Rare Causes of Unilateral Sensorineural Hearing Loss in Adults: Our Experience

Abstract

Bilateral hearing loss is attributed to almost 50% of times with genetic etiology, while most unilateral sensorineural hearing loss (USNHL) are not attributable to it. Limited literature is available on epidemiology of USNHL. Etiology of USNHL is very diverse and vast, it ranges from as common as Meniere's disease to as rare as an electric shock injury. A prospective study was carried out to find rare causes of USNHL in adults. In this manuscript, we present a case series of 7 rare etiologies of USNHL in adults like auditory neuropathy, chemoradiotherapy, dialysis-induced SNHL, common cavity inner ear malformation, multiple sclerosis, acute otitis media-induced SNHL and vertebrobasilar dolichoectasia. This study discusses the rare possible etiologies of USNHL that can be easily missed if these are not ruled out properly. We present these cases to consider these heterogeneous and distinct causes of USNHL because of rarity of these etiologies. If such an etiology is diagnosed in time, they may be managed effectively.

Keywords: Multiple sclerosis; Renal failure; Sensorineural hearing loss; Vertebrobasilar dolichoectasia.

Fig. 1

Showing pure tone audiogram of patient with profound SNHL in left ear

Fig. 2

Showing axial T2 weighted MRI of temporal bone, a single ovoid chamber representing both cochlea and vestibule on left (common cavity inner ear malformation), marked red arrow, b common cavity with neural connection at its centre through internal auditory canal, markd red arrow

Fig. 3

Showing moderate severe SNHL on left side with absent wave I and III and increased interaural latency for wave V in ABR

Fig. 4

Showing MRI brain images, a T2-weighted image of multiple hyperintense lesions, suggestive of multifocal white matter pathology with dawson finger (marked red arrow), b T1-weighted images showing multiple hyperintense lesions with a predominant involvement of the periventricular regions

Fig. 5

Showing pure tone audiogram of patient with profound SNHL in right ear

Fig. 6

Showing pure tone audiogram of patient with profound SNHL in right ear

Fig. 7

Showing auditory brainstem response of patient with absent neural responses in right ear

Fig. 8

Showing pure tone audiogram, a pre-treatment—left moderate SNHL at speech frequency with mixed at low frequency, b post-treatment—normal hearing sensitivity with mixed at low frequency

Fig. 9

Showing MRI of patient, a T2 weighted 3-D space sequence that shows the right vertebrobasilar dolichoectasia contacting and indenting (marked star) the vestibulocochlear nerve at internal acoustic meatus (marked red arrow), b Axial T1-weighted post contrast image of dilated and elongated right vertebrobasilar artery crossing nerve at internal auditory meatus (marked red arrow) and indenting (marked star)