Effect of Laryngopharyngeal Reflux Disease on Middle Ear Function: A Case–Control Study

Abstract

Aims

To identify the effect of acid reflux on the middle ear function in patients with laryngopharyngeal reflux disease (LPRD) with no pre-existing otologic complaints.

Materials and Methods

Patients presenting with complaints suggestive of LPRD were identified and Reflux Symptom Index (RSI) and Reflux Finding Score (RFS) were calculated. 73 individuals with RSI ≥ 13 and RFS ≥ 7 was diagnosed with LPRD and chosen as cases. An equal number of healthy controls who had no symptoms of LPRD, matched for age and sex were chosen. Pure tone audiometry (PTA) and Impedance Audiometry were done in both the groups to assess middle ear function and the findings were compared.

Results

PTA values indicated hearing impairment among 61.64% of cases as compared to 17.81% controls (p value < 0.001). Result of Impedance Audiometry also revealed that 54.8% cases of LPRD had deranged middle ear function compared to 6.85% of controls (p value < 0.001).

Conclusion

Laryngopharyngeal reflux disease can have silent manifestations in the ear in the form of altered middle ear function. This can lead to a wide spectrum of dysfunctions in the form of serous otitis media, retraction pockets and squamosal variant of chronic otitis media, which has its own set of complications. Hence, early management of LPRD can reduce possibility of middle ear disease.

Introduction

Laryngopharyngeal reflux disease (LPRD) refers to a condition characterized by the reflux of gastric and duodenal contents into the larynx and the pharynx [1]. It may have a prevalence rate as high as 30% in certain populations of the world [2].

The refluxate can cause changes within the laryngopharyngeal mucosa as well as some other sites leading to various presentations [3]. The laryngeal manifestations which are more common and well documented include chronic cough, laryngeal granulomas, vocal nodules and contact ulcers. Rarer complications include laryngeal stenosis and laryngeal carcinoma [3]. From the hypopharynx, the gastric contents may also reach up to the oropharynx or even as high as the nasopharynx, especially when the subject is in recumbent supine position. The eustachian tube (which serves as a pathway connecting the nasopharynx to the middle ear and has a primary function of maintaining middle ear ventilation & drainage) can be exposed to the ill effects of this corrosive refluxate for prolonged periods especially during sleep. The exposure to this acidic refluxate can lead to localised inflammation, oedema and ciliary dyskinesia of the Eustachian tube resulting in chronic tubal dysfunction. This can lead to derangement of middle ear function [4]. The latter can be easily assessed by hearing evaluation by Pure Tone Audiometry and measuring the compliance of the middle ear system by Impedance Audiometry. Unfortunately, very little research had been done on this subject and the role of LPRD on the middle ear function is still unclear [5].

The aim of our study was to identify the effect of the acid reflux on the middle ear function in patients presenting with LPRD who have no pre-existing otologic complaints.

Materials and Methods

The study was a hospital-based observational matched case-control study carried out for a duration of 4 months with the aim to identify the effect of LPRD on the functioning of the middle ear. The objectives of the study were as follows:

1. To identify patients presenting with LPRD without any pre-existing otologic complaints/symptoms.

2. To assess the middle ear functions in these patients.

3. To find the association between LPRD and the functioning of the middle ear, if any.

Clearance for the study was obtained from the Institutional Ethics Committee and informed written consent was taken from the subjects regarding participation in the study.

The study population (cases) consisted of patients above 18 years of age presenting to the Otorhinolaryngology outpatient department of our hospital with complaints suggestive of LPRD.

The exclusion criteria for the study were as follows:

1. All patients with any pre-existing ear or nose related complaints.

2. Any history of upper respiratory tract infection in one month preceding the study.

3. All patients with any known otogenic complaint.

The cases were first given a questionnaire to calculate their Reflux Symptom Index (RSI) as proposed by Belafsky et al. where symptoms are graded according to the severity. A score of RSI ≥ 13 was indicative of LPRD [6].

Considering that the RSI score is subjective in nature, an endoscopic examination of the larynx was done in all the cases and findings were graded according to the 8-item severity scale, the Reflux Finding Score (RFS), also devised by Belafsky. A score of RFS ≥ 7 was considered abnormal and indicative of LPRD [6]. Only those patients with RSI ≥ 13 and an RFS ≥ 7 were chosen as cases for further evaluation. In this manner, a total of 73 such cases were found during the study period.

