EVALUATION OF SENSORINEURALHEARING LOSS IN TUBOTYMPANIC TYPE OF CHRONIC SUPPURATIVE OTITIS

294 | P a g e EVALUATION OF SENSORINEURALHEARING LOSS IN TUBOTYMPANIC TYPE OF CHRONIC SUPPURATIVE OTITIS MEDIA Dr. P. Surendra Babu MS (ENT), Consultant, Department of ENT, Tirumala Super speciality Hospital, Kadapa, AP Article Info: Received 20 May 2019; Accepted 27 June. 2019 DOI: https://doi.org/10.32553/ijmbs.v3i6.1011 Address for Correspondence: Dr. P. Surendra Babu Conflict of interest: No conflict of interest.


han three mon
hs 1,2 CSOM can be classified on pathological bases into chronic suppurative otitis media tubotympanic type and chronic suppurative otitis media attico antral type.The disease may be active when infection & otorrhea are present or quiescent when they are not present.The length of active & quiescent periods varies from patient to patient.Individuals prone to upper respiratory infection & allergies tend to experience frequent & lengthier episodes of active disease 3 .

In fact, neglected acute suppurative otitis media of several months duration may still be essentially a self-limiting process that tends toward complete resolution, whereas epitympanic cholesteatoma from the very first day of otorrhea should be classified as CSOM.Thus it is not the duration f the discharge in days, weeks or months but rather the particular pathologic changes that cause otitis media to be classed as chronic rather than acute & self-limiting 4 .

Sensorineural hearing loss (SNHL) is indicated by air & bone thresholds that are or at least very close to one another.Sensorineural losses can be caused by a disorder of the cochlea or auditory nerve or both.The combined term (sensorineural) is used to highlight the fact that we cannot distinguish between cochlear (sensory) & eight nerve (neural) disorders from the audiogram 5 .However, it is better to use the terms cochlear & retro cochlear hearing loss if we use other audiological tests.

The SNHL associated with CSOM may be sudden onset, progressive or fluctuating.Disequilibrium or vertigo may or may not be present 5 .It has long been accepted that CSOM is often accompanied by SNHL related to the CSOM but not due to effect of conductive deafness on bone conduction 6 .

The pres nce of chronic middle ear infection and sensorineural hearing loss reveals various studies of this relationship, however there are few studies showing relationship between duration and clinical findings with sensorineural hearing loss.

One of the main consequences of CSOM is hearing los .80% of the people with CSOM present with hearing loss.It is calculated that about 13.8 -36.2% of the people have hearing impairment due to CSOM 7 .The classic type of hearing loss described for this condition is conductive.However, several inve tigators have reported sensorineural hearing loss (SNHL) do occur concomitantly or as a sequel of CSOM 7 .The presence of SNHL has been ascribed to contribution of the middle ear in hearing mechanism by bone conduction which is also known as Carhart's effect and/or cochlear damage resulting from extension of the inflammation in the middle ear cleft through round window membrane.It can also be due to direct invasion of inner ear by organisms.Other confounding factors like chronic use of antibiotic ear drops which can have a deleterious effect in the inner ear should also be borne in mind.But some studies have found very little evidence of them causing significant sensorineural hearing loss 8 .With the prevailing studies, it is still a controversy whether SNHL is significantly associated with CSOM or not.

Round window membrane is extremely thin comprising only three layers: outer-epithelial, intermediate connective tissue and inner layer which is continuation of cells lining the scala tympani.

It has been reported that certain forms of otitis media can result not only in catastrophic inner ear changes but also in subtle functional and pathological cochlear changes characterised by sensorineural loss and or endolymphatic hydrops.Although there is a local lymphatic passage from round window membr ne niche to the basal turn of cochlea, the round window membrane itself has been regarded as the main access for the potentially ototoxic substances from middle ear to inner ear.

Oval and round windows changes in otitis media in experimental animals were noted by Goycoolea M.V. et al(1980) 9 .The round window membrane changes from 1 day to 6 months after eustachean tube obstruction, revealed changes to be gradual and similar to that of mucoperiosteum.These changes noted are suitabl for the changes of permeability and suggested that round window membrane is very likely pathway from middle to inner ear.


Materials and Methods

Hospital based study of patients aged between 10 to 45years with unilateral chronic suppurative otitis media attending Tirumala Super speciality Hospital, Kadapa from December 2015 to November 2017 with sample size of 100 cases.Patients between age group 10-45 years with unilateral ch

nic suppurative otitis
media who are attending OPD/ wards for treatment at Tirumala Super speciality Hospital, after excluding certain patients mentioned under exclusion criteria by history, clinical examination and relevant investigations.


