Effects of Enlarged Adenoids on Middle Ear Pressure and Hearing

Background: Adenoids are common childhood upper respiratory tract problem which frequently obstruct the nasopharyngeal opening with tubal occlusion causes reduction in middle ear pressure with conductive hearing loss. Objective: To observe middle ear pressure and level of hearing in children with enlarged adenoids. Methods: This cross sectional observational study conducted among 72 children of enlarged adenoids admitted or attended in Dhaka Medical College Hospital and Bangabandhu Sheikh Mujib Medical University Dhaka. Results: 72 children of enlarged adenoids of age ranges between 5-12 years with male female ratio was 1.25:1. Mouth breathing (65.27%), hearing impairment (59.72%), nasal obstruction (55.55%) and snoring (56.94%) were the presenting symptoms of the patients. Majority of the patients of this study came from middle class (52.77%). Most of the patients with enlarged adenoids were grossly enlarged (51.38%). 43.05% grossly enlarged adenoids had significant hearing loss . In this series 65 ears (45.13%) had type A Tympanogram. 58 ears (40.27%) has Type B Tympanogram and 21 ears (14.58%) has Type C Tympanogram. Conclusion: This study revealed significant association between enlarged adenoids and conductive hearing loss of variable degree and negative middle ear pressure.


Introduction:
Adenoids hypertrophy are frequent health problem for young children. Adenoids are component of Waldeyer's ring and because of their anatomic position can be relevant in the pathogenesis of otitis media when they are inflammed and/or enlarged. Adenoids can create mechanical eustachian tube obstruction. Adenoids are very small at birth and progressively enlarge as a result of increased immunologic activity. The Adenoids appear to be at it's largest in the seven-yearold age group 1 . Involution of the adenoids begin after puberty. Regression of the adenoids occur rapidly after 15 years of age in most children 1 . Hypertrophied and chronically infected adenoids had increased load of pathogenic bacteria, especially betalactamase producers, as compared with nondiseased adenoids. An equilibrium exists between the normal flora of the adenoid tissue and their local immunologic response and this equilibrium can become disrupted with recurrent acute viral or bacterial infections or colonization with pathogenic bacteria, resulting in hypertrophied lymphoid tissue 2 .
Evaluation of adenoids are much more difficult because it is not easily accessible on physical examination. Lateral neck radiography may be helpful to assess adenoids hypertrophy .Historically, the adenoids has been associated with upper airway obstruction, and more recently with the persistence of otitis media with effusion. Clinical symptoms are more common in a younger age group, due to the relative small volume of the nasopharynx and the increased frequency of upper respiratory tract infections 3 .
The function of middle ear is to transmit sound wave from external ear to inner ear by its transformer mechanism. The normal middle ear pressure is -100mm of H 2 O to +50mm of H 2 O and normal middle ear compliance is 0.39 ml to 1.30ml 4 . Middle ear pressure (MEP) is believed to influence sound transmission primarily by increasing the stiffness and damping of tympanic membrane.
Due to mechanical obstruction of eustachian tube by enlarged adenoids, negative pressure is being created within the middle ear 5 . Resulting in vascular engorgement with increased capillary permeability leading to pouring of fluid in the middle ear 6 . Negative pressure is also responsible for retraction of tympanic membrane, together with accumulated fluid influence the middle ear mass effects producing reduced middle ear compliance and conductive type of hearing loss 7 .
The risk of otitis media with effusion was more than seven times as more among adenoidal group than among the non-adenoidal control. Gross nasopharyngeal obstruction is significantly associated with type B tympanogram .The diagnosis of otitis media with effusion correlated significantly with the degree of nasopharyngeal obstruction 8 . In otitis media with effusion middle ear pressure reduces below -100mm H 2 o 9 .In otitis media with effusion usually mild to moderate degree of hearing loss develops 7 .

