Traumatic endolymphatic hydrops.

Traumatic endolymphatic hydrops is an accumulation of endolymph in the cochlear duct caused by traumatic insult. The causative mechanisms are: (1) fistulization of the bony labyrinth, which causes a disturbance in the normal perilymph-endolymph pressure relationship; (2) direct injury to the membranous labyrinth, which may be just a collection of fluid in the cochlear duct from irritation, resulting in endolymphatic hydrops that may not be progressive and may subside in a short period of time after injury and hearing loss may occur; and (3) injury to the endolymphatic fluid drainage system, including a temporal bone fracture in which the fissure happens to extend through the vestibular aqueduct, causing fibro-osseous blockage of the endolymphatic duct and surgical injury to the saccule with obstruction of the longitudinal flow of endolymph, resulting in endolymphatic hydrops that may be delayed in onset and is usually persistent. The diagnosis of traumatic endolymphatic hydrops is made by a history of trauma, such as barotrauma, a blow to the head, or perhaps a previous ear operation, such as stapedectomy; the presence of typical symptoms of endolymphatic hydrops, including fullness, tinnitus, fluctuant hearing loss, and episodic vertigo; and an elevated negative summating potential and an increased summating potential:action potential ratio by electrocochleography. Three patients are presented to demonstrate this clinical entity.