What's the next step in managing a patient with a 6-month history of lower thoracic burning sensation, regurgitation when lying down, and normal endoscopy results, who hasn't improved with Proton Pump Inhibitor (PPI) therapy?

Management of Persistent Lower Thoracic Burning with Regurgitation Despite PPI Therapy

High resolution manometry (HRM) is the most appropriate next step for a patient with persistent lower thoracic burning sensation, regurgitation when lying down, and normal endoscopy who hasn't responded to PPI therapy.

Rationale for High Resolution Manometry

When a patient presents with persistent reflux symptoms despite PPI therapy and has a normal endoscopy, the American Gastroenterological Association (AGA) recommends esophageal manometry as the next diagnostic step 1, 2. This is because:

1. Rule out motility disorders: HRM can identify esophageal motility disorders that may mimic GERD symptoms, including:

   • Achalasia (particularly type II with pan-esophageal pressurization)
   • Esophageal spasm
   • Ineffective esophageal motility
   • Esophagogastric junction outflow obstruction

2. Assess anti-reflux barrier function: HRM evaluates the integrity of the lower esophageal sphincter and identifies hiatal hernias that may contribute to reflux 3.

3. Guide further testing: HRM results help determine the appropriate parameters for subsequent pH or impedance-pH monitoring 1, 2.

Why Other Options Are Less Appropriate

• Continuing PPI therapy (option A): Not recommended when there's been no response after 6 months. The AGA clearly states that after a normal endoscopy in a PPI non-responder, priority should be given to identifying alternative conditions for which effective therapy exists 1.

• CT thorax/abdomen (option C): Not indicated as the next step for suspected esophageal motility disorders or reflux disease with normal endoscopy.

• Isotope study for gastric emptying (option D): While gastroparesis can coexist with GERD, manometry should precede gastric emptying studies in the diagnostic algorithm when regurgitation is a prominent symptom 2.

• Prokinetic + baclofen (option E): Initiating this combination without confirming the underlying diagnosis is premature. Baclofen may help with regurgitation but should be used after proper diagnosis 2. Metoclopramide (a prokinetic) carries risks of extrapyramidal symptoms and tardive dyskinesia 4.

Diagnostic Algorithm for PPI-Refractory Symptoms

1. Endoscopy (already completed and normal in this case)
2. High resolution manometry (next appropriate step)
3. Ambulatory reflux monitoring (based on manometry results):
   • pH monitoring off PPI if manometry is normal
   • pH-impedance monitoring on PPI if manometry suggests GERD

Clinical Pearls and Caveats

• Regurgitation when lying down is particularly suggestive of a mechanical issue at the gastroesophageal junction that may be identified on HRM 1, 3.

• Up to 20% of patients with reflux symptoms may have a motility disorder that explains their symptoms 5.

• Normal endoscopy does not rule out GERD, but does necessitate objective confirmation through physiologic testing before escalating therapy 1, 2.

• HRM findings can significantly alter management decisions - identifying achalasia or esophageal spasm may lead to consideration of endoscopic or surgical interventions rather than continued medical therapy 6.

• Patients with normal esophageal studies who continue to have symptoms may have functional heartburn or reflux hypersensitivity, which respond better to neuromodulators than to acid suppression 2.