Cochleovestibular nerve involvement in sarcoidosis: a case series and a literature review.

Background: Sarcoidosis is a systemic inflammatory disease of unknown etiology. Cochleovestibular nerve involvement (CVNI) may occur as a rare manifestation of neurosarcoidosis. Comprehensive data on CVNI in neurosarcoidosis are scarce and outdated. This study aimed to provide an updated characterization of this condition.

Method: We analyzed medical records from Nantes University Hospital (2010-2023) and conducted a systematic literature review, identifying cases of neurosarcoidosis with CVNI. Data included demographics, clinical features, diagnostic findings (MRI, CSF), treatments, and outcomes.

Results: Among 39 patients (51% women, median age 40), CVNI appeared during the first flare of sarcoidosis in 90%, with hearing loss in 92%, often bilateral (78%) but rarely symmetrical (28%). Diagnostic imaging revealed internal auditory canal enhancement in 57% of cases and meningeal enhancement in 27%. CSF analysis demonstrated pleocytosis in 80% and elevated protein levels in 75%. No case had both normal MRI and CSF. Corticosteroids were used in 97%, with conventional immunosuppressants and anti-TNF-α agents in 46% and 19%, respectively. CVNI-specific improvement occurred in 59%, but only 17% achieved complete recovery. Addition of anti-TNF-α agents or conventional immunosuppressants did not improve outcomes beyond corticosteroid monotherapy.

Conclusion: CVNI in sarcoidosis is rare and diagnostically challenging. MRI and CSF analysis are key for diagnosis. Early corticosteroid treatment is essential, while additional immunosuppressive therapies offer limited short-term benefit. Prospective studies are needed to guide management.