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Table of Contents
Year : 2010  |  Volume : 12  |  Issue : 2  |  Page : 62-67

Laryngopharyngeal Reflux Disease (LPRD) and pH-metry King Saud University Experience

1 Communication and Swallowing Disorders Unit, ENT Department, King Abdulaziz University Hospital, Riyadh, Saudi Arabia
2 Medical Student, College of Medicine, King Abdulaziz University, Riyadh, Saudi Arabia
3 ENT Department, King Abdulaziz University Hospital, Riyadh, Saudi Arabia
4 GIT Department King Khalid University Hospital, King Saud university, Riyadh, Saudi Arabia

Date of Web Publication2-Jan-2020

Correspondence Address:
MD, PhD Khalid H Malki
P.O Box 245 Riyadh, 11411 ORL Department, Communication and Swallowing Disorders Unit (CSDU) King Abdulaziz University Hospital, Riyadh
Saudi Arabia
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1319-8491.274634

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Background/Hypothesis: Laryngopharyngeal reflux disease (LPRD) patients can present with a variety of symptoms such as throat clearing, persistent cough, globus throat sensation, and dysphonia. Although 24-hour double-probe pH-monitoring is assumed to be the most sensitive test for diagnosing LPRD, a lot of controversy does exist regarding the placement of the upper probe as well as the interpretation of its results. The aim of this study was to present the experience of King Saud University (KSU) Hospitals, Saudi Arabia in the application of pH-metry in patients suspected to have LPRD.
Materials and Methods: A retrospective chart review was done for the medical records of those patients who had a pH-metry study at KSU hospitals from 2005 to 2008. The main data that has been collected were demographics, causes of referral, main presenting symptoms, and pH study results. A correlation was done between pH-metry results and patients’ symptoms.
Results: Sixty seven patients were included in the study. Twenty eight patients had double-probe studies, while the remaining 39 patients had single probe (distal) pH-metry. Forty patients out of the 67 showed positive results whether in the distal or the proximal pH sensors. The main cause of referral was patients refractory to anti-LPRD medications. The most frequently presenting symptom was heartburn, while globus throat sensation was the only symptom that correlated significantly with positive double-probe pH-metry results.
Conclusion: pH-metry is not a commonly used primary tool for assessing LPRD-suspected patients in KSU hospitals. Most of the patients were given medical treatment once they were suspected to have LPRD. The pH-metry studies were only recommended for those patients who did not respond to medical treatment. Globus throat sensation appears to be the most extra-esophageal symptom that could be relevant to LPRD in the study group.

Keywords: pH-metry, LPRD, reflux, voice

How to cite this article:
Malki KH, Al Zahrani A, Farahat T M, Mesallam TA, Bukhari M, Al Amri S. Laryngopharyngeal Reflux Disease (LPRD) and pH-metry King Saud University Experience. Saudi J Otorhinolaryngol Head Neck Surg 2010;12:62-7

How to cite this URL:
Malki KH, Al Zahrani A, Farahat T M, Mesallam TA, Bukhari M, Al Amri S. Laryngopharyngeal Reflux Disease (LPRD) and pH-metry King Saud University Experience. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2010 [cited 2022 Nov 30];12:62-7. Available from: https://www.sjohns.org/text.asp?2010/12/2/62/274634

  Introduction Top

Gastroesophageal reflux (GER) refers to the backflow of stomach contents into the esophagus, while gastroe-sophageal reflux disease (GERD) is a clinical term that refers to GER that is excessive and causes symptoms and tissue damage, usually heartburn and esophagitis. While Laryngopharyngeal reflux (LPR) refers to the backflow of the stomach contents into the throat or the laryngopharynx .[1]

Laryngopharyngeal reflux disease (LPRD), defining the otolaryngologic manifestations of GERD, has been accepted as a distinct entity from the classic GERD [2]. The larynx is more vulnerable to gastric refluxate than the esophagus, so LPRD patients often present with laryngopharyngeal symptoms in the absence of heartburn and regurgitation [3].

