Approach

Diagnosis is made by demonstrating delayed gastric emptying in a symptomatic patient after excluding other potential causes of the symptoms.[1]​ The symptoms are nonspecific and can mimic other disorders, such as ulcer disease, partial gastric or small-bowel obstruction, gastric cancer, or pancreatobiliary disorders.[47] Clinicians should also recognize that gastroparesis could be a presenting symptom of a generalized gastrointestinal motility disorder.

History

Symptoms described by the patient that are suggestive of gastroparesis include early satiety, postprandial fullness, nausea, vomiting, bloating, and upper abdominal pain.[1] A possible cause may become apparent from the clinical history: for example, the patient is known to have diabetes mellitus, multiple sclerosis, or scleroderma, or they have had previous abdominal surgery for other pathology. Reviewing the patient's drug list is recommended and, if practical, any drugs that might exacerbate gastroparesis or prevent the beneficial actions of a prokinetic agent should be removed (e.g., opioids, anticholinergics, tricyclic antidepressants, proton-pump inhibitors, interferon alfa, glucagon, calcitonin, octreotide, alcohol).[47] About 80% of patients with gastroparesis are female.[20]

Physical examination

There are no characteristic findings of gastroparesis on physical examination, but occasionally a succussion splash might be heard.[58] This sign can be elicited by auscultating over the epigastrium while moving the patient from side to side or rapidly palpating the epigastrium. It indicates excessive fluid in the stomach from delayed gastric emptying or mechanical outlet obstruction.[47]

Initial investigations

The following tests are recommended initially:​[2][47]

  • Complete blood count

  • Metabolic profile including serum glucose, potassium, creatinine, liver function, total protein, and albumin

  • Serum amylase and lipase, to exclude acute pancreatitis if abdominal pain is significant

  • Thyroid-stimulating hormone, if hypothyroidism is a concern

  • HbA1c (to check for new diabetes and to assess glycemic control in patients with previously diagnosed diabetes)

  • Pregnancy test, if appropriate

  • Abdominal x-ray.

A cause for the symptoms may become apparent after these initial tests, such as pancreatitis or small bowel obstruction, in which case appropriate management is started.

Evaluation of organic disorders

Patients should then have esophagogastroduodenoscopy (EGD) to exclude mechanical gastric outlet obstruction, causes of which include pyloric stenosis, neoplasia, and active ulcer disease in the duodenum, pyloric channel, or prepyloric antrum. If no cause of obstruction is found and retained food is present in the stomach after an overnight fast, this may suggest gastroparesis. However, it should be noted that retained gastric food is frequently identified during EGD and should not in itself be deemed diagnostic of gastroparesis. Opioids, cardiovascular drugs, and acid suppressants have all been associated with retained gastric food.[1]​ Routine EGD, with or without biopsy sampling, is well established as a safe and effective procedure. Although several adverse events are associated with routine EGD, their overall incidence is low.[59]

If the patient has symptoms suggestive of small bowel pathology, such as profound distension, steatorrhea or feculent emesis, or dilated small bowel loops on plain abdominal radiograph, then it is more appropriate to order contrast radiography at this stage, as this will demonstrate small bowel pathology better.

Evaluation for delayed gastric emptying

Gastric emptying scintigraphy demonstrating the emptying of a solid-phase meal is the definitive test for the diagnosis of gastroparesis because it quantifies the emptying of a physiologic meal.[60]​ Patients fast overnight and consume the freshly prepared radionuclide meal (250 kcal, low fat) in the morning within 20 minutes. Anterior and posterior scintigraphic images of the stomach are then obtained within 1 minute of completion of the meal (defined as 0) and at 60, 120, 180, and 240 minutes. A shorter version of the scintigraphy test that employs detailed imaging for 90 minutes and mathematical extrapolation of half-life for the diagnosis of gastroparesis should not be used as it often produces erroneous results.[47][61]​ It is highly recommended that a 4-hour test be performed: retention of >10% of the test meal at the end of 4 hours, or >60% retention after 2 hours, supports a diagnosis of gastroparesis.​[62]​ Drugs that could impact on gastric emptying should be stopped for 48 hours before the test.[1]

A stable-isotope gastric emptying breath test (GEBT) is an alternative test for the diagnosis of gastroparesis. A standardized meal is given containing carbon-13 (C-13)-labeled spirulina. A minimum of five samples are required, and as the C-13 isotope is stable these can be collected with simple equipment in the office or at the bedside. Breath samples are collected at baseline and over a 4-hour period and sent for analysis. A half-life of 79 minutes or more is considered abnormal.[63]

Wireless motility capsule (WMC) is a noninvasive ambulatory test that measures transit times and pressure parameters throughout the gastrointestinal tract. It is a one-time use, nondigestible, portable, small capsule that, when swallowed, records and transmits data to a receiver as it travels through the gut. The capsule can measure pH, pressure, and temperature to track location, gastric contents, and expulsion time from the different regions of the bowel. It has been approved by the Food and Drug Administration (FDA) for measuring gastric transit.[1]​ The patient takes the capsule after eating a standardized meal and wears a small monitor that allows the telemetry recordings to be made. Gastric emptying time is assessed from ingestion of the capsule, a point at which there is a low pH reading, to the moment where there is an abrupt rise in pH after it moves into the small bowel.[64]​ A gastric emptying time of >5 hours compares favorably with gastric emptying scintigraphy for the diagnosis of gastroparesis.[65]​ WMC can also identify delays in small bowel and colonic transit, thus providing an opportunity to evaluate motor function throughout the entire gastrointestinal tract, which may be indicated in patients with gastrointestinal symptoms.[1][66]

If a diagnosis of gastroparesis is made, further tests are carried out to find a possible cause. The tests ordered are guided by the history and physical exam findings. A diagnosis of idiopathic gastroparesis is made only once all other causes have been excluded.

Emerging tests

Electrogastrography (EGG) is a noninvasive technique for recording gastric myoelectrical activity using cutaneous electrodes placed on the abdominal skin over the stomach. Studies suggest a complementary role of spatial mapping EGG for identification of the pathophysiologic mechanism of gastric function.[67]​ However, at this time, it is unclear if the information is clinically meaningful. Ongoing research of high-resolution EGG is needed to help clarify its clinical role.[1]

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