Toxicology - The National Emergency Medicine Board Review Course

Summary

The speaker, Dr. Billy Mallon, addresses a course on toxicology, emphasizing the gap between clinical reality and testing. He discusses the low mortality rate of drug overdoses treated with supportive care and the limited need for extensive toxicology knowledge in such cases. The lecture covers principles of toxicology, antidotes, and the importance of supportive care over specific therapies. Dr. Mallon also critiques the overuse of gastric decontamination and the reliance on tox screens, advocating for a more practical approach to toxicology.

Takeaways

• 👨‍🏫 The speaker emphasizes the difference between education for professional development and education for exams, suggesting a focus on teaching to the test in toxicology.
• 📚 Clinical reality in toxicology often conflicts with testing reality, as most drug overdoses that reach the emergency room are treatable with basic supportive care.
• 💊 The mortality rate for drug overdoses presenting to the ER is less than 1%, indicating that advanced toxicology knowledge may have limited impact on patient outcomes.
• 🧬 The speaker discusses the importance of understanding toxicology principles such as reducing exposure, absorption, and increasing elimination, and knowing when to intervene.
• 🚑 The 'coma cocktail' (dextrose, naloxone, thiamine, flumazenil, and others) is highlighted as a crucial knowledge area for medical professionals dealing with overdoses.
• 🚫 Use of flumazenil in benzodiazepine overdose is cautioned against due to the risk of precipitating a lethal withdrawal syndrome.
• 🩺 The script stresses the importance of checking glucose levels in patients presenting with focal neurological symptoms, as hypoglycemia can mimic more serious conditions.
• 🌿 Decontamination methods like gastric lavage and the use of activated charcoal are discussed, with a focus on their appropriate applications and limitations.
• 🚫 The speaker argues against the overuse of decontamination methods, stating that many patients are unlikely to benefit and may be subjected to unnecessary risks.
• 🔍 The limitations of toxicology screens are discussed, including high rates of false positives and negatives, and the importance of interpreting these results in context.
• 💧 The script mentions the use of hemodialysis in certain overdose cases, emphasizing the need for understanding which drugs are effectively removed by this method.

Q & A

What is the main difference between education for professional sake and education for exam sake?

Education for professional sake focuses on learning the necessary skills and knowledge for one's craft, while education for exam sake, often referred to as 'teaching to the test,' focuses on studying and memorizing information specifically to pass exams.

Why might a doctor call a Poison Center instead of relying on their own knowledge of toxicology?

A doctor might call a Poison Center for guidance because in many cases, they can provide immediate, expert advice on managing a poisoning case, especially if the doctor is not a toxicologist or if the situation is complex or time-sensitive.

What is the mortality rate of drug overdoses presenting to the emergency room?

The mortality rate of drug overdoses presenting to the emergency room is under 1%, meaning that 99% of patients are likely to survive with supportive care.

What is the 'coma cocktail' and why is it important to know?

The 'coma cocktail' refers to a set of tests and treatments used to diagnose and manage patients in a comatose state. It includes dextrose, naloxone, and thiamine. Knowing this cocktail is important because it helps in quickly ruling out common causes of altered mental status.

Why is it risky to administer flumazenil to a patient with a benzodiazepine overdose?

Administering flumazenil to a patient with a benzodiazepine overdose is risky because it can precipitate severe withdrawal symptoms, potentially leading to status epilepticus, which can be more dangerous than the overdose itself, especially in chronic benzodiazepine users.

What are some drugs associated with hypoglycemia?

Drugs associated with hypoglycemia include sulfonylureas, insulin, alcohol, and oral hypoglycemics.

Why has the use of gastric lavage declined in managing overdoses?

The use of gastric lavage has declined because many ingested substances are rapidly absorbed, and the procedure carries risks such as aspiration, and it is often not effective.

What is the role of activated charcoal in toxicology?

Activated charcoal is used to adsorb toxins in the gastrointestinal tract, preventing their absorption. It is typically administered to patients who have ingested toxic substances within the previous hour.

What is the significance of the anion gap in toxicology?

The anion gap is significant in toxicology as it can indicate the presence of certain toxic substances that cause metabolic acidosis, such as methanol, ethylene glycol, and salicylates.

Why are toxicology screens considered largely useless?

Toxicology screens are considered largely useless because they have high false positive and false negative rates, and their results can be misinterpreted, leading to mistreatment of overdoses.

What are some common false positives and false negatives in drug screening?

Common false positives include amphetamines with ephedrine, TCAs with cyclobenzaprine, and false negatives include methadone on opiate screens and benzodiazepines with fenil.