[Mitochondrial encephalomyopathy involves ophthalmology otorhinolaryngology neurology and their clinical features].

This study aimed to provide better understanding of the otolaryngologic features, combined with ophthalmologic and neurologic characteristics in mitochondrial encephalomyopathy（MEM）, and to help ENT and auditory practitioner making correct diagnosis as well. Twenty-eight patients with MEM were enrolled between September 2001 and January 2020. Information about family histories and clinical symptoms was retrospectively analyzed. All patients underwent otorhinolaryngological, ophthalmological and neurological examinations, including: pure-tone audiometry, acoustic immittance（AI）, distortion-product otoacoustic emissions（DPOAE）, auditory brainstem response（ABR）, cochlear micropotential（CM）, speech discrimination score（SDS）, electroneurography（ENoG）, computed tomography（CT） of the temporal bone and cranial magnetic resonance weighted imaging scan（MRI）, muscle biopsy and mtDNA gene testing. ENT subjective manifestations were present in 15 cases （53.6%） with sensorineural hearing loss（SNHL）, 4（14.3%） with tinnitus, 4（14.3%） with facial weakness, 3（10.7%） with dysphagia, 1（3.6%） with auditory agnosia. Ophthalmological and neurological symptoms included ptosis in 16 cases （57.1%）, exercise intolerance in 16（57.1%）, optic atrophy in 15（53.6%）, muscular atrophy in 6（21.4%）, and stroke-like episodes in 5（17.9%）. The results of objective examinations were as follows: DPOAE were not elicited in 18（64.3%） cases, ABR abnormalities in 18（64.3%） cases, hearing threshold shift in 15（53.6%） cases, AI normal and CM was not detected in all cases, SDS decreased in 6（21.4%） cases, facial ENoG abnormalities in 4（14.3%） cases, laryngeal ENoG abnormalities in 3（10.7%） cases, EMG abnormalities in 6（21.4%） cases, and ECG abnormalities in 8（28.6%） cases. Temporal CT were normal, but cranial MRI abnormalities were found in 19 cases（67.9%）, including central nerve demyelination, white matter hyperintensities, generalized cerebellar and cerebral atrophy, multiple cortical/subcortical infarct-like lesions, basal ganglia calcification. Multisystemic syndromes in MEM can present as a variety of otolaryngological, ophthalmological and neurological abnormalities, such as ptosis, audio-visual disturbance, exercise intolerance and stroke-like episodes etc. SNHL, tinnitus, auditory agnosia, facial weakness and dysphagia were ENT specific manifestations. SNHL in MEM is bilateral symmetrical progressive or of sudden onset since teenage. mtDNA testing may be helpful for adolescent patient whose SNHL was associated with neuromuscular symptoms. Muscle biopsy should be considered when middle-aged patients developed facial weakness and dysphagia. DPOAE and ABR are the optimal objective audiometric tests to monitor the progression of MEM associated with SNHL.