Review Question - QID 109495

A 74-year-old man with frontotemporal dementia, coronary artery disease, hypothyroidism, hyperlipidemia, and paraplegia secondary to spinal cord injury from a motor vehicle accident presents with altered mental status. At baseline, he is wheelchair-bound and dependent on nursing staff for all of his activities of daily living. He does not drink alcohol or smoke cigarettes. He rarely sits down but was more agitated than usual according to the nursing report brought by the emergency medical technician who transported him to the hospital. His medications include donepezil, aspirin, levothyroxine, simvastatin, tamsulosin, and hydralazine. His temperature is 97°F (36.1°C), blood pressure is 146/78 mmHg, pulse is 92/min, and respirations are 15/min. He is alert and oriented to name but not place and time. His physical exam is notable for an irregularly irregular rhythm on cardiac auscultation, bibasilar crackles, a non-tender abdomen, and left calf swelling. The patient is found to have atrial fibrillation and the ER physician instructs the resident to discharge the patient on a direct oral anticoagulant. 10 days later, the patient returns to the hospital with altered mental status again, but with a new finding shown in Figure A. On review of his medication list, a vitamin K epoxide reductase antagonist was recently prescribed. What is the most likely cause of this patient's presentation?