Introduction
Laryngopharyngeal reflux (LPR) is defined as the reflux of gastric content into the larynx and pharynx [
Vakil et al. 2006]. According to the Montreal Consensus Conference, the manifestations of gastroesophageal reflux disease (GERD) have been classified into either esophageal or extraesophageal syndromes and, among the latter ones, the existence of an association between LPR and GERD has been established [
Vakil et al. 2006]. LPR may be manifested as laryngeal symptoms such as cough, sore throat, hoarseness, dysphonia and globus, as well as signs of laryngeal irritation at laryngoscopy [
Vaezi et al. 2003]. Laryngopharyngeal symptoms are increasingly recognized by general physicians, lung specialists and ear, nose and throat (ENT) surgeons [
Richter, 2000]. In particular, there is a large number of data on the growing prevalence of laryngopharyngeal symptoms in up to 60% of GERD patients [
Jaspersen et al. 2003;
Koufman et al. 1996;
Richter, 2004]. In addition, some studies support the notion that GERD, as well as smoking and alcohol use, are risk factors for laryngeal cancer [
Freije et al. 1996;
Vaezi et al. 2006a]. According to the Montreal Consensus Conference, some critical issues have been highlighted, as follows:
1.
the rarity of extraesophageal syndromes occurring in isolation without a concomitant manifestation of typical GERD symptoms (i.e. heartburn and regurgitation);
2.
extraesophageal syndromes are usually multifactorial with GERD as one of the several potential aggravating cofactors;
3.
data supporting a beneficial effect of reflux treatment on the extraesophageal syndromes are weak [
Vakil et al. 2006].
Subsequently, the American Gastroenterological Association guidelines for GERD recommended against the use of acid-suppression therapy for acute treatment of patients with potential extraesophageal GERD syndromes (laryngitis, asthma) in the absence of typical GERD symptoms [
Kahrilas et al. 2008].
The specific reflux-related mechanisms leading to laryngopharyngeal symptoms and signs are currently unknown. Acidity of gastric juice alone may cause tissue damage at the upper airway level [
Wiener et al. 2009], but several studies have demonstrated that this is not the only etiologic factor involved in the pathogenesis of laryngopharyngeal reflux disease (LPRD). Indeed, recently, Pearson and colleagues [
Pearson et al. 2011] highlighted that, although acid can be controlled by proton pump inhibitor (PPI) therapy, all of the other damaging factors (i.e. pepsin, bile salts, bacteria and pancreatic proteolytic enzymes) remain potentially damaging on PPI therapy and may have their damaging ability enhanced. Particularly, pepsin can damage all extragastric tissues at pH up to 6 [
Ludemann et al. 1998]. Of note, detectable levels of pepsin have been shown by Johnston and colleagues to remain in laryngeal epithelia after a reflux event [
Johnston et al. 2007a]. The same authors described that pepsin is taken up by laryngeal epithelial cells by receptor-mediated endocytosis [
Johnston et al. 2007b], thus it may represent a novel mechanism, besides its proteolytic activity alone, by which pepsin could cause GERD-related cell damage independently of the pH of the refluxate [
Pearson et al. 2011].
To date, the diagnosis of LPR is a very difficult task and several controversies remain regarding how to confirm LPRD. Laryngoscopic findings, especially edema and erythema, are often used to diagnose LPR by ENT surgeons [
Vaezi et al. 2003]. However, it should be pointed out that, in a well-performed prospective study, laryngoscopy revealed one or more signs of laryngeal irritation in over 80% of healthy controls [
Milstein et al. 2005]. Moreover, it has been demonstrated that accurate clinical assessment of LPR is likely to be difficult because laryngeal physical findings cannot be reliably determined from clinician to clinician, and such variability makes the precise laryngoscopic diagnosis of LPR highly subjective [
Branski et al. 2002]. The sensitivity and specificity of ambulatory pH monitoring as a means for diagnosing GERD in patients with extraesophageal reflux symptoms have been challenged [
Vakil et al. 2006]. Furthermore, the sensitivity of 24-h dual-probe (simultaneous esophageal and pharyngeal) monitoring has ranged from 50% to 80% [
Koufman, 1991]. Recently, the availability of multichannel intraluminal impedance and pH monitoring (MII-pH) seems to show better performances in diagnosing extraesophageal manifestations of GERD thanks to its ability to evaluate acid and nonacid refluxes other than their proximal extension [
Carroll et al. 2012;
Savarino et al. 2009;
Sifrim et al. 2005;
Tutuian et al. 2006]. However, the poor sensitivity and specificity of all currently available diagnostic tests for LPR has been highlighted by several review articles [
Altman et al. 2011;
Katz et al. 2013;
Vaezi et al. 2003]. In a population of patients with laryngoscopic findings of LPR, our group showed that MII-pH confirmed GERD diagnosis in less than 40% of patients [
de Bortoli et al. 2012], thus highlighting the critical issue of nonspecific symptoms and laryngoscopic findings of LPR [
Zerbib and Stoll, 2010]. New promising diagnostic techniques have been developed for extraesophageal reflux syndromes, in particular, an immunologic pepsin assay (Peptest
TM), which has been shown to be a rapid, sensitive, and specific tool [
Bardhan et al. 2012;
Samuels and Johnston, 2010], and a new pH pharyngeal catheter (manufactured by Restech, San Diego, CA, USA) that recent study documented as highly sensitive and minimally invasive device for the detection of liquid or vapors of acid reflux in the posterior oropharynx [
Sun et al. 2009]. However, limited data on their diagnostic accuracy and potential clinical application are available.
