USMLE PRACTICE QUESTION OF THE WEEK

Question for December 26, 2025

A 62-year-old man with a history of atrial fibrillation is hospitalized for confusion, nausea, and blurred vision. He has been taking digoxin and furosemide. On exam, he is disoriented, with irregularly irregular pulse at 110/min and multiple ventricular ectopic beats. ECG shows scooped ST segments. Serum potassium is 2.8 mEq/L.

Which of the following is the most appropriate next step in management?

A. Activated charcoal

B. Digoxin-specific antibody fragments

C. Atropine

D. IV calcium gluconate

E. Multiple myeloma

Get Detailed Explanation

Correct Answer:

B. Digoxin-specific antibody fragments

Correct Answer Explanation:

This patient has digoxin toxicity precipitated by hypokalemia from diuretic use. The specific treatment is digoxin immune Fab, which rapidly binds circulating digoxin. Atropine is used for bradyarrhythmias, calcium gluconate for hyperkalemia, and magnesium sulfate for torsades de pointes.

Further Insight:

Classic digoxin toxicity: GI upset, visual changes, arrhythmias.
Hypokalemia increases digoxin binding to Na⁺/K⁺-ATPase, worsening toxicity