A Case of Jugular Bulb Diverticulum Invading the Internal Auditory Canal
A 54-year-old female presented with acute onset of severe whirling-type vertigo. The vertigo developed abruptly when the patient got out of the car and aggravated with positional change. The patient also complained of left pulsatile tinnitus like a "snoring" sound. Nausea and vomiting were accompanied initially, however, disappeared within 3 days. There were 5 episodes of vertigo, during the last 5 years. The vertigo was associated with some mental/physical exhaustion and the patient recovered in several days with no medical treatment. The patient denied otalgia, otorrhea and hearing loss.\nThe patient did not report any specific medical or surgical history but hyperlipidemia. The otoscopic and neurologic exams were unremarkable.\nSpontaneous horizontal nystagmus was observed toward the left side at first and changed toward the right side on the fifth hospital day. Pure-tone audiometry on the third hospital day showed SNHL of about 60 dBHL with descending type over 1 kHz and speech discrimination was 28% on the left side (). Vestibular evoked myogenic potential (VEMP) testing was performed on the fifth hospital day and showed to be normal. Saccade test, pursuit test and optokinetic test presented normal ranges, but caloric test showed the left canal paresis of 21% on the third hospital day and 73% on the eighth hospital day.\nMagnetic resonance imaging (MRI) was ordered to rule out the possibility of the left cerebellopontine angle (CPA) tumor. The official report did not identify any abnormal finding. However, we suspected high jugular bulb encroaching the IAC on the left side (). Computed tomography (CT) of the temporal bone revealed high jugular bulb and jugular bulb diverticulum with the eroded IAC on the left side ().\nWhen the left high-frequency SNHL was found on the third hospital day, we started to administer 5 mg dexamethasone, intravenously, three times a day, in a regimen of management for sudden sensorineural hearing loss (SSNHL). Even after JBD was diagnosed by radiologic evaluations, the patient received high-dose steroids with the forementioned method for 9 days and underwent a 5-day oral taper, expecting the anti-inflammatory effect of corticosteroids for the cochlear/vestibular nerve.\nOn the twenty-fifth hospital day, pure-tone audiometry showed high-frequency SNHL with partially recovered threshold of 40 dBHL and speech discrimination score was 72% on the left side. In a month after initial presentation, the patient still had positional vertigo and nystagmus, with newly developed benign positional paroxysmal vertigo and recovered completely in several days with repositioning maneuvers. Over 21 months after the onset, there has been no recurrence of vertigo, tinnitus or aggravated hearing deterioration.