title: Desferrioxamine ototoxicity in an adult transfusion-dependent population.
abstract: OBJECTIVE
  The purpose of this study was to identify the incidence of hearing loss in a population of 75 adult (19-68 years old) transfusion-dependent patients with thalassemia major, sickle cell disease, Diamond-Blackfan anemia, and various other hematologic disorders treated with regular transfusion schedules. Ninety-three percent (70/75) of patients had a history of long-term subcutaneous or intravenous desferrioxamine therapy.
  
  
  METHODS
  The patients underwent routine otolaryngologic history and physical examination, along with standard pure-tone audiometry at 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz, with hearing loss defined as 25 dB or greater at one or more frequencies.
  
  
  RESULTS
  Hearing loss was present in 57% (43/75) of patients. More importantly, hearing loss attributable to desferrioxamine ototoxicity was present in 29% (22/75) of patients. Sixteen patients treated previously with desferrioxamine were switched to the experimental oral chelating agent, L1. Eight of these 16 patients had hearing loss attributable to desferrioxamine, with 5 of these patients worsening with the experimental oral chelating agent L1. Seventy-nine percent (59/75) of patients were thalassemic. Fifty-four percent (33/59) of these thalassemic patients had hearing loss. However, 35% (21/59) of the thalassemic patients had hearing loss attributable to desferrioxamine ototoxicity. All thalassemic patients with desferrioxamine ototoxicity had high-frequency sensorineural hearing loss, with 33% (7/21) having a notch at 6 kHz. In addition, 5% (1/21) had notching at 3 khz. Few of the hearing losses were disabling.
  
  
  CONCLUSIONS
  Management of these patients requires proper dosing of desferrioxamine and transfusion therapy, along with regular monitoring of body iron burden and hemoglobin. In addition, regular otolaryngologic and audiometric follow-up with special care to include the frequencies of 3 and 6 kHz may help recognize and prevent permanent ototoxicity.
authors.affiliation: Department of Otolaryngology, University of Toronto, Toronto Hospital, Ontario.
authors.forename: A A
authors.initials: AA
authors.lastname: Chiodo
authors.forename: P W
authors.initials: PW
authors.lastname: Alberti
authors.forename: G D
authors.initials: GD
authors.lastname: Sher
authors.forename: W H
authors.initials: WH
authors.lastname: Francombe
authors.forename: B
authors.initials: B
authors.lastname: Tyler
mesh_terms: D000328:Adult; D000368:Aged; D000755:Anemia, Sickle Cell / Q000628:therapy; D001299:Audiometry; D003676:Deferoxamine / Q000009:adverse effects*; D016903:Drug Monitoring; D005199:Fanconi Anemia / Q000628:therapy; D005260:Female; D006311:Hearing Disorders / Q000139:chemically induced* / Q000175:diagnosis; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017262:Siderophores / Q000009:adverse effects*; D065227:Transfusion Reaction; D017086:beta-Thalassemia / Q000628:therapy
chemical_list: D017262:Siderophores; D003676:Deferoxamine