Laryngopharyngeal reflux: More questions than answers
ABSTRACTLaryngopharyngeal reflux (LPR), an extraesophageal variant of gastroesophageal reflux disease, is associated with hoarseness, chronic cough, throat-clearing, sore throat, and dysphagia. But because these symptoms are nonspecific, laryngoscopy is often done and the diagnosis of LPR is considered if edema, erythema, ventricular obliteration, pseudosulcus, or postcricoid hyperplasia is noted. Most patients with suspected LPR are given a 2-month trial of a proton pump inhibitor. Yet there is still little or no solid evidence on which to base the diagnosis or the treatment of LPR. We review the current understanding of the pathophysiology and discuss current diagnostic tests and treatment regimens in patients with suspected LPR.
KEY POINTS
- Laryngoscopy has high interrater variability, and results of pH monitoring do not reliably predict who will respond to treatment.
- A proton pump inhibitor twice daily for 2 months is currently recommended for patients with laryngeal signs and symptoms. If the condition responds to therapy, tapering to once-daily therapy and then to minimal acid-suppression to control symptoms is prudent.
- Patients whose symptoms do not respond to a proton pump inhibitor are unlikely to benefit from surgery. Other diagnoses should be entertained, while the drug is tapered to prevent rebound acid reflux.
Laryngoscopy is nonspecific and subjective
Because the key symptoms of LPR are nonspecific, many patients who present to an otolaryngologist undergo laryngoscopy, mainly to rule out malignancy. Once cancer is ruled out, many patients are given a diagnosis of LPR.
Furthermore, Branski et al17 performed transoral rigid laryngoscopy with videorecording in 100 consecutive patients presenting with a chief complaint of dysphonia. Five board-certified otolaryngologists individually viewed each recording, scored the degree of erythema and edema, and assessed the likelihood that LPR played a role in dysphonia and the severity of the LPR findings. The physicians’ ratings showed considerable interobserver variability. In other words, this study showed that laryngeal findings are often nonspecific and that the laryngoscopic diagnosis of LPR tends to be subjective.17
The Reflux Finding Score. Concerned by the lack of consistency in the diagnosis of LPR, Belafsky et al18 created a scoring system for documenting the physical findings and severity of disease on a standardized scale. Their Reflux Finding Score is based on eight laryngoscopic findings: subglottic edema, ventricular edema, erythema, vocal cord edema, diffuse laryngeal edema, hypertrophy of the posterior commissure, granuloma or granulation tissue, and thick endolaryngeal mucus. The total score can range from 0 (best) to 26 (worst).
In 40 patients with LPR confirmed by pH monitoring, the mean score was 11.5, compared with 5.2 in 40 age-matched controls. The authors calculated they could be 95% certain that a person with a score higher than 7 has LPR.18
However, this diagnostic method has not been validated in a large-scale randomized trial and so has yet to be incorporated into routine otolaryngology practice.
Ambulatory pH monitoring is not so golden for diagnosing LPR
Although pH monitoring was once the gold standard for diagnosing reflux, it has since been shown to be unreliable in patients who have laryngeal symptoms.4
How high or low in the esophagus the probe is placed is clearly critical for useful results. 4 But the test is subject to variability: different physicians place the probe in different locations, and the probe may shift. Another problem is that reflux may occur during untested periods.19
A pH of less than 4 in the esophagus had originally been shown to have high sensitivity and specificity,20 but Reichel and Issing21 suggested using a pH of less than 5 as the cutoff, which would identify more patients as having LPR. Further trials are needed to more precisely determine the pH threshold for the diagnosis of LPR.
Enthusiasm is waning for pharyngeal pH monitoring
In LPR, it was initially thought that pH monitoring in the pharynx was more accurate than in the distal or proximal esophagus.
Shaker et al22 monitored the pH in the pharynx, proximal esophagus, and distal esophagus in four groups: 14 patients who had both laryngeal signs and symptoms, 12 patients who had laryngeal symptoms only, 16 patients who had GERD but no laryngeal symptoms, and 12 healthy volunteers. They found that pharyngeal reflux was more frequent and in greater quantity in patients with laryngeal signs and symptoms than in the other groups. This study suggested that pharyngeal pH monitoring may be useful in diagnosing LPR in patients who have laryngeal signs and symptoms.
However, hypopharyngeal pH monitoring has several problems. One issue is that, even in this trial, 2 of 12 healthy volunteers had episodes of pharyngeal reflux.22 In other studies, the rate of false-positive results ranged from 7% to 17%.23,24 Additionally, in 12 previous studies, only 54% of 1,217 patients with suspected LPR had esophageal acid exposure, regardless of where the pH probe was placed.25
More importantly, another study found that patients with pharyngeal reflux documented by pH monitoring were no more likely to respond to acid-suppressive therapy than patients with no documented reflux.26 These findings dampen the enthusiasm for pharyngeal pH monitoring in LPR.
Impedance monitoring on therapy may be useful in refractory cases
Esophageal impedance monitoring, a newer test, uses a catheter that measures electrical resistance (impedance) between different points along the esophagus. Thus, it can detect the reflux of acid and nonacid liquid or gaseous material.
Pritchett et al27 performed esophageal impedance and pH monitoring in 39 patients who were on twice-daily PPI therapy and then evaluated the same patients with wireless pH monitoring while they were off therapy. The most prevalent complaint in the study group was cough (56%), followed by heartburn (18%) and sore throat (10%).
Of the 39 patients, 25 (64%) had normal results on impedance/pH monitoring while on therapy, ruling out reflux. On pH monitoring off therapy, 28 (72%) of the 39 patients had abnormal results; this group included 13 (93%) of the 14 patients who had abnormal results on impedance/pH monitoring while on therapy. The authors recommended on-therapy testing with impedance monitoring in patients with refractory reflux, since it provides more useful clinical information.27 If the results of impedance/pH monitoring are negative in these patients, a diagnosis other than reflux should be considered.
