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Difficulty: Very hardGeneral Internal Medicine

Match each patient's clinical presentation with the most appropriate specific therapeutic intervention.

  • A 42-year-old man on monotherapy for latent tuberculosis is brought in actively seizing. Seizures have persisted for 20 minutes despite adequate doses of intravenous midazolam and phenytoin. Laboratory testing reveals a profound unexplained metabolic acidosis.Intravenous pyridoxine
  • A 68-year-old man with opioid use disorder maintained on a synthetic mu-opioid agonist is treated with a macrolide antibiotic for an upper respiratory infection. He presents with recurrent syncope. Telemetry shows bursts of wide-complex tachycardia with constantly changing amplitude around the isoelectric line.Intravenous magnesium sulfate
  • A 55-year-old woman with recurrent depression, stably managed on a long-acting selective serotonin reuptake inhibitor, is hospitalized for a complex soft tissue infection and started on an oxazolidinone antibiotic. Within 48 hours, she develops severe agitation, diaphoresis, a temperature of 39.8°C (103.6°F), and spontaneous myoclonus.Oral cyproheptadine
  • A 34-year-old man managed for acute mania presents with profound confusion, a coarse intentional tremor, and new-onset ataxia after a recent bout of severe rotavirus diarrhea. His estimated glomerular filtration rate has acutely dropped to 25 mL/min/1.73m², and a specific serum drug assay returns at 4.6 mEq/L.Emergent hemodialysis
  • A 75-year-old woman with chronic systolic heart failure and atrial fibrillation presents with anorexia, vomiting, and fatigue. Her spouse notes she recently complained of a yellowish tint to her vision. Cardiac monitoring demonstrates bidirectional ventricular tachycardia, and serum potassium is 5.9 mEq/L.Digoxin-specific antibody fragments

Answer

Latent TB/seizures matches Intravenous pyridoxine. Methadone/macrolide/polymorphic VT matches Intravenous magnesium sulfate. SSRI/linezolid/hyperthermia matches Oral cyproheptadine. Lithium tox/AKI matches Emergent hemodialysis. Heart failure/xanthopsia/bidirectional VT matches Digoxin-specific antibody fragments.
Each correct pairing links a complex toxicological presentation with its specific, life-saving intervention. Isoniazid depletes pyridoxine, leading to refractory seizures. Methadone and macrolides interact to cause QT prolongation and Torsades de pointes, treated with magnesium. Linezolid and SSRIs interact to cause serotonin syndrome, treated with cyproheptadine. Lithium toxicity > 4.0 mEq/L with AKI requires hemodialysis. Digoxin toxicity presenting with severe hyperkalemia and bidirectional VT requires specific antibody fragments.

Step-by-Step Solution

1
Analyze each patient's clinical presentation and medication history to identify the specific toxidrome or adverse drug reaction.
Patient 1 has isoniazid toxicity. Patient 2 has Torsades de pointes from QT-prolonging agents. Patient 3 has serotonin syndrome. Patient 4 has lithium toxicity. Patient 5 has digoxin toxicity.
Accurate recognition of life-threatening toxidromes based on nuanced historical clues is required before selecting an antidote.
2
Select the definitive, targeted therapy for each identified condition, bypassing generic algorithmic treatments that may be ineffective or harmful.
Pyridoxine for isoniazid seizures; magnesium for Torsades; cyproheptadine for serotonin syndrome; hemodialysis for severe lithium toxicity; and digoxin-specific antibodies for digoxin toxicity with hyperkalemia.
Toxicological emergencies often require specific antidotes or extracorporeal removal rather than standard supportive care.

Key Concept

Targeted management and antidote selection for complex, multi-drug or severe toxicological emergencies in internal medicine.
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Topics

General Internal Medicine

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