Monosymptomatic Clinically Isolated Syndrome With Sudden Sensorineural Hearing Loss Case Report and Critical Review of the Literature Maria C. Anagnostouli, MD, PhD,* Elias S. Sotirchos, MD,* Ioannis Zalonis, PhD,* Fotini Christidi, MSc,* Stavros Korres, MD, PhD,w Michael Rentzos, MD, PhD,* and Panagiota Davaki, MD, PhD* Introduction: Isolated cranial nerve involvement is rare in patients with multiple sclerosis (10.4%) and extremely rare is an eighth nerve palsy, especially in the context of a clinically isolated syndrome (< 1%). Case Report: A 34-year-old male presented with a history of left-sided tinnitus and sudden sensorineural hearing loss (SSNHL). Magnetic resonance imaging of the brain revealed >9, nonenhancing periven- tricular and corpus callosum lesions. Brainstem auditory evoked potentials were abnormal, ipsilateral to the affected ear, consistent with the presumed underlying demyelinating pathology. Visual evoked potentials showed bilateral prolonged P100 latencies. Oligoclonal bands were not detected in the cerebrospinal fluid, but IgG index was marginally elevated. After administration of corticosteroids, the patient recovered auditory function over a several month period. Conclusions: This report describes a case of SSNHL in the context of magnetic resonance imaging of the brain and electrophysiological findings consistent with a demyelinating etiology. SSNHL is a rare and possibly underrecognized manifestation of clinically isolated syndrome. Key Words: multiple sclerosis, clinically isolated syndrome, hearing loss, brainstem auditory evoked potentials, sudden sensorineural hearing loss, neuropsychological assessment (The Neurologist 2012;18:302–305) S udden sensorineural hearing loss (SSNHL) during the course of multiple sclerosis (MS) is a well-recognized clinical manifestation with a reported prevalence of 0.4% to 5%. 1–4 In contrast, clinically isolated syndrome (CIS) with SSNHL is an exceptional manifestation and only recently reported in a series, 2,3 apart from published case reports. 5–13 In a recent study, isolated cranial nerve involvement in MS was present in 10.4% of 483 patients, either as a presenting symptom (7.3%) or a symptom of disease relapse (3.1%). In this study, the frequency of eighth nerve involvement, as a sole initial symptom, was almost 0%. 1 A retrospective magnetic resonance imaging of the (MRI) study of 1070 patients with SSNHL over a 5-year period, revealed only 1 patient with CIS. 14 Reviewing the literature from 1980 to the present time, we found only 14 reported CIS cases with SSNHL. Here, we present a case of CIS presenting with SSNHL. We also review clinical, neurophysiological, neuroimaging, neuro- psychological, and therapeutic parameters, which need to be further discussed regarding auditory pathway involvement in MS. CASE REPORT A 34-year-old right-handed male presented with a history of left- sided tinnitus and hearing loss. His symptoms began abruptly, when the patient first noticed tinnitus in his left ear upon awakening. He also experienced a distorted perception of sound, difficulty in following conversations, and sensitivity to loud sounds. These symptoms per- sisted throughout the day intermittently and over the next few days his tinnitus progressively worsened in intensity and became constant. Ipsilateral hearing loss also became evident. The patient was initially evaluated by an otolaryngologist. Pure tone audiometry showed left- sided SSNHL. Impedance audiometry was also performed. The tym- panogram was normal and the acoustic reflex was absent in the left ear. Treatment was initiated for SSNHL with intratympanic dex- amethasone. The patient received 3 doses on alternate days and was followed with serial audiograms that showed no improvement of auditory function. Computed tomographic (CT) scan of the temporal bone was normal. Brainstem auditory evoked potentials (BAEPs) of the right ear were normal, but on the left wave V was absent; BAEP abnormalities are not a feature of labyrinthine disease and the absence of wave V is a finding consistent with an underlying demyelinating pathology of the brainstem (Fig. 1). 2,15 Subsequently, the patient was referred to a neurologist for further evaluation. At 1 month from the onset of symptoms, a brain MRI was performed and it showed > 9 typical, nonenhancing hyperintense T2 lesions in the periventricular and juxtacortical white matter and also one in the corpus callosum. No lesions were detected along the audi- tory pathways and brainstem (Fig. 2). The patient was treated with a 5-day course of intravenous methylprednisolone (1 g/d), with partial improvement in hearing and less so in tinnitus. Over the next few weeks, his auditory function improved and he was referred to us for further evaluation. The patient reported some residual tinnitus and hearing loss. In retrospect, he also described epi- sodes of dystonic cramps and causalgia in his legs, in the years preceding this attack. Neurological examination was normal. Family history was significant for a maternal aunt with scleroderma. Routine blood tests were normal. Extensive immunologic tests for various autoimmune diseases were normal, except for antinuclear antibodies 1/80 (normal <1/80), serum angiotensin-converting enzyme (SACE) 89 IU/I (normal, 8 to 52 IU/I), and C-reactive protein 1.55 mg/dL (normal, 0 to 0.05 mg/dL). Because of the increased SACE, chest CT was performed to rule out sarcoidosis; no pathologic findings were detected. All tests in serum and cerebrospinal fluid were negative for HSV 1-2, cytomegalovirus, Epstein-Barr, Coxsackie, Hepatitis B and C, and also for Borrelia burgdorferi. Cerebrospinal fluid cell count, protein, and glucose were normal. Oligoclonal bands were not present, but the From the *A’ Department of Neurology, Medical School, National & Kapodistrian University of Athens, Aeginition Hospital; and wNeur- ootology Unit, Ippokration Hospital, Athens, Greece. The authors declare no conflict of interest. Reprints: Maria C. Anagnostouli, MD, PhD, A’ Department of Neurology, Medical School, National & Kapodistrian University of Athens, Aeginition Hospital, Vas. Sofias 72-74, Athens 115-28, Greece. E-mail: managnost@med.uoa.gr. Copyright r 2012 by Lippincott Williams & Wilkins ISSN: 1074-7931/12/1805-0302 DOI: 10.1097/NRL.0b013e3182675479 CASE REPORT/CASE SERIES 302 | www.theneurologist.org The Neurologist  Volume 18, Number 5, September 2012