|Year : 2011 | Volume
| Issue : 1 | Page : 18-21
24-hour dual-probe ambulatory pH-metry findings in cases of laryngopharyngeal reflux disease
Karuna Datta, Rakesh Datta, MD Venkatesh, Deepanjan Dey, Raksha Jaipurkar
Department of Physiology and ENT, AFMC, Pune, India
|Date of Web Publication||7-Feb-2011|
Department of Physiology, ACMS, Delhi Cantt, Delhi
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Laryngopharyngeal reflux disease (LPRD) cases are common in clinical practice and usually neglected for want of a definitive diagnosis. Diagnosis requires a documented evidence of fall in pH levels in the laryngopharynx with dual-probe 24-hour ambulatory pH-metry. Aim: To study pH-metry findings in laryngopharyngeal reflux cases. Settings and Design: Study was done in a tertiary teaching hospital. Material and Methods: A total of 30 normal volunteers (Group A) and 65 patients (Group B) with complaints of hoarseness of voice for more than six weeks in the age group of 20 to 40 years were studied. A thorough ENT examination including fiberoptic laryngoscopy (FOL) was done on all cases. Group B was further divided into two subgroups. Subgroup B1 (n = 32) consisted of FOL positive and subgroup B2 (n = 33) comprised of FOL negative patients by reflux finding score. 24-hour ambulatory pH-metry was done for both groups. Results: Group A had no abnormal reflux patterns. In Subgroup B1, all 32 patients showed at least single laryngopharyngeal reflux episode over the 24-hour period. The most common pattern was 2 to 5 episodes occurring in 16/32 cases. Of the 32, five (15.6%) also had abnormal De Meester's score (gastroesophageal reflux disease [GERD] positive). In subgroup B2, 2 of 33 patients showed a typical LPR on 24-hour ambulatory pH-metry, despite showing LPRD negativity on FOL. None had an abnormal De Meester's score. Conclusion: LPRD may not coexist with GERD. Two to five reflux episodes pattern were found to be more common in LPR patients. Dual-sensor pH-metry is confirmatory for establishing diagnosis of LPRD.
Keywords: Dual channel, laryngopharyngeal reflux, pH-metry
|How to cite this article:|
Datta K, Datta R, Venkatesh M D, Dey D, Jaipurkar R. 24-hour dual-probe ambulatory pH-metry findings in cases of laryngopharyngeal reflux disease. J Laryngol Voice 2011;1:18-21
|How to cite this URL:|
Datta K, Datta R, Venkatesh M D, Dey D, Jaipurkar R. 24-hour dual-probe ambulatory pH-metry findings in cases of laryngopharyngeal reflux disease. J Laryngol Voice [serial online] 2011 [cited 2022 May 17];1:18-21. Available from: https://www.laryngologyandvoice.org/text.asp?2011/1/1/18/76132
| Introduction|| |
Laryngopharyngeal reflux disease (LPRD) is caused due to the exposure of acidic gastric contents on the sensitive laryngeal mucosa which may occur with or without a classical gastroesophageal reflux disease (GERD). It has been implicated as a contributory factor causing various otolaryngological manifestations, including laryngeal cancer.  Though many times this diagnosis is made empirically, the definitive diagnosis of LPRD requires a full dual-probe 24-hour ambulatory pH-metry study which measures the pH levels simultaneously in the esophagus and upper esophageal sphincter (UES).  However, the patterns of pH-metry findings have not been well described in literature and some controversy exists about the same. The present study was undertaken to assess the pH changes and patterns of pH-metry changes in such patients, as determined by dual-probe 24-hour ambulatory pH-metry.
| Material and Methods|| |
The present study was conducted in Gastrointestinal Physiology Laboratory at department of physiology in the institute. A total of 30 normal male volunteers (Group A) and 65 male patients (Group B) with complaints of hoarseness of voice for more than six weeks in the age group of 20 to 40 years were studied. After a thorough systemic and ENT examination including fiberoptic laryngoscopy (FOL), group B was further divided into two subgroups. Subgroup B1 (n = 32) consisted of LPRD positive and subgroup B2 (n = 33), LPRD negative, as judged by FOL and rating using the standard reflux finding score (RFS).  Twenty-four-hour dual-channel ambulatory pH-metry was done for both groups.