In this review, we will discuss the current treatment options in patients with LPRD and their pro/cons, and we will provide a perspective on the development of new therapies.
Surgical therapy
Laparoscopic antireflux surgery (LARS) is a well-established and highly efficacious treatment for GERD and has been shown to provide durable relief from the typical reflux symptoms [
Papasavas et al. 2003]. In particular, the surgical therapy is helpful in allowing the majority of patients suffering from GERD to discontinue acid suppression therapy, to achieve resolution of associated esophagitis, and to arrest or perhaps even reverse the metaplasia/dysplasia induced by frequent exposure of the esophageal mucosa to gastric contents [
Oelschlager et al. 2003;
Parise et al. 2011;
Rossi et al. 2006].
Few controversial data are available about surgical outcome of LPRD. A clinical prospective study in patients with LPRD selected for surgical treatment, in which the symptoms and signs had responded to antireflux medication, the laparoscopic fundoplication was found to be an effective and safe treatment of LPRD [
Sala et al. 2008]. Moreover, in patients with objective evidence of GERD, LARS was effective in relieving LPR symptoms [
Catania et al. 2007;
Lindstrom et al. 2002]. On the other hand, LARS has shown disappointing results in controlling LPR-related symptoms in patients unresponsive to aggressive PPI therapy [
Swoger et al. 2006]. Likewise, prior studies demonstrated a poor surgical outcome for the resolution of laryngeal symptoms especially in PPI nonresponders [
Chen and Thomas, 2000;
So et al. 1998].
It is necessary for the surgeon to perform a detailed workup including esophagogastroduodenoscopy, esophageal manometry, gastric emptying test, MII-pH or pH-metry, and upper gastrointestinal radiography for all patients scheduled for LARS, primarily to exclude malignancy and motility problems such as achalasia and gastroparesis and then to detect a cause–effect relation between pathological acid exposure time and laryngeal symptoms/findings [
Zerbib et al. 2013].
The patients who are selected for LARS must be informed that laparoscopic fundoplication may correct the underlying mechanical defect but they should be warned that the response of their laryngeal symptoms to surgery would still be uncertain [
Chen and Thomas, 2000]. The LARS approach could be more strongly suggested if patients showed a complete relief of laryngeal symptoms during PPI therapy or if 24-h pathophysiological studies demonstrated that nonacid reflux events are predominant. Moreover, the surgeon must carefully select patients before suggesting LARS and a Regional Referral Center specialized in esophageal surgery is recommended to reduce postoperative complications. In this matter, patients should be warned of possible postoperative dysphagia, bloating, flatulence, diarrhea, and recurrence of the symptoms [
Richter, 2013].
To date, the clinical guidelines of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) recommend antireflux surgery for patients who: (1) have failed or are unable to tolerate medications; (2) have significant extraesophageal manifestation such as aspiration, asthma, or cough; (3) have the complication of GERD-like peptic stricture.
Speech therapy and rehabilitation techniques
Actually, newer treatment options are considered as alternative possibilities in the treatment of GERD, and in particular LPRD, deserving careful investigations.
The LES, surrounded by diaphragmatic muscle, prevents gastroesophageal reflux and, indirectly, LPR. It is believed that synergy of the function of the LES and its surrounding crura of the diaphragm, when superimposed, are of importance for competent closure [
Mittal and Balaban, 1997]. When these structures became incompetent, gastric contents may be traced back along the esophagus and cause LPR. The importance of the diaphragm muscle is also demonstrated by experimental studies: even after surgical removal of LES, a pressure zone is detectable due to contractions of the crura of the diaphragm [
Klein et al. 1993]. Like any other striated muscle of the body, the diaphragm muscle should be amenable to improved performance by physical exercise. For these reasons, alternative therapies for the treatment of reflux disease have recently been studied, and in particular speech therapy/relaxation techniques such as training of the diaphragm muscle with maneuvers and breathing exercises have been considered.
