SENSORINEURAL LOSS IN UNSAFE CHRONIC SUPPURATIVE OTITIS MEDIA IN PAEDIATRIC AGE GROUP K.K. Hands, Senior Resident, S.B.S. Mann, Professor and Head A.K. Gupta, Assistant Professor Aru Handa, Ex-Resident Department of Otorhinolaryngology, Postgraduate Institute of Medical Education and Research, Chandigarh-16012 113 cases of unilateral unsafe chronic suppurative otitis media were taken and the preoperative bone conduction was compared between the diseased and the normal ears. A statistically significant different was found between the diseased and the normal ear at all four frequencies i.e. 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. lt was also found that the relative sensorineural loss varied significantly with the duration of the disease, it was more at the higher frequencies and patients with active middle ear disease were more prone to sensorineural loss. However, there was no relation between age, presenting symptom, performation size and the amount of relative sensorineural loss. Key words: Sensorineural loss, Chronic suppurative otitis media
Sensorineural loss in cases of unsafe chronic 'suppurative otitis media with or without cholesteatoma has always been a matter of discussion and debate. It has been observed by different authors' 2 that there are a number of patients who do not have any symptoms of labyrinthitis but still have raised bone conduction thresholds. This either reflects a high prevalence of sensorineural loss in the general population or is due to the disease process affecting the inner ear. Though a number of workers collected data in support of evidence of sensorineural loss in chronic otitis media but most of these studies have only compared the percentage of patients meeting specific criteria for sensorineural hearing loss but have not reported the actual difference in amount of hearing loss between the diseased and the control ears ,3, * IJO & HNSNoI. 48, No. 2, April -June, 1996
The study of biological behaviour of unsafe chronic suppurative otitis media with or without cholesteatoma in children as compared to adult has also been very interesting. Most authors agree that the behaviour in children is more aggressive than adults 5 . But there is hardly any study which has studied the characteristics of sensorineural hearing loss in unsafe CSOM in children. In this study we have taken unilateral cases of unsafe chronic suppurative otitis media and quantified relative amount of sensorineural hearing loss by using normal ear as the control ear. We also studied the relationship between the various disease parameters and operative findings with the degree of sensorineural hearing loss. 125
Sensorineural Loss in Unsafe Chronic Suppurative Otitis Media in Paediatiric Age Group — K. K. Handa eta!.
Material and Methods
113 paediatric patients (age 5-14 years) of unilateral unsafe CSOM who presented to the Nehru Hospital of Postgraduate Institute of Medical Education and Research, Chandigarh between July 1992 to July 1995 and were subsequently operated were considered for the study. Children below the age of 5 years were excluded because of the difficulty in obtaining the proper audiological profile. Also excluded from the study were patients with history of head trauma, congenital cholesteatoma traumatic perforation, prior ear surgery, hereditary causes, labyrinthitis, labyrinthine fistula and patients with bilateral disease. Cases of only unilateral unsafe CSOM were taken so that the normal ear could serve as the control ear. This helped reduce the influence of age, sex, noise exposure, ototoxic drug exposure and heredity. Table-I Mean and Standard Deviation of the Preoperative Bone Conduction Difference Between the Diseased and the Control Mean S.D. Frequency 8.5 500 Hz 5.88 1000 Hz 9.10 6.65 9.14 2000 Hz 7.26 11.34 4000 Hz 9.55 Average mean = 7.34 In all the patients sex, age, duration of disease, exposure, otoscopic findings and pre-operative audiograms were recorded. Preoperative bone conduction thresholds were obtained for both the normal and affected ears in the frequencies 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. Preoperative data was used to elimiante the possibility of surgery induced hearing loss. The difference between the preoperative bone coduction thresholds between the diseased and the normal par was calculated and was defined as sensorineural hearing loss due to CSOM. Also noted were the intraoperative details like type of surgery, extent of the disease, type of IJO & HNSNol. 48, No. 2, April-June, 1996
