What is the first line of treatment for hearing loss due to Tuberculosis (TB)?

Management of Hearing Loss in Tuberculosis

The first-line treatment for hearing loss due to tuberculosis is immediate discontinuation of the ototoxic medication, particularly aminoglycosides like streptomycin, amikacin, and kanamycin, and switching to alternative non-ototoxic anti-TB medications.

Pathophysiology and Prevalence

Hearing loss in TB treatment is primarily caused by aminoglycoside antibiotics, which are commonly used as second-line agents for drug-resistant TB. According to systematic reviews:

• Aminoglycosides cause ototoxicity through damage to cochlear hair cells
• Pooled prevalence of ototoxic hearing loss is approximately 40.6% across all aminoglycosides 1
• Drug-specific hearing loss rates:
  • Kanamycin: 49.7%
  • Amikacin: 38.9%
  • Capreomycin: 10.2% 1

Management Algorithm for TB-Related Hearing Loss

Step 1: Immediate Assessment and Drug Modification

• Discontinue the ototoxic agent immediately (particularly streptomycin, amikacin, or kanamycin)
• Perform baseline audiometric testing if not already done
• Switch to non-ototoxic TB medications based on susceptibility patterns

Step 2: Alternative Medication Selection

• Replace aminoglycosides with oral medications according to susceptibility:
  • For drug-susceptible TB: Use the core first-line regimen of isoniazid (INH), rifampin (RIF), ethambutol (EMB), and pyrazinamide (PZA) 2
  • For MDR/RR-TB: Consider newer all-oral regimens containing bedaquiline, linezolid, and fluoroquinolones 2

Step 3: Monitoring and Prevention

• Perform baseline audiometric testing before starting potentially ototoxic medications
• Monitor hearing function monthly during treatment with aminoglycosides 2
• Conduct vestibular testing and Romberg testing at baseline and with any symptoms 2
• Monitor renal function, as impaired renal clearance increases risk of ototoxicity 2, 3

Special Considerations

Pregnancy

• Streptomycin is absolutely contraindicated in pregnancy due to risk of fetal hearing loss 2
• Use alternative regimens with isoniazid, rifampin, and ethambutol 2

Renal Impairment

• Aminoglycosides require dose adjustment in renal impairment:
  • Reduce dosing frequency to 2-3 times weekly rather than daily
  • Maintain the same mg/kg dose per administration
  • Monitor drug levels to avoid toxicity 2
  • Administer after hemodialysis in patients requiring dialysis 2

Children

• Children whose visual acuity cannot be monitored (typically under age 6) should generally avoid ethambutol
• If aminoglycosides must be used, careful monitoring of hearing is essential 2

Prevention Strategies

1. Primary Prevention:

   • Follow updated WHO guidelines that recommend all-oral regimens for MDR-TB
   • Use bedaquiline-based regimens instead of injectable agents 2
   • This approach could prevent approximately 50,000 hearing loss cases annually 1

2. Secondary Prevention:

   • Early detection through regular audiometric monitoring
   • Immediate drug discontinuation at first sign of ototoxicity

Common Pitfalls to Avoid

1. Delayed recognition: Hearing loss may be irreversible if ototoxic medications are continued after symptoms develop
2. Inadequate monitoring: Failure to perform baseline and regular audiometric testing
3. Ignoring renal function: Decreased renal clearance significantly increases risk of ototoxicity
4. Continuing injectable agents: Persisting with aminoglycosides despite availability of effective oral alternatives

By following this approach, clinicians can minimize the risk of permanent hearing loss while effectively treating tuberculosis infection.