What is the likelihood of improvement with sudden sensorineural hearing loss using intra-tympanic (in the middle ear space) dexamethasone injections?

Likelihood of Improvement with Intratympanic Dexamethasone for Sudden Sensorineural Hearing Loss

Intratympanic dexamethasone injections for sudden sensorineural hearing loss (SSNHL) show improvement rates ranging from 26.7% to 75%, with an average success rate of approximately 40-50% when used as salvage therapy after failed systemic steroid treatment. 1, 2

Efficacy Based on Treatment Protocol

The likelihood of improvement varies significantly based on several key factors:

Timing of Treatment

• Early intervention is critical:
  • Patients treated within 2 weeks of onset show significantly better outcomes 2
  • Recovery rates decrease progressively with delayed treatment
  • After 36 days, the likelihood of significant improvement drops dramatically 3
  • Treatment within 2-6 weeks after onset shows approximately 26% improvement rate 3

Dosage and Concentration

• Higher concentrations yield better results:
  • 24 mg/mL dexamethasone shows superior outcomes (53% improvement) compared to 10 mg/mL (17% improvement) 4
  • Methylprednisolone at 40-62.5 mg/mL shows improvement rates of 55-75% 1

Administration Protocol

• Multiple injections are more effective than single injections:
  • 4 injections over a 2-week period: 47-55% improvement 1
  • Single injection: 26.7-33% improvement 1

Definition of Improvement

The reported success rates vary based on how "improvement" is defined:

• 10 dB HL improvement in pure-tone average (PTA): 33-55% of patients 1
• 15 dB HL improvement in PTA: 47-75% of patients 1
• 20 dB HL improvement in PTA: 26.7-27.5% of patients 1, 3
• 30 dB HL improvement in PTA: 53.3% of patients 1

Comparison to Control Groups

When compared to no additional treatment after failed systemic steroids:

• Intratympanic steroid group: 39.4-47.6% improvement
• Control group (no additional treatment): 6.1-10% improvement 5, 6

Factors Affecting Outcomes

1. Severity and type of hearing loss:

   • Pantonal SSNHL shows better global improvement 7
   • High-frequency SSNHL shows selective improvement at 1.5 and 3 kHz 7
   • Profound SSNHL or sudden deafness shows improvement primarily at lower frequencies (0.5-1 kHz) 7

2. Previous treatment response:

   • Used as salvage therapy after systemic steroid failure: 39.4-47.6% improvement 5, 6
   • Higher success rates when used as primary therapy

Practical Considerations

• Optimal protocol:

  • Use 24 mg/mL dexamethasone or 40-62.5 mg/mL methylprednisolone 1, 4
  • Administer 4 injections over a 2-week period 2
  • Position patient with affected ear up for 15-30 minutes after injection 2

• Monitoring:

  • Obtain audiogram before each injection and at completion of treatment 2
  • Final hearing levels typically reached by 1-3 months in 97% of patients 1

• Safety profile:

  • Minimal systemic side effects
  • Safe for patients with diabetes, cataracts, glaucoma, and other conditions that contraindicate systemic steroids 2
  • Main risks include transient pain, brief vertigo, and rare tympanic membrane perforation 2

In summary, intratympanic dexamethasone offers a reasonable chance of hearing improvement for SSNHL, particularly when administered early at higher concentrations with multiple injections. The treatment is most effective when initiated within the first 2-6 weeks after onset of hearing loss, with diminishing returns beyond this timeframe.