In a 68-year-old man with obesity, diabetes mellitus, longstanding GERD, worsening heartburn despite proton pump inhibitor therapy, frequent regurgitation, and post‑prandial chest pain with a normal esophagogastroduodenoscopy, which diagnostic study is required to confirm achalasia?

Esophageal Manometry is Required to Confirm Achalasia

High-resolution esophageal manometry is the necessary diagnostic study to confirm achalasia in this patient. 1

Why Manometry is the Gold Standard

The American Gastroenterological Association explicitly states that manometry is indicated to establish the diagnosis of dysphagia when mechanical obstruction cannot be found, particularly when achalasia is suspected. 1 This patient's clinical presentation—progressive regurgitation, postprandial chest pain, and PPI-refractory symptoms despite a normal EGD—raises strong suspicion for a motility disorder rather than reflux disease. 2

High-resolution manometry (HRM) remains the gold standard for diagnosing achalasia because it demonstrates the two cardinal features required for diagnosis: 1, 3

• Impaired deglutitive lower esophageal sphincter (LES) relaxation (elevated integrated relaxation pressure >15 mm Hg)
• Absent peristalsis in the esophageal body

The 2024 AGA guidelines emphasize that HRM is essential not only for confirming achalasia but also for defining the achalasia subtype (I, II, or III) according to the Chicago Classification, which is crucial for phenotype-directed treatment and optimal patient outcomes. 1

Why the Other Options Are Insufficient

Repeat EGD (Option 1)

A repeat EGD is not necessary since the patient had a normal study 6 months ago that excluded masses and Barrett's esophagitis. 2 Endoscopy can suggest achalasia (frothy retained secretions, puckered gastroesophageal junction) but cannot confirm the diagnosis, which requires demonstration of abnormal esophageal motility. 1

Barium Esophagram (Option 2)

While a timed barium esophagram can show retention of barium and structural changes suggestive of achalasia, it only suggests the diagnosis and cannot confirm it. 1 The AGA guidelines position barium studies as complementary tests that should be performed alongside—not instead of—manometry in the comprehensive workup. 1

Endoscopic Ultrasound (Option 3)

Endoscopic ultrasound has no role in diagnosing primary achalasia. 1 EUS is reserved for evaluating EGJ outflow obstruction when pseudoachalasia from infiltrative disease or malignancy is suspected, which is not the primary concern in this straightforward presentation. 1

Esophageal pH Testing (Option 5)

pH monitoring is not indicated for diagnosing achalasia and cannot confirm or exclude motility disorders. 1, 3 The AGA explicitly states that manometry should not be used for diagnosing GERD, and conversely, pH testing should not be used for diagnosing achalasia. 1 pH testing would be appropriate only after manometry confirms normal motility and true refractory reflux is suspected. 2

Clinical Algorithm for This Patient

Given PPI failure with regurgitation and postprandial chest pain after normal endoscopy, the diagnostic pathway should proceed as follows: 2, 3

1. Perform high-resolution esophageal manometry to evaluate for achalasia or other major motility disorders
2. Obtain timed barium esophagram concurrently to assess structural changes and confirm outflow obstruction 1
3. Consider FLIP (functional luminal impedance planimetry) as an adjunct if manometry findings are equivocal 1

Critical Pitfall to Avoid

The most catastrophic error would be proceeding to antireflux surgery without first performing manometry to exclude achalasia. 1, 3 The AGA guidelines emphasize that manometry is mandatory before antireflux surgery if there is any question of an alternative diagnosis, especially achalasia, because performing fundoplication on an achalasia patient leads to devastating outcomes. 1