What is functional dyspepsia?

Functional Dyspepsia: Definition and Clinical Approach

Functional dyspepsia (FD) is a common disorder of gut-brain interaction characterized by bothersome epigastric pain or burning, early satiation, and/or postprandial fullness persisting for more than 8 weeks without evidence of structural abnormality to explain the symptoms. 1

Diagnostic Criteria and Classification

FD is diagnosed based on symptom patterns and the exclusion of organic disease. According to the Rome IV criteria, FD is classified into two distinct subtypes:

1. Postprandial Distress Syndrome (PDS):

   • Early satiation (feeling full during meal consumption)
   • Postprandial fullness (uncomfortable feeling of persistent fullness after meals)
   • Symptoms should occur at least three times per week

2. Epigastric Pain Syndrome (EPS):

   • Epigastric pain or burning not exclusively postprandial
   • Symptoms should occur at least once per week 1

Many patients, particularly in secondary and tertiary care, have overlapping features of both subtypes 1. The British Society of Gastroenterology recommends using less restrictive "clinical criteria" requiring only 8 weeks of symptoms rather than the Rome IV requirement of 3 months with onset 6 months prior to diagnosis 1.

Epidemiology and Impact

• FD affects approximately 7% of individuals in the community 1
• Most patients with dyspepsia (approximately 80%) will have FD as the underlying cause after investigation 1
• FD significantly impacts quality of life and healthcare utilization 1

Pathophysiology

Multiple mechanisms contribute to FD development:

• Delayed gastric emptying (in approximately 30% of patients) 2
• Impaired gastric accommodation (particularly important in PDS) 2
• Visceral hypersensitivity 2
• Duodenal mucosal alterations (impaired barrier function, low-grade inflammation) 2
• Microbial dysbiosis 2
• Psychological factors 2
• Post-infectious changes 1

Diagnostic Approach

Initial Evaluation

• Establish diagnosis based on symptom pattern: bothersome epigastric pain/burning, early satiation, and/or postprandial fullness for >8 weeks 1
• Distinguish from GERD (heartburn/acid regurgitation as predominant symptoms) 1
• Note: vomiting is atypical and should prompt consideration of other disorders 1

Laboratory Testing

• Full blood count in patients ≥55 years 1, 3
• Coeliac serology in patients with overlapping IBS-type symptoms 1, 3
• Non-invasive testing for H. pylori (urea breath test or stool antigen test) 1, 3

Endoscopy Indications

• Age ≥55 years with weight loss 1, 3
• Age >40 years from area with increased risk of gastric cancer 1, 3
• Family history of gastro-oesophageal cancer 1, 3
• Age ≥55 years with treatment-resistant dyspepsia 1, 3
• Age ≥55 years with raised platelet count or nausea/vomiting 1, 3
• Any age with dysphagia 3

Additional Testing

• Consider urgent abdominal CT in patients ≥60 years with abdominal pain and weight loss to exclude pancreatic cancer 1, 3
• Gastric emptying studies and 24-hour pH monitoring are not routinely recommended 3

Common Pitfalls in Diagnosis

• Failing to distinguish between FD and GERD, which require different management approaches 3
• Overreliance on individual alarm symptoms in patients <60 years, which are poor predictors of malignancy 3
• Repeated endoscopies in patients with typical FD symptoms without new alarm features 3
• Not testing for H. pylori before initiating empiric acid suppression therapy 3
• Not considering overlapping conditions such as IBS and GERD 3

Clinical Approach to Management

1. Establish an effective doctor-patient relationship and provide clear explanation of FD as a disorder of gut-brain interaction 1
2. Test for H. pylori and treat if positive 1, 3
3. If H. pylori negative or symptoms persist after eradication, offer empirical acid suppression therapy (preferably with proton pump inhibitors) 1, 3
4. Consider dietary modifications (smaller, more frequent meals; avoid trigger foods) 2, 4
5. For persistent symptoms, consider prokinetics for PDS-predominant symptoms or neuromodulators (e.g., low-dose tricyclic antidepressants) for visceral hypersensitivity 5, 2, 6

By understanding the diagnostic criteria, pathophysiology, and appropriate management strategies for functional dyspepsia, clinicians can provide effective care for this common disorder that significantly impacts patients' quality of life.