Gastroparesis

Gastroparesis is a motility disorder characterized by delayed gastric emptying of solids without mechanical obstruction.  It classically presents with nausea/vomiting, early satiety/postprandial fullness, and upper abdominal pain.  The most common causes are idiopathic (postviral), diabetic, and postsurgical.

Normal postprandial gastric activity is a multistep process that involves the parasympathetic and sympathetic nervous systems and occurs in response to food ingestion.  After food passes down the esophagus, vagally stimulated enteric neurons release nitric oxide to induce relaxation of the fundus of the stomach and accommodate the incoming food bolus.  Specialized gastric pacemaker cells (interstitial cells of Cajal) initiate pacesetter potentials (slow waves), which generate circumferential contractions of the gastric smooth muscle (peristalsis).  Peristalsis facilitates food mixing and propulsion toward the pylorus.

Impairments in this process can lead to