Gastroparesis and Functional Dyspepsia: Spectrum of Gastroduodenal Neuromuscular Disorders or Unique Entities?

Abstract

Gastroparesis is defined by delayed gastric emptying in the absence of mechanical obstruction of the stomach. Patients experience symptoms of nausea, vomiting, abdominal pain, fullness, and early satiety. The recognition of the disorder has progressed due to availability of gastric emptying scintigraphy and advancements made in understanding its pathophysiology and treatment options. The clinical presentation and treatment of gastroparesis overlap with a more commonly recognized disorder of gut-brain interaction, functional dyspepsia. Recent studies have reenergized the discussion whether these two are separate entities or perhaps reflect a spectrum of gastroduodenal neuromuscular disorders. The societal guidelines conflict on the utility of gastric emptying scintigraphy in assessment of patients with upper gastrointestinal symptoms. A better appraisal of similarities and differences between gastroparesis and functional dyspepsia will allow targeted treatment for these disorders. This is particularly important as specific pharmacological and endoscopic treatment options are being developed for gastroparesis which are unlikely to be helpful for functional dyspepsia. This review makes the case for considering these disorders in a spectrum where identification of both would most ideally position us toward providing the optimal clinical care.

Keywords: Diabetes mellitus; Gastric accomodation; Gastric emptying; Interstitial cells of Cajal; Treatment.

Figure 1

Overlap and differences in symptoms and pathophysiology of gastroparesis and functional dyspepsia. Nausea and vomiting are more prominent in gastroparesis, whereas postprandial abdominal pain or discomfort is more classical for functional dyspepsia. Overtime, the characteristics and severity of symptoms may change in both gastroparesis and functional dyspepsia. Additionally, the influence of local factors, physiology, and molecular changes overlaps between gastroparesis and functional dyspepsia.

Figure 2

Gastric emptying scintigraphy (A) An example of normal gastric emptying where expected amount of the test meal is emptied at 1, 2, and 4 hrs. (B) A case of gastroparesis with increased retention of the test meal at 2 and 4 hrs (clinically relevant delayed GE is defined as a percentage retention >60% at 2 h and/or >20% at 4 h). (C) An example of a symptomatic, diabetic patient with rapid GE. (gastric emptying 85% at 2 h). GE, gastric emptying.