From the Guidelines
For a 79-year-old male with unexplained right-sided hearing loss and a normal CT head, I strongly recommend proceeding with dedicated temporal bone CT and MRI of the internal auditory canals (IACs) for comprehensive evaluation. The initial CT head was insufficient to identify the cause of hearing loss as it did not show any acute intracranial abnormalities or obvious explanations for the symptoms [ 1 ]. Specialized imaging is necessary because hearing loss in elderly patients can result from various conditions that require different imaging techniques to detect.
Key Considerations
- Temporal bone CT provides excellent visualization of bony structures including the middle ear, mastoid, and cochlea, which could reveal otosclerosis, trauma, or chronic infections.
- MRI of the IACs is particularly important to evaluate for vestibular schwannomas (acoustic neuromas), other tumors, or vascular abnormalities that could compress the vestibulocochlear nerve [ 1 ].
- While awaiting these studies, the patient should undergo comprehensive audiometric testing to characterize the type and severity of hearing loss.
Rationale
The patient's presentation with asymmetric sensorineural hearing loss (ASNHL) warrants further evaluation, as ARHL is typically symmetric [ 1 ]. The standard work-up for ASNHL often includes a MRI of the internal auditory canals to exclude retrocochlear pathology, such as a vestibular schwannoma or meningioma. This approach is supported by recent clinical practice guidelines [ 1 ].
Next Steps
This combination of specialized imaging and audiometry will provide the necessary information to determine appropriate treatment, which might include hearing aids, medical management, or in some cases, surgical intervention depending on the underlying cause [ 1 ].
From the Research
Evaluation of Hearing Loss
- The patient's CT head scan shows no acute intracranial abnormality and no findings to explain the reported right-sided hearing loss 2.
- Given the lack of findings on the CT head scan, further evaluation with temporal bone CT and/or MRI of the internal auditory canals (IACs) may be necessary to comprehensively assess the structures involved in hearing 2.
Role of Imaging in Hearing Loss
- High-resolution computed tomography (CT) of the temporal bone and magnetic resonance imaging (MRI) are the preferred imaging modalities for evaluating ear structures in cases of hearing loss 2.
- CT is best suited for visualizing the external auditory canal, middle ear space, mastoid, petrous apex, and otic capsule, while MRI is preferred for suspected retrocochlear pathology 2.
- A case study highlights the value of CT scans in diagnosing middle ear osteoma, a rare cause of conductive hearing loss with a normal tympanic membrane 3.
Relevance of Provided Studies
- Study 4 is not relevant to the evaluation of hearing loss, as it discusses the effects of histamine on guinea-pig atria.
- Studies 2 and 3 provide relevant information on the role of imaging in evaluating hearing loss and the importance of considering further evaluation with temporal bone CT and/or MRI of the IACs if clinically warranted.