How do you differentiate between Gastroesophageal Reflux (GER) and functional dyspepsia in a patient?

Differentiating GER from Functional Dyspepsia

Ask the patient to identify their single most predominant symptom—if heartburn or acid regurgitation occurring more than once weekly dominates, treat as GERD; if epigastric pain, burning, or discomfort centered in the upper abdomen dominates, treat as functional dyspepsia. 1

Core Symptom-Based Distinction

The American Gastroenterological Association provides clear definitional boundaries that should guide your clinical approach:

• GERD is characterized by: Heartburn (burning sensation starting in the epigastrium but radiating to the chest) or acid regurgitation occurring more than once weekly 1, 2
• Functional dyspepsia is characterized by: Epigastric pain, burning, early satiation, or postprandial fullness centered in the upper abdomen, lasting more than 8 weeks 1, 2

The critical clinical maneuver is asking patients to identify their predominant symptom, as this single question guides both diagnosis and treatment direction 1.

The Reality of Symptom Overlap You Must Navigate

Do not assume clean separation between these conditions in clinical practice:

• 63-66% of patients with heartburn also experience coexisting epigastric pain, making pure symptom-based diagnosis challenging 1, 2
• Approximately one-third of functional dyspepsia patients have coexisting GERD symptoms 2
• 19% of patients with dyspepsia cannot identify their predominant symptom 1
• There is considerable clinical and genetic overlap between GERD and functional dyspepsia, with shared pathophysiological mechanisms 3

Practical Diagnostic Algorithm

Step 1: Symptom Localization and Character

• Heartburn radiating to chest + regurgitation = GERD 1, 2
• Epigastric pain/burning staying in upper abdomen = Functional dyspepsia 1, 2
• Duration matters: Functional dyspepsia requires symptoms lasting more than 8 weeks 2

Step 2: Recognize Functional Dyspepsia Subtypes

If functional dyspepsia is suspected, further classify:

• Epigastric Pain Syndrome (EPS): Bothersome epigastric pain or burning at least 1 day per week 2
• Postprandial Distress Syndrome (PDS): Bothersome postprandial fullness or early satiation at least 3 days per week 2

Step 3: Key Distinguishing Feature from IBS

• In functional dyspepsia, abdominal pain is unrelated to defecation 2
• In IBS, pain is related to bowel movements 2

Critical Pitfalls to Avoid

Do not assume heartburn always means GERD—heartburn can coexist with dyspepsia, and the predominant symptom determines treatment direction 1.

Do not over-rely on endoscopy for differentiation—most GERD patients have normal endoscopy (non-erosive reflux disease), and most dyspepsia patients have functional disease with no structural abnormality 1, 2. Endoscopy is performed to exclude structural disease, not to differentiate GERD from functional dyspepsia 3, 2.

Do not fail to ask about the predominant symptom—this single omission leads to misclassification and inappropriate treatment 1.

Do not diagnose functional dyspepsia in patients ≥55-60 years with new-onset symptoms without appropriate investigation, as malignancy must be excluded 2.

Management Implications Based on Diagnosis

If GERD is Predominant:

• Empiric PPI therapy (omeprazole 20 mg once daily or lansoprazole 30 mg once daily) 1, 4, 5
• Take PPIs before meals 5
• Lifestyle modifications: elevate head of bed for nocturnal symptoms 6

If Functional Dyspepsia is Predominant:

• Test-and-treat for H. pylori if prevalence ≥10% in your population 1
• H. pylori eradication provides 6-14% therapeutic gain and prevents future peptic ulcer disease and gastric cancer 2
• If H. pylori negative or symptoms persist after eradication, trial PPI therapy 1
• Avoid fatty foods and large meals that delay gastric emptying 6
• Regular aerobic exercise may improve dyspeptic symptoms 6

When Both Coexist:

• Treat the predominant symptom first 1
• PDS symptoms (postprandial fullness, early satiation) have the most significant effects on daily life satisfaction, anxiety, depression, and mental health, even more than GERD symptoms 7
• Do not overlook coexisting functional dyspepsia symptoms when managing GERD, as they significantly impair quality of life 7

Diagnostic Testing Considerations

Functional diagnostic testing (24-hour pH-impedance monitoring, high-resolution manometry) is the only way to objectively differentiate GERD from functional reflux symptoms, as patients with functional complaints suffer just as much as those with objectively diagnosed GERD 8.

However, in primary care, most patients (80%) with dyspepsia will have functional dyspepsia as the underlying cause after investigation 3, making empiric treatment based on predominant symptoms a reasonable first approach 1.