mrcem2-0360

A 45 year old man presents to the emergency department complaining of dizziness. The patient describes a sensation of the room spinning around him and a constant ringing in his ears. He mentions feeling nauseated and experiencing a decrease in his hearing ability. These symptoms began an hour ago, but he had a similar episode earlier in the week that lasted for 2-3 hours. The patient did not seek medical attention at that time, thinking the symptoms would resolve on their own. There is no significant medical history to note. Upon examination, the patient’s vital signs are within normal range, and his cardiovascular and respiratory systems appear normal. The ears appear normal upon examination with an otoscope. Rinne’s test reveals that air conduction is greater than bone conduction in both ears, while Weber’s test shows lateralization to the right ear. When asked to march on the spot with his eyes closed, the patient stumbles and requires assistance to maintain balance. No other abnormalities are detected in the cranial nerves, and the patient’s limbs exhibit normal power, tone, and reflexes.

What is the most likely diagnosis?