Rapidly progressive bilateral sensory neural hearing loss as a presentation of mitochondrial neurogastrointestinal encephalomyopathy

Abstract

A 23-year-old woman presented to the department of Otolaryngology–Head and Neck Surgery at Rambam Medical Center because of a rapidly progressive bilateral sensory neural hearing loss (SNHL) that worsened 3 days before presentation. The patient had been hospitalized and treated a month before, at another institution, because of sudden onset bilateral SNHL (right left), which developed after an acute upper respiratory infection. At that time, she was treated with oral steroids and carbogen inhalations and discharged 5 days later with no improvement. Her audiogram at that time showed bilateral SNHL (left ear: average loss at speech frequencies of 27 dB; right ear: average loss at speech frequencies of 70 dB). At presentation to our department, a detailed history revealed no previous exposure to loud noise, no prior ear infections or surgery, and no history of chronic diseases, tinnitus, or vertigo; she was not being treated with any known ototoxic medications. Family history revealed that her parents were first cousins and that her brother died at the age of 17 because of pancreatitis and an obscure neurologic disease. There was no family history of hearing loss. On physical examination, mild hirsutism and bilateral ptosis were noted. Her intellect was normal. All deep tendon reflexes were absent; there was mild general muscle wasting and polyneuropathy. Otoscopy was normal; cranial nerve function was preserved. There were no vestibular or cerebellar deficits or nystagmus. By this time, the audiogram showed an average loss at speech frequencies of 60 dB in the left ear and profound hearing loss ( 90 dB) in the right ear. Routine laboratory tests for sudden SNHL were performed and included complete blood count, which was normal except for mild macrocytosis. Erythrocyte sedimentation rate, thyroid function tests, electrolytes, glucose, and coagulation profiles were all normal. Lactate dehydrogenase, -glutamyl transpeptidase, and alanine amino transferase were all slightly elevated. A chest radiograph and echocardiogram were both normal. Despite the elapsed time interval from onset treatment for sudden SNHL, treatment was attempted and included carbogen inhalations, intravenous magnesium sulfate, and oral steroids. Despite this treatment, her condition worsened, and serial audiograms showed a rapid progressive deterioration over 3 days time. She progressed to a bilateral profound SNHL. A brain stem–evoked response threshold was performed and showed an absence of waves I, III, and V and a hearing threshold of more than 95 dB on the right and an absence of waves I and III and a hearing threshold of 95 dB on the left A magnetic resonance imaging (MRI) of the brain was performed (Fig 1). The MRI shows diffuse plaques seen as high signal intensity areas within the white matter of the brain, particularly in the periventricular area. These imaging findings raised the possibility of multiple sclerosis (MS) or a metabolic disorder including a mitochondrial disorder. The patient was referred for a neurologic and a genetic consultation. Repeated detailed history and physical exFrom the Department of Otolaryngology–Head and Neck Surgery, *Institute of Diagnostic Imaging, Rambam Medical Center and Technion Faculty of Medicine, Haifa, Israel. Address correspondence to David Goldenberg, MD, 6509 Copper Ridge Drive, Apt 201, Baltimore MD, 21209. Copyright 2003 Elsevier, Inc. All rights reserved. 0196-0709/03/2402-0001$30.00/0 10.1053/ajot.2003.25