LPRD patients can present with a variety of symptoms. The International Survey of American Bronchoesophageological Association stated that those patients may present with throat clearing (98%), persistent cough (97%), globus pharyngeus (95%), and change of voice (95%) in addition to other symptoms [4]. Lam et al [5] cited that the two commonest symptoms among pH-documented LPRD are change of voice and throat clearing, but the only statistically significant symptom suggestive for LPRD was burping. Using 24-hour double-probe pH-monitoring, an abrupt decrease in pH to less than 4 in the proximal (upper esophageal) probe following or synchronous with a drop at the distal (lower esophageal) probe is considered a cut off value in diagnosing LPRD,[6] but in the hypopharynx, a drop to less than 5 is probably a more reliable indicator for proximal reflux because neutralizing factors can raise pH value [7].

Adding a hypopharyngeal sensor to the esophageal pH monitoring system has been advocated for assessing LPRD. An abnormal pH test was found in 98% of LPRD cases with triple sensor combination compared with 71% if only dual esophageal sensors were used [8]. However, some studies showed that only 50% of the patients suspected to have LPRD have positive pH-metry[9].

Recently, gastric acid levels in the refluxate and patterns of reflux can be assessed using tetra-probe 24-hour pH- monitoring, where four sensors are placed as follows; proximal probe is placed in the hypopharynx above the upper esophageal sphincter (UES), the second one is placed in the middle of esophagus, the third probe is placed few centimeters above the lower esophageal sphincter (LES), and the distal probe is placed in the stomach. Tetra-probe 24-hour pH-monitoring system also provides a functional examination to evaluate antireflux medications efficacy [10]. A new pH sensor (The Restech® pH probe) has been designed specifically to monitor the pharyngeal pH. This sensor detects aerosolized or liquid acid, resists drying, and does not require contact with fluid or tissue for electrical continuity. The probe has a teardrop shape with the sensor oriented downward to avoid becoming covered with food or mucus [11]. Variability in testing methods and lack of agreement on normative values have raised questions about the sensitivity of pH monitoring studies for detecting LPRD [12]. A lot of controversies do exist about pH-monitoring regarding probe positioning and normative values. Different hospitals and voice and swallowing centers worldwide use different pH-metry study standards. Our study aimed at presenting the experience of King Saud University (KSU) hospitals, namely King Khalid University hospital (KKUH) and King Abdulaziz University Hospital (KAUH), in using pH-metry as a diagnostic procedure for assessing acid reflux. Furthermore, we compared those who were more likely to have LPRD based on positive double-probe pH-metry results with those who had negative double-probe pH-metry in relation to their symptoms.

  Methodology Top

Patients and study design:

This is a retrospective study, where the medical records for all patients who underwent pH-metry in pH-metry clinic at KKUH between 2005 and 2008 were evaluated. This clinic is under the gastrointestinal tract (GIT) unit, and conducted once a week. It receives all patients who are referred for pH metry from different departments at KKUH or KAUH. The system used for pH-metry in this clinic is Digitrapper pH 400 (Medtronic A/S, Skovlunde, Denmark) with Zinetics single-use 2-channel 15 cm apart catheters (Medtronic A/S, Skovlunde, Denmark).

Suspected GERD or LPRD patients were referred to pH-metry clinic from both, KAUH and KKUH. KAUH is referring otorhinolaryngology patients, since otorhino- laryngology department is located in this hospital. Also, patients suspected to have GERD were referred from GIT unit at KAUH and KKUH.

As a standard protocol in pH-metry clinic, every patient has to undergo endoscopic examination prior to pH-metry study in order to make sure that there is no contraindication for conducting pH-metry, like esophageal strictures, bleeding points, or tumors. Esophageal manometry was performed to locate the LES. Then, the double-probe pH catheter was introduced through the nose until the distal probe is 5 cm above the previously determined LES. The proximal probe was located at a fixed distance of 15 cm from the distal probe.

