Neurophysiological and neuro-otological study of homozygous beta-thalassemia under long-term desferrioxamine (DFO) treatment

Abstract

This report presents data on visual evoked potentials (VEPs) and brainstem auditory evoked potentials (BAEPs), as well as neurologic, ophthalmologic and otologic assessments performed on 120 patients with beta-thalassemia major undergoing long-term DFO treatment. A total of 32 patients showed abnormal VEPs and 14 abnormal BAEPs; seven had both VEP and BAEP abnormalities; 12 had sensorineural hearing loss (SNHL); 18 had conductive hearing loss, while 14 showed a combination of SNHL and conductive hearing loss. After DFO administration was modified (taking in consideration the serum ferritin levels) patients with abnormal findings were retested. The values of 15 patients of 23 who underwent VEP examinations had been normalized. Eleven of 15 who repeated the BAEP test had also gained normal values. The audiogram had not returned to normal in any patient with SNHL. In a second repetition of the examinations, no change was observed. It is concluded that in a great percentage of thalassemics at least one of the above examinations shows abnormal values. These abnormalities are mostly reversible, and probably reflect a dysfunction of the visual or auditory system, due either to DFO neurotoxicity or to iron overload or both.

Evaluation of the Incidence of Sensorineural Hearing Loss in Beta-Thalassemia major Patients under Regular Chelation Therapy with Desferrioxamine

“…In addition to the ophthalmic and auditory neurotoxicity, sensorimotor neuropathy (paresthesias and weakness) [11], renal toxicity, moderate to severe pulmonary syndrome [1], growth retardation and bone abnormalities [12], local irritation at the site of subcutaneous infusion and allergic reactions have been reported in thalassemia patients receiving DFO. The reported rate of auditory toxicity varies widely in different studies [6, 13, 14, 15].…”

Subclinical central nervous system involvement and thrombophilic status in young thalassemia intermedia patients of Greek origin

“…Studies conducted have involved transfusion-dependent patients on desferrioxamine; the increased latencies were mainly attributed to the neurotoxic effect of the latter. More specifically, as regards to BAEP and VEP, pathological rates are mentioned ranging between 0-25% and 3.1-32%, respectively [29][30][31][32][33][34]. Similar references involving nontransfused thalassemic patients do not exist to date.…”

Brainstem auditory evoked potentials features in thalassemia major

“…Sensorineural hearing impairment was reported by Triantafyllou,et al in 12 patients (36.66%) from 44 patients, 22 whereas other studies reported sensorineural hearing impairment in all of patients with hearing impairment by BAEPs examination. [17][18][19] Previous studies by conventional audiometry, demonstrated sensorineural hearing impairment was higher compared to conductive hearing impairment 4,6,[8][9][10][11][12] Sensorineural hearing impairment in the current study was demonstrated in 94.74% patients from all of hearing impairment as well as the previous studies.…”

“…21 Other BAEP studies reported between 12% to 36.6% patients. [17][18][19]22 This differrence results were probably as the result of the difference in methods.…”

“…Triantafyllou, et al performed BAEP investigation and found 15% patients with conductive hearing impairment, 22 whereas other investigators did not find it. [17][18][19] In the current study, conductive hearing impairment was found in 1 patient (1.54%).…”