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Update your Knowledge with MKSAP 18 Q&A: Answer and Critique

Answer

D: Sudden sensorineural hearing loss

Educational Objective

Diagnose sudden sensorineural hearing loss.

Critique

The most likely diagnosis for this patient's acute, unilateral hearing loss is sudden sensorineural hearing loss (SSHL). The right-sided hearing loss and the finding of lateralization to the left ear on Weber testing support the diagnosis. Approximately 90% of cases of SSHL are idiopathic; however, viral infection, drug reactions, acoustic neuroma, multiple sclerosis, head injury, vascular issues, systemic immune-mediated conditions, and Meniere disease can all be causes. SSHL most commonly presents as unilateral tinnitus and ear fullness; vertigo occurs less often. Because this patient lacks other features to explain the acute hearing loss, she should undergo urgent referral to an otolaryngologist for audiometry, clinical assessment, and MRI to exclude tumors, multiple sclerosis, or vascular causes. Treatment involves oral glucocorticoids, although strong evidence of efficacy is lacking.

Meniere disease, which is associated with endolymphatic hydrops (excess fluid in the endolymphatic spaces), can cause unilateral sensorineural hearing loss, but its presentation is characterized by episodic vertigo (lasting between 20 minutes and 24 hours) and tinnitus, which is often low pitched. The hearing loss may be described as fluctuating, and early in the disease it often involves low frequencies. Meniere disease may also present with a sensation of ear fullness.

Otosclerosis involves bony overgrowth on the footplate of the stapes, leading to a lack of functioning of the ossicles. This middle ear process typically causes gradual, painless, bilateral conductive hearing loss, not sensorineural hearing loss, as seen in this patient. Otosclerosis occurs more often in women, and there is often a family history of the condition.

Ototoxicity also can result in sensorineural hearing loss; it may be caused by a variety of medications, including antibiotics (particularly aminoglycosides), chemotherapeutic agents, loop diuretics, and aspirin or other NSAIDs. Often occurring gradually and bilaterally, ototoxicity may be reversible or permanent, depending on the agent involved. This patient is not taking and has not been exposed to drugs known to be ototoxic.

Key Point

All patients with sudden sensorineural hearing loss should undergo audiometric evaluation, and most patients will require MRI.

Bibliogrpahy

Chin CJ, Dorman K. Sudden sensorineural hearing loss. CMAJ. 2017;189:E437-E438. [PMID: 28385715] doi:10.1503/cmaj.161191

Back to the July 2019 issue of ACP International