Aminoglycoside ototoxicity in cystic fibrosis. Evaluation by high-frequency audiometry
T. I. McRorie, J. Bosso and L. Randolph
Department of Pharmacy Practice, School of Pharmacy, University of Utah, Salt Lake City.
In this study, we sought to determine the clinical usefulness of
high-frequency audiometry (8000 to 20,000 Hz) in detecting
aminoglycoside-induced increases in pure-tone hearing thresholds before
they are noticed in conventionally tested frequencies. We measured hearing
thresholds from 250 to 20,000 Hz in 22 patients with cystic fibrosis who
were treated with aminoglycosides. The audiograms were age-matched and were
compared with those from 13 patients with cystic fibrosis and 38 subjects
without cystic fibrosis, all of whom had never received aminoglycoside
therapy. In patients with cystic fibrosis who were treated with
aminoglycosides (younger than 20 years), there were statistically
significant elevations only in frequencies higher than 16,000 Hz. Patients
with cystic fibrosis who were treated with aminoglycosides who were 20
years and older had elevated thresholds in all frequencies tested. Patients
with cystic fibrosis who were not treated with aminoglycosides did not
differ statistically from controls. High-frequency audiometry may serve as
a useful measure of elevation in pure-tone hearing thresholds that precede
noticeable loss of auditory acuity in patients with cystic fibrosis who are
receiving long-term aminoglycoside therapy.
