diagnosis of extraesophageal reflux disease

Diagnosis of eerd
There is, at present, no ideal diagnostic tool for laryngopharyngeal reflux detection. Various methods including pH monitoring, intraluminal impedance, scintigraphy, ultrasound, barium studies, fluoroscopy, and esophageal biopsy have been used both in adults and children. Results produced by these techniques, however, are not reproducible in patients with PLPR. The current gold standard diagnostic test for laryngopharyngeal reflux is the dual probe 24-hour pH monitoring. It is, however, an invasive test of low sensitivity, with an incidence of false-negative results reaching as high as 50% . The proximal probe is placed 2 cm above the upper esophageal sphincter and can be confirmed endoscopically. ( Jamieson JR, et al , 2013)
Manometry is often required to confirm positioning of the distal probe, which is normally placed 5 cm above the lower esophageal sphincter. Normal pH values of the distal esophagus have been well established in the literature . However, much controversy still surrounds what constitutes PLPR. The criteria used to diagnose GERD cannot be applied to PLPR because baseline pH values for the hypopharynx are still unknown. Some authors regard any number of episodes of pharyngeal reflux as positive evidence of laryngopharyngeal reflux .The total amount of time of acid exposure, expressed as a percentage of a 24-hour period, has been suggested by Postma et al as a suitable diagnostic criterion. Although widely used, pH monitoring does have limitations. For example, the probe does not detect nonacidic or gaseous reflux. Furthermore, ambulatory monitoring is time consuming, invasive, and not tolerated well by children. The technique of multichannel intraluminal impedance measures changes in electrical conductivity between 2 electrodes during the passage of a bolus of liquid, food, or gas within the esophagus .( Postma GN, et al , 2002)
Impedance catheters are placed within the esophagus and have multiple electrodes to allow detection of the direction and speed of the bolus. Further studies are required to validate the use of this modality as a diagnostic tool, but preliminary results are encouraging for the use of this technique in the paediatric population. Scintigraphy is useful for demonstrating reflux and for estimating gastric emptying. However, the correlation of scintigraphy with pH monitoring is poor . Esophageal biopsy and bronchoalveolar lavage does not correlate with endoscopic findings . Carr et al found that 65% of their study cohort who had GERD had normal esophageal biopsies. Furthermore, they found that 40% had normal laryngotracheal appearance on endoscopy.( Mandell DLet al ,2004)