In the literature, there are few scientific publications regarding the rehabilitation treatment of reflux and in some centers such therapy is proposed in an empirical way without medical evidence-based support. In addition, the proposed rehabilitation treatments have been studied in relation to the symptoms and not in relation to the demonstration of a real reduction of acid reflux events.
One of the most characteristic symptoms of the LPRD is globus pharyngeus [
Chevalier et al. 2003;
Park et al. 2006;
Tokashiki et al. 2002]. Given the benign nature of the condition and the recent notion that GERD is a major cause of globus, empirical therapy with high-dose PPIs has been tried [
Lee and Kim, 2012]. In patients nonresponsive to this therapy, when GERD was demonstrated by tests such as endoscopy, MII-pH monitoring, and manometry, alternative therapies may be considered, including speech and language techniques. In some studies, a number of exercises to relieve pharyngolaryngeal tension, voice exercises, and vocal tract voice hygiene to relieve discomfort and tension have provided significant results in reducing persistent globus symptoms [
Khalil et al. 2003]. However, further research is needed to determine whether speech and language rehabilitation techniques have a specific effect or whether patients with globus pharyngeus simply benefit from general attention and reassurance [
Millichap et al. 2005].
More recently laryngeal rehabilitation therapies have been applied in cases of chronic cough associated with GERD, with significant symptom improvement [
Pacheco et al. 2013]. Carvalho de Miranda Chaves and colleagues [
Carvalho de Miranda Chaves et al. 2012] showed, by performing esophageal manometry, that inspiratory muscle training incremented LES pressure in patients with GERD after an 8-week program. Eherer and colleagues [
Eherer et al. 2012], in a randomized controlled study, showed that actively training the diaphragm muscle by breathing exercise, can improve reflux disease. Quality-of-life scales, pH-metry, and on-demand PPI usage were assessed to monitor patients in the short- and long-term follow up [
Eherer et al. 2012].
All of these studies confirm that the rehabilitation therapy that acts on the crural diaphragm is a potential alternative method to treat GERD and LPRD, reducing long periods of drug treatment or surgical procedures. These findings need to be confirmed in further studies with a larger sample, longer follow up and controlled with quality of life scores and instrumental examinations such as MII-pH.
Discussion
The effects of the symptoms of both GERD and LPRD are believed to be secondary to the irritative effects of gastric refluxate on the sensitive esophageal and pharyngeal mucosa [
Bough et al. 1995]. The optimal treatment of LPRD is neither standardized nor validated [
Hogan and Shaker, 2001]. This is due to the multifactorial nature of the disease, whose symptoms are nonspecific, and to the difficulty of making an accurate diagnosis of LPRD for the poor sensitivity and specificity of all currently available diagnostic tests. New techniques (i.e. Peptest, Restech) may be of great interest to improve the diagnostic accuracy of LPRD, paving the way towards the development of new targeted therapies. Indeed, pepsin inhibitors and pepsin receptor antagonists are the new possible frontiers of research [
Pearson et al. 2011].
As we discussed in this review, the management of LPRD can be divided into lifestyle modifications, medical and/or surgical treatment. Behavior changes and lifestyle modifications are considered the first-line treatment with the lowest possibility of side effects. Weight loss, smoking cessation, alcohol avoidance, meal habit modifications, and head elevation during sleep need to be strongly suggested to patients. As to the medical therapy, currently, the treatment is focused on increasing the pH of the refluxate, thus it is recommended to start with PPIs twice daily for a period of 8–12 weeks. Refractory patients with objective evidence (reflux monitoring) of ongoing reflux as the cause of symptoms should be considered for alternative therapies, such as visceral pain modulators or laparoscopic antireflux surgery. The surgical approach needs to be tailored for each patient and very carefully considered. Up and coming results are available with speech therapy but these results need to be evaluated in future trials. Surgery should be indicated in select patients, in which high-volume refluxate and incompetence of LES are demonstrated with esophageal pathophysiological evaluations.
To date, we can conclude that, although many studies are still needed to assess the optimal therapeutic management in LPRD, a multidisciplinary approach including providers in ENT, pulmonology, and gastroenterology evaluations is recommended to improve diagnosis and therapy in patients with LPRD.