What causes low frequency hearing loss?

Causes of Low Frequency Hearing Loss

Low frequency hearing loss is most characteristically associated with Ménière's disease, which presents with fluctuating hearing loss affecting the lower frequencies, often accompanied by episodic vertigo. 1

Primary Causes

Ménière's Disease

• Ménière's disease is the classic cause of low frequency hearing loss, presenting with an isolated low-frequency hearing trough on audiometry 1
• Characterized by fluctuating hearing loss that may affect one or both sides, with episodes of vertigo 1
• Hearing typically declines in a stepwise or fluctuating manner but may occasionally decline suddenly 1
• Most commonly presents unilaterally, though bilateral involvement can occur 1

Autoimmune Inner Ear Disease

• Presents with fluctuating bilateral hearing loss that may preferentially affect low frequencies 1
• Often accompanied by vertigo in some cases 1
• Bilateral involvement is common at onset, distinguishing it from typical sudden sensorineural hearing loss 1

Conductive Hearing Loss Mimicking Low Frequency Loss

• Any conductive pathology preferentially affects lower frequencies and must be excluded through otoscopy and tuning fork testing 1, 2
• Causes include cerumen impaction, middle ear fluid, otitis media, perforated tympanic membrane, and otosclerosis 1
• Weber and Rinne tuning fork tests help differentiate conductive from sensorineural causes 1, 2

Secondary and Systemic Causes

Infectious Etiologies

• Syphilis can cause bilateral fluctuating hearing loss with low frequency involvement 1
• Lyme disease presents with fluctuating bilateral audiovestibular symptoms 1
• Meningitis (infectious, inflammatory, or neoplastic) may cause bilateral hearing loss 1

Metabolic and Genetic Disorders

• MELAS (metabolic encephalopathy, lactic acidosis, and stroke-like episodes) can present with hearing loss affecting various frequencies 1
• Other mitochondrial disorders demonstrate variable phenotypes including low frequency hearing loss 1
• Genetic disorders may be syndromic or nonsyndromic, with variable audiometric patterns 1

Ototoxic Medications

• Certain drugs cause sensorineural hearing loss that may initially affect lower frequencies 1, 3, 4
• Aminoglycosides, cisplatin, loop diuretics (furosemide), and phosphodiesterase-5 inhibitors are particularly ototoxic 3, 4
• Ototoxicity is dose-dependent and may worsen even after drug withdrawal 3

Clinical Evaluation Approach

History Red Flags

• Antecedent fluctuating hearing loss on one or both sides strongly suggests Ménière's disease or autoimmune causes 1
• Recent viral illness, bacterial meningitis, or exposure to ototoxic medications 1, 5
• History of head trauma, acoustic trauma, or barotrauma 1
• Concurrent eye symptoms (pain, redness, photophobia) suggest Cogan's syndrome 1

Physical Examination Priorities

• Otoscopy is essential to exclude conductive causes such as cerumen impaction or middle ear fluid 1
• Perform Weber and Rinne tuning fork tests to differentiate conductive from sensorineural loss 1, 2
• Assess for vestibular symptoms, nystagmus, and focal neurologic signs 1
• Look for syndromic features: pigmentary anomalies, branchial arch abnormalities, or renal involvement 1

Common Pitfalls

• Failing to remove cerumen before establishing diagnosis can lead to misdiagnosis of sensorineural loss when conductive loss is present 1
• Assuming all low frequency loss is Ménière's disease without considering autoimmune, infectious, or ototoxic causes 1
• Missing bilateral presentation, which should prompt evaluation for systemic causes including autoimmune disease, infection, or ototoxicity 1
• Not recognizing that fluctuating hearing loss requires different evaluation than sudden, stable hearing loss 1