Teaching Video NeuroImages: An Uncommon Cause of Hearing Loss.

A 66-year-old woman presented with right-sided hearing loss, insidious in onset. Otoscopic examination showed pulsation of the tympanic membrane in a seated position (Video 1) which diminished on lying down. A CT venogram of the auditory canal showed a dehiscent right jugular bulb along the hypotympanic surface (Figures 1 and 2). A dehiscent jugular bulb develops because of the absence of sigmoid plate separating the bulb from the middle ear. It appears as blue mass behind the tympanic membrane which may distend with Valsalva or internal jugular vein compression. Affected individuals, while often asymptomatic, can experience conductive/sensorineural hearing loss, tinnitus, or vestibular dysfunction.1 The patient is followed with imaging periodically for disease progression. Over 10 years, her hearing has been stable. Neurologists should be familiar with the otoscopic appearance of auditory canal dehiscence as tinnitus, and vestibular dysfunction is a common presentation. Treatment involves reassurance and follow-up with serial imaging. Surgical or endovascular intervention is reserved for intolerable symptoms.2