Functional dyspepsia: Is symptom based diagnosis sufficient?

Functional dyspepsia is a chronic disorder of gastrointestinal tract with no abnormal physical signs and investigations such as endoscopy or radiological examination reveal no structural abnormality that could account for the symptoms. Consequently, classification of functional dyspepsia has been entirely symptom based. In the past two decades, 'Rome criteria' have been proposed and updated on three occasions to help make a positive diagnosis of FGIDs including Functional Dyspepsia. Clinicians and clinical investigators applied these criteria and have found FD to be common, has significant impact on quality of life. However, there has been conflicting data on the pathophysiology, slow progress in etiology and therapy of functional dyspepsia until recently when inflammation of the GI tract became the focus of research. The shift in focus began in 2005 when Mearin studied a population in Spain after an outbreak of salmonella gastroenteritis and found that the prevalence of dyspepsia and irritable bowel syndrome increased after 3, 6 and 12 months. In 2010, Ford reported a study from Ontario, Canada that symptoms of dyspepsia after an outbreak of bacterial dysentery was more prevalent (OR 2.30). Patients with presumed post-infectious functional dyspepsia based on history had delayed solid gastric emptying, hypersensitivity to gastric distension and significantly impaired fundic accommodation. Apart from bacteria that cause gastroenteritis, the main pathogen in the upper GI is Helicobacter pylori. The relationship between H.pylori and functional dyspepsia has been a subject of debate over the past 3 decades. The Cochrane collaboration in 2008 demonstrated that 3 to 12 months post eradication therapy, symptom improvement occurred in 10% of patients. Fourteen patients needed to be treated (NTT) for one case of functional dyspepsia. A recent study in 2011 showed that 49% of patients after eradication therapy improved and number needed to treat reduced to 8 thus strengthening the case for eradication therapy. A meta-analysis in 2014 on studies with 12-month follow up showed that H.pylori eradication therapy is associated with improvement of dyspeptic symptoms in FD patients and symptom improvement has been demonstrated in Asian, European and American population. One study included in the meta-analysis demonstrated that H.pylori eradication was just as efficacious as prokinetic therapy and one third of patients have symptom resolution, another one third has symptoms improvement and the remaining third reported persistent symptom. Moving from symptom based diagnosis to diagnosis based on pathology and microbiology will open up a new area of research into functional dyspepsia.