Sudden Sensorineural Hearing Loss (SSNHL)

A 52-year-old man presents to the emergency department 36 hours after waking up with sudden complete loss of hearing in the right ear, accompanied by loud constant high-pitched tinnitus and aural fullness. He denies recent upper respiratory infection, head trauma, ototoxic medication use, or loud noise exposure. On examination, Weber tuning fork test lateralizes to the left, and pure-tone audiometry shows thresholds of 70–90 dB HL across 250 Hz to 2 kHz on the right with no response at 4 and 8 kHz, meeting diagnostic criteria for the condition marked **A** in the diagram. MRI excludes retrocochlear pathology and serologies are negative. Which of the following is the most appropriate initial management?