Toxicological Emergencies and Overdose Management Flashcards

Which ECG finding is most characteristic and specific for severe digoxin toxicity?

Answer: Bidirectional ventricular tachycardia

Bidirectional ventricular tachycardia, characterized by alternating QRS axis polarity beat-to-beat, is a highly specific ECG marker for severe digoxin toxicity and requires urgent treatment with digoxin-specific Fab fragments.

A patient presents with severe agitation, hypertension, and hyperthermia after cocaine intoxication. Which is the most appropriate initial treatment?

Answer: IV benzodiazepines for CNS and cardiovascular stabilization

Benzodiazepines reduce CNS stimulation from cocaine, addressing agitation, hypertension, and hyperthermia simultaneously; non-selective beta-blockers are contraindicated due to the risk of unopposed alpha-adrenergic stimulation.

What is the Rumack-Matthew nomogram used for in the emergency management of overdose?

Answer: Determining hepatotoxicity risk in acetaminophen overdose based on serum level and time since ingestion

The Rumack-Matthew nomogram plots acetaminophen serum concentration against time post-ingestion to identify which patients are at risk for hepatotoxicity and need N-acetylcysteine treatment.

A worker exposed to hydrofluoric (HF) acid has severe burns, hypocalcemia, and life-threatening cardiac dysrhythmias. What specific treatment is required?

Answer: Calcium gluconate gel topically and IV calcium replacement

Hydrofluoric acid depletes tissue calcium; calcium gluconate gel neutralizes fluoride ions locally at the burn site, and IV calcium corrects systemic hypocalcemia that drives life-threatening dysrhythmias.

A patient with severe lithium toxicity presents with tremor, confusion, ataxia, and seizures. Which intervention is the highest priority?

Answer: Supportive care and urgent hemodialysis consultation

Hemodialysis is the definitive treatment for severe lithium toxicity as there is no specific antidote; activated charcoal does not bind lithium, and supportive care manages acute symptoms until dialysis can clear the drug.

Which drug class is absolutely contraindicated in cocaine-induced coronary vasospasm and chest pain?

Answer: Non-selective beta-blockers (e.g., propranolol)

Non-selective beta-blockers in cocaine toxicity block beta-2 vasodilation while leaving alpha-adrenergic vasoconstriction unopposed, worsening coronary vasospasm, hypertension, and potentially myocardial injury.

What is the first-line pharmacologic treatment for severe symptomatic methemoglobinemia (MetHb >30%)?

Answer: Methylene blue IV (1–2 mg/kg)

Methylene blue donates electrons via the NADPH-methemoglobin reductase pathway, rapidly reducing ferric (Fe3+) hemoglobin back to functional ferrous (Fe2+) hemoglobin and restoring oxygen-carrying capacity.