European Journal of Cardiovascular Medicine

Chronic otitis media (COM) is a condition characterized by persistent inflammation of the middle ear, leading to long-term or permanent changes in the tympanic membrane.[1] This condition typically may develop as a consequence of previous episodes of acute otitis media (AOM) or otitis media with effusion (OME). It can contribute to Eustachian tube dysfunction and negative middle ear pressure, potentially resulting in a tympanic membrane defect involving either the pars tensa or pars flaccida. [2,3] The worldwide, WHO estimated that 65-330 million of people are affected by COM among this 50% suffer from hearing impairment and 28,000 death per annum reported.[4]

COM is classified into two types: tubotympanic (mucosal) and attico-antral (squamous).[5] Several factors influence its development, including adenoidal hypertrophy, nasal and sinus disorders, deviated nasal septum, allergic rhinitis, socioeconomic status, mastoid air cell size, genetic predisposition, and middle ear infections.[6]

The pathogenesis of COM is primarily linked to Eustachian tube dysfunction, which can also impact the contralateral ear. [7] The contralateral ear is defined as the unaffected or less affect ear defined based on hearing loss, otorrhea and discomfort.[7,8] According to the continuum hypothesis, effusions, retraction pockets, perforations, and cholesteatoma represent progressive stages that may occur bilaterally. When tubal dysfunction initiates COM, there is a significant likelihood of bilateral impairment, though the severity may vary between the ears. [9] There were various theories about the pathogenesis of chronic otitis media (COM), the most common model that named "continuum theory" which adopted by Minneapolis group, where it based on the development of a continuous series of events in the subepithelial and epithelial levels in middle ear cleft. The contralateral ear (CLE) is defined as the asymptomatic ear in unilateral chronic otitis media.. It is to be remembered that both ears have a common portal of drainage i.e. the nasopharynx. The affected ear may well be the endpoint of pathology in the contralateral ear . contralateral is merely past reflection of what the diseased ear was yesterday and needs attention. The main purpose of this study was derived from the fact that nasopharynx act as a common portal for drainage for both ears through left and right Eustachian tube, and hence factors responsible of contralateral ear in patients with unilateral COM. Contralateral ear is defined as the asymptomatic ear or the ear with no history of ear discharge or hearing impairment as Continuum Theory.

Diagnosis involves otoscopy, pure-tone audiometry, and HRCT of the temporal bone. [10] Currently, limited literature addresses the contralateral ear's condition in COM patients. Evaluating CLE is essential for understanding disease progression and etiology. Since both ears are not always affected simultaneously, early identification of changes in the contralateral ear can aid in preventing further complications. Timely intervention, guided by thorough otoscopic, audiological, and radiological assessments, is crucial for optimal management. Therefore, the aim of the present study to assess the status of contralateral ear in chronic otitis media.

This cross-sectional observational study was conducted over 18 months in the ENT Department of a tertiary care hospital. Prior to conduct a study institutional ethical committee approval was obtained. Total 120 COM patients enrolled in the study.

The study included patients of all age groups diagnosed with unilateral COM, provided the CLE had an intact tympanic membrane. Patients with a history of previous ear surgery, head or ear trauma, or those unwilling to participate were excluded.

Patients underwent a comprehensive evaluation of the contralateral ear through history, clinical examination, and diagnostic assessments, including otoscopy, pure tone audiometry, X-ray mastoid (lateral oblique view), and HRCT temporal bone as indicated. The contralateral ear was classified as normal or abnormal, with abnormalities defined by:

·         Otoscopy: Retraction (graded by Sade or Tos classification), tympanosclerosis, or tympanic membrane atrophy.

·         Pure Tone Audiometry: Hearing loss type and severity based on WHO classification.

·         Imaging (X-ray/HRCT): Assessment of mastoid sclerosis, ossicles, middle ear, dural plate, and sinus plate.

Statistical Analysis:

Data were analyzed using SPSS version 20 with descriptive statistical methods. Data comparison is done by applying specific statistical test to find out the statistical significance of the comparisons. The p-value <0.05 is considered significant.

A total of 120 patients were evaluated, out of which 69 were male and 51 females. Sex ratio was 1.35:1 with slight male preponderance. The mean age of presentation was 37.48±12.46 years, with commonest age group being 31-40 years with 39 patients. Right ear was affected in 61 cases, left ear in 59 cases. Out of 120 ears, 37 (30.8%) ears had squamosal disease and 83 (69.2%) had mucosal disease.

Table 1. Distribution of Otoscopic findings in diseased Ear according to type of CSOM.

