How can I differentiate between functional dyspepsia and dyspepsia due to an underlying condition?

Differentiating functional dyspepsia from dyspepsia caused by an underlying condition primarily involves clinical assessment for alarm symptoms and targeted investigations. Functional dyspepsia is diagnosed when dyspeptic symptoms occur without evidence of an organic cause after appropriate evaluation NICE CKS.

Key steps include:

• Assess for alarm symptoms: These include weight loss, persistent vomiting, dysphagia, gastrointestinal bleeding, anaemia, or age over 55 with new symptoms. Presence of alarm features suggests an underlying organic pathology requiring urgent investigation, often endoscopy NICE CKS,NICE NG12.
• Review symptom characteristics: Functional dyspepsia typically presents with recurrent epigastric pain or discomfort, early satiety, bloating, or nausea without structural abnormalities, whereas organic causes may have more severe or progressive symptoms NICE CKS,NICE CG184.
• Medication and history review: Identify use of drugs that may cause or exacerbate dyspepsia (e.g., NSAIDs, bisphosphonates) and consider Helicobacter pylori infection status, as eradication may resolve symptoms related to peptic ulcer disease or gastritis NICE CKS,NICE CKS,NICE CG184.
• Non-invasive testing: In the absence of alarm symptoms, test for H. pylori using urea breath or stool antigen tests after a PPI washout period; positive cases receive eradication therapy NICE CKS,NICE CKS,NICE CG184.
• Empirical treatment trial: A trial of proton pump inhibitors (PPIs) for 4 weeks can be used to assess symptom response, which may help differentiate acid-related organic causes from functional dyspepsia NICE CKS,NICE CG184.
• Consider psychological factors: Functional dyspepsia is often associated with higher rates of anxiety and depression; managing these may improve symptoms, although psychological therapies have uncertain long-term benefit NICE CKS,NICE CKS[Ford 2013; Lu 2016].

In summary, the presence of alarm symptoms or abnormal investigation findings points towards dyspepsia caused by an underlying condition, whereas their absence, combined with normal investigations and symptom patterns, supports a diagnosis of functional dyspepsia.