Methods:
This study was done in the department of Otolaryngology and Head-Neck surgery in the Bangabandhu Sheikh Mujib Medical University, Dhaka and Dhaka Medical College Hospital, Dhaka from February 2012 to August 2012. Inclusion criteria were all patients with enlarged adenoids of both sex from 5 to 12 years of age.Exclusion criteria were Patients or their guardian who refused to include this study,Patient with hearing loss due to chronic suppurative otitis media or other causes than adenoids ,child with profound hearing loss, congenital deafness, cleft palate.
With proper ethical consideration after taking an informed consent from the guardian of all selected patients were interviewed, examined and investigated. Total 72 patients were included in this study. Diagnosis of enlarged adenoids was based on the symptoms and clinical presentation of the patient, clinical examination and radiological investigation (e.g. X-ray nasopharynx lateral view). Middle ear condition was assessed by clinical examination, otoscopy, microscopic examination of ears and tympanometry. Hearing threshold was assessed by audiometry (pure tone audiometry) along with clinical assessment. All the information and data was recorded and compiled in a structured data sheet. All the data was analyzed by a standared statistical methods and computer software (SPSS-16, Sigma Stat-3.2)

Results:
Maximum numbers of patients presented with enlarged adenoids belonged to 5 -8 years (77.78%). In this study among the patients with enlarged adenoids 55.55% were male and 44.44% were female. Thus male to female ratio was 1.25:1.     Among the patients with grossly enlarged adenoids air bone Gap <15dB was in 11 Ears(13.92%), air bone Gap range 20dB-30 dB was in 42 Ears(53.16%) and air bone Gap >30dB was in 9 Ears (11.39%).The severity of conductive (AC) loss had found significantly related with the size of adenoids enlargement. (P = 0.001). and 21 ears 14.58% respectively. There was no significant relation between the right and left ears in middle ear pressure and compliance in tempanometry (P = 0.774).

Discussion:
Enlarged adenoids are common among the children. Adenoids hypertrophy has been identified as an aetiological factor in recurrent or persistent otitis media with effusion. To determining adenoidal hyperplasia, the physician typically relies on ent examinations , lateral neck radiograms, and history. Only physical examination gives little information about size of adenoids. On the other hand, the lateral neck radiograph provides an excellent view of the adenoids. Radiologically adenoids mildly enlarged when nasopharyngeal airway obstruction < 1 / 3 ,moderately enlarged when nasopharyngeal airway obstruction > 1 / 3 but < 2 / 3 and grossly enlarged when nasopharyngeal airway obstruction > 2 / 3 .
This study was conducted to finds out the correlation of hearing and middle ear pressure in children with enlarged adenoids. This study also finds out the different demographic factors related to the enlarged adenoids. Finally, this study finds out the different degree of conductive hearing loss among the children with enlarged adenoids In this study the patients age range between 5-12 years 10 . Male female ratio was 1.25:1. 11 Majority of the patients presented with more than one symptoms. The common symptoms of the patients of adenoids were mouth breathing (65.27%) hearing impairment (59.72%).These findings of this series are consistent with the findings of a repoted series. A study showed mouth breathing and hearing impairment in 77.00% and 83.00% cases respectively 12  Most of the patient with enlarged adenoids came from middle class 52.77%(38 patient), the next highest incidence 33.33%(24 patient) in the poor class. The relative lower incidence in poor class is possibly due to lack of knowledge ,ignorance about the health problems and failure to pay attention to health problems over the other daily requirements and hence failing to attend the hospital.
In the present study patients with enlarged adenoids has the incidence of conductive hearing loss is 59.72%(43 patient).Grossly enlarged adenoids has significant hearing loss 43.05%(31 patients In this study 37 patients(51.38%) has grossly enlarged adenoids. Among the patients with grossly enlarged adenoids air bone gap <15dB was in 11 ears(13.92%), air bone gap range 20db-30 dB was in 42 ears(53.16%) and air bone gap >30dB was in 9 ears (11.39%). The severity of conductive (AC) loss had found significantly related with the size of adenoids enlargement. A study shown that the adenoids hypertrophy in children may lift the hearing threshold level 18 .
In this series 65 ears(45.13%) has type A Tympanogram .Type B Tympanogram and Type C Tympanogram has 58 ears (40.27%) and 21ears (14.58%) respectively.The reduced middle ear pressure is due to blockage of the eustachian tube by enlarged adenoids ,absorption of middle ear air and presence of fluid in middle ear 9 .
In this study it is seen that middle ear pressure change and hearing impairment mostly affecting bilaterally. This bilateral ear involvement was due to enlargement of adenoid tissue from midline interfering the tubal function 10 .