Definition:

Delayed endolymphatic hydrops (DEH) is a disorder, characterized by episodic vertigo that develops some time after the onset of a profound, typically unilateral sensorineural hearing loss. DEH can be differentiated from Meniere's disease. The age of onset of symptoms is typically in later childhood and adolescence or between 40 and 60 years of age. DEH probably is caused by atrophy or fibrous obliteration of the endolymphatic resorptive system of the membranous labyrinth. It has been reported that genetic factors may sometimes be the cause of this disease. Two types of DEH exist: the ipsilateral type, in which the ear with profound hearing loss suffers progressive endolymphatic hydrops, and the contralateral type, in which the formation of progressive endolymphatic hydrops takes place in the ear opposite to the previously deafened ear. DEH requires conservative treatment, such as that typically used for Meniere's disease, including the appropriate concomitant use of diuretics, such as isosorbide or steroids for at least 3-6 months. When recurrent episodic vertigo cannot be remedied through conservative treatment, labyrinthectomy and vestibular neurectomy on the deaf ear are curative for ipsilateral DEH. However, no such surgical treatment is available for the contralateral type.