ADVERTISEMENT
Sudden Sensorineural Hearing Loss: A Potential Result of Acoustic Neuroma and Secondary Neoplasm of the Temporal Bone
ABSTRACT: Primary care providers should obtain hearing testing whenever a patient presents with a sudden change in hearing. Although often confused with the transient hearing loss that commonly results from upper respiratory tract infections, sudden sensorineural hearing loss (SSNHL) may be a consequence of either a primary neoplasm originating within the temporal bone or a secondary neoplasm metastasizing to the temporal bone. Acoustic neuroma and metastatic adenocarcinoma of the breast are the most commonly identified primary and secondary neoplasms, respectively. Once considered rare, secondary metastatic lesions are being reported in far greater numbers than had previously been appreciated. Two illustrative cases of SSNHL are described herein, the first resulting from an acoustic neuroma and the second associated with adenocarcinoma of the breast metastasizing to the temporal bone.
KEYWORDS: Sudden sensorineural hearing loss, acoustic neuroma, secondary neoplasm of the temporal bone, hearing testing, magnetic resonance imaging
__________________________________________________________________________________________________________________
Approximately 1 in 8 individuals aged 12 years or older in the United States have a bilateral hearing loss, and 1 in 5 have a unilateral hearing loss.1 Disorders anywhere along the auditory pathway from the external auditory canal to the central nervous system may result in diminished hearing. Patients presenting with sudden hearing loss, however, demand a more urgent and vigilant approach, given that rapid diagnosis and treatment may increase the possibility of hearing recovery as well as lead to the earlier identification of potentially treatable pathology.
The National Institutes of Health’s National Institute on Deafness and Other Communication Disorders has defined sudden sensorineural hearing loss (SSNHL) as a decrease in hearing of 30 dB or greater across at least 3 consecutive frequencies over a period of 3 days or less.2 Others have sought to expand the definition by including individuals who simply experience a sensorineural loss in fewer than 3 days.3,4 SSNHL has long bedeviled clinicians and sufferers alike in that the etiology in up to 90% of cases remains elusive.3 The remaining 10% or so of cases have been associated with neoplastic, autoimmune, infectious, circulatory, coagulation, and demyelinating disorders.5,6
Although hearing loss is the preponderant otologic manifestation noted to occur in primary and secondary neoplasms of the temporal bone, tinnitus, disequilibrium, and vertigo also may present in either group. Acoustic neuroma (AN) is a benign lesion that commonly arises from the vestibulocochlear nerve (cranial nerve VIII) and may be located in the internal auditory canal, cerebellopontine angle, or both sites simultaneously. The secondary group, comprising malignant neoplasms that have metastasized to the temporal bone, may involve regional and/or distant sites, resulting in a number of unanticipated clinical signs and symptoms. Health care providers should be highly suspicious of an underlying malignancy when a patient presents with either a sudden bilateral hearing loss or a unilateral loss in the presence of pain, dizziness, facial nerve paralysis, or chronic ear discharge.7 Secondary malignant lesions often represent primary neoplasms with a propensity to invade bone.8 Carcinoma of the breast is the most prevalent neoplasm to metastasize to the temporal bone.9,10
Case Report 1
A 63-year-old man presented with a sudden change in hearing in the right ear that he had first appreciated approximately 3 to 4 days prior to his visit. He also reported a clogged sensation and tinnitus in the affected ear along with slight episodic disequilibrium. There was no recent history of upper respiratory tract infection, acoustic trauma, or manipulation of the ear canal. His medical history was notable for hypercholesterolemia and hypertension; his medications included losartan, atorvastatin, and a daily aspirin.
Physical examination of the ears, nose, and throat failed to identify any pathology. An immediate hearing test was obtained, the results of which revealed a significant asymmetry between the right and left ears, with a moderate to moderately severe hearing loss involving the right ear (Figure 1).
Figure 1. Audiogram of the patient with a right AN who presented with SSNHL (case report 1).
