Imaging and clinical findings in large endolymphatic duct and sac syndrome

OBJECTIVE: Large endolymphatic duct and sac syndrome (LEDS) is known as the most common kind of inner ear malformations, which is radiologically detectable. Nevertheless, nowadays many questions are not fully cleared and LEDS is relatively unknown among general radiologists. The aim of this study was to evaluate the incidence of LEDS in the own patient population and to present our experiences regarding imaging findings, clinical presentation and follow up. MATERIALS AND METHODS: Based on a complete recording of all patients, sent from ENT department to radiology, we identified all radiological diagnosed cases of inner ear malformations including LEDS and all patients in whom an inner ear malformation was clinically suspected. The retrospective study included clinical records, HR-CT and MRI performed between 1994 and 2002. RESULTS: Among 169 patients (338 ear), 17 of patients (median age: 12 years) and 28 ears, respectively, had enlarged endolymphatic structures. In 10 patients - 6% - (15 ears), no other abnormalities were detected, called isolated LEDS, seven patients showed additional inner ear abnormalities. One patient showed a labyrinthine hemorrhage after sudden hearing loss. Audiometric data revealed sensorineural hearing loss in 22 ears, deafness in 5 ears and normal hearing in 1 case of 28 ears. In 10 (67%) of 15 ears with isolated LEDS, the hearing loss was downward-fluctuating progressive. Twelve patients (eight with isolated LEDS) had partly repeated sudden hearing losses. A trigger for worsening of hearing was found in five patients. A correlation between the severity of morphological changes on imaging and the degree of hearing disturbances could not be detected. Only four young patients underwent a radiological examination within the first or second year after onset of hearing loss. Three patients received a cochlear implant. CONCLUSIONS: LEDS might be the cause of progressive hearing loss and repeated acute hearing losses in children and young adults. Imaging plays an important role in making the diagnosis.