Exclusion criteria:

The following patients were excluded from the study 1.Patients with bilateral chronic suppurative otitis media.2. Patients with unilateral sensorineural hearing loss with a known cause like Meniere's disease, labyrinthitis, Acoustic neuroma, Temporal bone fracture, Syphilis, Meningitis.R

ults 100 patients ag
d between 10 to 45 years with unilateral chronic suppurative otitis media attending ENT department of Tirumala Super speciality Hospital, Kadapa from December 2015 to November 2017 with sample size of 100 cases were studied.Observations recorded in the study are described under the following heading.


Percentage of sensorineural hearing loss:

Out of the 100 cases, 10 patients were having sensorineural hearing loss.Thus the percentage is 10%.


Sex distribution:

Out of 100 patients 52 were males and 48 were females.Out of 10 patients with sensorineural hearing loss 6 were males and 4 were females.4. Relation

etween duration of ear discharge and senso
ineural hearing loss:

The duration of ear discharge ranged from 3 months to more than 15 years.Among t

100 patients stud
ed 64 had ear discharge from 3months to 5yr.16 had ear discharge from 6-10yr, 11 had ear discharge from 11-15yr and 9 had ear discharge of more than 15years.


Frequency analysis of sensorineural hearing loss:

Mean bone conduction at different frequencies was calculated, and compared with normal ear.

The mean bone conduction

ars were significa
tly raised than normal control ears at all frequencies.Furthermore the mean bone conduction threshold differences were statistically significant and ranged from 5 to 23.82 dB across the frequency range with greater me n bone conduction differences at higher frequencies, by applying "t" test.One of the earliest observations was made by Huizing E.H 10 .In 1964 acknowledged the presence of bone conduction loss in otitis media, stating that while the loss is generally considered

be due to cochlear damage resulting from inflamma
ion, more often lowered bone conduction thresholds have middle ear origin which he described as "middle ear bone conduction loss" and a "pseudo perceptive loss".Dorothy C Moore 11 et al in 1980 selected a sample of 80 children with otitis media and sensorineural involvement and was compared to 80 children with same histories, but whose audiogram does not display any sensorineural hearing loss.95% of patients with sensorineural involvement showed a dip at the freq

ncies 2 and
4 KHz.Analysis of other 80 children showed, 70% of the developed spontaneous perforation and achieved normal hearing after some time.They hypothesized that the absence of sensory neural loss in control group could be due to perforation, resulting in the release of middle ear fluid and cochlea was no longer at a risk of chemical contamination.

Paperalla 12 et al in 1984 presented additional evidence to support the hypothesis that both acute purulent otitis media and chronic suppurative otitis media can cause high frequency hearing loss.In selected patients and in animals (chinchillas), using electrophysiological methods-both, temporary threshold shifts as well as permanent threshold shifts of basal cochlear turn were demonstrated in purulent otitis media.Patients with purulent otitis media are more susceptible to regional basal turn temporary threshold shifts than patients with chronic otitis media.

Papp Z 13  According to our study, the relationship of SNHL was found to be significant even for tubotympanic type of CSOM despite the common notion that it occurs more in Attic type of CSOM.Risk of SNHL in Chronic otitis media of tubotympanic variety was found by Mohsin et al 15 and Azevedo et al 16 .But study by Razooqi et al 17 stated that the presence of cholesteatoma has a significant correlation with the occurrence of SNHL.

Though gender didn't have any positive correlation with regards to SNHL, there was a male predominance in our study group.The same male predominance was noted in the study conducted by Mohsin et al 15 and Gulati et al 18 .Females were the predominant population in the study carried out by Md Daud et al 19 .In contrast, Alabbasi et al. 20 found that there was no significant gender difference in CSOM patients.

Kamaljit Kaur et al 21 found that that incidence of SNHL in CSOM is 24% and incidence of SNHL increas d with the increasing duration of disease.They advised high frequency audiometry test (i.e.10,000 Hz to 20,000 Hz) in all patients of CSOM.However in our study the percentage of SNHL came to be 10%.The highest frequency we took into consideration was 8000Hz.

Rohit Sharma et al 22 proposed that though greater SNHL was seen in patients of CSOM with cholesteatoma, it was not statistically significant.
he results of the study by Aws A. Hussona et al 23 in 2008 indicate that there is a definite sensorineural component to the hearing loss in cases of Chronic suppurative otitis media.Bone conduction in diseased ears is depressed to a statistically significant degree when compared to that in normal control ears.The longer the disease process and the more complicated the pathology (Polyp or granulation tissue) the greater the possibility of sensorineural hearing loss.


Conclusion

1. Our study shows presence of significant (10%) sensorineural hearing loss in patients with chronic suppurative otitis media.

2. Sensorineural hearing loss was found to be more in patients between the age group of 36-45 years.

3. In this series male to female ratio is approximately 1.08:1.

4. Duration of ear discharge correlates well with sensorineural hearing loss.


5.

No significant correlation between sex and sensorineural hearing loss.

6. Higher frequencies are more affected than lower frequencies.

In the light of the study, there is a need for continual assessment of sensorineural function in patients with CSOM and it should be managed