The following parameters were considered for diagnosing a “positive” proximal episode: a drop in the pH level of proximal probe to less than 4.0, with a decrease in the proximal pH level immediately following distal esophageal acid exposure, and a rapid and sharp decrease in the proximal sensor pH level rather than a gradual one. A drop in the pH level during eating or swallowing was excluded.[13]

Data Collection:

Data regarding age, gender, referral sources, causes of referral, and symptoms were all obtained from the medical records. Moreover, details of pH-metry results were collected from pH-metry clinic at KKUH in order to determine the types of sensors used (double- or single-probed) for each patient and the results of those studies. Patients who had positive proximal and distal probe readings were considered to have LPRD (Group I), while those with negative proximal and distal probe readings were considered to have negative LPRD diagnosis (Group II).

Statistical analysis:

Fisher’s Exact test was used to compare Group I to Group II patients regarding their symptoms. This test was used because chi-square test is not applicable because the expected count for one cell or more is less than 5 (i. e, we have a matrix 2 by 2 and the expected count for one cell or more is less than 5). P- value of less than 0.05 was used to indicate statistical significance. Statistical package for social sciences (SPSS, version 16) was used for statistical data analysis.

  Results Top

A total of 73 patients underwent pH-metry at pH-metry clinic (KKUH) during the study period. Six patients were excluded because of incomplete data. So, the study group was composed of 67 patients. They were 34 males (50.7%) and 33 females (49.3%). The mean age of the study group was 38.3 years (15.5 SD) and 39.0 years (13.02 SD) for males and females, respectively. Twenty eight patients had double-probe while the remaining 39 patients had single-probe (distal) pH-metry. Among those who had double-probe examination (28 patients); nine patients showed positive results in both probes (LPRD cases), ten patients were negative on both probes (mostly non-LPRD cases), and nine patients had a positive distal but negative proximal probe results (GERD cases). Based on this distribution, there were nine patients with LPRD (Group I) and 10 patients with mostly negative LPRD diagnosis (Group II). The latter group was considered as a control. Single probe pH- metry was positive in 22 patients and negative in 17 patients.

The main referring source from both hospitals was Otorhinolaryngology department at KAUH (32.8%). [Table 1] shows the different referring specialties in both hospitals. The main cause of referral among the study group was those patients whose symptoms did not respond to medical treatment with proton pump inhibitor (PPI) [Table 2].
Table 1: Distribution of referral sources for pH-metry according to specialty.

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Table 2: Distribution of pH-metry cases according to causes of referral.

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Distribution of the symptoms in patients who had pH-metry at KKUH based on the data collected from medical records is shown in [Table 3]. The most frequently reported symptom was heartburn (50%) followed by chest pain, difficulty swallowing and dysphonia (46%, 28%, and 26% respectively). By comparing symptoms in the two study groups, only lump sensation in the throat “Globus” was significantly higher in group I than group II, with a p-value of 0.03 [Table 4].
Table 3: Distribution of the symptoms in patients who had pH-metry

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Table 4: Comparison of symptoms between Group I and Group II.

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  Discussion Top

The current study is the first study that describes the experience of pH metry studies in one of the biggest hospitals in Riyadh city, Saudi Arabia namely, KSU hospitals. The GIT unit at KKUH is the only current unit at KSU hospitals that performs this kind of investigation. Being a once per week clinic that usually accepts 2-3 patients in a day, explains the limited number of patients who underwent pH-metry study over a period of almost 3 yeas. The main referring speciality for pH-metry was the otorhinolaryngology department. This may reflect the high rate of patients that are suspected to have LPRD among patients seen in the Otorhinolaryngology practice. It may also indicate higher awareness of acid reflux among otorhinolaryn- gologests at KSU.

The main cause of referral for pH-metry in KKUH was those patients whom symptoms did not responding to PPI treatment. This indicates that the vast majority of patients at KSU who were suspected to have LPRD or GERD were treated on the basis of their pattern of symptoms not on the basis of investigations. Only those patients who did not respond to PPI trials were sent for further pH metry studies. This practice seems to be in accordance with the international standards in management of suspected LPRD.[13] A more reliable tool is needed for early diagnosis of LPRD, which will lessen the empirical overuse of PPI for long periods without having sufficient evidence-based medical diagnosis. The pH-metry protocol used at KSU, whether single or double probes are inserted, depends on the source and cause of referral. Those patients referred from otorhinolaryngology department with laryngeal-related complaints underwent double-probes pH-metry studies, while those referred from GIT department and other clinics underwent single-probe pH-metry studies. This may indicate that some GIT physicians are more interested in the esophageal manifestations of GERD more than the extra-esophageal or LPRD manifestations.