A history of alcohol intake and smoking formed exclusion criterion, as it was felt that they could confound the results being independent risk factors for GERD. Also, patients on drugs like alpha blockers, beta blockers, anticholinergics, morphine, dopamine, and barbiturates were excluded from the study as these drugs are known to reduce the tone of lower esophageal sphincter (LES).  Cases with neurological causes of dysphonia like vocal cord paresis/palsy and functional causes were also excluded as they were not considered relevant to the present study.
A 24-hour ambulatory, dual-channel pH meter (Mark IV gastrograph, MIC, Switzerland) with antimony electrodes (SME Medizintechnik) was used. The dual-channel probe has two separate sensors for measuring pH, separated on the same probe. The calibration for both sensors was done using buffer solution (SME Medizintechnik and Reagecon) of pH 7 and 4 before the placement of probe. The probe is passed like a nasogastric tube and placed in a manner such that the lower sensor is located in the lower esophagus, 5 cm above LES, and the upper sensor just below the UES. , The lower and UESs were localized before the insertion of the probe using a 16-channel high-resolution GI Manometer. The probe was left in situ for 24 hours along with an ambulatory data logger and patients were encouraged to follow their routine day-to-day activities including physical work, meals, sleep, etc. They followed their usual diet frequency and content and no dietary restrictions were advised. The data were transferred to a computer the following day and pH levels plotted using Win Reflux® software. The results of the pH-metry were further analyzed to quantify the number, duration, and severity of change in pH. The parameters considered were number of reflux episodes per 24-hour study, percentage of time pH <4, percentage of supine time pH <4, percentage of upright time pH <4. Each period of laryngopharyngeal reflux was defined as a drop in pH in the proximal probe to 4 preceded by a drop in esophageal pH and met the criteria laid down by Postma. 
De Meester's score is a score which is calculated for diagnosis of GERD. It takes parameters like percentage of total time pH <4, percent total upright time, and percent total supine time, with the total number of reflux episodes at the sensor 5 cm above LES. All these parameters are given varying weightage and then this score is derived. De Meester's score >14.7 was used to diagnose GERD. The score gives an idea of the reflux at the lower esophageal junction and is not to be used to interpret LPRD.
The data logger also logs the position of the patient as supine and upright and also the time when pH falls to 4. The percentage of the time when pH levels remained below 4 indicates the severity of the reflux.
All subjects were counseled about the nature of the study and informed consent was taken. All subjects were given the freedom to withdraw from the study at any time. The procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional or regional) and with the Helsinki Declarationof 1975, as revised in 2000. The data collected was then subjected to statistical analysis using ANOVA and post hoc Tukey's test.
| Results|| |
The average age of the subjects in group A and group B was 34 years (range, 23-40 years). In the control group (Group A), 24-hour pH-metry showed no abnormal reflux patterns. There was no evidence of LPR and the De Meester's score was also within normal limits.
Fibreoptic laryngoscopic findings in the patient group (Group B) showed varied etiology of the hoarseness, as shown in [Table 1]. In the patients with a positive RFS (subgroup B1), the most common finding was that of chronic laryngitis which included the picture of LPRD in isolation. In contrast, in subgroup B2, where the RFS was not significant, the most common finding was vocal nodules.
On pH-metry, patients in subgroup B1 showed at least single laryngopharyngeal reflux episode over the 24-hour period. The most common pattern was two to five episodes occurring in 50% (16/32) of cases, as in [Table 2].
The duration of the time the pH drop was less than 4 in the proximal sensor ranged from one minute to 32 minutes, with a mean time of 5.3 minutes.
In subgroup B1, the pH in the distal sensor stayed below 4 for average of approximately 6.41% of total duration, as shown in [Figure 1]. The percentage of time pH fell below 4 in upright and supine posture was analyzed for all the patients. It was found that the percentage of time reflux occurred in upright posture was significantly higher as compared with supine position (P<0.05). In the subgroup B1, five cases had a positive De Meester's Score of 14.7 and above, and hence also had concomitant pathological gastroesophageal reflux.
|Figure 1: Averaged percentage time pH < 4 in patients with LPR (subgroup B1)|
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| Discussion|| |
There are four lines of defense which are required to be broken down to show a laryngopharyngeal reflux. These are the LES, esophageal acid clearance (EAC), epithelial resistance, and the UES. The resting luminal pressure measured by manometry at the pharyngoesophageal junction (UES) is about 50 to 150 mmHg above atmospheric pressure.  LPRD requires the break of the UES barrier and may be seen with or without GERD.
