Title: American Gastroenterological Association technical review on the diagnosis and treatment of gastroparesis
Abstract: This literature review and the recommendations herein were prepared for the American Gastroenterological Association Clinical Practice Committee. The paper was approved by the Committee on May 16, 2004, and by the AGA Governing Board on September 23, 2004. This literature review and the recommendations herein were prepared for the American Gastroenterological Association Clinical Practice Committee. The paper was approved by the Committee on May 16, 2004, and by the AGA Governing Board on September 23, 2004. Normal gastric emptying reflects a coordinated effort between different regions of the stomach and the duodenum as well as extrinsic modulation by central nervous system (CNS) and distal gut factors. Important events related to normal gastric emptying include fundic relaxation to accommodate food, antral contractions for trituration of large food particles, pyloric relaxation to allow food to exit the stomach, and antropyloroduodenal coordination of motor events. Gastric dysmotility includes delayed gastric emptying (gastroparesis), rapid gastric emptying (as seen in dumping syndrome), and other motor dysfunctions such as impaired fundic distention most commonly found in functional dyspepsia. The importance of gastric dysrhythmias has not been clearly defined. Disorders of gastric motility may present with a spectrum of symptoms of variable severity. This technical review systematically assesses the clinical research literature and formulates recommendations for the diagnosis and management of patients with gastroparesis. The published peer-reviewed literature on gastroparesis was searched on PubMed using the key words gastroparesis, gastric motility, and gastric dysmotility. Referenced articles from published manuscripts, book chapters, and recent abstracts from national and international meetings were included in this review. Gastroparesis is a symptomatic chronic disorder of the stomach characterized by delayed gastric emptying in the absence of mechanical obstruction. Symptoms of gastroparesis are variable and include early satiety, nausea, vomiting, bloating, and upper abdominal discomfort. In 146 patients with gastroparesis, nausea was present in 92%, vomiting in 84%, abdominal bloating in 75%, and early satiety in 60%.1Soykan I. Sivri B. Sarosiek I. Kierran B. McCallum R.W. Demography, clinical characteristics, psychological profiles, treatment and long-term follow-up of patients with gastroparesis.Dig Dis Sci. 1998; 43: 2398-2404Crossref PubMed Google Scholar Complications of gastroparesis may contribute to patient morbidity and include esophagitis, Mallory–Weiss tear, and vegetable-laden bezoars.2Parkman H.P. Schwartz S.S. Esophagitis and other gastrointestinal disorders associated with diabetic gastroparesis.Arch Intern Med. 1987; 147: 1477-1480Crossref PubMed Google Scholar, 3Blum M.E. Lichtenstein G.R. A new endoscopic technique for the removal of gastric phytobezoars.Gastrointest Endosc. 2000; 52: 404-408Abstract Full Text Full Text PDF PubMed Google Scholar Symptoms of gastroparesis are nonspecific and may mimic structural disorders such as ulcer disease, partial gastric or small bowel obstruction, gastric cancer, and pancreaticobiliary disorders.2Parkman H.P. Schwartz S.S. Esophagitis and other gastrointestinal disorders associated with diabetic gastroparesis.Arch Intern Med. 1987; 147: 1477-1480Crossref PubMed Google Scholar There also is an overlap between the symptoms of gastroparesis and functional dyspepsia. Functional dyspepsia is characterized by chronic or recurrent upper abdominal discomfort; however, many individuals report symptoms of dysmotility, including nausea, vomiting, and early satiety, and subsets of patients with functional dyspepsia exhibit delays in gastric emptying.4Stanghellini V. Tosetti C. Paternico A. Barbara G. Morselli-Labate A.M. Monetti N. Marengo M. Corinaldesi R. Risk indicators of delayed gastric emptying of solids in patients with functional dyspepsia.Gastroenterology. 1996; 110: 1036-1042Abstract Full Text Full Text PDF PubMed Scopus (395) Google Scholar, 5Sarnelli G. Caenepeel P. Geypens B. Janssens J. Tack J. Symptoms associated with impaired gastric emptying of solids and liquids in functional dyspepsia.Am J Gastroenterol. 