Contralateral delayed endolymphatic hydrops: Clinical features and long term outcome.

Background: Contralateral delayed endolymphatic hydrops (CDEH) is a clinical entity characterized by fluctuating low frequency hearing loss and/or vertigo, mimicking Ménière's disease (MD), that manifests after the appearance of severe non-hydropic hearing loss (NHHL) at the other ear.

Objectives: to describe the clinical features and the course of 57 patients affected by CDEH.

Method: this is a retrospective study; 57 patients affected by CDEH, out of 1065 patients seen in the same period and affected by MD, were subjected to otoscopy, PTA threshold evaluation, impedance testing, ABR, research of positioning nystagmus, vestibular function evaluated by means of bithermal caloric test under video-oculographic, and MRI with gadolinium.

Results: the CDEH was definite in 24 cases (42%), probable in 2 (4%) and possible in 31 (54%). The mean PTA threshold at the hydropic ear was 41 dB. At the last follow-up, 40 patients (70%) did not report vertigo or fluctuating hearing loss. Among the 17 patients who still reported symptomatology, 11 (64%) were affected by fluctuating hearing loss alone, 4 (23%) reported a subjective worsening of hearing loss and 2 (12%) an acute vertigo crisis.

Conclusions: contralateral delayed endolymphatic hydrops is a relatively rare form of Ménière disease that manifests more frequently as a definite form or with fluctuating low-frequency hearing loss. The prognosis at a long term follow-up is relatively good in terms of vertigo resolution. Contralateral delayed endolymphatic hydrops rarely determines a severe hearing loss in the better ear.