Otoscopy was done to exclude pre-existing problems like silent perforations etc. In all cases, a Pure Tone Audiometry (PTA) was done to assess the hearing and quantify any hearing loss if present. The audiometric findings were graded according to the WHO Grades of Hearing Impairment [7]. This was followed by Impedance Audiometry to assess middle ear function by measurement of the compliance of the middle ear sound conduction pathway. According to the type of the curve obtained, the findings were classified as either Type A (indicative of a normal middle ear compliance), As (indicative of reduced middle ear compliance), Ad (indicative of increased middle ear compliance), Type B (indicative of fluid in the middle ear, most commonly seen in otitis media with effusion) or Type C (negative middle ear pressure indicative of gross eustachian tube dysfunction).

The control group was selected from among fit, healthy adults who were apparently asymptomatic for symptoms of LPRD. All controls were matched for age and sex. Otoscopy was also done to exclude any pre-existing disease of the tympanic membrane and middle ear. Pure tone audiometry and tympanometry were done and the results were recorded.

All the findings were then tabulated and analysed with respect to their statistical significance. Data was analysed on STATA V.14.1 (STATA Corp, LLC, Texas). Chi Square test was used to calculate statistical significance.

Results

The study showed that a significant portion of the cases (30.14%) belonged to the age group of 41–50 years of age and females (64.4%) outnumbered males (35.6%) in the ratio 1.8:1 (Figs. 1 and 2; Table 1).

Fig. 1.

Age distribution of cases & controls

Fig. 2.

Sex distribution of cases and controls

Table 1.

Case distribution according to the presenting symptoms for calculation of RSI (A) and according to the endoscopic findings for calculation of RFS (B)

(A)
S. No	Reflux symptoms in cases	Number of patients	Percentage of patients (%)
1.	Hoarseness or a problem with voice	59	80.82
2.	Throat clearing	66	90.41
3.	Excess throat mucus or postnasal drip	64	87.67
4.	Difficulty swallowing food, liquids, pills	61	83.56
5.	Coughing after eating or lying down	58	79.45
6.	Breathing difficulties/choking episodes	54	73.97
7.	Troublesome or annoying cough	63	86.30
8.	Sensation of something abnormal sticking in the throat/lump in throat	70	95.89
9.	Heartburn, chest pain, indigestion or stomach acid coming up	68	93.15
(B)
S. No	Laryngeal findings in cases during assessment of RFS	Number of patients	Percentage of patients (%)
1.	Subglottic edema	0	0
2.	Ventricular obliteration	52	71.23
3.	Erythema/hyperaemia of laryngeal mucosa	71	97.26
4.	Vocal fold edema	65	89.04
5.	Diffuse laryngeal edema	1	1.37
6.	Posterior commissure hypertrophy	48	65.75
7.	Granuloma/granulation tissue	12	16.44
8.	Thick endolaryngeal mucus	9	12.33

As mentioned in the inclusion criteria, all the cases had a Reflux Symptom Index ≥ 13 and a Reflux Finding Score > 7. Sensation of a lump in the throat was the most common symptom while calculating the RSI (95.89%) followed by heart burn and chest pain as the second most common complaints in 93.15% cases. The most common laryngeal finding on endoscopy was erythema of the laryngeal mucosa (97.26%) followed by vocal fold oedema in 89.04% cases (Table 2).

Table 2.

Pure Tone Audiometry findings (A) and Impedance Audiometry findings (B) among cases and controls

(A)
Grade of impairment	Hearing deficit (in decibels)	Number of cases	p value	Number of controls	Percentage of controls (%)
Normal	≤ 25	28		60	82.19
Mild	26–40	42		11	15.07
Moderate	41–60	3	< 0.001	2	2.74
Severe	61–80	0		0	0
Profound	≥ 81	0		0	0
(B)
Impedance audiometry findings	Number of cases	Percentage of cases (%)		Number of controls	Percentage of controls (%)
Type A curve in both ears	33	45.20	< 0.001	68	93.15
Type As curve in one/both ears	1	1.37		0	0
Type Ad curve in one/both ears	0	0		0	0
Type B in both ears, or Type B in one ear with Type A in the other ear	28	38.36		3	4.11
Type C in both ears, or Type C in one ear, with Type A in the other ear	9	12.33		1	1.37
Type B in one ear and Type C in the other ear	2	2.74		1	1.37

Among the cases, 38.36% had normal hearing and 57.33% had mild hearing loss. However, among the controls, 82.19% had normal hearing and only 15.07% had mild hearing loss. This indicated the proportion of individuals with hearing loss to be much higher among the cases as compared to the controls. The p value for the above findings was found to be < 0.001 which means that it was statistically significant.

