A 73-year-old woman comes to the emergency department due to vision changes. Over the last few days, she has noticed blurred vision and scattered blind spots while watching television. She reports poor appetite and fatigue since an episode of gastroenteritis 2 weeks ago. She has no fever, headache, or muscle weakness but admits feeling unsteady.
Her past medical history is significant for hypertension, type 2 diabetes mellitus, heart failure with reduced ejection fraction (ejection fraction of 15%) , and mild chronic obstructive lung disease. Her medications include tiotropium, torsemide, ramipril, carvedilol, spironolactone, digoxin, and empagliflozin. The patient is adherent with her medications and clinic visits. She is a former smoker with a 35-pack-year history.
Her blood pressure is 144/90 mm Hg supine and 140/90 mm Hg standing. Pulse is 52/min in both positions. BMI is 19 kg/m². The mucous membranes appear dry. Lungs are clear to auscultation and no murmurs are heard on cardiac examination. There is mild epigastric tenderness on deep palpation. There is no peripheral edema. Neurologic examination is unremarkable except for mild unsteady gait.
Fingerstick glucose is 109 mg/dL.
Which of the following is the most likely diagnosis?

Question

Quizplus · Accepted Answer

This patient's clinical presentation suggests digoxin toxicity, likely precipitated by recent gastroenteritis. Digoxin has a narrow therapeutic range (0.8-2.0 ng/mL; range of 0.5-0.8 ng/mL recommended in heart failure) and is cleared by the kidneys. Recent illnesses (eg, gastroenteritis) can lead to volume depletion and/or acute kidney injury with impaired digoxin clearance. Other potentiating factors include hypokalemia, hypomagnesemia, hypercalcemia, and myocardial ischemia. Acute digoxin toxicity presents with significant anorexia, nausea, vomiting, abdominal pain (possible nonocclusive mesenteric ischemia), confusion, and weakness. Chronic digoxin toxicity occurs gradually and presents with less pronounced gastrointestinal symptoms but more significant neurologic symptoms (eg, lethargy, fatigue, delirium, confusion, disorientation, weakness) and visual symptoms (eg, changes in color vision, blurred vision, scotomas, blindness). Digoxin toxicity can cause a wide range of cardiac arrhythmias including atrial tachycardia, atrioventricular block, and ventricular tachycardia. (Choice A) Acute angle-closure glaucoma usually presents with red eye, decreased peripheral vision, light-halos, headache, severe eye pain, nausea, and vomiting. (Choice B) Chronic heart failure may present with weight loss and symptoms of anorexia, early satiety, and depression. Although this patient may also have cardiac cachexia, her visual and gastrointestinal symptoms are more suggestive of digoxin toxicity. (Choice C) Symptoms of cerebellar stroke include headache, vertigo, nystagmus, vomiting, gait ataxia, and limb incoordination. Although this patient has a mild unsteady gait, she does not have the other symptoms. (Choice D) Patients with diabetic retinopathy are asymptomatic for years and may present with blurred vision, partial or total loss of vision, and floaters. Those with good glycemic control (such as this patient) are less likely to develop diabetic retinopathy complications. Educational objective: Digoxin toxicity can be precipitated by recent illness that causes volume depletion or by drugs that impair renal clearance of digoxin. Patients usually present with gastrointestinal disturbances, neurologic dysfunction, vision changes, electrolyte imbalances, and cardiac arrhythmias. __________ References: Mechanisms, manifestations, and management of digoxin toxicity in the modern era. (http://www.ncbi.nlm.nih.gov/pubmed/16555861)

A 73-Year-Old Woman Comes to the Emergency Department Due to Vision