Dietary and pharmacologic treatment
Although clinicians might consider recommending dietary modifications to treat gastroparesis or functional dyspepsia, the literature contains little evidence about their efficacy in these indications, said Dr. Nguyen. Based on a study by Tack and colleagues, some clinicians recommend small, frequent meals that are low in fat and low in fiber to patients with gastroparesis. Such a diet could be harmful, however, to patients with comorbid diabetes, irritable bowel syndrome, or renal failure.
Common dietary recommendations for functional dyspepsia include small, frequent meals; decreased fat consumption; and avoidance of citrus and spicy foods. These recommendations are based on small studies in which patients reported which foods tended to cause their symptoms. Trials of dietary modifications in functional dyspepsia, however, are lacking.
Nevertheless, the literature can guide the selection of pharmacotherapy for these disorders. Talley et al. examined the effects of neuromodulators such as amitriptyline, a tricyclic antidepressant, and escitalopram in functional dyspepsia. About 70% of the sample had postprandial distress syndrome, and 20% met criteria for idiopathic gastroparesis. Amitriptyline provided greater symptomatic relief to these patients than did placebo, but escitalopram did not. Patients who met criteria for idiopathic gastroparesis did not respond well to tricyclic antidepressants, but patients with epigastric pain syndrome did. Furthermore, compared with patients with normal gastric emptying, those with delayed emptying did not respond to tricyclic antidepressants. A separate study found that the tricyclic antidepressant nortriptyline did not improve symptoms of gastroparesis (JAMA. 2013;310[24]:2640-9).
Promotility agents may be beneficial for certain patients. A study published this year suggests that, compared with placebo, prucalopride is effective for nausea, vomiting, fullness, bloating, and gastric emptying in patients with idiopathic gastroparesis (Am J Gastroenterol. 2019;114[8]:1265-74.). A 2017 meta-analysis, however, found that proton pump inhibitors were more effective than promotility agents in patients with functional dyspepsia (Am J Gastroenterol. 2017;112[7]:988-1013.).
Pyloric dysfunction may accompany gastroparesis in some patients. Increased severity of gastric emptying delay is associated with increased pylorospasm. Endoscopists have gained experience in performing pyloric myotomy, and this treatment has become more popular. Uncontrolled studies indicate that the proportion of patients with decreased symptom severity after this procedure is higher than 70% and can be as high as 86% (Gastrointest Endosc. 2017;85[1]:123-8). The predictors of a good response include idiopathic etiology, male sex, moderate symptom severity, and greater delay in gastric emptying.
Functional dyspepsia should perhaps be understood as normal gastric emptying and symptoms of epigastric pain syndrome, said Dr. Nguyen. Those patients may respond to neuromodulators, she added. Idiopathic gastroparesis appears to be characterized by severe delay in gastric emptying, postprandial symptoms, nausea, and vomiting. “In the middle is the gray zone, where you have these patients with postprandial distress with or without delayed gastric emptying,” said Dr. Nguyen. Functional dyspepsia and gastroparesis could be two ends of a spectrum, and the best management for patients with symptoms that occur in both disorders is unclear.