2003; 98: 783-788Crossref PubMed Scopus (229) Google Scholar Indeed, idiopathic gastroparesis can be considered one of the causes of functional dyspepsia. Recently, a quantitative instrument for gastroparesis-related symptoms has been validated.6Revicki D.A. Rentz A.M. Dubois D. Kahrilas P. Stanghellini V. Talley N.J. Tack J. Development and validation of a patient-assessed gastroparesis symptoms severity measure the Gastroparesis Cardinal Symptom Index.Aliment Pharmacol Ther. 2003; 18: 141-150Crossref PubMed Scopus (87) Google Scholar Symptom correlation with delayed gastric emptying is variable for diabetic gastropathy, idiopathic gastroparesis, and functional dyspepsia.7Horowitz M. Harding P.E. Maddox A.F. Wishart J.M. Akkermans L.M. Chatterton B.E. Shearman D.J. Gastric and oesophageal emptying in patients with type 2 (non-insulin-dependent) diabetes mellitus.Diabetologia. 1989; 32: 151-159Crossref PubMed Google Scholar, 8Koch K.L. Stern R.M. Stewart W.R. Vasey M.W. Gastric emptying and gastric myoelectrical activity in patients with diabetic gastroparesis effect of long-term domperidone treatment.Am J Gastroenterol. 1989; 84: 1069-1075PubMed Google Scholar, 9Talley N.J. Shuter B. McCrudden G. Jones M. Hoschl R. Piper D.W. Lack of association between gastric emptying of solids and symptoms in nonulcer dyspepsia.J Clin Gastroenterol. 1989; 11: 625-630Crossref PubMed Google Scholar In recent studies, early satiety, postprandial fullness, and vomiting have been reported to predict delayed emptying in patients with functional dyspepsia.4Stanghellini V. Tosetti C. Paternico A. Barbara G. Morselli-Labate A.M. Monetti N. Marengo M. Corinaldesi R. Risk indicators of delayed gastric emptying of solids in patients with functional dyspepsia.Gastroenterology. 1996; 110: 1036-1042Abstract Full Text Full Text PDF PubMed Scopus (395) Google Scholar, 5Sarnelli G. Caenepeel P. Geypens B. Janssens J. Tack J. Symptoms associated with impaired gastric emptying of solids and liquids in functional dyspepsia.Am J Gastroenterol. 2003; 98: 783-788Crossref PubMed Scopus (229) Google Scholar In patients with diabetes, abdominal fullness and bloating were found to predict delayed gastric emptying.10Jones K.L. Russo A. Stevens J.E. Wishart J.M. Berry M.K. Horowitz M. Predictors of delayed gastric emptying in diabetes.Diabetes Care. 2001; 24: 1264-1269Crossref PubMed Google Scholar In some drug trials of prokinetic agents, the correlation between symptom improvement and acceleration of gastric emptying has been poor. In contrast, cisapride was reported to reduce epigastric pressure and bloating in association with improved emptying.11Jian R. Ducrot F. Ruskone A. Chaussade S. Rambaud J.C. Modigliani R. Rain J.D. Bernier J.J. Symptomatic, radionuclide and therapeutic assessment of chronic idiopathic dyspepsia.Dig Dis Sci. 1989; 34: 657-664Crossref PubMed Google Scholar In individuals with symptoms of gastroparesis who have normal rates of gastric emptying, other motor, myoelectric, or sensory abnormalities may elicit symptoms. Abdominal discomfort or pain is present in 46%–89% of patients with gastroparesis but is usually not the predominant symptom, in contrast to its prominence in functional dyspepsia.1Soykan I. Sivri B. Sarosiek I. Kierran B. McCallum R.W. Demography, clinical characteristics, psychological profiles, treatment and long-term follow-up of patients with gastroparesis.Dig Dis Sci. 1998; 43: 2398-2404Crossref PubMed Google Scholar, 12Hoogerwerf W.A. Pasricha P.J. Kalloo A.N. Schuster M.M. Pain the overlooked symptom in gastroparesis.Am J Gastroenterol. 1999; 94: 1029-1033Crossref PubMed Google Scholar Abdominal pain in gastroparesis responds poorly to treatment of gastroparesis.12Hoogerwerf W.A. Pasricha P.J. Kalloo A.N. Schuster M.M. Pain the overlooked symptom in gastroparesis.Am J Gastroenterol. 