Hearing impairment as an unusual presenting sign of Cryptococcus gattii meningoencephalitis

Hearing loss is an unusual presenting feature of Cryptococcus gattii meningoencephalitis. Two cases of HIV-negative patients who presented with hearing loss are discussed and a literature review of published cases was conducted. Possible mechanisms for hearing loss with C. gattii infection are explored. This case series aims to raise awareness among clinicians that hearing loss can be a concerning feature in patients with persistent headache necessitating further investigation.

Cryptococcal meningitis presented as sudden hearing loss: A case study

BACKGROUND

This case report emphasizes that cryptococcal meningitis could be uncommonly presented to otolaryngologists as sudden onset of hearing loss, especially in patients with underlying diseases that could cause immunocompromise, and highlights the importance of differentiated diagnosis on sudden hearing loss before steroid therapy. It also demonstrates that prompt and sufficient fungicidal therapy with appropriate supportive treatment is crucial for a good prognosis on cryptococcal meningitis.

CASE PRESENTATION

A diabetic adult with untreated chronic hepatitis B was admitted complaining of sudden onset of left-sided hearing loss, following unexpected aggravating headache with meningeal signs after hospitalization with days of intratympanic steroid therapy. Cryptococcal meningitis was confirmed through lumbar puncture showing positive India ink staining and microbial culture of the cerebrospinal fluid (CSF). Fortunately, the patient recovered after prompt and adequate fungicidal therapy plus appropriate supportive treatment at last, though persistent hearing loss remained.

CONCLUSIONS

Cryptococcal meningitis could be presented in a very concealed way as sudden hearing loss, especially in patients with underlying diseases that could cause immunosuppression. Differentiated diagnosis on sudden hearing loss before steroid therapy is important.

Auditory neuropathy

Neural disorders of the auditory nerve are associated with particular disorders of auditory perceptions dependent on processing of acoustic temporal cues. These include: (1) speech perception; (2) localizing a sound's origin in space; and (3) identifying sounds in background noise. Auditory neuropathy (AN) is a consequence of: (1) presynaptic disorders affecting inner hair cell ribbon synapses; (2) postsynaptic disorders of auditory nerve dendrites; and (3) postsynaptic disorders of auditory nerve axons. The etiologies of these disorders are diverse, similar to other cranial or peripheral neuropathies. The pathologies cause attenuated and dyssynchronous auditory nerve discharges. Therapies and management of patients with AN are reviewed.