The current guidelines as published by the American College of Gastroenterology (ACG) on the management of gastroparesis are summarized below.

Gastroparesis is a common disorder that produces symptoms of gastric retention in the absence of physical obstruction. Patients report nausea, vomiting, early satiety, and fullness. These symptoms may be intermittent or continuous. Less recognized symptoms include pain and bloating. Gastroparesis may cause diminished caloric intake as well as vitamin (A, B6, C, K) and mineral (iron, potassium, zinc) deficiencies. Management of gastroparesis includes correction of these nutritional deficiencies, relief of symptoms of gastric emptying and, in diabetics, improvement of glycemic control. If oral intake is not adequate, enteral nutrition via jejunostomy tube needs to be considered. Medical therapy uses prokinetic and antiemetic drugs (i.e. metoclopramide, domperidone, erythromycin), as well as centrally acting antidepressants (used as symptom modulators). Gastric electrical stimulation (GES) may relieve symptoms, such as vomiting. Surgical approaches include a venting gastrostomy and feeding jejunostomy. Partial gastrectomy and pyloroplasty should be used only in carefully selected patients.

DEFINITION

• The diagnosis of gastroparesis is based on the combination of symptoms, absence of gastric outlet obstruction or gastric ulceration, and delay in gastric emptying.
• Accelerated gastric emptying and functional dyspepsia can present with similar symptoms to those of gastroparesis; documentation of delayed gastric emptying is recommended before selecting therapy with prokinetic agents or gastric electrical stimulation (GES).

CAUSE OF GASTROPARESIS

• Patients should be screened for diabetes mellitus, thyroid dysfunction, neurological disease, a history of prior gastric or bariatric surgery, and autoimmune disorders.
• A prodrome suggesting viral illness may lead to gastroparesis (postviral gastroparesis).
• Uncontrolled ( > 200 mg/dl) glucose levels may aggravate symptoms of gastroparesis and delay gastric emptying. Optimization of glycemic control may improve symptoms of delayed gastric emptying.
• Medication-induced delay in gastric emptying (i.e. from narcotic and anticholinergic agents) should be considered.
• Gastroparesis can be associated with gastroesophageal reflux disease (GERD) and should be considered in patients with refractory GERD.

DIAGNOSIS

• Delay in gastric emptying is required for the diagnosis of gastroparesis. Scintigraphic gastric emptying of solids is the standard for a diagnosis of gastroparesis. The most reliable method is gastric retention of solids at 4 h measured by scintigraphy. Medications that affect gastric emptying should be stopped at least 48 h before diagnostic testing and patients with diabetes should have blood glucose <275mg/d before starting the gastric emptying test.

DIFFERENTIAL DIAGNOSIS

• The presence of rumination syndrome, cyclic vomiting syndrome (CVS) or eating disorders (anorexia nervosa, bulimia) should be considered.
• Chronic cannabinoid agent usage may cause a CVS like syndrome.

MANAGEMENT
I. NUTRITIONAL THERAPY

• Management includes restoration of fluids and electrolytes, nutritional support and optimization of glycemic control in diabetics.
• Oral intake is preferable for nutrition and hydration.
• Patients should receive dietician counseling regarding frequent small low fat, low fiber meals.
• Enteral nasoenteric or jejunostomy tube feeding should be pursued, if oral intake is insufficient, especially if unintentional weight loss of 10% during a period of 3–6 months or repeated hospitalizations occur.
• Enteral postpyloric feeding is preferable to gastric feeding and preferable to parenteral nutrition.

II. GLYCEMIC CONTROL

• Good glycemic control should be the goal as hyperglycemia inhibits gastric emptying.
• Pramlintide and GLP-1 analogs may delay gastric emptying in diabetics. Cessation of these treatments should be considered before initiation of therapy for gastroparesis.

III. PHARMACOLOGIC THERAPY

• Prokinetic therapy should be used to improve gastric emptying and gastroparesis symptoms.
• Metoclopramide is the first line therapy and should be administered at the lowest effective dose (in a liquid formation to facilitate absorption). The risk of tardive dyskinesia is estimated to be <1%. Discontinue therapy if involuntary movements develop.
• Domperidone can be prescribed with investigational new drug (IND) clearance from the Food and Drug Administration (FDA). It appears as effective as metoclopramide without causing central nervous system side effects. Domperidone may prolong the corrected QT interval on electrocardiogram; a baseline electrocardiogram is recommended and treatment withheld if the corrected QT is >470ms in male and 450ms in female patients. Follow-up electrocardiogram on treatment with domperidone is advised. Erythromycin improves gastric emptying. Erythromycin should be given iv in hospitalized patients. Oral treatment with erythromycin improves gastric emptying, however, effectiveness of oral therapy is limited by tachyphylaxis.
• Treatment with antiemetic agents will improve nausea and vomiting but not improve gastric emptying.
• Tricyclic antidepressants (TCA) can be considered for refractory nausea and vomiting in gastroparesis but will not result in improved gastric emptying and may even worsen gastric emptying.

IV. INTRAPYLORIC BOTULINUM TOXIN INJECTION

• Intrapyloric botulinum toxin injection is not recommended.

V. GASTRIC ELECTRICAL STIMULATION

• GES may be considered for compassionate treatment in patients with refractory symptoms, particularly nausea and vomiting. Symptom severity and gastric emptying have been shown to improve in patients with diabetic gastroparesis (DG), but not in idiopathic (IG) or postsurgical gastroparesis (PSG).

VI. SURGICAL TREATMENTS: VENTING GASTROSTOMY, GASTROJEUNOSTOMY, PYLOROPLASTY, AND GASTRECTOMY

• A venting gastrostomy and feeding jejunostomy may be performed for symptom relief.
• Completion gastrectomy could be considered in patients with PSG who remain markedly symptomatic and fail medical therapy.
• Surgical pyloroplasty or gastrojejunosotomy have been performed for treatment for refractory gastroparesis, but further studies are needed before advocating this treatment.
• Partial gastrectomy and pyloroplasty should only be used in carefully selected patients.

VII. ALTERNATIVE MEDICINES

• Acupuncture has been associated with improved rates of gastric emptying and reduction of symptoms.

UG’s addendum to these guidelines: Some of our patients have also responded well to Iberogast, an OTC herbal preparation.