1999; 94: 1029-1033Crossref PubMed Google Scholar Patients with functional dyspepsia exhibit heightened sensitivity to gastric distention suggestive of afferent neural dysfunction as a contributor to symptom pathogenesis.13Lemann M. Dederding J.P. Flourie B. Franchisseur C. Rambaud J.C. Jian R. Abnormal perception of visceral pain in response to gastric distension in chronic idiopathic dyspepsia.Dig Dis Sci. 1991; 36: 1249-1254Crossref PubMed Google Scholar Similarly, in diabetic patients with dyspeptic symptoms, gastric distention elicits exaggerated nausea, bloating, and abdominal discomfort, suggesting that sensory nerve dysfunction may participate in symptom genesis in some patients with gastroparesis.14Samsom M. Salet G.A.M. Roelofs J.M.M. Akkermans L.M. Vanberge-Henegouwen G.P. Smout A.J. Compliance of the proximal stomach and dyspeptic symptoms in patients with type 1 diabetes mellitus.Dig Dis Sci. 1995; 40: 2037-2042Crossref PubMed Scopus (101) Google Scholar The majority of patients with gastroparesis are women. In one large investigation, 82% of gastroparetic patients were female.1Soykan I. Sivri B. Sarosiek I. Kierran B. McCallum R.W. Demography, clinical characteristics, psychological profiles, treatment and long-term follow-up of patients with gastroparesis.Dig Dis Sci. 1998; 43: 2398-2404Crossref PubMed Google Scholar Women tend to exhibit slower emptying rates than men, especially during the later portion of the menstrual cycle (the luteal phase).15Datz F.L. Christian P.E. Moore J. Gender-related differences in gastric emptying.J Nucl Med. 1987; 28: 1204-1207PubMed Google Scholar, 16Gill R.C. Murphy P.D. Hooper H.R. Bowes K.L. Kingma Y.J. Effect of the menstrual cycle on gastric emptying.Digestion. 1987; 36: 168-174Crossref PubMed Google Scholar It is believed that gastric muscle contractility is reduced by progesterone. The prevalence and socioeconomic impact of gastroparesis are difficult to estimate due to the incomplete correlation of symptoms with gastric emptying and the apparently higher prevalence of the disorder in academic medical centers than in the community. Most population-based studies in patient subsets at risk for development of gastroparesis have focused on symptoms rather than gastric scintigraphy findings. In such investigations, 11%–18% of individuals with diabetes report symptoms consistent with upper gastrointestinal dysmotility such as nausea and vomiting.17Bytzer P. Talley N.J. Leemon M. Young L.J. Jones M.P. Horowitz M. Prevalence of gastrointestinal symptoms associated with diabetes mellitus.Arch Intern Med. 2001; 161: 1989-1996Crossref PubMed Google Scholar, 18Maleki D. Locke G.R. Camilleri M. Zinsmeister A.R. Yawn B.P. Leibson C. Melton III, J. Gastrointestinal tract symptoms among persons with diabetes mellitus in the community.Arch Intern Med. 2000; 160: 2808-2816Crossref PubMed Google Scholar However, the prevalence of gastroparesis, as assessed by gastric emptying studies, in randomly selected patients in a diabetes clinic at an academic medical center was 48%.10Jones K.L. Russo A. Stevens J.E. Wishart J.M. Berry M.K. Horowitz M. Predictors of delayed gastric emptying in diabetes.Diabetes Care. 2001; 24: 1264-1269Crossref PubMed Google Scholar Using validated questionnaires, investigators have reported that symptoms of gastroparesis are associated with reduced quality of life both in diabetic patients and in community populations.19Enck P. Dubois D. Marquis P. Quality of life in patients with upper gastrointestinal symptoms results from the Domestic/International Gastroenterology Surveillance Study (DIGEST).Scand J Gastroenterol. 1999; 34: 48-54Crossref Google Scholar, 20Farup C.E. Williams G.R. Leidy N.K. Helbers L. Murray M. Quigley E.M.M. Effect of domperidone on the health-related quality of life of patients with symptoms of diabetic gastroparesis.Diabetes Care. 1998; 21: 1699-1706Crossref PubMed Scopus (50) Google Scholar Health care expenditures for care of gastroparesis are significant. In an analysis of the 1998 North Carolina Hospital Discharge database, there were 45 admissions with a primary diagnosis of diabetic gastroparesis and an additional 1431 admissions for diabetic patients in which gastroparesis was a contributing factor to the need for hospitalization.21Bell R.A. Jones-Vessey K. Summerson J.H. Hospitalizations and outcomes for diabetic gastroparesis in North Carolina.South Med J. 2002; 95: 1297-1299PubMed Google Scholar The average hospital stay in this study was 5 days. In an unpublished study of patients with severe gastroparesis, health care costs from gastroparesis were estimated to average $6972 per patient per month.22Abell T.L. Luo J. Cutts T.F. Mealer W. Kores R. Rashed H. Gastric electrical stimulation is superior to standard pharmacological treatment in reducing health care costs and hospital stays and in improving quality of life in patients with severe upper GI motor disorders (abstr).Am J Gastroenterol. 