Prevalence and pattern of hearing loss in patients undergoing hemodiaylisis at Muhimbili national hospital

Abstract

Background: Hearing loss in chronic kidney disease (CKD) patients undergoing hemodialysis (HD) is sensorineural and bilateral and occurs at high or low frequencies. Hearing loss in HD is caused by osmotic disorders, changes in fluid and electrolytes in the cochlea’s endolymph, and possible exposure to membrane dialyzer. However the magnitude and pattern of hearing loss among patients undergoing hemodialysis at Muhimbili National Hospital is not known. Objective: The broad objective of the study was to assess the prevalence, pattern of hearing loss among patients undergoing hemodialysis at Muhimbili National Hospital. Methods: This study was hospital based cross sectional study whereby it was done at Muhimbili National hospital to patients undergoing hemodialysis.106 patients enrolled who had completed three session of hemodialysis. History and physical examination to every patient to rule out anomalies associated with hearing loss was done. Then head and neck were examined, the mouth was examined using tongue depressor and inspected as well. Otoscopic examination was done by using handheld otoscope to examine ear canal and tympanic membrane. Impacted cerumen and foreign bodies were removed before audiological examination if feasible and were referred to ORL department at MNH for any difficulties. Laboratory results from each patient were recorded. The results recorded were; Creatinine levels, Hemoglobin concentration and Serum electrolytes (Potassium and Sodium). Blood pressure and Diuretics dosage were recorded. Audiological examination were carried out this test was performed using single channeled calibrated clinical audiometer with standard headphone. Examination were conducted in a quiet room to avoid background noise and measured at four frequencies 500HZ, 1000HZ, 2000HZ, and 4000HZ, at an intensity of 25dB for both ears separately. This was conducted after three cycle of hemodialysis. Results: Hearing loss was found in 24.5% had hearing loss of which all of them (100%) were bilateral and of the sensorineural type with approximately twice the number of males as compared to females (M:F = 1.89:1). Hearing loss was common (31.3%) in those patients who were in the age group of 41-50 years. Among the 26 patients who had hearing loss, 61.5% had mild hearing loss while 38.5% had moderate hearing loss.Mild hearing loss was more prevalent across all age groups except for those who were above 60 years in whom majority (75%) had moderate hearing loss. Among male patients with hearing loss, majority (70.6%) of them had mild hearing loss compared to female patients with hearing loss in whom moderate hearing loss was common (55.6%). Majority of the patients with hearing loss (n=26) had undergone dialysis for less than one month (61.5%), with 75% of this group having mild hearing loss. Majority of patients with over one month duration of dialysis had moderate hearing loss 57.2% and 66.7% for 1-6 months and more than 6 months respectively. Most of the patients with hearing loss(n=26) had Hypertension and Diabetes Mellitus (46.2%), with majority in this group having moderate hearing loss (58.3%), all patient with Diabetes and HIV only had mild hearing loss while those with Hypertension only, majority(60%) had moderate hearing loss. The difference in severity of hearing loss amongst the comorbidities is statistically significant with a p value of 0.032 . Conclusion:Hearing loss in CKD patients undergoing hemodialysis is prevalent among patients attending dialysis unit at Muhimbili National Hospital.The most pattern hearing loss was sensorineural, bilateral, and mild to moderate hearing threshold.Diabetes mellitus and hypertension were common cormorbid diseases associated with hearing loss in CKD.