Rapid Gastric Emptying: An Alternative Cause of Functional Dyspepsia

Case Report: M.S. is a 65-year-old woman with a history of type 2 diabetes mellitus, diastolic heart failure and irritable bowel syndrome (IBS). IBS was diagnosed approximately 4 years ago with predominance of constipation but also occasional loose stool. She presented with a new complaint of abdominal fullness after meals with early satiety and an inability to complete a full meal for numerous months. She complained of epigastric discomfort following meals but denied nausea, vomiting, heartburn, dysphagia, or weight loss. On examination, her vital signs were within normal limits; she appeared comfortable and had no abdominal tenderness, succussion splash or hepatosplenomegaly. Laboratory studies including white count, hemoglobin and liver tests were normal. Hemoglobin A1C ranged from 6.2-7.3 over the past 10 years. A double contrast upper GI series was unremarkable and negative for gastroesophageal reflux. Due to concern for potential gastroparesis in the setting of diabetes and dyspepsia, the patient underwent a gastric emptying scintigraphy which revealed rapid gastric emptying, with T1/2 of 41 minutes, 26% activity in the stomach at 1 hour and 2% activity in the stomach at 2 hours. Discussion: Functional dyspepsia, as seen in this patient, is defined by Rome III criteria as one or more of the following symptoms: bothersome postprandial fullness, early satiation, epigastric pain or burning without any evidence of structural disease. Functional dyspepsia is a complaint in approximately 15-20% of the population within a given year and is contributing to an increasing health burden. It has been noted that the symptoms associated with functional bowel disorders are endorsed by 40% of patients seeking medical care. There are many considerations for causes of functional dyspepsia in the general population. Among diabetics, functional dyspepsia is often presumed to be gastroparesis, but as seen in this case, rapid gastric emptying can also be an explanation. Rapid gastric emptying is likely indicative of poor accommodation of the stomach and impaired postprandial receptive relaxation. Consequently, there is an accelerated exposure of the duodenum to nutrients, particularly lipids. Typically, once there is inflow of fatty chyme into the duodenum there is a negative feedback mechanism resulting in the inhibition of antral contraction and an increase in pyloric resistance. In patients with rapid gastric emptying, the duodenum is overwhelmed and therefore cannot appropriately initiate the feedback loop, causing similar symptoms as seen in dumping syndrome. In this patient, treatment with an antispasmodic agent (dicyclomine) prior to meals, resulted in significant improvement in symptoms.