TRAUMATIC ENDOLYMPHATIC HYDROPS

Traumatic endolymphatic hydrops is an accumulation of endolymph in the cochlear duct caused by traumatic insult. The causative mechanisms ar e: (1) fistulization of the bony labyrinth, which causes a disturbance in the normal perilymph-endolymph pressure relationship; (2) direct i njury to the membranous labyrinth, which may be just a collection of f luid 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 fractu re in which the fissure happens to extend through the vestibular aqued uct, causing fibro-osseous blockage of the endolymphatic duct and surg ical injury to the saccule with obstruction of the longitudinal flow o f endolymph, resulting in endolymphatic hydrops that may be delayed in onset and is usually persistent. The diagnosis of traumatic endolymph atic hydrops is made by a history of trauma, such as barotrauma, a blo w to the head, or perhaps a previous ear operation, such as stapedecto my; the presence of typical symptoms of endolymphatic hydrops, includi ng fullness, tinnitus, fluctuant hearing loss, and episodic vertigo; a nd an elevated negative summating potential and an increased summating potential:action potential ratio by electrocochleography. Three patie nts are presented to demonstrate this clinical entity.