Otoscopic findings in diseased Ear according to type of CSOM, showed that LCP 41(34.2%), MCP 30(25.0%), and SCP 12(10.0%) were the most common otoscopic findings found among CSOM. It showed that LCP, MCP and SCP were not seen in unsafe ear while LCP, MCP & SCP were found in 41(34.2%), 30(25.0%), & 12(10.0%) safe ear cases. Attic erosion and perforation and PSQ with attic retraction were found only in 9(7.5%) & 8(6.7%) unsafe ear cases while it was not found in safe ear cases. There was statistically highly significant difference found in Otoscopic findings in diseased Ear between safe & unsafe ear cases. (P=0.001). (Table 1)

Distribution of Otoscopic findings in Contralateral Ear according to type of CSOM was found normal in 38(31.7%) cases. Tympanosclerotic patch was found in only in 2(1.7%) unsafe ear cases and in 16(13.3%) cases. Grade 1 retraction of TM was seen in 10(8.3%) unsafe and 20(16.7%) safe ear cases. Grade 3 retraction of TM seen in 5(4.2%) unsafe ear cases and only in 1(0.8%) safe ear cases. Healed TM was seen in 5(4.2%) & 4(3.3%) in unsafe & safe ear cases respectively. There was statistically highly significant difference found in Otoscopic findings in Contralateral Ear between safe & unsafe ear cases. (Table 2)

Table 3: Distribution of Radiological findings in Diseased Ear according to type of CSOM.

Distribution of Radiological findings in Diseased Ear revealed that all 37(30.8%) unsafe & 83(69.2%) safe ear cases had sclerosed type of mastoid. (Table 3)

Table 4: Distribution of Radiological findings in Contralateral Ear according to type of CSOM.

Distribution of Radiological findings in Contralateral Ear showed that out of 120 cases, 40(33.3%) had normal contralateral ear. Out of 37 unsafe ear cases, 28(23.3%) had diploeic and 6(5.0%) had sclerosed type of mastoid. Out of 83 safe ear cases, 46(38.3%) had diploeic type of mastoid and no one had sclerosed. There was statistically highly significant difference found in distribution of Radiological findings in Contralateral Ear between safe & unsafe year. (P=0.001). (Table 4)

Table 5-Distribution of Audiological findings through Rinne test in Contralateral Ear according to type of CSOM.

Distribution of audiological findings through Rinne test in Contralateral Ear according to type of CSOM showed that Rinne test was positive in 11(9.2%) unsafe ear cases and 69(57.5%) safe ear cases while it was negative among 26(21.7%) unsafe and 14(11.7%) ear cases. There was statistically highly significant difference found in distribution of audiological findings through Rinne test in Contralateral Ear between safe & unsafe cases. (P=0.001). (Table 5)

TABLE 6: Distribution of Pure tone audiometry Findings in Contralateral ear according to type of CSOM.

Distribution of pure tone audiometry Findings in Contralateral ear showed that 84(70.0%) cases had normal ear. Only 1(0.8%) had Moderate & moderately severe hearing loss. Out of 37 unsafe ear cases, 19(15.8%) had mild hearing loss. Out of 83 safe ear cases 15(12.5%) had mild hearing loss. There was statistically significant difference found in distribution of pure tone audiometry Findings in Contralateral ear between safe & unsafe ear. (P=0.001). (Table 6)

TABLE 7: Comparative evaluation of Mean Pure tone audiometry (dB) between safe & Unsafe Ear in diseased & contralateral ear.

Comparative evaluation of Mean Pure tone audiometry(dB) between safe & Unsafe Ear in diseased & Contralateral ear showed that Mean Pure tone audiometry(dB) was 41.54±9.28 db & 41.07±7.96 among unsafe and safe CSOM Cases in diseases ear. There was statistically no significant difference found in Mean Pure tone audiometry(dB) between safe & Unsafe Ear in diseased ear. (P=0.778) Mean Pure tone audiometry(dB) was 26.43±6.97 & 22.27±5.25 96 among unsafe and safe CSOM Cases in contralateral ear. There was statistcally significant difference found in Mean Pure tone audiometry(dB) between safe & Unsafe Ear in contralateral ear. (P=0.001). (Table 7)

Table 8: Distribution of Impedance Findings in Contralateral ear according to type of CSOM.

