Acute Bilateral Hearing Loss: An Unheard of Thalamic Syndrome

Despite the involvement of the thalamus in the auditory pathway, hearing loss is not commonly recognized as a sequela of thalamic hemorrhage. Interestingly, only a few case reports in the literature describe thalamic hemorrhage as a cause of sudden sensorineural hearing loss (SSHL). The use of brainstem evoked potentials (BAEPs) to evaluate hearing loss in these patients has not been reported in the literature.

A 56-year-old man presented to the emergency room for an acute onset of hearing loss and left perioral and foot numbness. On neurological examination, he was found to have mild left hemiparesis, sensory deficit, ataxia, and complete hearing loss. His National Institutes of Health Stroke Scale was 6. Initial noncontrast head computed tomography (CT) showed a focal acute parenchymal hemorrhage in the right thalamus and posterior limb of the internal capsule. Magnetic resonance imaging (MRI) of the brain confirmed the presence of the right thalamocapsular hematoma, and the gradient echo sequence demonstrated remote hematoma in the left lentiform nucleus. Otolaryngology was consulted and diagnosed the patient with idiopathic sudden sensorineural hearing loss. Given the unclear etiology, BAEPs were pursued and revealed an intact brainstem auditory pathway and suggested reduced activity in thalamic auditory regions. He was discharged on prednisone taper and referred for formal outpatient audiometry testing.

This case highlights sensorineural hearing loss as a potential thalamic syndrome and the utilization of BAEPs as diagnostic tools in suspected central origin of hearing impairment.