Idiopathic Labyrinthitis: Symptoms, Clinical Characteristics, and Prognosis

BACKGROUND: Labyrinthitis is an inner ear disorder of unknown incidence, characterized by sudden hearing loss and concurrent vertigo. Cohort studies of patients diagnosed with labyrinthitis are nonexistent. This study aims to describe the clinical characteristics and prognosis of patients diagnosed with idiopathic labyrinthitis. METHODS: Patients with labyrinthitis in the absence of a clear viral, bacterial, or autoimmune pathogenesis were retrospectively identified from electronic patient files. Symptoms at presentation and results from vestibular testing were retrieved. The 9-item Vestibular Activity Avoidance Instrument, administered during follow-up interviews by telephone, was used to assess the presence of persistent balance problems and activity avoidance behavior. RESULTS: Sixty-one patients with idiopathic labyrinthitis were included. All patients had vestibular weakness at presentation. After a median of 61 months of follow-up (interquartile range 81), 72.5% of patients still experienced balance problems. Subjective hearing recovery only occurred in 20% of cases. CONCLUSION: Patients presenting in a tertiary dizziness clinic with idiopathic labyrinthitis have a poor prognosis for both hearing and balance function impairment. Prospective observational cohorts are required to establish objectifiable vestibular and audiological follow-up data.