Diagnosis of Laryngopharyngeal Reflux: Past, Present, and Future-A Mini-Review

Abstract

Laryngopharyngeal reflux (LPR) is a variant of gastroesophageal reflux disease (GERD) in which gastric refluxate irritates the lining of the aerodigestive tract and causes troublesome airway symptoms or complications. LPR is a prevalent disease that creates a significant socioeconomic burden due to its negative impact on quality of life, tremendous medical expense, and possible cancer risk. Although treatment modalities are similar between LPR and GERD, the diagnosis of LPR is more challenging than GERD due to its non-specific symptoms/signs. Due to the lack of pathognomonic features of endoscopy, mounting evidence focused on physiological diagnostic testing. Two decades ago, a dual pH probe was considered the gold standard for detecting pharyngeal acidic reflux episodes. Despite an association with LPR, the dual pH was unable to predict the treatment response in clinical practice, presumably due to frequently encountered artifacts. Currently, hypopharygneal multichannel intraluminal impedance-pH catheters incorporating two trans-upper esophageal sphincter impedance sensors enable to differentiate pharyngeal refluxes from swallows. The validation of pharyngeal acid reflux episodes that are relevant to anti-reflux treatment is, therefore, crucial. Given no diagnostic gold standard of LPR, this review article aimed to discuss the evolution of objective diagnostic testing and its predictive role of treatment response.

Keywords: hypopharyngeal multichannel intraluminal impedance-pH; laryngopharyngeal reflux; pharyngeal acid reflux episodes.

Figure 1

(A) In patients with suspected LPR and concomitant typical reflux symptoms, the pre-testing probability of a positive pH is high; thus, a positive composite pH may not predict laryngeal symptom response to PPI therapy. It is likely that factors other than reflux may also contribute to the laryngeal symptoms. (B) In patients with suspected isolated LPR symptoms, the pre-testing probability of a positive composite pH is low. Thus, a positive composite pH may predict laryngeal symptom response to PPI therapy and acid is likely the cause of the laryngeal symptoms [40]. LPR, laryngopharyngeal reflux; PPI, proton pump inhibitors.

Figure 2

An example of pharyngeal acid reflux episodes detected by 24 h ambulatory hypopharyngeal multichannel intraluminal impedance-pH test. The mixed gas–liquid refluxate can be tracked from the distal esophagus along the entire esophagus to the hypopharynx [54]. The arrow indicates retrograde changes of pH and impedence levels.

Figure 3

Compared to LPR patients with concomitant typical reflux symptoms (A), patients with isolated LPR symptoms (B) had fewer pharyngeal acid reflux episodes and a lower sensory response to the acid perfusion test in the distal esophagus while showing a similar symptom response rate to PPI therapy, suggesting a reflexogenic mechanism for symptoms generation [10]. The downward solid-line arrow means decrease; the oblique dotted-line arrow means vago-vagal reflex or referred pain. LPR, laryngopharyngeal reflux; PPI, proton pump inhibitors.

Figure 4

Management protocol of personalized approach for suspected LPR. LPR, laryngopharyngeal reflux; CXR, chest X-ray; LDCT, low-dose computed tomography of lungs; TNE, transnasal esophagoscopy; EGD, esophagogastroduodenoscopy; PFT, pulmonary function test; ACEI, angiotensin converting enzyme inhibitors; CTRS, concomitant typical reflux symptoms; ILPRS, isolated LPR symptoms; HRM, high resolution esophageal manometry; HMII-pH, hypopharyngeal multichannel intraluminal impedance-pH; PPI, proton pump inhibitors.