Sudden hearing loss as the sole manifestation of neurosarcoidosis

Sarcoidosis is a chronic, idiopathic granulomatous disease with frequent pulmonary, ocular, and lymphatic systemic manifestations. Central nervous system involvement is rare (1% to 5%), yet the most frequent presenting symptoms (48%) in patients with neurosarcoidosis are neurologic. Eighth cranial nerve abnormalities occur in 20% of these patients, typically in association with other cranial neuropathies or overt systemic disease. Isolated eighth nerve disease is very rare. We report two cases of neurosarcoidosis manifest as isolated, sudden onset sensorineural hearing loss, one of which had a cerebellopontine angle (CPA) granuloma that mimicked an acoustic neuroma. Both patients experienced marked steroid-induced hearing improvement that persisted after termination of therapy. Brainstem evoked response audiometry (BSER) abnormality persisted despite normalization of audiologic parameters. The implications for diagnosis and treatment of sarcoidosis-induced hearing loss are described. Neurosarcoidosis must be considered when evaluating patients with sudden hearing loss. Prompt steroid therapy offers hope for significant hearing recovery in these patients.