The double-probe pH-metry study was performed with the proximal probe is in a constant distance of 15 cm away from the distal probe, the latter being placed 5 cm above the LES. Although this technique is widely used in many centres as well, a controversy does exist regarding its sensitivity in diagnosing LPRD. [13],[14] From otorhinolaryngology perspective, the technique used at KSU to place the proximal probe at a fixed distance of 15 cm from the distal probe is not considered optimal for detection of pharyngeal reflux episodes.[13] Many alternative techniques with different placement positions of the proximal probe have been described in many studies.[1],[15],[16],[17],[18],[19],[20],[21],[22],[23],[24],[25] In these studies, the proximal probe was placed in a zone from within the UES to 2 cm above it. The data of these studies suggested that the proximal probe readings gave more accurate and consistent information about LPRD when it was placed in this zone.

Despite these challenges, studies reported that normal ranges of proximal probe readings with pH<4 is 0% to 1.4% when the proximal probe is positioned 20 cm above the LES,[14],[26] and 0% to 1.0% when it is positioned just above the upper esophageal sphincter.[1],[27] Because these numbers are quite low, it is also practical to carefully analyze the pH tracing in order to determine whether the pH drop represents true proximal reflux or an artifact.[27],[28],[29] Criteria such as a pH drop of 2 to 3 units, an abrupt decrease within 30 seconds, and a good temporal correlation with distal acidification may help to distinguish true laryngopharyngeal reflux.[29]

Multi-channel intramural impedance (MII) monitoring is a recently introduced technique that allows detection of the retrograde extent of the refluxate up in the esophagus regardless of its pH. It can also differentiate acid from non-acid reflux if coupled with pH probes. The combined use of MII and pH-metry may give more reliable information about true LPRD diagnosis.(30, 31) Moreover, this combined technique might provide several other advantages, particularly in the evaluation of some difficult to manage problems including 1- Persistent LPRD symptoms in patients despite they are on maximum dosage of PPI therapy or those undergone Fundoplication, 2- Paradoxical vocal folds motion, 3- Chronic cough, and 4- Pediatric/neonatal reflux. At the same time, important questions about the effect of nonacid or alkaline reflux on the larynx could be answered based on the MII-pH technology. [13] At KSU hospitals, we are looking in our future plans to implement the simultaneous application of MII technology and double-probe pH monitoring in order to augment our diagnosis of LPRD.

The only symptom that showed a significant difference between the suspected LPRD patients and their control group was globus sensation. This coincides with the findings of Wilson et al[32] who reported that LPRD is found to account for up to 68% of patients with globus pharyngeous. However, Papakonstantinou et al[33] concluded that no specific symptom clusters adequately capture the full range of potential reflux symptoms regularly encountered in otolaryngology patients. This reflects the controversy regarding determining specific laryngeal symptoms that could be related to LPRD. The limitations in the current study include the small sample size beside the problem of having some missing data in the patients’ records which is one of the disadvantages of the retrospective studies. However, this study was mainly descriptive aiming at describing the used pH-metry technique in our institute, who is referring suspected cases, and why and when they were referred. The results can still be seen as a useful pilot assessment for the current methodology used in assessment of GERD and LPRD at KSU hospitals. In conclusion, the current study indicates that the 24-hour double-probe pH-metry has an overall limited use in KSU hospitals. It was used mainly for those cases referred from the otorhinolaryngology department. Otherwise, a single pH probe was used. The study revealed that empirical PPI treatment was the most commonly used tool by the clinicians for diagnosing LPRD. The pH-metry studies were mainly recommended for those patients who did not respond to medical treatment. Globus throat sensation appears to be the most extra-esophageal symptom that could be relevant to LPRD in the study group.

  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]


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