Unveiling Idiopathic Intracranial Hypertension as a Stealthy Culprit of Unilateral Hearing Loss: A case report

Authors: Subhashini D1, Amith Thomas2

1Department of Hearing Studies, Dr SR Chandrasekhar Institute of Speech and Hearing
2Department of Audiology, Queen Elizabeth Hospital King’s Lynn NHS Foundation Trust

Background: One of the uncommon causes for late onset Hearing Loss is Idiopathic Intracranial Hypertension (IIH). Due to its rarity and varied yet covert symptom profile, timely diagnosis is challenging. No cause till date has been directly attributed to IIH as no localizing neurologic signs are seen and more importantly, imaging studies reveal no anomalies such as enlarged ventricles or even cerebral oedema which are expected in intracranial hypertension. We discuss the audiologic profile of a 24-year-old woman with unilateral unspecified type of hearing loss due to IIH.

Method: Following our patient’s complaint of reduced hearing and pulsatile tinnitus in the right ear accompanied with giddiness, a detailed audiologic test battery was administered.

Results: Our patient had bilateral A type tympanogram with present ipsilateral and absent contralateral reflexes. PTA showed normal hearing sensitivity in the left ear and severe hearing loss in the right ear with air bone gap. Despite the PTA showing a mixed loss in right ear, her OAEs were present bilaterally hence considered an unspecified type of Hearing Loss. Neurodiagnostic ABR showed normal findings in the left ear and abnormal in the right ear. Reduced amplitude was noted in right ear for CVEMPs and interestingly OVEMPs were absent on the left side. Abnormal saccades were noted on the right side for VHIT and VNG as well. All these results brought to light the definitive presence of a retro cochlear pathology and suggested further medical investigations. Although MRI-plain was unremarkable, a contrast MRI revealed presence of IIH.

Conclusion: The known clinical manifestations of IIH can easily be misinterpreted unless looked at with a keen eye. Due to the extreme variability of audiologic findings in patients with IIH, heightened vigilance, careful history taking, and appropriate referrals are crucial to arrive at the correct diagnosis.