Pathophysiological classification of functional dyspepsia using a novel drinking-ultrasonography test.

Background: Functional dyspepsia (FD) is a heterogeneous disease characterized by various upper abdominal symptoms. The major mechanism of FD symptoms includes impaired fundic accommodation, delayed gastric emptying, and visceral hypersensitivity. We developed a novel drinking-ultrasonography test to combine a drink test with ultrasonography to assess gastric motility and sensory function of FD patients.

Method: Subjects were 60 successive FD patients according to the Rome III criteria. A drinking-ultrasonography test was performed after subjects had fasted. The subjects ingested 200 ml of water at 2-min intervals 4 times (total 800 ml) through a straw. The maximum cross section of the proximal stomach was visualized before water intake, after each water intake, and 5 and 10 min after the completion of drinking using extracorporeal ultrasonography. Abdominal symptoms were evaluated using the visual analog scale (VAS) a total of 5 times. The normal range of cross-sectional area and VAS were set using average +/- standard deviations of 33 healthy volunteers. Cases outside the normal range were diagnosed with a motor or sensory disorder.

Results: The drinking-ultrasonography test classified FD patients into four groups without adverse effect or trouble. The distribution of each group was 27% in the normal group, 15% in the impaired relaxation group, 10% in the delayed emptying group, and 48% in the visceral hypersensitivity group. There was no significant correlation between the pathophysiological classification and subtypes of FD defined by the Rome III criteria.

Conclusion: We developed a novel drinking-ultrasonography test that was effective in classifying FD patients according to pathophysiological features.