A 65-year-old man with nonischemic cardiomyopathy treated with furosemide, carvedilol, lisinopril, and digoxin comes to the emergency department with palpitations. His last left ventricular ejection fraction was 35%. His blood pressure is 160/100 mm Hg and pulse is 130/min and irregular. Lungs are clear to auscultation. The abdomen is soft and nondistended. ECG shows atrial fibrillation with rapid ventricular response and nonspecific T-wave changes. Therapy with rivaroxaban and amiodarone is initiated with improvement in symptoms. The patient is discharged home after 2 days, with these new medications added to his initial regimen. Two weeks later, he returns to the emergency department with profound anorexia, nausea, and generalized weakness. Which of the following is the most likely cause of this patient's symptoms?

Question

A 65-year-old man with nonischemic cardiomyopathy treated with furosemide, carvedilol, lisinopril, and digoxin comes to the emergency department with palpitations.  His last left ventricular ejection fraction was 35%.  His blood pressure is 160/100 mm Hg and pulse is 130/min and irregular.  Lungs are clear to auscultation.  The abdomen is soft and nondistended.  ECG shows atrial fibrillation with rapid ventricular response and nonspecific T-wave changes.  Therapy with rivaroxaban and amiodarone is initiated with improvement in symptoms.  The patient is discharged home after 2 days, with these new medications added to his initial regimen.  Two weeks later, he returns to the emergency department with profound anorexia, nausea, and generalized weakness.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d349_0eff_bc81_ab6e7513285c_MD0003_00 This patient's presentation is consistent with digoxin toxicity, most likely due to addition of amiodarone to his medication regimen. Acute digoxin toxicity typically presents with gastrointestinal symptoms (eg, anorexia, nausea, vomiting), along with possible weakness and confusion. Chronic digoxin toxicity presents with less pronounced gastrointestinal symptoms but more significant neurologic (eg, lethargy, fatigue, confusion, disorientation) and visual (eg, changes in color vision, scotomas, blindness) symptoms. Amiodarone (or verapamil, quinidine, and propafenone) increases the serum levels of digoxin (by interfering with digoxin metabolism) and can lead to toxicity in a patient who has previously been on a stable digoxin regimen. It is recommended that the digoxin dose be decreased by 25%-50% when initiating amiodarone therapy, with close monitoring of digoxin levels once weekly for the next several weeks. (Choice B) Erosive gastritis can cause nausea, abdominal discomfort, and/or mild anorexia; however, it would be unlikely to cause profound anorexia and generalized weakness. (Choice C) This patient's gastrointestinal manifestations are likely due to digoxin toxicity; there are no symptoms or signs (eg, hematochezia, melena) suggestive of gastrointestinal bleeding. (Choice D) Mesenteric ischemia presents with severe periumbilical abdominal pain, which is often out of proportion to findings on abdominal examination. Although this patient does have risk factors for developing mesenteric ischemia (eg, atrial fibrillation, severe cardiomyopathy), he has been on anticoagulation with rivaroxaban and does not have the typical clinical presentation of mesenteric ischemia. (Choice E) Occult carcinomas are a frequent cause of new-onset anorexia in older patients. However, this patient does not have other specific symptoms to suggest malignancy (eg, weight loss, increased abdominal girth, gastrointestinal bleeding), and his symptoms seem to be temporally related to medication changes. (Choice F) Acute pancreatitis presents with nausea, vomiting, and epigastric abdominal pain radiating to the back. This patient does not have typical symptoms or risk factors for developing pancreatitis (eg, alcohol use, gallstones, hypertriglyceridemia). Educational objective: Amiodarone can increase the serum levels of digoxin and cause toxicity in a patient on a stable digoxin regimen. Acute digoxin toxicity typically presents with gastrointestinal symptoms (eg, anorexia, nausea, vomiting, abdominal pain). Chronic digoxin toxicity presents with less pronounced gastrointestinal symptoms but more significant neurologic and visual symptoms (eg, changes in color vision, scotomas, blindness). References: Mechanisms, manifestations, and management of digoxin toxicity in the modern era. (http://www.ncbi.nlm.nih.gov/pubmed/16555861)

A 65-Year-Old Man with Nonischemic Cardiomyopathy Treated with Furosemide, Carvedilol