A 76-year-old woman comes to the emergency department due to fatigue, nausea, and abdominal pain for the past 2 weeks. She feels weak and has not been eating much. She also has "black spots" in her vision when she watches television. Medical history includes hypertension, type 2 diabetes mellitus, persistent atrial fibrillation, myocardial infarction with coronary artery bypass grafting 10 years ago, and ischemic cardiomyopathy with an ejection fraction of 30%. The patient was hospitalized 6 months ago with an episode of decompensated heart failure but has had no recent illnesses. Medications include aspirin, furosemide, valsartan, carvedilol, atorvastatin, spironolactone, digoxin, warfarin, and insulin.
Temperature is 36.7 C (98 F), blood pressure is 120/74 mm Hg, and pulse is 50/min. Mucous membranes are dry and the neck veins are flat. The lungs are clear to auscultation. Heart sounds are regular with a faint ejection systolic murmur present over the aortic area. The abdomen is soft with mild, diffuse tenderness over the epigastric area with deep palpation. Neurologic examination is unremarkable.
Laboratory results are as follows:
ECG shows a regular narrow-complex rhythm at 48/min, no P waves, and occasional ventricular premature beats. While in the emergency department, the patient also has an asymptomatic 9-beat run of nonsustained ventricular tachycardia that resolves spontaneously.
Which of the following is the best treatment for this patient?

Question

A 76-year-old woman comes to the emergency department due to fatigue, nausea, and abdominal pain for the past 2 weeks.  She feels weak and has not been eating much.  She also has "black spots" in her vision when she watches television.  Medical history includes hypertension, type 2 diabetes mellitus, persistent atrial fibrillation, myocardial infarction with coronary artery bypass grafting 10 years ago, and ischemic cardiomyopathy with an ejection fraction of 30%.  The patient was hospitalized 6 months ago with an episode of decompensated heart failure but has had no recent illnesses.  Medications include aspirin, furosemide, valsartan, carvedilol, atorvastatin, spironolactone, digoxin, warfarin, and insulin.
Temperature is 36.7 C (98 F), blood pressure is 120/74 mm Hg, and pulse is 50/min.  Mucous membranes are dry and the neck veins are flat.  The lungs are clear to auscultation.  Heart sounds are regular with a faint ejection systolic murmur present over the aortic area.  The abdomen is soft with mild, diffuse tenderness over the epigastric area with deep palpation.  Neurologic examination is unremarkable.
Laboratory results are as follows:
 ECG shows a regular narrow-complex rhythm at 48/min, no P waves, and occasional ventricular premature beats.  While in the emergency department, the patient also has an asymptomatic 9-beat run of nonsustained ventricular tachycardia that resolves spontaneously.
Which of the following is the best treatment for this patient?

Quizplus · Accepted Answer

This patient's clinical presentation is consistent with digoxin toxicity. The therapeutic window of digoxin is small, and acute kidney injury leading to impaired digoxin clearance is a common cause of toxicity. Acute toxicity usually presents with gastrointestinal symptoms (eg, anorexia, nausea, vomiting, abdominal pain). Chronic toxicity may present with less pronounced gastrointestinal symptoms but more significant neurologic and visual symptoms (eg, changes in color vision, scotomas, blindness). Cardiac arrhythmias (eg, sinus bradycardia, atrioventricular block, ventricular tachycardia) can occur and are a common cause of mortality. Digoxin toxicity does not correlate well with serum digoxin levels (toxicity can occur with normal or subtherapeutic levels); therefore, the diagnosis should be based on clinical presentation and ECG findings. Initial treatment involves intravenous hydration. In addition, digoxin-specific antibody (Fab) fragments should be given in patients with any of the following: Life-threatening cardiac arrhythmia (eg, advanced conduction block with junctional rhythm as in this patient)End-organ dysfunction due to hypoperfusionHyperkalemia (serum potassium >5.5 mEq/L) Life-threatening cardiac arrhythmia (eg, advanced conduction block with junctional rhythm as in this patient) End-organ dysfunction due to hypoperfusion Hyperkalemia (serum potassium >5.5 mEq/L) Hemodialysis is ineffective for digoxin toxicity due to the high molecular weight and large volume of distribution of the drug. (Choices A and C) Digoxin toxicity causes excessive inhibition of the sodium-potassium-ATPase in cardiac myocytes, leading to hyperkalemia. The hyperkalemia itself does not cause death, but it is a marker of severity and a predictor of mortality in acute digoxin toxicity. Therefore, therapy in these patients should be aimed at lowering serum digoxin levels; medications to treat hyperkalemia (eg, calcium gluconate, insulin) are not indicated and may lead to hypokalemia as therapy with Fab fragments rapidly lowers potassium levels. (Choice D) Intravenous amiodarone is useful for treating atrial and ventricular tachyarrhythmias. However, it is contraindicated in digoxin toxicity as it competes with digoxin for renal excretion and can increase serum digoxin levels. (Choice E) Intravenous glucagon is an antidote for beta blocker and calcium channel blocker toxicity but is not effective for digoxin toxicity. Educational objective: Digoxin has a small therapeutic window, and decreased renal function is a common precipitant of toxicity. Clinical manifestations of digoxin toxicity include gastrointestinal disturbance, neurologic and visual dysfunction, electrolyte imbalance, and cardiac arrhythmia. Treatment involves intravenous hydration; in addition, patients with life-threatening arrhythmia, end-organ dysfunction, or hyperkalemia should be given digoxin-specific antibody (Fab) fragments. __________ References: Mechanisms, manifestations, and management of digoxin toxicity in the modern era. (http://www.ncbi.nlm.nih.gov/pubmed/16555861)

A 76-Year-Old Woman Comes to the Emergency Department Due to Fatigue