Epigastric fullness

Epigastric fullness may be caused by a disordered gastric motor function, resulting in delayed gastric emptying, but may also be caused by rapid emptying, leading to a distention of the proximal small intestine. A rational diagnostic approach to a patient complaining of epigastric fullness is needed to reveal the underlying disorder or disease and to enable an ade-quate, targeted therapy. The clinical impression based on symptoms is unreliable and cannot distinguish function disorders and benign disease from severe conditions.

E pigastric fullness or pain, in particular after the ingestion of a meal, as well as bloating, belching, early satiety and nausea with or without vomiting may be due to a disordered gastric motor function resulting in delayed gastric emptying, but may have its origin in rapid emptying, leading to a distention of the proximal small intestine (1). Symptoms are not reliable indicators of underlying disorders (2). In a study of 101 patients with symptoms of dyspepsia, an extended workup, including assessments of esophageal motility and transit, gastroesophageal reflux, gastric emptying, hepatobiliary function and lactose absorption, revealed abnormalities, potentially accounting for symptoms in 47 cases; no more than 11 had gastric stasis, whereas 21 had endoscopy--negative gastroesophageal reflux, six had biliary dyskinesia and five had lactase deficiency (3).
How should patients complaining of epigastric fullness be approached? The indispensable first step, taking a thorough history, may yield important clues. Patients must be asked about the occurrence and course of their symptoms; the relation between their symptoms and the composition, volume, frequency and timing of meals; self-imposed dietary restrictions or peculiarities; appetite; regurgitation; vomiting; pat-terns of alcohol intake; smoking habits; frequency and consistency of stools; operations and traumata; and antecedent and ongoing illnesses and their treatment. In some patients, the occurrence of symptoms may be related to the more or less recumbent position they choose to take after the evening meal in front of their television set. Advising the patient to alter her or his eating habits and postprandial activities may yield symptom relief. In patients taking medications known to affect gastrointestinal motor activity, a change in the therapeutic regimen may be beneficial.
The physical examination is often unremarkable but may suggest gastric dilation, eg, by a succussion splash. Biochemical, hematological and urine analyses may reveal hitherto unnoticed metabolic diseases, eg, diabetes mellitus or electrolyte imbalances such as hypokalemia or hypomagnesemia. Their treatment may be associated with alleviation or cessation of symptoms.
If the above-mentioned measures fail to improve a patient's condition, the patient is young and presents with no alarm symptoms (ie, weight loss, dysphagia, recurrent vomiting, anemia or evidence of bleeding), an empirical therapeutic approach may be chosen. If delayed gastric emptying is suspected, treatment may consist of a prokinetic agent for four weeks and, if gastroesophageal reflux disease is suspected, a four-week course of an antisecretory drug, preferably a proton-pump inhibitor. The latter can be taken with or without an additional prokinetic agent. In this case, further investigations should be undertaken only if the treatment fails (4,5). It must be taken into account that there is no clear cut relationship between the type and severity of symptoms, and the rate of gastric emptying (6,7).
In older patients as well as in patients with alarm symptoms, an esophagogastroduodenoscopy is indicated to rule out structural abnormalities and mucosal disorders. If a lesion or structural abnormality is found, the underlying disorder must be treated. For the evaluation of patients with symptoms of dyspepsia, the American College of Physicians recommended, in 1985, that endoscopy should be reserved for patients older than 45 years and for those who do not respond to an empirical antisecretory therapy lasting seven to 10 days or whose symptoms had not resolved after six to eight weeks without treatment (8). However, no controlled trials have compared the efficiency and costs of an approach comprising primary empirical therapy with an approach comprising immediate diagnostic evaluation and subsequent therapy based on the findings. Radiographic investigations were shown to be inferior to endoscopy in the detection of structural abnormalities (9,10). The above-mentioned guidelines of the American College of Physicians maintain that endoscopy rather than radiography should be the primary investigative tool (8).
When endoscopy or barium contrast studies are unrevealing in patients with symptoms likely to be caused by delayed gastric emptying, gastric emptying should be studied. When emptying is normal, further investigations should be aimed at elucidating the cause of the symptoms, ie, primarily tests for gastroesophageal reflux activity, hepatobiliary and pancreatic function, carbohydrate absorption, as well as perhaps duodenogastric reflux, and small intestinal motor and transport function.
If no explanation for the symptoms is found, it should not be assumed that one does not exist but only that the more serious and treatable causes have been excluded. To reassure the patient and to camouflage our own ignorance, we may stick to a diagnosis of 'functional' or 'idiopathic' dyspepsia.