The patient was started on a prednisone 60-mg taper over a 2-week period, which resulted in slight improvement in his hearing. Magnetic resonance (MR) imaging of the internal auditory canals with gadolinium contrast identified an approximately 0.7 × 0.5 × 0.3-cm enhancing mass within the right internal auditory canal suggestive of an AN (Figure 2). After appropriate consultation, the patient elected to undergo stereotactic radiosurgery, and he is being carefully monitored.
Figure 2. MR imaging revealing an enhancing mass in the right internal auditory canal (arrow) consistent with acoustic neuroma (case report 1).
Case Report 2
A 74-year-old woman was seen in consultation for a sudden change of hearing in the right ear upon awakening 2 days prior to her initial visit. She denied any concurrent vertigo, tinnitus, aural fullness, or prior history of ear disease. Her medical history was notable for temporal arteritis, hypertension, and carcinoma of the left breast that had resulted in a mastectomy 15 years prior to her consultation. Her medications included aspirin, simvastatin, tamoxifen, fosinopril, prednisone, and diltiazem. At the time of the visit, she was also being attended to by an oncologist because of metastatic carcinoma of the breast to the skull and other locations.
Examination of the ears, nose, and throat failed to identify any pathology. No cranial nerve deficits were detected. Audiometric testing was performed (Figure 3), and a presumptive diagnosis of SSNHL was made based on her history and the significant difference in hearing acuity between the right and left ears.
Figure 3. Audiogram of the patient with metastatic carcinoma of the breast to the skull/temporal bone who presented with SSNHL in the right ear (case report 2). The results reveal asymmetric hearing loss.
MR imaging of the brain (Figures 4 and 5) identified diffuse epidural enhancement, as well as enhancement in the right internal auditory canal. Inasmuch as this patient was on low-dose prednisone for temporal arteritis, intratympanic steroid treatment was utilized but brought about no improvement in hearing acuity.
Figure 4. Axial MR image identifies diffuse epidural enhancement along with convexities that represent direct epidural extension from calvarial metastatic disease (case report 2).
Figure 5. Coronal MR imaging showing slight enhancement within the right internal auditory canal, likely secondary to epidural disease (case report 2).
NEXT: Assessment of Hearing Loss
ABSTRACT: Primary care providers should obtain hearing testing whenever a patient presents with a sudden change in hearing. Although often confused with the transient hearing loss that commonly results from upper respiratory tract infections, sudden sensorineural hearing loss (SSNHL) may be a consequence of either a primary neoplasm originating within the temporal bone or a secondary neoplasm metastasizing to the temporal bone. Acoustic neuroma and metastatic adenocarcinoma of the breast are the most commonly identified primary and secondary neoplasms, respectively. Once considered rare, secondary metastatic lesions are being reported in far greater numbers than had previously been appreciated. Two illustrative cases of SSNHL are described herein, the first resulting from an acoustic neuroma and the second associated with adenocarcinoma of the breast metastasizing to the temporal bone.
KEYWORDS: Sudden sensorineural hearing loss, acoustic neuroma, secondary neoplasm of the temporal bone, hearing testing, magnetic resonance imaging
__________________________________________________________________________________________________________________
Approximately 1 in 8 individuals aged 12 years or older in the United States have a bilateral hearing loss, and 1 in 5 have a unilateral hearing loss.1 Disorders anywhere along the auditory pathway from the external auditory canal to the central nervous system may result in diminished hearing. Patients presenting with sudden hearing loss, however, demand a more urgent and vigilant approach, given that rapid diagnosis and treatment may increase the possibility of hearing recovery as well as lead to the earlier identification of potentially treatable pathology.
