What is the differential diagnosis and workup for a patient with tinnitus and suspected otosclerosis (otospongiosis) in both ears?

Differential Diagnosis and Workup for Tinnitus and Suspected Otosclerosis

For patients with tinnitus and suspected bilateral otosclerosis, a comprehensive audiological evaluation including pure tone audiometry, speech audiometry, tympanometry, and acoustic reflex testing should be performed within 14 days of symptom onset, followed by referral to an otolaryngologist for definitive diagnosis and management. 1

Differential Diagnosis

Common Causes of Tinnitus with Bilateral Hearing Loss:

1. Otosclerosis (Otospongiosis)

   • Characterized by conductive or mixed hearing loss
   • Normal otoscopic examination (distinguishing feature) 2
   • Typically presents with progressive hearing loss
   • Tinnitus is a common symptom 3

2. Other Conditions to Consider:

   • Age-related hearing loss (presbycusis)
   • Noise-induced hearing loss
   • Ototoxic medication exposure
   • Meniere's disease (fluctuating hearing with vertigo)
   • Autoimmune inner ear disease
   • Bilateral acoustic neuromas (rare)

Red Flags Requiring Urgent Evaluation:

• Sudden onset of bilateral hearing loss
• Focal neurological findings
• Severe headaches
• Concurrent severe bilateral vestibular loss 1

Diagnostic Workup Algorithm

Step 1: Initial Clinical Assessment

• Characterize tinnitus: duration, quality, associated symptoms, impact on quality of life 1
• Classify as pulsatile vs. non-pulsatile, unilateral vs. bilateral
• Perform otoscopic examination (otosclerosis typically shows normal tympanic membranes) 2

Step 2: Basic Audiological Testing

• Tuning Fork Tests:
  • Weber test: In otosclerosis, sound typically lateralizes to the more affected ear 4
  • Rinne test: Negative Rinne (bone conduction > air conduction) suggests conductive hearing loss 4

Step 3: Comprehensive Audiological Evaluation

• Pure tone audiometry (air and bone conduction)
  • Otosclerosis typically shows conductive hearing loss pattern, often with a "Carhart notch" 5
• Speech audiometry
• Tympanometry (typically normal shape in otosclerosis)
• Acoustic reflex testing (absent stapedial reflexes in otosclerosis) 5
• Otoacoustic emissions (absent in otosclerosis) 5

Step 4: Advanced Testing Based on Clinical Findings

• Imaging:
  • CT temporal bones: May show demineralization of otic capsule in otosclerosis
  • MRI with contrast: Indicated for asymmetric hearing loss or neurological symptoms 1
  • CT/MR angiography: For pulsatile tinnitus 1

Step 5: Laboratory Testing (if indicated)

• Consider testing for autoimmune markers, Lyme disease, or syphilis if bilateral sudden hearing loss is present 1

Management Considerations

• Referral to Otolaryngologist: Essential for definitive diagnosis and management options 1
• Audiologist Referral: For comprehensive hearing evaluation and rehabilitation options 1
• Treatment Options for Otosclerosis:
  • Surgical: Stapedectomy/stapedotomy
  • Medical: Sodium fluoride may stabilize hearing thresholds and improve tinnitus 6
  • Hearing aids for rehabilitation 3
  • Cognitive behavioral therapy for tinnitus management 1

Common Pitfalls to Avoid

1. Failure to remove cerumen before assessment, which can mimic conductive hearing loss 1
2. Misdiagnosing otosclerosis as another cause of hearing loss due to normal otoscopic appearance 2
3. Overlooking non-otologic causes of tinnitus and hearing loss 1
4. Delayed referral for persistent or progressive symptoms 1
5. Using unproven medications without proper evaluation 1
6. Caution with bisphosphonates: Some reports suggest potential for sudden hearing deterioration in otosclerosis patients treated with bisphosphonates 7

Remember that while otosclerosis is a common cause of conductive hearing loss with tinnitus, definitive diagnosis is often confirmed during surgery. The audiological pattern of normal tympanogram with absent stapedial reflexes is highly suggestive of otosclerosis when combined with progressive conductive hearing loss and normal otoscopic examination.