Spectrum of ocular digoxin toxicity in the elderly: A case report

Introduction: We report a case of digoxin intoxication with severe visual symptoms. Patients (or Materials) and Methods: Digoxin 0.25 mg QD for atrial fibrillation was prescribed to a 91-year-old woman with an estimated creatinine clearance of 18 mL/min. Within 2 to 3 weeks, she developed nausea, vomiting, and dysphagia, and began complaining of snowy and blurry vision, photopsia, dyschromatopsia, aggravated bedtime visual and proprioceptive illusions (she felt as being on a boat), and colored hallucinations. She consulted her family doctor twice and visited the eye clinic once until, 1 month after starting digoxin, impaired autonomy led her to be admitted to the emergency department. Results: Digoxin intoxication was confirmed by a high plasma level measured on admission (5.7 μg/L; reference range, 0.8-2 μg/L). After stopping digoxin, general symptoms resolved in a few days, but visual symptoms persisted. Ophtalmologic care and follow-up diagnosed digoxin intoxication superimposed on pre-existing left eye (LE) cataract, dry age-related macular degeneration (DMLA), and Charles Bonnet syndrome. Visual acuity was 0.4 (right eye, RE) and 0.5 (LE). Ocular fundus was physiologic except for bilateral dry DMLA. Dyschromatopsia was confirmed by poor results on Ishihara test (1/13 OU). Computerized visual field results revealed nonspecific diffuse alterations. Full-field electroretinogram (ERG) showed moderate diffuse rod and cone dysfunction. Visual symptoms progressively improved over the next 2 months, but ERG did not. Complete resolution was not expected due to the pre-existing eye disease. The patient was finally discharged home after a 5-week hospital stay. Conclusion: Digoxin intoxication can go unrecognized by clinicians, even in a typical presentation. The range of potential visual symptoms is far greater than isolated xanthopsia (yellow vision) classically described in textbooks. Newly introduced drugs and all symptoms must be actively sought after, because they significantly affect quality of life and global functioning, especially in the elderly population, most liable not to mention them.