Gastrointestinal
Typical GERD Symptoms and Esophageal pH Monitoring Are Not Enough to Diagnose Pharyngeal Reflux

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Background

Abnormal pharyngeal reflux of acid (PR) (as measured by pH monitoring) is associated with microaspiration, and is a good predictor of airway symptom response to medical and surgical anti-reflux therapy. However, in clinical practice the link between airway disease and Gastroesophageal reflux disease (GERD) is still based on the presence of typical symptoms (e.g., heartburn) and/or standard esophageal function testing (manometry and 24-pH monitoring). PR is rarely measured directly. We undertook this study to determine if typical symptoms and standard testing could reliably predict the presence of PR.

Methods

The study group consisted of 518 patients with suspected reflux induced airway disease evaluated from December 1998 through January 2002. Each patient completed a standardized symptom questionnaire, underwent esophageal manometry, and 24-h esophageal and pharyngeal pH monitoring. Patients were classified having abnormal pharyngeal reflux (PR+) if they had >1 episode of PR detected during pH monitoring.

Results

One hundred eighty-one patients were PR+ and 337 were PR−. The most common symptoms, namely cough (PR +73%, PR− 68%), hoarseness (PR +64%, PR− 66%), and dyspnea (PR +59%, PR− 59%) were present with similar incidence in PR+ and PR− patients. The incidence of heartburn was 54% in the PR+ and 52% in the PR− patients. Logistic regression analysis revealed that abnormal esophageal acid exposure was a predictor of PR+ (P < 0.001). Neither the presence of heartburn or specific respiratory symptoms, the pressure of the lower esophageal sphincter (LES) or upper esophageal sphincter (UES), or amplitude of esophageal contractions predicted PR+. There was substantial variability in esophageal length (UES to LES), thus the placement of the distal pH probe from the LES varied considerably (median = 13 cm, 2–20 cm). Using established normal values of acid exposure at multiple levels of the esophagus, 24% of PR+ patients had normal amounts of esophageal acid exposure.

Conclusions

Typical GERD symptoms, such as heartburn, and typical symptoms of aspiration such as hoarseness, cough, or dyspnea are not enough to positively identify PR. While patients with abnormal esophageal acid exposure are three times more likely than those with normal values to have PR, abnormal esophageal acid exposure alone does not identify all patients with PR. Therefore, relying on symptoms and standard diagnostic testing may fail to identify patients with extraesophageal reflux. Pharyngeal pH monitoring should be considered for patients with suspected reflux-induced airway disease.

Introduction

Gastroesophageal reflux disease (GERD) is a well-recognized potential etiology for many laryngeal and respiratory symptoms. However, airway symptoms such as cough, hoarseness, and dyspnea may be caused by several other etiologic factors. Thus, in patients with these symptoms it is important to be able to determine if gastroesophageal reflux is the culprit. Although the combination of symptoms and traditional diagnostic tests of esophageal function have been reported to help determine whether reflux in a given patient is the cause for respiratory symptoms, a gold standard for this diagnosis remains elusive and the work-up of these patients varies widely among centers.

Heartburn and regurgitation is often absent in patients with airway disease even though objective evidence of GERD is present when tested [1, 2, 3]. These so-called “silent refluxers” are difficult to detect and require a high index of suspicion. For this reason, most authors have advocated the liberal use of 24-h pH monitoring in these patients. While considered the gold standard for confirming the presence of GERD, esophageal pH monitoring has certain limitations in this population. First, because of the high prevalence of heartburn in this country (approximately 20% of American adults have typical reflux symptoms at least once a week) [4], many patients who present with respiratory symptoms will have a positive pH study by happenstance but that finding does not necessarily mean reflux is the cause of the airway symptoms. Second, respiratory diseases may be the cause, not the result, of gastroesophageal reflux. Airway disease may change intrathoracic pressure, symptoms such as cough may transiently relax the LES, bronchodilators relax the LES, and anatomy and dynamics of the diaphragm are changed by long standing lung disease. Lastly, it is possible that patients who reflux only physiological amounts to the distal esophagus may have reflux extend to the upper esophagus/pharynx. Thus, aspiration may occur even in the presence of normal amounts of gastroesophageal reflux.

Patti and colleagues introduced the concept of measuring reflux in the upper esophagus as a proxy for laryngopharyngeal reflux. They showed that patients with respiratory symptoms caused by GERD had substantially greater amounts of acid reflux to the proximal esophagus [5]. Admittedly, there are likely different mechanisms by which GERD can cause respiratory symptoms (microaspiration, vagal nerve stimulation from esophageal acid exposure, etc.). We have used pharyngeal monitoring, with a probe just above the UES, as an indirect indication of microaspiration in an attempt to improve on the identification of laryngopharyngeal reflux. This provides additional diagnostic information in patients with possible reflux induced respiratory disease. We found that the presence of reflux to the level of the pharynx is a very good predictor of response to both medical and surgical therapy [6, 7]. Certainly, many patients with GERD related airway disease will not have pharyngeal reflux. The presence of pharyngeal reflux, however, provides strong evidence for this association. In this paper we examined the relationship between GERD, airway symptoms, and the findings of standard esophageal monitoring. We compared the accuracy of these diagnostic studies to predict aspiration as measured by pharyngeal pH monitoring in a large number of patients with symptoms of airway disease. In other words, is pharyngeal pH monitoring likely to have independent value if added to traditional diagnostic methods?

Section snippets

Methods

Our study population consisted of 518 consecutive patients referred to our esophageal function laboratory with laryngeal or respiratory symptoms thought to be a result of reflux between December 1998 and January 2002. All patients underwent evaluation via: 1) a self-administered questionnaire about symptoms presence, severity and frequency, 2) esophageal manometry, and 3) 24-h esophago-pharyngeal pH monitoring.

Results

Sixty five percent of our patients (337/518) were found to have normal pharyngeal acid exposure (0 episodes = 227 patients, 1 episode = 59 patients). Thirty-five percent (187/518) patients were found to have abnormal pharyngeal acid exposure (PR+). The median number of episodes within this group was four (range 2–63).

Discussion

We have reported that direct measurement of pharyngeal pH, although not perfect, improves substantially in our ability to diagnose positively the association between reflux and airway disease [6, 7, 9, 11]. Indeed, airway symptoms in patients with abnormal pharyngeal acid exposure are more likely to respond to medical [7] and surgical therapy [7] than in patients with normal pharyngeal exposure. Because direct measurement of pharyngeal reflux is more demanding and complex, we wished to explore

Conclusions

Clinical history and individual symptoms, while important for creating a suspicion of reflux-induced airway disease, cannot predict the presence of PR and microaspiration with accuracy. This is particularly true of typical symptoms like heartburn that are often absent in these patients, and the typical symptoms of airway disease that are almost always present. Similarly, although manometry has an important role in the evaluation of these patients, its findings do not help differentiate those in

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