2001; 235: s258Crossref Google Scholar Most expenditures in this study were attributed to requirements for hospitalization and temporary or long-term use of intravenous hyperalimentation. Diagnostic testing in patients with presumed gastroparesis is associated with significant costs, especially from performance of endoscopy and gastric emptying scintigraphy. For some less well-established diagnostic modalities performed in referral centers (eg, antroduodenal manometry, electrogastrography [EGG]), reimbursement from third-party payers may be difficult to obtain despite the recent granting of procedure codes.23Botoman V.A. Rao S. Dunlap P. Abell T. Falk G.W. Motility and GI function studies billing and coding guidelines.Am J Gastroenterol. 2003; 98: 1228-1236Crossref PubMed Scopus (8) Google Scholar Similarly, novel treatments for patients with refractory gastroparesis (eg, pyloric injection of botulinum toxin, gastric electrical stimulation) have been considered experimental by some insurers and reimbursement has been denied. Gastroparesis is diagnosed by demonstrating delayed gastric emptying in a symptomatic individual after exclusion of other potential etiologies of symptoms (Table 1). Gastroparesis is often suspected in patient subgroups with specific profiles. Typical symptoms in an individual with long-standing type 1 diabetes mellitus suggest diabetic gastroparesis, whereas similar symptoms in a young woman are consistent with idiopathic gastroparesis. A diagnosis of functional dyspepsia may be entertained if pain is the dominant symptom, whereas coexistent defecation abnormalities suggest the possibility of irritable bowel syndrome. Delayed gastric emptying may develop after abdominal surgery, especially if the vagus nerve has been damaged. Vomiting associated with gastroparesis must be differentiated from regurgitation due to gastroesophageal reflux disease (GERD) or rumination syndrome, episodic vomiting in cyclic vomiting syndrome, self-induced vomiting with bulimia, and abdominal pain and vomiting in superior mesenteric artery syndrome. Patients with long-standing, severe symptoms of gastroparesis may appear dehydrated or malnourished. A succussion splash, detected by auscultation over the epigastrium while moving the patient side to side or rapidly palpating the epigastrium, indicates excessive fluid in the stomach from gastroparesis or mechanical gastric outlet obstruction.24Quigley E.M.M. Hasler W. Parkman H.P. AGA technical review on nausea and vomiting.Gastroenterology. 2001; 120: 263-286Abstract Full Text Full Text PDF PubMed Google ScholarTable 1Evaluation of Patients Suspected to Have Gastroparesis1. Initial investigation A. History and physical examination B. Blood tests Complete blood count Complete metabolic profile, including glucose, potassium, creatinine, total protein, albumin, calcium Amylase, if abdominal pain is significant symptom Pregnancy test, if appropriate C. Abdominal obstruction series, if vomiting or pain is acute or severe2. Evaluate for organic disorders A. Upper endoscopy to evaluate for mechanical obstruction or mucosal lesions (alternative: barium upper gastrointestinal series, often with small bowel follow-through) B. Biliary ultrasonography if abdominal pain is a significant symptom3. Evaluate for delayed gastric emptying A. Solid-phase gastric emptying test B. Screen for secondary causes of gastroparesis Thyroid function tests (thyroid-stimulating hormone) Rheumatologic serologies (eg, antinuclear antibody, scleroderma antibody [Scl70]) Glycosylated hemoglobin (HbA1C)4. Treatment trial with prokinetic agent and/or antiemetic agent5. If no clinical response, consider further investigation A. EGG B. Antroduodenal manometry C. Small bowel evaluation with enteroclysis or small bowel follow-through D. Further laboratory tests, if indicated ANNA, tissue transglutaminase antibody Open table in a new tab Most