pathology i.e. cholesteatoma or granulations or both and the status of the ossicles. Table -II Type of Pathology Cholesteatoma 56 Cholesteatoma + Granulation 25 Granulations - 32 All the obtained data was subjected to statistical analysis. The significance of the difference in results between the diseased and the control ears was evaluated using the Wilcoxon's matched pairs signed rank test. The relationships of the continuous variables such as the age, duration of the disease and the type of pathology to the audiological variables were investigated by means of Spearman's rank correlation coefficient. Results From the total of 113 patients in the study 76 (67.3%) were males and 37 (32.7%) were females. 62 patinets (54.9%) had involvement of the left ear and 51 patients (45.1%) had involvement of the right ear. The mean age of presentation was 10.98 years and the mean duration of the disease was 4.47 years. 56 percent patients had ear discharge as the main presenting symptom while 44 percent had hearing loss as their main presenting symptom. The mean and the standard deviation of the differeneces in the preoperative bone conduction in different frequencies were calculated (Table I). The mean values at 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz were 5.88, 6.65, 7.26 and 9.55 respectively. The average of means of the difference in bone conduction of all the frequencies was 7.34. The maximum difference was at 4000 Hz followed by 3000 Hz. The difference of preoperative bone conduction between the diseased and the control normal ears was statistically significant at each of the 4 frequencies (p<0.01). The duration of illness varied from 3 months to 10 years with a mean of 4.47 years (Fig. 1). The 126
Sensorineural Loss in Unsafe Chronic Suppurative Otitis Media in Paediatiric Age Group — K. K. Handa et al.
statistical analysis was done using coefficient of correlation and it ws found that the relation was statistically significant between the duration of disease and the amount of sensorineural loss at all the 4 frequencies (p < 0.01 ; Fig. 3). There was no relationship between the age of patient, presenting symptom, perforation size and the amount of relative sensorineural hearing loss. Per-operatively, of the 113 patients 56 patients had cholesteatoma, 32 patients had granulations while 25 patients had both cholesteatoma and granulations (Table 2). There was no statistically significant correlation between the typy of the pathology and the amount of relative sensorineural hearing loss. However, in cases with cholesteatoma it was found that relative sensorineural hearing loss was greater when disease was present in he mesotympanum. However, it was statistically significant only at 1000 Hz and 2000 Hz. There was a statistically significant relationship between the status of the ossicles and the amount of hearing loss. The relative sensorineural hearing loss was greater when either of the malleus, incus or stapes was diseased (Table 3). This was statistically significant at 2000 Hz and 4000 Hz. Only 4 patients in our series had fixed stapes.
• • • • •
Table-III Ossicular Status Necrosed incus Necrosed malleus Only suprastructure stapes present and mobile Only suprastructure stapes present and fixed No ossicles present
44 24 16 4 25
Discussion In this study the evaluation of unilateral unsafe CSOM cases with the opposite ear as control helped in reducing the effect of variables such as age, noise exposure, ototoxic drugs and IJO & HNS(Vol. 48, No. 2, April-June, 1996
heredity. A relative sensorineural hearing loss was observed in all the 4 tested frequencies and was statistically significant and the maximum mean difference of 9.55 dB was at 4000 Hz followed by 7.26 dB at 2000 Hz, 6.65 dB at 1000 Hz and 5.88 dB at 500 Hz showing that higher frequencies are more prone to sensorieural loss due to unsafe CSOM.