The National Institutes of Health’s National Institute on Deafness and Other Communication Disorders has defined sudden sensorineural hearing loss (SSNHL) as a decrease in hearing of 30 dB or greater across at least 3 consecutive frequencies over a period of 3 days or less.2 Others have sought to expand the definition by including individuals who simply experience a sensorineural loss in fewer than 3 days.3,4 SSNHL has long bedeviled clinicians and sufferers alike in that the etiology in up to 90% of cases remains elusive.3 The remaining 10% or so of cases have been associated with neoplastic, autoimmune, infectious, circulatory, coagulation, and demyelinating disorders.5,6
Although hearing loss is the preponderant otologic manifestation noted to occur in primary and secondary neoplasms of the temporal bone, tinnitus, disequilibrium, and vertigo also may present in either group. Acoustic neuroma (AN) is a benign lesion that commonly arises from the vestibulocochlear nerve (cranial nerve VIII) and may be located in the internal auditory canal, cerebellopontine angle, or both sites simultaneously. The secondary group, comprising malignant neoplasms that have metastasized to the temporal bone, may involve regional and/or distant sites, resulting in a number of unanticipated clinical signs and symptoms. Health care providers should be highly suspicious of an underlying malignancy when a patient presents with either a sudden bilateral hearing loss or a unilateral loss in the presence of pain, dizziness, facial nerve paralysis, or chronic ear discharge.7 Secondary malignant lesions often represent primary neoplasms with a propensity to invade bone.8 Carcinoma of the breast is the most prevalent neoplasm to metastasize to the temporal bone.9,10
Case Report 1
A 63-year-old man presented with a sudden change in hearing in the right ear that he had first appreciated approximately 3 to 4 days prior to his visit. He also reported a clogged sensation and tinnitus in the affected ear along with slight episodic disequilibrium. There was no recent history of upper respiratory tract infection, acoustic trauma, or manipulation of the ear canal. His medical history was notable for hypercholesterolemia and hypertension; his medications included losartan, atorvastatin, and a daily aspirin.
Physical examination of the ears, nose, and throat failed to identify any pathology. An immediate hearing test was obtained, the results of which revealed a significant asymmetry between the right and left ears, with a moderate to moderately severe hearing loss involving the right ear (Figure 1).
Figure 1. Audiogram of the patient with a right AN who presented with SSNHL (case report 1).
The patient was started on a prednisone 60-mg taper over a 2-week period, which resulted in slight improvement in his hearing. Magnetic resonance (MR) imaging of the internal auditory canals with gadolinium contrast identified an approximately 0.7 × 0.5 × 0.3-cm enhancing mass within the right internal auditory canal suggestive of an AN (Figure 2). After appropriate consultation, the patient elected to undergo stereotactic radiosurgery, and he is being carefully monitored.
Figure 2. MR imaging revealing an enhancing mass in the right internal auditory canal (arrow) consistent with acoustic neuroma (case report 1).
Case Report 2
A 74-year-old woman was seen in consultation for a sudden change of hearing in the right ear upon awakening 2 days prior to her initial visit. She denied any concurrent vertigo, tinnitus, aural fullness, or prior history of ear disease. Her medical history was notable for temporal arteritis, hypertension, and carcinoma of the left breast that had resulted in a mastectomy 15 years prior to her consultation. Her medications included aspirin, simvastatin, tamoxifen, fosinopril, prednisone, and diltiazem. At the time of the visit, she was also being attended to by an oncologist because of metastatic carcinoma of the breast to the skull and other locations.
Examination of the ears, nose, and throat failed to identify any pathology. No cranial nerve deficits were detected. Audiometric testing was performed (Figure 3), and a presumptive diagnosis of SSNHL was made based on her history and the significant difference in hearing acuity between the right and left ears.
Figure 3. Audiogram of the patient with metastatic carcinoma of the breast to the skull/temporal bone who presented with SSNHL in the right ear (case report 2). The results reveal asymmetric hearing loss.
MR imaging of the brain (Figures 4 and 5) identified diffuse epidural enhancement, as well as enhancement in the right internal auditory canal. Inasmuch as this patient was on low-dose prednisone for temporal arteritis, intratympanic steroid treatment was utilized but brought about no improvement in hearing acuity.
Figure 4. Axial MR image identifies diffuse epidural enhancement along with convexities that represent direct epidural extension from calvarial metastatic disease (case report 2).
Figure 5. Coronal MR imaging showing slight enhancement within the right internal auditory canal, likely secondary to epidural disease (case report 2).
NEXT: Assessment of Hearing Loss
