Review Question - QID 211056

A 67-year-old man presents to his primary care physician for a decline in his hearing that he noticed over the past week. The patient has a medical history of hypertension and diabetes mellitus and was recently diagnosed with bladder cancer which is currently being treated. The patient is a hunter and often goes shooting in his spare time. His recent sick contacts include his grandson who is being treated with amoxicillin for ear pain. His temperature is 98.7°F (37°C), blood pressure is 137/88 mmHg, pulse is 79/min, respirations are 12/min, and oxygen saturation is 98% on room air. A physical exam is notable for decreased hearing bilaterally. The Weber test does not localize to either ear, and the Rinne test demonstrates air conduction is louder than bone conduction. Which of the following is the most likely etiology for this patient's hearing loss?