Diagnosis is based on combination of: symptoms, absence of gastric outlet obstruction/ulceration, and delay in gastric emptying.

Screen for diabetes mellitus, thyroid dysfunction, neurological disease, prior gastric/bariatric surgery, and autoimmune disorders. Biochemical screens for diabetes and hypothyroidism should be performed; other tests as clinically indicated.

Viral illness may lead to postviral gastroparesis, which may improve over time. Clinicians should inquire about prior acute illness suggestive of viral infection.

Markedly uncontrolled (>200 mg/dL) glucose levels may aggravate symptoms and delay gastric emptying.

While recent studies question whether optimizing diabetes control actually improves gastric emptying, optimization of glycemic control should be target of therapy since this impacts the natural history of diabetes and its complications, and it may impact gastric emptying.

Medication-induced delay in gastric emptying should be considered before diagnosis (narcotics, anticholinergics, GLP-1/amylin analogs, tricyclic agents, etc). Agents that delay gastric emptying should be stopped for ≥48 hrs prior to gastric emptying test.

Gastroparesis can be associated with and aggravate GERD. Patients with GERD refractory to acid-suppressive treatment should be considered for evaluation for presence of gastroparesis.

Documented delay in gastric emptying is required for diagnosis. The standard for evaluation and diagnosis is scintigraphic gastric emptying of solids. The most reliable method and parameter for diagnosis is gastric retention of solids at 4 h. Shorter studies or those based on liquid challenge results in decreased diagnostic sensitivity.

Alternative approaches include wireless capsule motility testing and 13C breath testing using octanoate or spirulina incorporated into a solid meal. Further validation is needed before considering for diagnosis (note that octanoate is not FDA-approved).

Medications that affect gastric emptying should be stopped at least 48 h before testing; may need >48 h based on medication pharmacokinetics.

Patients with diabetes should have blood glucose measured before emptying test, and test started after relative euglycemia, with blood glucose <275 mg/dL.

Rumination syndrome and/or eating disorders should be considered. These disorders may be associated with delayed gastric emptying, and identification may alter management.

Cyclic vomiting syndrome (CVS) should be considered during the patient history. These patients may require alternative therapy.

Chronic use of cannabinoid agents may cause a syndrome similar to CVS. Patients with symptoms of gastroparesis should be advised to stop use of these agents.

Documentation of delayed gastric emptying is recommended prior to therapy with prokinetics or GES.

First line management should include restoration of fluids and electrolytes, nutritional support, and optimization of glycemic control in diabetics.

Patients should receive counseling from a dietician regarding frequent small volume nutrient meals low in fat and soluble fiber, or use of a small particle diet, based on a published RCT. If unable to tolerate solid food, then use of homogenized or liquid nutrient meals is recommended.

If oral intake is insufficient, then enteral alimentation by jejunostomy tube feeding should be pursued (after trial of nasoenteric tube feeding). Indications include unintentional loss of ≥10% of usual body weight during a 3-6 month period and/or repeated hospitalization for refractory symptoms.

Postpyloric feeding is preferable to gastric feeding as gastric delivery can be associated with erratic nutritional support due to impaired gastric emptying.

Enteral feeding is preferable to parenteral nutrition.

Since acute hyperglycemia inhibits gastric emptying, it is assumed that improved glycemic control may improve gastric emptying and symptoms. However, recent studies question whether optimizing diabetes control actually improves gastric emptying, and therefore additional treatment such as prokinetics and anti-emetics will be required if symptoms persist despite optimized glycemic control.

Pramlintide and GLP-1 analogs or agonists may delay gastric emptying in diabetics. Should consider stopping and using alternative approaches before starting gastroparesis therapy.

In addition to dietary therapy, prokinetic therapy should be considered (taking risks/benefits into account).

Metoclopramide is the first line of prokinetic therapy and should be administered at the lowest effective dose. Risk of tardive dyskinesia is <1%. Patients should discontinue if they develop side effects (there is a black box warning from the FDA guiding physicians on indications and duration of prescriptions for metoclopramide).

For patients unable to use metoclopramide, domperidone can be prescribed with investigational new drug clearance (FDA). It is as effective as metoclopramide without propensity for CNS side effects. Baseline EKG is recommended and treatment withheld if QT >470 ms in males (>450 ms in females). Follow-up EKG on treatment is advised.

Erythromycin improves gastric emptying and symptoms (usually in the short term only, due to tachyphylaxis). IV erythromycin should be considered when IV therapy is needed (hospitalized patients). Oral treatment also improves gastric emptying; however, long-term effectiveness is limited by tachyphylaxis.

Treatment with antiemetics should occur for nausea and vomiting, but will not improve gastric emptying.

TCA can be considered in refractory nausea and vomiting (or associated pain), but will not improve and may potentially retard gastric emptying.

Gastrostomy for venting and/or jejunostomy for feeding may be performed for symptom relief.

Completion or subtotal gastrectomy could be considered in patients with PSG who remain markedly symptomatic and fail medical therapy.

Surgical pyloroplasty or gastrojejunostomy have been performed for refractory gastroparesis, however further studies are needed. Partial gastrectomy and pyloroplasty should be used rarely. Peroral endoscopic pyloroplasty is still experimental and indications and efficacy are still being studied.