individuals suspected to have gastroparesis require upper endoscopy or a radiographic upper gastrointestinal series to exclude mechanical obstruction or ulcer disease. Mechanical gastric outlet obstruction can be caused by pyloric stenosis, neoplasia, or active ulcer disease in the duodenum, pyloric channel, or prepyloric antrum. The presence of retained food in the stomach after overnight fasting without obstruction is suggestive of gastroparesis. Bezoars may develop in severe cases. Endoscopy is more sensitive for detection of mucosal lesions than barium radiography.24Quigley E.M.M. Hasler W. Parkman H.P. AGA technical review on nausea and vomiting.Gastroenterology. 2001; 120: 263-286Abstract Full Text Full Text PDF PubMed Google Scholar Double-contrast techniques have increased the sensitivity of radiologic studies. Contrast radiography of the small intestine is performed in those patients with refractory symptoms, those with symptoms suggestive of a small bowel etiology (eg, profound distention, steatorrhea, feculent emesis), or those who exhibit dilated small bowel loops on plain radiography. When upper gastrointestinal radiography is ordered, a small bowel follow-through can be included to screen for small bowel lesions. The small bowel follow-through is accurate for detection of high-grade small bowel obstruction, usually provides an adequate assessment of the terminal ileum, and may rarely suggest superior mesenteric artery syndrome. Enteroclysis (small bowel enema), obtained after placement of a nasoduodenal or oroduodenal tube, provides double-contrast images and is more accurate in detecting small intestinal mucosal lesions, mild to intermediate grades of obstruction, and small bowel neoplasia.25Herlinger H. Guide to imaging of the small bowel.Gastroenterol Clin North Am. 1995; 24: 309-329PubMed Google Scholar Computed tomographic scanning with oral and intravenous contrast may also be useful for detection and localization of intestinal obstruction. After exclusion of mechanical disease of the stomach and small bowel, determination of the rate of gastric emptying of solid foods is usually obtained using scintigraphy. An abnormal gastric emptying test result suggests but does not prove that symptoms are caused by gastroparesis. If gastric emptying is normal, other causes for symptoms should be considered. However, a disorder of gastric motor function cannot be dismissed in symptomatic patients with normal gastric emptying because regional dysfunctions of the stomach, including impaired fundic relaxation or gastric myoelectric dysrhythmias, may be associated with symptoms.26Hornbuckle K. Barnett J.L. The diagnosis and work-up of the patient with gastroparesis.J Clin Gastroenterol. 2000; 30: 117-124Crossref PubMed Scopus (48) Google Scholar Other testing to complement the finding of delayed gastric emptying includes thyroid chemistries to rule out hypothyroidism, glycosylated hemoglobin levels to assess long-term glycemic control in diabetic patients, and other blood tests to screen for rheumatologic disorders, neuromuscular conditions, or paraneoplastic phenomena. Idiopathic gastroparesis is diagnosed after other causes are excluded. Several methods have been proposed for quantification of gastric emptying, motor function, and myoelectric activity (Table 2).Table 2Tests to Assess Gastric Motor and Myoelectrical FunctionAdvantagesDisadvantagesTests assessing gastric emptying Upper gastrointestinal barium radiographic studyAssess for mucosal lesionsNonphysiologicRadiation exposure (moderate) ScintigraphyGold standardRadiation exposure (minimal)NoninvasiveAble to assess solid and liquid emptying Breath tests using 13Lemann M. Dederding J.P. Flourie B. Franchisseur C. Rambaud J.C. Jian R. Abnormal perception of visceral pain in response to gastric distension in chronic idiopathic dyspepsia.Dig Dis Sci. 1991; 36: 1249-1254Crossref PubMed Google ScholarCNoninvasiveNeed normal small intestinal absorption, liver metabolism, pulmonary excretion Ultrasonography for serial changes in antral areaNoninvasiveRequires expertise for imaging and interpretation Primarily measures liquid emptyingPhysiologic Magnetic resonance imagingNoninvasiveExpensive, time consumingNeed specialized centers and softwareTests assessing