; call for law enforcement or a crisis unit if necessary to "minimize potential injury to paramedics."

•Initial Assessment: Begins with a general impression, rapidly identifying concerns with mental status, airway, breathing, and circulation. Address life threats quickly.

•Focused History and Physical Examination: Tailored to trauma or medical cases (most poisonings/overdoses). Utilize OPQRST for chief complaint in medical cases.

•Detailed Physical Examination: Conducted en route to the ED, especially in trauma with significant MOI. Ongoing assessment is crucial, including reassessment, reprioritizing, and checking intervention effectiveness, as "a stable patient may become unstable enroute as more toxin is absorbed over time."

•ALS Prehospital Care Basics: Ensure scene safety, maintain airway, ensure adequate breathing and circulation, administer high-concentration supplemental oxygen, establish vascular access, be prepared to manage shock, coma, seizures, and arrhythmias, and transport as soon as possible.

6. Specific Substances and Their Management:

•Stimulants (Cocaine, Amphetamines, Methamphetamine): High abuse potential, rapid addiction possible. Toxic levels can lead to psychosis, hyperpyrexia, tremors, seizures, and cardiac arrest. Management focuses on airway, oxygenation, seizure prevention with sedation, and monitoring.

•Marijuana and Cannabinoids: Classified as a hallucinogen but doesn't produce true hallucinations. Signs and symptoms include euphoria, drowsiness, decreased short-term memory, diminished motor coordination, and increased appetite. Management is generally supportive; transport is rarely warranted unless significant nausea and vomiting occur.

•Hallucinogens (LSD, PCP, Ketamine, Psilocybin Mushrooms): Cause distortion of perception. Effects vary widely. PCP can cause mind-body separation and violent outbreaks with an "unfathomable ability to withstand pain" and "almost superhuman strength." Ketamine is an analogue of PCP, often found in powdered form and can be addicting. Management is primarily supportive.

•Sedatives and Hypnotics (Barbiturates, Benzodiazepines, GHB): CNS depressants. Barbiturate overdose resembles alcohol intoxication; management includes airway protection, ventilatory support, cardiac monitoring, and potential use of activated charcoal or urine alkalinization (with medical control). Benzodiazepine overdose causes altered mentation, drowsiness, confusion, slurred speech, and ataxia; treatment is mainly supportive with a potential antidote (Flumazenil/Anexate). GHB ("liquid ecstasy") causes hypnosis, disinhibition, anterograde amnesia, CNS depression, and airway compromise, requiring transport.

•Narcotics, Opiates, and Opioids: Common cause of overdose deaths. Classic presentation includes euphoria, hypotension, respiratory depression, and pinpoint pupils. Management prioritizes airway and ventilation, with the administration of naloxone. Be aware that chronic users may not respond to naloxone for acute withdrawal.

•Carbon Monoxide: Causes more accidental poisoning deaths than any other substance. Colorless, odorless, and tasteless, it displaces oxygen in the blood. Difficult to diagnose prehospital. Treatment involves removing the patient from exposure and providing the "highest concentration of oxygen possible."

•Chlorine Gas: Widespread use. Exposure symptoms depend on concentration and duration, ranging from minor irritation to severe respiratory distress. Treatment priority is removing the patient from exposure and irrigating eyes.

•Cyanide: Rapid-acting and deadly. Causes cellular suffocation. May have a "classic odour of bitter almonds on the breath." Treatment involves removal from the source and supportive care, as most Canadian paramedics do not carry an antidote.

•Pesticides (Organophosphates and Carbamates): Toxic effects occur at nerve cell junctions, leading to SLUDGE/DUMBELS symptoms. Management includes decontamination, airway management, oxygen, and administration of atropine and pralidoxime (with ALS protocols).

•Poisonous Plants: Few are truly poisonous. Many cause contact dermatitis. Ingestion can cause gastroenteritis or more severe effects depending on the plant (e.g., calcium oxalate crystals, cyanide release from fruit pits, cardiac glycosides from foxglove/monkshood/yew berries, CNS toxins from water hemlock). Management is often supportive, with consultation with the Poison Centre crucial to determine appropriate treatment.

•Poisonous Mushrooms: Toxicity varies. Amanita and Lepiota species are often involved in fatalities. Symptoms and management depend on the type and time of onset. Contacting the Poison Centre and medical control is essential.

•Over-the-Counter Products (Acetaminophen, NSAIDs, Salicylates): Acetaminophen overdose has an antidote (N-acetylcysteine/Mucomyst) best given early. NSAID overdose is usually supportive. Salicylate toxicity presentation varies; management is supportive.

•Common Household Items & Caustics: Average home poses toxicological risks. Caustics (strong acids/alkalis) cause direct tissue injury. Management of dermal/ocular exposure involves copious irrigation. For ingestion in alert patients, a single glass of water may be given.

•Metals (Iron): Acute poisonings rare except for iron (especially pediatric ingestions). Systemic poisoning can lead to cardiovascular collapse and hepatotoxicity.

•Hydrocarbons: Primarily a risk through inhalation ("recreational") or accidental ingestion (especially in young children). Respiratory distress is a danger signal. Symptomatic patients should be transported.

•Toxic Alcohols (Ethylene Glycol, Methyl Alcohol): Ethylene glycol has toxic metabolites; treatment includes ethanol as an antidote. Methyl alcohol's metabolites (formaldehyde and formic acid) cause toxicity; prehospital care is supportive.

•Cardiac Medications: Overdose can cause bradycardia, hypotension, weakness, confusion, nausea, vomiting, headache, and dyspnea.

•Psychiatric Medications (Lithium, SSRIs, Tricyclic Antidepressants): Lithium has a narrow therapeutic window. SSRI overdose is generally less severe. Tricyclic antidepressant overdose can have significant cardiotoxic effects (tachycardia, hypotension, QRS widening) and anticholinergic symptoms; management includes airway support, ECG monitoring, and potential sodium bicarbonate administration (with medical control). Serotonin syndrome is a potential idiosyncratic complication of some psychiatric medications.

•Oral Hypoglycemics: Can cause symptomatic hypoglycemia, treated with intravenous dextrose prehospital. An antidote (octreotide) is available in the hospital.

•Arthropod Bites and Stings (Scorpions, Spiders, Hymenoptera): Scorpion stings require Poison Centre consultation. Canadian spider bites are generally not medically significant (supportive care). Hymenoptera stings can cause anaphylaxis; management includes addressing airway and breathing.

•Snakebites (Pit Vipers): Envenomation signs include metallic taste, nausea, vomiting, tachycardia, hypotension, and edema. Prehospital care involves keeping the patient calm and motionless, immobilizing the extremity, and immediate transport (do not apply tourniquets or ice).

•Tick Bites: Risk of Lyme disease; treatment is careful removal. Tick paralysis requires transport.

7. Summary of Key Areas:

The document concludes by summarizing the major areas covered: types of toxicological emergencies, routes of absorption, toxidromes, substance abuse, assessment and management principles, and occupational and environmental toxins.

Conclusion:

This resource provides essential information for paramedics responding to toxicological emergencies. It underscores the diverse nature of these incidents, the importance of a systematic approach to assessment and management, the critical role of poison control centers, and the need for vigilance regarding specific toxic substances and their potential effects. Paramedics must prioritize scene safety, perform thorough assessments, provide appropriate supportive care, and ensure timely transport to definitive medical care.