[A case of hearing loss caused by overdrainage of cerebrospinal fluid after ventriculo-peritoneal shunting procedure]

We describe a case of intracranial hypotension syndrome due to overdrainage of cerebrospinal fluid presented with hearing loss after ventriculoperitoneal shunting procedure. A 69-year-old man suffering from subarachnoid hemorrhage presented with an angiogram showing two aneurysms, one of the right internal carotid and one of the middle cerebral artery. Neck clipping was performed. One month later, he developed normal pressure hydrocephalus (NPH), which was treated by ventriculoperitoneal (NPH), which was treated by ventriculoperitoneal shunting procedure using low pressure Pudenz system. Trias of NPH were improved by insertion of shunt system. However, he complained of hearing loss which was worsened by upright position and improved by lying down. Such kinds of phenomenon were demonstrated by audiogram showing that the transitory decrease of hearing and electrocochleography showing the elongation of N1 latency at upright position. These data suggested that his hearing loss was caused by inner ear or auditory nerve lesion. After the shunt system was replaced into the antisiphon device, his hearing disturbance improved. Axial computed tomography of bone window at the level of orbitomeatal line demonstrated widely perilymphatic duct on both sides. This finding suggested that the fluctuation of intracranial pressure was easily transmitted into the cochlear through the widened perilymphatic duct, resulting in hearing disturbance.