Early hearing threshold changes and peculiarities of audiometric assessments among patients in a drug-resistant tuberculosis treatment center.

Background: Hearing threshold changes occurred relative to baseline at both one and two weeks after onset of aminoglycoside therapy.

Objectives: To assess changes in audiometric hearing thresholds between pre-treatment values and two weeks into therapy. To document observed changes, and occurrence of ototoxicity within the period.

Methods: Prospective analytical cohort study on drug-resistant tuberculosis patients. Basic demographic parameters were taken. Three-point audiometric assessments within two weeks into therapy were done. Percentage of patients with ototoxicity were calculated. Pure tone threshold changes between the three audiometric values were compared.

Results: Audiograms of 53 patients comprising 56.6% males; age range was 13 to 91 years. Both air and bone conduction hearing thresholds significantly worsened between baseline and one week into therapy (p=0.011, and 0.015 respectively), and between baseline and two weeks into therapy (p=0.003 and 0.042 respectively). Minimal insignificant reduction occurred between both air and bone conduction hearing values of week 1 and week 2 of therapy (p= 1.000 and 0.856 respectively). By audiometric criteria, 4 patients (7.5%) developed ototoxicity within two weeks of treatment.

Conclusion: Audiometric assessments within two weeks into therapy with anti-tuberculous therapy may not represent baseline audiometry. 7.5% of the patients developed ototoxicity within two weeks of therapy.