gastric contractile activity Antroduodenal manometryAssesses contractility in fasting and postprandial periodsInvasiveNeed expertise to perform and interpret Gastric barostatMeasures proximal stomach relaxation and contractionInvasiveResearch techniqueTests assessing gastric myoelectrical activity EGGNoninvasiveMovement artifact may make recording difficult to interpretTests assessing gastric accommodation Gastric barostatMeasures proximal stomach accommodation responseInvasiveResearch techniqueBalloon may interfere with accommodation Satiety testMeasures combination of accommodation and sensitivitySimpleNot well standardized or acceptedAdapted from Quigley et al24Quigley E.M.M. Hasler W. Parkman H.P. AGA technical review on nausea and vomiting.Gastroenterology. 2001; 120: 263-286Abstract Full Text Full Text PDF PubMed Google Scholar and Hasler WL, Koch KL. Diabetic gastroparesis. AGA Postgraduate Course, May 19–20, 2001. Open table in a new tab Adapted from Quigley et al24Quigley E.M.M. Hasler W. Parkman H.P. AGA technical review on nausea and vomiting.Gastroenterology. 2001; 120: 263-286Abstract Full Text Full Text PDF PubMed Google Scholar and Hasler WL, Koch KL. Diabetic gastroparesis. AGA Postgraduate Course, May 19–20, 2001. The upper gastrointestinal barium series is an insensitive method for measuring gastric emptying because it is difficult to quantitate the relative fraction of contrast delivered to the intestine and because barium is not a “physiologic” test meal.27Parkman H.P. Harris A.D. Krevsky B. Urbain J.L. Maurer A.H. Fisher R.S. Gastroduodenal motility and dysmotility update on techniques available for evaluation.Am J Gastroenterol. 1995; 90: 869-892PubMed Google Scholar Nevertheless, gastric retention may be suggested by poor emptying of barium from the stomach, gastric dilation, and the presence of retained food or a gastric bezoar. Little or no emptying of barium at 30 minutes and retention of gastric barium at 6 hours are suggestive of gastroparesis.28Malagelada J.-R. Rees W.D.W. Mazzotta L.J. Go V.L. Gastric motor abnormalities in diabetic and postvagotomy gastroparesis effect of metoclopramide and bethanechol.Gastroenterology. 1980; 78: 286-293PubMed Google Scholar The greatest value of barium radiography lies in the exclusion of mucosal lesions and mechanical outlet obstruction. Gastric emptying scintigraphy of a solid-phase meal is considered the gold standard for the diagnosis of gastroparesis because this test quantifies the emptying of a physiologic caloric meal. Measurement of gastric emptying of solids is more sensitive for detection of gastroparesis because liquid emptying may remain normal even in patients with advanced disease. Liquid-phase emptying scans are more commonly performed after gastric surgery in patients suspected of having dumping syndrome. The usefulness of gastric scintigraphy in directing therapy and predicting response has been debated.11Jian R. Ducrot F. Ruskone A. Chaussade S. Rambaud J.C. Modigliani R. Rain J.D. Bernier J.J. Symptomatic, radionuclide and therapeutic assessment of chronic idiopathic dyspepsia.Dig Dis Sci. 1989; 34: 657-664Crossref PubMed Google Scholar, 29Galil M.A. Critchley M. Mackie C.R. Isotope gastric emptying tests in clinical practice expectation, outcome, and utility.Gut. 1993; 34: 916-919Crossref PubMed Google Scholar Some clinicians have proposed performance of dual solid- and liquid-emptying scintigraphy in patients who have undergone gastric surgery to determine if symptoms might result from delayed solid emptying or rapid liquid emptying. For solid-phase testing, most centers use a 99mTc sulfur colloid–labeled egg sandwich as a test meal.27Parkman H.P. Harris A.D. Krevsky B. Urbain J.L. Maurer A.H. Fisher R.S. Gastroduodenal motility and dysmotility update on techniques available for evaluation.Am J Gastroenterol. 1995; 90: 869-892PubMed Google Scholar More recently, a meal using Eggbeaters egg whites (ConAgra Foods, Inc, Downers, IL) with standard imaging at 0, 1, 2, and 4 hours postprandially has been proposed to provide a degree of standardization between different centers.30Tougas G.H. Eaker E.Y. Abell T.L. Abrahamsson H. Boivin P.L. Chen J. Hocking M.P. Quigley E.M. Koch K.L. Tokayer A.Z. Stanghellini V. Chen Y. Huizinga J.D. Ryden J. Bourgeois I. McCallum R.W. Assessment of gastric emptying using a low fat meal establishment of international control values.Am J Gastroenterol. 