LPRD is a common, underreported, and misdiagnosed condition due to the vague presenting symptoms. Diagnostic tools to diagnose LPR include a laryngeal examination, manometric studies, pH measurements, and esophagoscopy. An ambulatory dual-probe 24-hour pH-metry is considered to be the most reliable indicator and considered as 'gold standard' to diagnose such cases.  Moreover, traditional tests done for GERD are often negative in these patients, which suggest a different mechanism for laryngopharyngeal reflux.
In the present study, only 5 of 32 cases (15.62%) in group B1 were positive for significant GER. However, all the patients in this subgroup (n = 32) had at least a single episode of laryngopharyngeal reflux. This highlights that a single probe at LES to identify LPRD is insufficient and may lead to a high false negativity. A review of a series of 334 pharyngeal-positive pH studies by Postma et al. demonstrated that 38% had normal esophageal acid exposure times in the esophageal probe.  Similarly, another study conducted on pH documented that laryngopharyngeal reflux cases showed that only 12% of patients had esophagitis.  Therefore, it is concluded that use of a dual probe is essential to diagnose these cases and one should not rule out LPRD with a single-channel study. ,,
The pH plots need to be carefully interpreted, because many times, a false-positive reading may be obtained from the occurrence of a "pseudopharyngeal reflux" event.  This is due to the pharyngeal sensor not coming in contact with mucosa and reporting a lower pH. However, the pattern of pseudopharyngeal reflux events is different from that of true pharyngeal reflux events as it is not preceded by a drop in esophageal pH. Set criteria have been identified by Postma that should be met in order for an event to be defined as a pharyngeal reflux episode  and have been followed in the present study. These include a decrease in pharyngeal pH level to less than 4.0, immediately preceded by a distal esophageal exposure. Also, this fall is a rapid and sharp drop in levels rather than a gradual one. pH level decrease during eating and swallowing are disregarded
A study conducted by Ludemann et al. in 1998 showed that even minute amounts of acid as shown in animal studies have been proved to cause dramatic laryngeal injuries.  It is therefore important to regard even a single episode of LPR as pathological. In our control group, we did not record even one episode of LPR. However, the presence of laryngopharyngeal reflux in entirely asymptomatic individuals has also been reported by certain authors.  Nevertheless, current evidence suggests that even one such episode in a patient, with features suggestive of LPR, should be considered significant.  In the present series, all subjects were symptomatic in Group B and thus even a single reflux episode was considered as pathological.
In a study done in 2003  on 139 patients, 97 patients with laryngopharyngeal symptoms and 42 with gastroenterological symptoms, the results of 24-hour pH-metry revealed that the incidence of laryngopharyngeal reflux was significantly higher in the laryngopharyngeal symptom group than in the other (52 vs 38%). The patients with laryngopharyngeal reflux from both groups showed no significant differences in terms of number of acid reflux episodes, percentage of times pH was 4, and EAC. Upright and supine parameters did not show significant differences between the patient groups. However, upright acid reflux episodes were common in both groups at the lower esophageal and laryngopharyngeal segments.
In our study, we found significantly higher incidence of upright reflux than supine reflux cases of LPR. A similar result was observed by Postma et al., where patients with LPR were found to have significantly better EAC than those with GERD. These data suggest that patients with LPR have superior esophageal function in comparison with cases of GERD.  The study suggested that LPR patients are predominantly upright (daytime) refluxers, which is also significant as exclusively upright refluxers would be presumed to have less esophagitis than supine refluxers, because the total acid exposure times in the former group are less for nighttime refluxers with GERD.
In subgroup B2, two cases were found to be positive for LPR on pH-metry, though FOL findings were negative for LPR. Since they were symptomatic, there emerges a distinct possibility for existence of FOL-negative LPR entity, much like endoscopically negative GERD. It also highlights the probable existence of subclinical LPRD. This highlights the importance of dual-channel pH-metry, because it would be extremely important for diagnosis of these symptomatic cases with negative findings on FOL.
| Conclusion|| |
Laryngopharyngeal reflux may be called as a distinct entity. Cases with a suspicion of reflux as determined by flexible laryngoscopy/indirect laryngoscopy should undergo further evaluation by 24-hour ambulatory dual-probe pH-metry. All patients with LPRD, as diagnosed by FOL, showed pH-metry findings confirming LPR. Of these, only five had a concomitant GERD, which suggests that LPRD may not coexist with GERD. The most common reflux pattern in confirmed cases was between 2 to 5 episodes. The presence of symptomatic pH-metry-positive patients with negative FOL findings suggest the existence of a small subset of laryngoscopically negative LPRD.
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[Table 1], [Table 2]