Distribution of Impedance Findings in Contralateral ear according to type of CSOM revealed thst out of 120 cases, 89(74.2%) had Type A curve, 11(9.2%) type B curve and 20(16.7%) had type C curve. Out of 37 unsafe ear cases, 21(17.5%) had type A, 2(1.7%) type B and 14(11.7%) had type C curve. Out of 83 safe ear cases, 68(56.7%) had type A, 9(7.5%) type B and 6(5.0%) had type C curve. There was statistically highly significant difference found in distribution of Impedance Findings in Contralateral ear between safe and unsafe ear (P=0.001). (Table 8)

In the present study, chronic otitis media (COM) was most prevalent in the 31–40 years age group (32.50%), followed by the 21–30 years and 41–50 years age groups (22.50%). The age distribution of participants ranged from 11 to 61 years, with a mean age of 37.48±12.13. These findings were consistent with a study by Gupta DK et al.,[4] which reported a high proportion of patients in the 21–30 years age group (40.3%), followed by the 11–20 years group (28.3%). Their study included patients aged 13 to 56 years, with a mean age of 28.02 years. Buruhanudeen et al.,[11]  the mean age of patients 39.53 ± 13.64 years.

Similarly, Khan YA et al., [12] conducted a study on 105 patients, where the majority belonged to the 21–30 years and 31–40 years age groups, with an average age of 26.3 ± 12.2 years. These findings suggested that COM was more commonly observed in the early decades of life.

In current investigation, among 120 patient's majority were male 69 (57.50%), 51 (42.50%) were female. COM affected the right ear in 61 patients (50.80%) and the left ear in 59 patients (49.20%). The most commonly reported symptoms were ear discharge, often accompanied by hearing loss. The highest discharge duration was between 1-5 years (38.30%). Current study investigation revealed radiological assessment using X-ray and HRCT showed sclerosed mastoids in all diseased ears. The contralateral ear status showed 40(33.30%) had normal finding, 74 patients (61.70%) had diploic mastoids, and 6 (5.00%) had sclerosed mastoids with statistically significant p <0.0001.

Comparing these findings with previous studies, Shireen et al.,[13] reported a higher prevalence of pneumatized contralateral mastoids (42.4%), while diploic mastoids were observed in 37.3%, and sclerosed mastoids in 20.3%.  Similarly, Gupta DK et al., found a pneumatic pattern in 69.1% of cases, followed by a diploic pattern in 30.9%, with no cases of sclerotic mastoids.

Contralateral ear findings in the present study revealed that the most common abnormality was Grade 1 tympanic membrane (TM) retraction (24.20%), followed by tympanosclerotic patches (15.00%), Grade 2 TM retraction (13.30%), Grade 3 TM retraction (5.00%), and Grade 4 TM retraction in four patients. Additionally, 9 patients had a healed TM.

The previous studies, Niyatharuni R., [14] reported TM retraction in 22.66% of cases as the most frequent abnormality, along with distorted COL (21.33%), neomembrane formation (13.33%), tympanosclerotic patches (12%), absent COL (10.66%), opaque TM (5.66%), and TM thinning (5.33%). Similarly, Soni S. et al., [15] observed that 80% of patients had abnormal contralateral ears, with 38% exhibiting TM retraction. Kumar S. et al.,[3] documented TM retraction in 45% of cases, with 39% involving the pars tensa (PT) and 6% affecting the pars flaccida (PF).

In this study, 112 patients (93.33%) had conductive hearing loss in the diseased ear, with an average loss of 43.65 ± 14.16 dB, while 82 patients (68.30%) had normal hearing in the contralateral ear. These findings align with Buruhanudeen et al.,[11] who reported minimal to mild CHL in 86.7% of contralateral ears.

Impedance audiometry showed a Type B tympanogram in all diseased ears. In contralateral ears, 74.20% had Type A tympanogram, Type B tympanogram in 11 patients (9.20%), and a Type C tympanogram in 20 patients (16.70%).Khan YA et al.,[12]  reported a Type B tympanogram in 70 diseased ears. In contralateral ears, 20 had Type A, 50 had Type B, and among 35 diseased ears with Type C, 12 contralateral ears had Type A and 23 had Type C tympanograms.

Patients with unilateral COM are at risk of developing pathological changes in the contralateral ear. In this study, the most common contralateral ear findings were Grade 1 TM retraction, followed by Grade 2 and Grade 3 TM retraction, as well as tympanosclerotic patches. The mild hearing loss was observed in the contralateral ear. These findings highlight the importance of thorough contralateral ear evaluation, even in asymptomatic cases, for early detection and timely intervention. Patient education and regular follow-up are crucial in preventing disease progression and optimizing treatment outcomes. Therefore, routine contralateral ear assessment is recommended in all cases of unilateral COM.

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