CEN Toxicology and Environmental Emergencies 2 — Questions and Answers
Question 1: A patient presents with confusion, lactic acidosis, and bradycardia after intentional ingestion of his wife's heart medication. Bedside glucose is 220 mg/dL. Which medication overdose is most likely?
- Digoxin
- Metformin
- Calcium channel blocker (Correct answer)
- Beta-blocker
Correct answer: Calcium channel blocker
Calcium channel blocker toxicity causes bradycardia, hypotension, and hyperglycemia (by blocking insulin release from pancreatic beta cells).
Question 2: A patient with digoxin toxicity has a potassium level of 6.2 mEq/L and multiple PVCs. Which treatment is indicated?
- Calcium gluconate IV
- Digoxin-specific antibody fragments (Digibind/DigiFab) (Correct answer)
- Magnesium sulfate IV
- Atropine 0.5 mg IV
Correct answer: Digoxin-specific antibody fragments (Digibind/DigiFab)
Digoxin-specific Fab fragments directly bind and inactivate digoxin, reversing toxicity including dysrhythmias and hyperkalemia.
Question 3: A patient presents with fever of 40.5°C, muscle rigidity, clonus, diaphoresis, and agitation after starting a new antidepressant. Which condition is most likely?
- Neuroleptic malignant syndrome
- Anticholinergic toxidrome
- Serotonin syndrome (Correct answer)
- Malignant hyperthermia
Correct answer: Serotonin syndrome
The triad of altered mental status, autonomic instability, and neuromuscular abnormalities (clonus, hyperreflexia) is characteristic of serotonin syndrome.
Question 4: A patient with carbon monoxide poisoning has a carboxyhemoglobin level of 30% and is confused. Which oxygen delivery is the treatment priority?
- Nasal cannula at 4 L/min
- 100% oxygen via non-rebreather mask (Correct answer)
- Hyperbaric oxygen therapy
- Intubation with 40% FiO2
Correct answer: 100% oxygen via non-rebreather mask
100% oxygen via non-rebreather mask is the immediate treatment for CO poisoning; it reduces CO half-life from ~5 hours on room air to ~60–90 minutes.
Question 5: A patient presents with confusion, the smell of bitter almonds on their breath, and lactic acidosis after a house fire. Which antidote should be given?
- Sodium thiosulfate alone
- Hydroxocobalamin (Cyanokit) (Correct answer)
- Methylene blue
- Sodium bicarbonate
Correct answer: Hydroxocobalamin (Cyanokit)
Hydroxocobalamin binds cyanide to form cyanocobalamin, which is safely excreted; it is the preferred antidote for cyanide poisoning.
Question 6: A 3-year-old ingests an unknown number of iron tablets. Which finding indicates severe iron toxicity?
- Vomiting and diarrhea within 30 minutes
- Apparent improvement 6–24 hours after ingestion
- Hemodynamic instability and metabolic acidosis (Correct answer)
- Blood glucose of 90 mg/dL
Correct answer: Hemodynamic instability and metabolic acidosis
Hemodynamic instability and metabolic acidosis indicate systemic iron toxicity affecting cellular metabolism, representing severe poisoning.
CEN Toxicology and Environmental Emergencies 2
A patient presents with confusion, lactic acidosis, and bradycardia after intentional ingestion of his wife's heart medication.
Bedside glucose is 220 mg/dL.
Which medication overdose is most likely?