Symptoms and visceral perception in severe functional and organic dyspepsia

Abstract

Background: Hypersensitivity of gastric afferent pathways may play an aetiological role in symptoms of functional dyspepsia.

Aims: To determine whether patients with severe organic dyspepsia (associated with tissue irritation/injury) and those with functional dyspepsia (no detectable tissue irritation) differ in their perception of gastric distension and whether this difference is reflected in differences in their gastrointestinal and psychological symptoms.

Methods: Perceptual thresholds, referral patterns, and gastrointestinal and psychological symptoms were compared in 23 patients with functional dyspepsia, 10 organic dyspeptics, and 15 healthy controls.

Results: Fifteen (65%) functional dyspeptics and no organic dyspeptics had reduced perceptual thresholds for fullness, discomfort, or pain (odds ratio (OR) 19.56, 95% confidence interval (CI) 1.95 to 476.09, p = 0.0017). Either reduced perceptual thresholds or altered referral was found in 20 (87%) functional dyspeptics and four (20%) organic dyspeptics (OR 10.0, 95% CI 1.34 to 89.54, p = 0.014). During sham distension fullness, discomfort and pain were reported by healthy controls, organic dyspeptics, and functional dyspeptics. A sham response of pain but no other sensation was more frequent among functional dyspeptics (43%) than healthy controls (7%) (OR 10.77, 95% CI 1.10 to 257.35, p = 0.026). Gastrointestinal and psychological symptoms and gastric compliance were similar in the functional and organic groups.

Conclusions: Alterations in the perception of gastric distension distinguishes between functional and organic dyspepsia, while symptoms do not. A total of 87% of functional dyspeptics studied had evidence of altered visceral afferent function. In this study population, psychological abnormalities or changes in compliance did not explain the findings.

Figure 1

Viscerosomatic referral during gastric distension. A typical referral pattern from a healthy control subject (also typical of the organic dyspeptics) and the corresponding pattern from a patient with FD.

Figure 2

Perceptual response to gastric distension (ramp). *p<0.01 for FD versus organic dyspeptics and healthy controls.

Figure 3

Pain thresholds during gastric distension (ramp). The cut off line for a normal pain threshold was selected to include all the healthy controls. This cut off was the mean −1.6 SD (90th percentile) (2/15 healthy controls did not report pain up to gastric volumes of 1500 ml).

Figure 4

Gastric compliance. (A) Ramp distension. Gastric compliance (dV/dP) at each volume was the same in functional dyspeptics, organic dyspeptics, and healthy control subjects (not shown for clarity). Gastric perceptual thresholds in relation to the pressure/volume curve are indicated for functional dyspeptics (open boxes) and organic dyspeptics (solid boxes). (B) Phasic distension. Gastric compliance was the same for functional dyspeptics and healthy controls at each pressure tested.

Figure 5

Perceptual thresholds during sham distension. Mean perceptual threshold volumes were measured for all subjects during actual gastric distension and during sham distension.