Diagnosing reflux disease means deciding when symptoms are enough to treat and when the esophagus must be examined directly.
Endoscopy is not indicated in all patients with suspicious GERD, because in more than 50% of the cases patients with typical symptoms of GERD such as heartburn and regurgitation do not have visible GERD; this is NERD (non-erosive reflux disease).
Several tests are available and answer different questions: imaging, EGDS (esophagogastroduodenoscopy), 24-hour pH-metry, 24-hour pH-impedance and manometry. Testing is not reserved for difficult cases; up-front esophageal testing is used for atypical symptom categories and PPI non-responders, and before long-term medical management or anti-reflux surgery.
EGDS
EGDS is useful for the differential diagnosis of erosive esophagitis, ulceration, Barrett esophagus and neoplasia.
The indications for EGDS in the diagnosis of GERD are:
- atypical symptoms after specialist diagnosis
- typical symptoms with co-occurrence of alarm symptoms
- typical symptoms that persist after therapy
- sudden occurrence of symptoms after 45 years of age
- relapsing symptoms
- follow-up of Barrett esophagus
Age alone does not decide the matter, and EGDS is not routinely indicated in patients younger than 45 years of age who have typical symptoms and no alarm features.
The diagnosis of GERD based on EGDS is positive if the patient has:
- grade B, C or D erosive esophagitis
- stenosis
- Barrett esophagus
Reflux monitoring and manometry
Ambulatory reflux monitoring measures the esophageal acid exposure time (AET), the percentage of the recording spent below pH 4. By the Lyon consensus, an AET above 6% is conclusive evidence of pathological reflux, an AET below 4% is normal, and values in between are inconclusive. These measurements matter because they predict the response to acid suppression and to anti-reflux surgery.
Manometry assesses peristaltic function and excludes alternative motility disorders such as achalasia. It is also performed before anti-reflux surgery.