Fig. 1
It can also be inferred from the study that the patients with the longer disease duration have more chances of developing sensorineural loss. However, there was no significant relationship between the age, presenting symptom, perforation size and the amount of relative sensorineural hearing loss. We also found that patients with active middle ear disease were more prone to relative sensorineural hearing loss. This is evident from the statistically significant relationship between the cholesteatoma in the middle ear, and the diseased ossicles with the relative sensorineural hearing loss. These findings support the work of Paparella et alb, and English and Northern 7 on the role of round window in the development of SNHL in CSOM. Round window is a semipermeable membrane through which some substances can pass. Some of the substances can pass through it in physiological conditions. However, others such as microtoxins can only pass during active inflammation when there is a 127
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DIFF IN PREOP. B.C. BETWEEN DISEASED AND CONTROL EARS
LINEAR REGRESSION ANALYSIS OF DISEASE DURATION TO SNHL
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lowering of the pH. However, with persistence of inflammation a thickening of epithelial and subepithelial layers occurs with frequent obliteration of the round window niche 8 . Hence round window theory alone cannot explain tlhe development of SNHL in CSOM. There are probably other factors which contribute to the damage. An hyposic damage to the inner ear can occur due to thickening of the round window membrane which blocks the routine diffusion of oxygen from the middle ear to perilymph which is corroborated by the pressure difference between the twos. The inflammation can also cause circulatory disturbances due to vasodilatation of the mucosal vessels of the round window and can also cause lymphatic blockage in subepithelial layer of the round window 10 . A mechanical factor can also
play a role by altering the stiffness and mass of the middle ear". However, as only 4 patients out of 113 had a fixed stapes in our series (3.5%) the Carhart's effect had very minimal effect on our results. The findings of this study done in a Paediatric population (age 5-14 years) shows that a small but significant amount of sensorineural hearing loss occurs in unsafe CSOM in children as also seen in adult or mixed population 12 . There is a tendency towards increasing sensorineural hearing loss with increasing duration of disease ,and active middle ear disease. This is more pronounced in the higher frequencies. However, more experimental studies need to be done to further elaborate about the pathogenesis of sensorineural loss in unsafe CSOM.
References 1. Arnold, W., Ganzer, U. and Kleinmann, H. (1977): Sensorineural -hearing loss in mucous otitis. Archives of Otorhinolaryngology, 215: 91-93. 2. Walby, A.P., Barrera, A. and Schuknecht, H.F (1983): Cochlear pathology in chronic suppurative otitis media. Annals of Otology, Rhinology, Laryngology, 92 (Suppl.): 103. 3. Aviel, A. and Ostfeld, E. (1983): Acquired irreversible sensorineural hearing loss associated with otitis media with effusion. American Journal of Otolaryngology, 3: 217-220. 4. Vartiainen, E. and Karjalainen, S.(1987): Factors influencing sensorineural hearing loss in chronic otitis media. American Journal of Otolaryngology, 8: 13-15. Tos M., Lau T. (1987): Cholesteatoma in children. Am J Otolaryngol 8: 364. 5. 6. English G.M., Northern J.L., Fria T.J. (1973): Chronic otitis media as a cause of sensorineural hearing loss. Arch Otolaryngol Head Neck Surg 1973; 98: 18-22. 7. Paparella M.M., Brady D.R., Hoel R. (1970): Sensorineural hearing loss in chronic otitis media and martoiditis. Trans Am Acad Ophthalmol Otoloaryngol 74: 108-115. 8. Sahni R.S., Paparella M.M., Schechern P.A., Goycoolea M.V., Le Chap, T. (1987): Thickness of the human round window membrane in different forms of otitis media. Archives of Otolaryngology 113: 630-634. Mass, B., Baumgartel, H., Laubers D.M. (1976): Lokale pO 2 and pH2 Messungen mit 9. Nadeleelektroden zum Studium der Sauerstoversorgung und Mikrozirkulation des Innenorres. Archives Ohren Nasen und Kehlkopfheilkunde 4: 109-124. 10. Muncher, G. (1981): Inner ear hearing loss in actue and chronic otitis media. Advances in OtoRhino-Larngology 27: 138-143. 11. Tonndorf J. (1966): Animal experiments on bone conduction. Acta Otolaryngologica Suppl. 213. 12. Dumich PS., Harper S.G. (1983): Cochlear functions in chronic otitis media. Laryngoscope 93: 583-586. IJO & HNSNol. 48, No. 2, April-June, 1996
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