Gastric Myoelectrical Activity Subtypes in Functional Dyspepsia and Gastroparesis

Abstract

Background/aims: Gastric dysrhythmias, loss of normal 3 cycles per minute (CPM) gastric myoelectrical activity (GMA), and variable loss of interstitial cells of Cajal are reported both in gastroparesis (GP) and functional dyspepsia (FD). We hypothesize that the patients with GP, and FD with normal gastric emptying (NGE) and delayed gastric emptying (DGE) may vary in symptom severity, and GMA profiles.

Methods: Symptoms and their severity were evaluated by gastroparesis cardinal symptom index (GCSI), Abell scoring, short-form Nepean dyspepsia index (SF-NDI), the World Health Organization quality of life, and Rome IV subtyping for FD. Solid-meal gastric emptying was assessed by nuclear scintigraphy. Water load satiety test (WLST)-based electrogastrography determined GMA.

Results: Patients with GP (n = 40) had higher GCSI than those with FD (n = 39; [12 DGE, 27 NGE] (2.79 [2.17-3.33] vs 1.67 [0.83-2.61] vs 0.83 [0.55-1.93]; P < 0.001, in GP vs FD-NGE vs FD-DGE, respectively), severe Abell grade (Grade III in 17 [43%] vs 0% vs 0%, in GP vs FD-NGE vs FD-DGE, respectively), severe SF-NDI (80.5 [63.5-102.5] vs 50 [27-91] vs 30 [21.25-45.5]); and poor QOL. Sixteen (40%) GP had impaired gastric accommodation (< 238 mL). Post-WLST 3 CPM normal/hypernormal GMA was observed in 17 (42%), 18 (67%), and 5 (42%) patients with GP, FD (NGE), and FD (DGE), respectively; and 3 CPM hyponormal in remaining patients in each group. Post-WLST dysrhythmia was comparable.

Conclusions: WLST-electrogastrography coupled with GE study may distinguish between normal/dysrhythmic GMA revealing pathophysiologicalphenotypes of GP and FD. Analysing extent of power change in normogastric, and dysrhythmic frequencies may comprehensively elucidate disease severity.

Keywords: Bradygastria; Electrogastrography; Normogastria; Tachygastria; Water load satiety test.

Figure 1

Gastric emptying in patients with gastroparesis (GP) and function dyspepsia (FD). (A) Gastric emptying scintigraphy in patients with GP and functional dyspepsia FD, who presented with delayed gastric emptying (DGE). (B) Qualitative estimation of gastric emptying delay with respect to time, in patients presenting with DGE. (C) Quantitative estimation of gastric emptying rates (%) in patients with GP and FD with DGE (FD-DGE). P-values lower than 0.05 were considered significant. NGE, normal gastric emptying.

Figure 2

Symptom severity in patients with gastroparesis (GP) and functional dyspepsia (FD). (A) FD subtyping on the basis of epigastric pain syndrome (EPS) and/or postprandial distress syndrome (PDS), (B) Abell grading to show severity of GP, (C) short-form Nepean dyspepsia index and associated health related quality of life. Higher scores indicate more symptom severity and poor quality of life. (D) Gastroparesis cardinal symptom index (GCSI) subscale scores and total score to show severity of gastroparesis. Higher scores imply more severity. (E) World Health Organization’s quality of life scores, in patients with gastroparesis and functional dyspepsia who presented with normal/delayed gastric emptying. The domain scores show quality of life in 4 domains, physical, psychological, social, and environmental. Higher domain scores represent better quality of life. P-values lower than 0.05 were considered significant. VAS, visual analogue scale; FD-NGE, functional dyspepsia with normal gastric emptying; FD-DGE, functional dyspepsia with delayed gastric emptying.

Figure 3

Water load satiety test and its relationship with symptom severity. (A) The water load satiety test in patients with gastroparesis (GP) and functional dyspepsia (FD). The patients were grouped on the basis of their gastric emptying status. Water load refers to the maximum amount of water tolerated (consumed) by the patient in 5 minutes after fasting electrogastrography. The median volume consumed by GP was significantly lower than FD with normal gastric emptying (FD-NGE) and FD with delayed gastric emptying (FD-DGE). (B) Correlation plot showing relationship between water load (mL) and gastroparesis cardinal symptom index (GCSI) score or GCSI subscale score, in patients with gastroparesis (n = 40) and functional dyspepsia (n = 39). Each data point represents the water volume consumed, and the corresponding GCSI score/subscale score of the individual patients. The trend line shows a downward slope, implying inverse relationship, ie, higher the volume of water consumed, lower was the GCSI score/subscale score. The coefficient of correlation (r) represents the strength of the relationship. P-values lower than 0.05 were considered significant. WLST, water load satiety test.

Figure 4

Gastric myoelectrical activity profile in patients with gastroparesis (GP) and functional dyspepsia (FD). (A) 3 cycles per minute gastric myoelectrical activity (CPM GMA) in fasting state. (B) Accompanied gastric dysrhythmia in fasting state. (C) Duodenal activity in fasting state. (D) Post-water load satiety test 3 CPM GMA. (E) Post-WLST accompanied gastric dysrhythmia. (F) Post-WLST duodenal activity. (G) Fasting and post-WLST power distribution in patients with GP and FD. P-values lower than 0.05 were considered significant.

Figure 5

Power distribution and power change in patients with gastroparesis (GP) and functional dyspepsia (FD). (A) Post-water load satiety test (WLST) power distribution in patients with GP and FD, who were segregated on basis of gastric solid emptying (delayed vs normal) and interstitial cells of Cajal (ICC) functionality (dysfunctional, ie, 3 cycles per minute [CPM] hyponormal vs functional ICC, ie, 3 cpm normal/hypernormal). If patients showed hyponormal 3 CPM gastric myoelectrical activity (GMA), then the ICC status was dysfunctional. (B) Observation of power change in patients with GP and FD, who were segregated on basis of gastric motility (delayed vs normal emptying) and ICC functionality (dysfunctional ICC, ie, 3 CPM hyponormal vs functional ICC, ie, 3 CPM normal/hypernormal). It may be noted that patients with gastroparesis and functional dyspepsia experience symptom overlap and so there may be transition of patients from one category to another, which may explain outliers observed in a category. (C) Correlation of frequencies with respect to power distribution vs power change. Each data point represents the post-WLST power distribution in bradygastria (or power change in bradygastria), and the corresponding post-WLST power distribution in normogastria (or power change in normogastria) of the individual patients. The trend line shows a downward slope, implying inverse relationship. The coefficient of correlation (r) represents the strength of the relationship. P-values lower than 0.05 were considered significant. DGE, delayed gastric emptying; NGE, normal gastric emptying.