Sensorineural hearing loss in hemodialysis patients

Chronic renal failure affects all organ systems. Senses are not exception and hearing impairment is common, particularly sensorineural hearing loss (SNHL). The term SNOS of unknown origin or uremic deafness is related to only a smaller part of the cases with unclear etiology of the impairment. The study searched for SNOS in 66 chronic hemodialysis (HD) patients, mean age 51.50 +/- 12.70 years. They were treated by HD for 69.70 +/- 53.80 months. The relation between the severity of the impairment and the patients' age, duration of HD treatment (months) and a set of laboratory parameters typical for chronic HD patients was examined. The aim of the study was to detect potential causes of the impairment. The increased hearing threshold (HT) of above 20 dB for all frequencies was found in 42 patients (mean HT 26 +/- 10.50 dB), for speaking area frequencies in 22 patients (mean HT 19.70 +/- 8.80 dB), and in 56 patients for high frequencies (mean HT 41.70 +/- 19.70 dB). The significant positive correlation of HT was found only with the patients' age (r = 0.49, p < 0.01). The patients older than 45 years had higher mean HT than those younger, and those older than 65 also had higher HT than the younger ones. Patients with pathological value of HT were significantly more common among the older subgroup of patients, when divided according to the age at both cutoff values of 45 and of 60 years. Mean HT did not differ significantly according to the duration of HD treatment (subgroups A- no longer than 60 months, B- from 61 to 120 months, and C- longer than 120 months). The patients with pathological HT did not differ significantly in frequency among those subgroups, and the subgroups were not different according to the mean age (A--50.30 +/- 13.20 years; B--51.40 +/- 12.75 years; C--55.80 +/- 10.55 years). In conclusion, our results along with other authors'published data report on SNHL as very frequent finding among chronic HD patients and suggest multifactorial etiology. Accurate proportion of those with SNHL of unknown origin is not possible to determine. Those cases are probably not caused by uremic polyneuropathy and/or preterm vascular aging only, although those factors are likely to play crucial roles.