ENT · Otolaryngology
The facts most likely to be tested
Presbycusis is the most common cause of sensorineural hearing loss in the elderly, characterized by bilateral, symmetric, high-frequency hearing loss.
Weber test lateralizes to the unaffected ear in sensorineural hearing loss, while Rinne test shows air conduction > bone conduction (positive) in both ears.
Ménière disease presents with the classic triad of episodic vertigo, sensorineural hearing loss, and tinnitus due to endolymphatic hydrops.
Acoustic neuroma (vestibular schwannoma) presents with unilateral sensorineural hearing loss, tinnitus, and disequilibrium, requiring gadolinium-enhanced MRI of the internal auditory canal for diagnosis.
Ototoxicity from aminoglycosides, loop diuretics, or cisplatin typically manifests as bilateral high-frequency sensorineural hearing loss.
Sudden sensorineural hearing loss is defined as a decrease of at least 30 dB over at least three contiguous frequencies occurring within 72 hours, requiring urgent corticosteroid therapy.
Noise-induced hearing loss classically shows a 4000 Hz notch on audiometry due to chronic exposure to high-intensity sound.
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A 68-year-old male presents to the clinic complaining of difficulty hearing his grandchildren during family gatherings. He reports that he can hear people talking, but struggles to understand the words, especially in noisy environments. He denies vertigo, ear pain, or discharge. Physical examination reveals normal tympanic membranes bilaterally. Weber test does not lateralize, and Rinne test is positive bilaterally.
What is the most likely diagnosis?
Presbycusis
The patient's presentation of bilateral, symmetric, high-frequency hearing loss in an elderly patient with normal physical exam findings and positive Rinne tests is classic for presbycusis, as described in Bet 1.
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High yield triage
Etiology / Epidemiology
Presbycusis is the most common cause; ototoxicity and acoustic neuroma are high-yield board etiologies.
Clinical Manifestations
Weber test lateralizes to the unaffected ear; Rinne test shows AC > BC (normal/positive).
Diagnosis
Audiometry is the gold standard; sensorineural loss shows equal decline in air and bone conduction.
Treatment
Hearing aids are first-line; cochlear implants for profound loss; avoid ototoxic drugs.
Prognosis
Permanent damage; early detection is critical to prevent social isolation and cognitive decline.
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Epidemiology & Etiology
Sensorineural hearing loss (SNHL) results from damage to the cochlea or vestibulocochlear nerve. Presbycusis (age-related) is the leading cause. Other critical etiologies include Meniere disease, acoustic neuroma, and exposure to ototoxic agents.
Pertinent Anatomy
The pathology involves the organ of Corti or the CN VIII pathway. Unlike conductive loss, the external and middle ear structures remain intact, meaning sound transmission to the oval window is preserved.
Pathophysiology
Damage to the hair cells prevents the conversion of mechanical sound waves into electrical impulses. In acoustic neuroma, a schwannoma compresses the nerve, disrupting signal transmission. Chronic noise exposure causes cumulative damage to the basilar membrane.
Clinical Manifestations
Patients report difficulty hearing in noisy environments and muffled speech. The Weber test lateralizes to the unaffected ear, while the Rinne test remains positive (AC > BC). Red flags include unilateral loss, pulsatile tinnitus, or asymmetric symptoms, which mandate MRI to rule out vestibular schwannoma.
Diagnosis
Pure-tone audiometry is the gold standard, demonstrating a gap between air and bone conduction that is absent (both are reduced). Speech discrimination scores are typically poor. MRI of the internal auditory canal with gadolinium is the diagnostic choice for suspected retrocochlear pathology.
Treatment
Hearing aids are the primary intervention for most patients. Cochlear implants are indicated for severe-to-profound loss. Ototoxic drugs such as aminoglycosides, loop diuretics, and cisplatin must be discontinued immediately to prevent further damage.
Prognosis
SNHL is generally irreversible. Patients require long-term audiometric monitoring to track progression. Untreated loss is associated with cognitive decline and depression in the elderly.
Differential Diagnosis
Presbycusis: high-frequency bilateral loss
Meniere disease: episodic vertigo and aural fullness
Acoustic neuroma: unilateral loss with asymmetric tinnitus
Ototoxicity: history of recent antibiotic or diuretic use
Cerumen impaction: conductive loss with BC > AC