2000; 95: 1456-1462Crossref PubMed Google Scholar This test meal has a very low fat content and theoretically might produce different results than conventional meals. Whatever meal is used, the radiolabel needs to be cooked into it to ensure radioisotope binding to the solid phase. This prevents elution of the radiotracer into the liquid phase, which might produce an erroneous measurement of the faster liquid-phase gastric emptying.31Kim D.-Y. Myung S.-J. Camilleri M. Novel testing of human gastric motor and sensory functions Rationale, methods, and potential applications in clinical practice.Am J Gastroenterol. 2000; 95: 3365-3373Crossref PubMed Google Scholar Scintigraphic assessment of emptying should be extended to at least 2 hours after meal ingestion. Even with extension of the scintigraphic study to this length, there may be significant day-to-day variability (up to 20%) in rates of gastric emptying.32Lartigue S. Bizais Y. Des Varannes S.B. Murat A. Pouliquen B. Galmiche J.P. Inter- and intrasubject variability of solid and liquid gastric emptying parameters. A scintigraphic study in healthy subjects and diabetic patients.Dig Dis Sci. 1994; 39: 109-115Crossref PubMed Scopus (0) Google Scholar For shorter durations, the test is less reliable due to larger variations of normal gastric emptying. Extending scintigraphy to 4 hours has been advocated by some investigators to improve the accuracy in determining the presence of gastroparesis.33Thomforde G.M. Camilleri M. Phillips S.F. Forstrom L.A. Evaluation of an inexpensive screening scintigraphic test of gastric emptying.J Nucl Med. 1995; 36: 93-96PubMed Google Scholar, 34Guo J.-P. Maurer A.H. Fisher R.S. Parkman H.P. Extending gastric emptying scintigraphy from two to four hours detects more patients with gastroparesis.Dig Dis Sci. 2001; 46: 24-29Crossref PubMed Scopus (59) Google Scholar Emptying of solids typically exhibits a lag phase followed by a prolonged linear emptying phase. A variety of parameters can be calculated from the emptying profile of a radiolabeled meal. The simplest approach for interpreting a gastric emptying study is to report the percent retention at defined times after meal ingestion (usually 2 and 4 hours). The half emptying time also may be calculated; however, extrapolation of the emptying curve from an individual who did not empty 50% of the ingested meal during the actual imaging time may provide an inaccurate determination of the half emptying time.35Camilleri M. Hasler W. Parkman H.P. Quigley E.M. Soffer E. Measurement of gastroduodenal motility in the GI laboratory.Gastroenterology. 1998; 115: 747-762Abstract Full Text Full Text PDF PubMed Google Scholar Patients should discontinue medications that may affect gastric emptying for an adequate period before this test based on drug half-life (Table 3). For most medications, this will be 48–72 hours. Opiate analgesics and anticholinergic agents delay gastric emptying. Prokinetic agents that accelerate emptying may give a falsely normal gastric emptying result. Serotonin receptor antagonists such as ondansetron, which have little effect on gastric emptying, may be given for severe symptoms before performance of gastric scintigraphy. Hyperglycemia (glucose level >270 mg/dL) delays gastric emptying in diabetic patients.26Hornbuckle K. Barnett J.L. The diagnosis and work-up of the patient with gastroparesis.J Clin Gastroenterol. 2000; 30: 117-124Crossref PubMed Scopus (48) Google Scholar It is not unreasonable to defer gastric emptying testing until relative euglycemia is achieved to obtain a reliable determination of emptying parameters in the absence of acute metabolic derangement. Premenopausal women have slower gastric emptying than men,15Datz F.L. Christian P.E. Moore J. Gender-related differences in gastric emptying.J Nucl Med. 1987; 28: 1204-1207PubMed Google Scholar, 16Gill R.C. Murphy P.D. Hooper H.R. Bowes K.L. Kingma Y.J. Effect of the menstrual cycle on gastric emptying.Digestion. 1987; 36: 168-174Crossref PubMed Google Scholar so some advocate using separate reference values for premenopausal women.4Stanghe