Abstract
Delayed endolymphatic hydrops (DEH), a disease entity different from Ménière's disease, typically develops in patients experiencing profound, long-term hearing loss in 1 ear. This condition was first reported by Kamei et al. ('71), Wolfson and Leiberman ('75) and Nadol et al. ('75). Schuknecht ('78) defined DEH and classified it into 2 types : ipsilateral and contralateral. The underlying pathophysiologic mechanism for DEH development was explained as progressive endolymphatic hydrops in the inner ear due to delayed atrophy or fibrous obliteration of endolymphatic resorption system, resulting from previous inner-ear injury. According to the literature, the period between the onset of preexisting deafness in 1 ear and DEH onset ranges from several months to 74 years. The cause of preexisting deafness is unilateral profound deafness due to obscure etiology since early childhood in more than half of the cases of both types of DEH. Other causative disorders of the inner ear leading to DEH are mostly due to inflammation (viral and bacterial) and trauma (physical and acoustic). Ipsilateral DEH is more common than the contralateral type. The age at onset in contralateral DEH is generally higher than that of ipsilateral. Medical treatment may be effective in both types of DEH. Complete relief from episodic recurrent vertigo is expected in 65% of cases within 5 years after the onset of vertigo. Labyrinthectomy or vestibular nerve section in the deaf ear is curative in ipsilateral DEH, but no satisfactory surgical therapy is available for contralateral.