Impedance audiometry findings indicate that among the cases, 40 cases (54.79%) have deranged middle ear function whereas among the controls, only 5 (6.85%) have deranged middle ear function. The p value was calculated to be < 0.001, proving the findings to be significant statistically.

Discussion

Our study showed a higher preponderance of females among patients presenting with LPRD (64.38%) as compared to males. Other studies have also shown a similar gender distribution [8], although some have also claimed that LPRD occurs equally both in men as well as in women [9].

Most of the patients belonged to the 41–50 years age group (30.14%) and very few of the patients were more than 70 years of age. In a similar study, the most common age group of presentation was found to be 30–40 years [9].

Most of the patients (95.89%) had complaints of “a lump in the throat” or “sensation of something abnormal sticking in the throat” making it the most common symptom elicited while calculating the RSI. Other studies also found the same symptom to be the most common when measuring the RSI [10]. The most common findings on laryngoscopy were erythema of the laryngeal mucosa (97.26%) and vocal fold oedema (89.04%). Contrarily though, some other studies found thick endolaryngeal mucus and vocal fold oedema as the most common complaints [9].

Even though none of the cases presented with any otologic complaint, PTA revealed the presence of mild conductive hearing loss in 42 out of 73 cases (57.53%). On the contrary, among the control group, only 17.81% subjects had PTA findings suggestive of hearing loss while 82.19% subjects had normal hearing. A rigorous search of the literature reveals that comparable studies regarding changes in middle ear function among human subjects with LPRD are lacking.

On impedance audiometry, it was found that only 33 cases (45.20%) had a normal findings (Type A) while 40 individuals (54.80%) among our cases had findings indicative of impaired middle ear functioning. As compared to this, among the controls, 68 of them (93.15%) had a Type A curve in both the ears, whereas only 5 patients (6.85%) had either a Type B or a C curve on the tympanogram, or both. As in the previous instance, we could not find any reference in the literature regarding studies assessing the impedance audiometry results in patients with LPRD.

Our study findings suggest that subclinical hearing loss due to underlying LPRD may be exceedingly common in the community and may remain undetected or progress with time. If left untreated, long standing eustachian tube dysfunction can be a precursor to fluid accumulation in the middle ear (secretory otitis media) with higher degrees of hearing loss and its own set of handicaps [11]. Persistently negative middle ear pressure can also result in the formation of retraction pockets with a possibility of development of squamosal type of chronic otitis media. This can progress to its own set of intra-temporal and intra-cranial complications [12]. Mucosal type of chronic otitis media is far more common in occurrence than squamosal type. Only anecdotal evidence suggest that acid reflux may have an association with chronic otitis media in children [13]. Therefore, a lot more research needs to be done in this direction in order to clearly establish the role of LPRD in the causation of ear disease.

The sheer number of cases of LPRD in the population suggests that there may be a huge number of patients with hearing abnormalities who remain undiagnosed and have the potential to progress further. Prompt management of LPRD can therefore restore the middle ear function of these patients back to normal and bring down the prevalence of middle ear disease in the community at large.

Conclusion

Laryngopharyngeal reflux disease can have silent manifestations in the ear in the form of altered middle ear function. This can lead to a wide spectrum of disorders from mild undetected hearing loss to higher degrees of deafness due serous otitis media, retraction pockets and even squamosal variant of chronic otitis media, which has its own set of life-threatening complications. Hence, early management of LPRD may reduce the burden of ear disease in the community.

Funding

None.

Data Availability

Raw data were generated at Teerthankar Mahaveer Medical College and Research Center, Moradabad. Derived data supporting the findings of this study are available from the corresponding author on request.

Declarations

Ethical Approval

IRB No and Date of Approval – IRB/108/2023, Date – 14/06/2023.

Informed Consent

Informed written consent was taken from the subjects regarding participation in the study. They were counselled regarding the study hypothesis, the investigations to be done and the fact that the study data would be sent for publication.

Competing Interest

None.