What is the recommended workup for a patient presenting with diminished hearing?

Workup for Diminished Hearing

Begin with a targeted history and physical examination to distinguish conductive from sensorineural hearing loss, followed by comprehensive audiometry, with imaging reserved for specific clinical features suggesting retrocochlear pathology or asymmetric hearing loss.

Initial Clinical Assessment

History and Physical Examination

Perform a focused evaluation to identify the type and potential etiology of hearing loss 1:

• Onset and duration: Sudden onset (within 72 hours) constitutes an otologic emergency requiring urgent evaluation 1
• Laterality: Unilateral vs bilateral hearing loss 1
• Associated symptoms: Tinnitus, vertigo, otalgia, otorrhea, or focal neurologic findings 1
• Recurrent episodes: Prior fluctuating hearing loss suggests Ménière's disease or autoimmune inner ear disease 1
• Risk factors: Noise exposure, ototoxic medications, head trauma, recent infections 2, 3

Otoscopic Examination

Examine the external auditory canal and tympanic membrane to identify 2, 3:

• Cerumen impaction (potentially curative if removed)
• Tympanic membrane perforation
• Middle ear effusion
• Cholesteatoma
• External canal stenosis or foreign body

Tuning Fork Testing

Use Weber and Rinne tests to differentiate conductive from sensorineural hearing loss 1, 2:

• Weber test: Lateralization to the affected ear suggests conductive loss; lateralization away suggests sensorineural loss in the opposite ear
• Rinne test: Bone conduction better than air conduction indicates conductive hearing loss

Audiometric Evaluation

Timing and Indications

Obtain comprehensive audiometry as soon as possible, ideally within 14 days of symptom onset for sudden hearing loss 1:

• Prompt audiometry (mandatory): Unilateral hearing loss, persistent symptoms ≥6 months, or associated hearing difficulties 1
• Routine audiometry (optional): All patients presenting with hearing loss regardless of laterality or duration 1

Audiometry confirms the diagnosis, quantifies severity, and establishes baseline for monitoring 1.

Imaging Studies

MRI of Internal Auditory Canals

Obtain MRI (or auditory brainstem response if MRI contraindicated) for retrocochlear pathology evaluation in patients with 1:

• Asymmetric sensorineural hearing loss (≥15 dB difference at 2+ frequencies or ≥15% speech recognition score difference) 1
• Unilateral tinnitus 1
• Sudden sensorineural hearing loss 1
• Focal neurologic abnormalities 1

MRI with dedicated internal auditory canal protocol using thin-section, high-resolution 3-D T2-weighted sequences is the imaging modality of choice for detecting vestibular schwannomas, meningiomas, and other retrocochlear pathology 1. Contrast administration may facilitate visualization of inflammatory changes but lacks proven incremental benefit over non-contrast protocols 1.

CT Temporal Bone

Consider CT temporal bone when 1:

• History suggests temporal bone fracture or head trauma
• Clinical suspicion for otosclerosis (mixed conductive-sensorineural loss)
• Evaluating for superior semicircular canal dehiscence
• Assessing anatomic abnormalities of the ossicular chain

Imaging NOT Recommended

Do not obtain routine head CT in the initial evaluation 1—it is insensitive for detecting retrocochlear pathology and provides insufficient detail of inner ear structures 1.

Laboratory Testing

Do not obtain routine laboratory tests 1—they lack proven benefit in idiopathic hearing loss. Order targeted serologic testing only when history or examination suggests specific systemic conditions 1:

• Bilateral sudden hearing loss: Consider autoimmune panels, Lyme serology, syphilis testing (FTA-ABS), or inflammatory markers 1
• Fluctuating hearing loss with systemic symptoms: Evaluate for autoimmune inner ear disease or Cogan syndrome 1
• Suspected infection: Meningitis workup, cytomegalovirus testing in congenital cases 1, 4

Red Flags Requiring Urgent Referral

Refer immediately to otolaryngology for 1, 2:

• Sudden sensorineural hearing loss (≥30 dB loss within 72 hours)—time-sensitive condition requiring treatment initiation within 2 weeks of onset
• Bilateral sudden hearing loss
• Focal neurologic findings (diplopia, dysarthria, ataxia, severe headache)
• Pulsatile tinnitus
• Concurrent severe vestibular loss with oscillopsia

Common Pitfalls

• Delaying audiometry: Confirmation of hearing loss type and severity guides all subsequent management decisions 1
• Over-ordering imaging: Reserve MRI for asymmetric or sudden sensorineural hearing loss, not routine age-related hearing loss 1
• Missing cerumen impaction: Always examine the ear canal—removal may be curative 2, 3
• Ignoring medication history: Ototoxic drugs (aminoglycosides, loop diuretics, platinum chemotherapy) are reversible causes 1, 2, 3
• Assuming symmetry equals benign: Age-related hearing loss should be symmetric; asymmetry warrants retrocochlear workup even in older adults 1