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Difficulty: EasyGeneral Internal Medicine

Match each patient's clinical presentation following a toxic ingestion or medication overdose to the most appropriate initial specific pharmacologic antidote or therapy.

  • A 24-year-old man presenting with a respiratory rate of 6/min, pinpoint pupils, and profound lethargy.Intravenous naloxone
  • A 35-year-old woman presenting with right upper quadrant pain and an AST level of 4,200 U/L 48 hours after an analgesic overdose.Intravenous N-acetylcysteine
  • A 42-year-old man presenting with severe bradycardia, hypotension, and a blood glucose of 55 mg/dL after ingesting his roommate's blood pressure medication.Intravenous glucagon
  • A 28-year-old woman presenting with dry flushed skin, dilated pupils, and an ECG showing a QRS duration of 140 msec after an antidepressant overdose.Intravenous sodium bicarbonate
  • A 65-year-old man presenting with nausea, yellow-tinted vision, and an ECG showing atrial tachycardia with AV block after a recent dosage increase of his heart failure medication.Intravenous digoxin-specific antibody fragments

Answer

The presentations match their specific antidotes as follows: the patient with opioid toxicity requires naloxone; the patient with acetaminophen hepatotoxicity requires N-acetylcysteine; the patient with beta-blocker overdose requires glucagon; the patient with tricyclic antidepressant cardiotoxicity requires sodium bicarbonate; and the patient with digoxin toxicity requires digoxin-specific antibody fragments.
Each clinical vignette presents a classic toxic ingestion that dictates a specific antidote. Opioid overdose (miosis, respiratory depression) is reversed by naloxone. Acetaminophen overdose (hepatocellular injury) is treated with N-acetylcysteine. Beta-blocker overdose (bradycardia, hypoglycemia) is treated with glucagon. Tricyclic antidepressant overdose (anticholinergic toxicity, QRS widening) is treated with sodium bicarbonate. Digoxin toxicity (visual changes, arrhythmias) is treated with digoxin-specific antibody fragments.

Step-by-Step Solution

1
Analyze the first clinical presentation (respiratory depression, pinpoint pupils).
Identify opioid toxidrome.
The triad of miosis, CNS depression, and respiratory depression is pathognomonic for an opioid overdose.
2
Analyze the second clinical presentation (massive AST elevation after analgesic overdose).
Identify acetaminophen hepatotoxicity.
Acetaminophen is a common over-the-counter analgesic that causes acute liver failure in toxic doses.
3
Analyze the third clinical presentation (bradycardia, hypotension, hypoglycemia).
Identify beta-blocker overdose.
Beta-blockers reduce cardiac output and inhibit catecholamine-mediated glycogenolysis, leading to hypoglycemia.
4
Analyze the fourth clinical presentation (anticholinergic signs, QRS prolongation).
Identify tricyclic antidepressant (TCA) overdose.
TCAs block muscarinic receptors (causing dry skin and mydriasis) and myocardial fast sodium channels (causing wide QRS).
5
Analyze the fifth clinical presentation (yellow-tinted vision, atrial tachycardia with AV block).
Identify digoxin toxicity.
Digoxin inhibits the Na-K-ATPase pump, leading to characteristic visual changes and arrhythmias.
6
Select the specific pharmacologic antidote for each identified toxidrome.
Match opioids to naloxone, acetaminophen to N-acetylcysteine, beta-blockers to glucagon, TCAs to sodium bicarbonate, and digoxin to antibody fragments.
Specific antidotes target the distinct pathophysiologic mechanism of each toxin to rapidly reverse life-threatening manifestations.

Key Concept

Recognition of classic toxidromes and selection of specific, life-saving pharmacologic antidotes.
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Topics

General Internal Medicine

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