What means are available to assess gastric motor function and its net effect -gastric emptying? A fluoroscopic barium contrast examination can, apart from providing hints at anatomical abnormalities and structural lesions, provide information about residual gastric secretions, food retained despite a prolonged fast, and the shape and size of the stomach. If the resting tension of the gastric musculature is high, the stomach is short and holds the ingested barium in the fundus and corpus; the latter parts appear globular and the antrum tubular. By contrast, if the stomach is hypotonic, it will lengthen with barium ingestion, the greater curve sags into the pelvis and the antrum appears funnel shaped.
Examinations employing a double-contrast barium meal have a better diagnostic yield than the conventional con-trast technique. The stomach and duodenum are distended by carbon dioxide, and the mucosal surface is repeatedly coated with a fine layer of barium.
Although the emptying of luminal contents and gastric contractions can be detected fluoroscopically, it is not possible to obtain quantitative information. Furthermore, the imaging time is limited by the high radiation burden.
There have been attempts to use radio-opaque markers for the assessment of gastric emptying. Spheres with a diameter of 1.4±0.3 mm and a specific gravity of about 1 have been shown to be emptied from the stomach at a rate similar to that of radiolabelled liver and consistently faster than 2.4 mm spheres (11), which tend to remain in the stomach until the occurrence of an activity front of the interdigestive migrating motor complex (12). However, even small spheres are not suited for the assessment of gastric emptying because the physiological feedback control mechanisms important for the emptying of a meal, which depend on receptors responding to the composition of the chyme delivered to the small intestine, do not come into play (13)(14)(15).
Scintigraphic techniques to quantify gastric emptying are the methods best suited and documented for clinical use. The ensuing radiation burden is less than half of the radiation burden resulting from a plain radiography of the abdomen, so that recordings in children and repeat studies to evaluate treatment effects are feasible; pregnancy, however, should be ruled out. A limiting factor is the availability of a gamma scintillation camera and the necessary camera time.
The radiolabelled test meal employed should be palatable, and include nutrient solid and liquid components with a total caloric load of more than 1260 kJ (5), ie, be sufficient to challenge feedback regulation of emptying by receptors located in the small intestine (13)(14)(15). Ideally, the emptying of liquid and solid meal components, which may be quite different (16), should be measured simultaneously. However, because symptoms originate mainly from a disordered emptying of solids, the assessment of liquid emptying may not be crucial (17). When gamma camera time is scarce, the use of a semisolid meal is advisable. Such a meal is emptied after a very short lag phase -the phase during which the first part of the ingesta is ground down by the antrum and thus becomes ready for delivery to the duodenum at a rate similar to that of solid meals after the lag phase (18)(19)(20). As a consequence, the time needed to assess the emptying of a semisolid meal is considerably shorter than the time needed to assess the emptying of a solid meal.
In gastric emptying studies, standardization is of utmost importance. The results are reported as the percentage of meal remaining in the stomach at specific time points after ingestion, eg, 50 min after the ingestion of a semisolid and 100 to 120 min after ingestion of a solid meal. Alternatively, the time taken for 50% of the respective meal to empty is reported. An approach that accounts for changes in emptying rate over the recording period is to express the results as the area under the curve (21). The shape of the curve may also be reported (22), although its clinical significance has not been defined. The result of an emptying study must be compared with results obtained in a large group of healthy, symptom-free subjects of all age classes and both sexes. In patients with diabetes, the blood-glucose levels prevailing immediately before and during the recording have to be noted when interpreting the results because they may influence the rate of emptying (23).
Scintigraphy permits the quantification not only of emptying, but also of the distribution of the meal between the fundus, corpus and antrum at various time points after ingestion (24). Techniques have been developed for assessing the amplitude and propagation velocity of antral contractions (18)(19)(20)(25)(26)(27)(28). Their clinical utility has not yet been established.
Tracer techniques record, at given time points after the ingestion of a labelled meal, the concentrations of a marker substance in the breath or blood under the assumption that the tracer is rapidly absorbed from the small intestine but not the stomach. It is further assumed that the disappearance of the tracer from the blood is constant, and that there is little or no recirculation of tracer from other pools within the body.
The only tracer test available that enables the quantification of the emptying of a solid meal uses 14 carbon-or 13 carbon-labelled octanoic acid as a marker (29). Octanoic acid dissolves easily in, and is firmly bound to, egg yolk; the mixture is prepared as a scrambled egg. The binding is broken down in the duodenum as a result of the hydrolytic activity of pancreatic enzymes, and carbon-octanoic acid is rapidly absorbed, oxidized to carbon dioxide in the liver and excreted via the lungs. Because no apparatus is needed except for a simple device to sample the breath, the test can be carried out at the bedside. The analysis, however, is expensive because it requires a mass spectrophotometer but may become more affordable with infrared spectroscopy. The radiation burden arising from 14 carbon is no more than about 1% of that arising from scintigraphic emptying studies. Radiation can be avoided, with no loss of diagnostic value, by substituting the radioactive 14 carbon label with the stable isotope 13 carbon (29). However, the relation between results obtained by the breath test and results obtained scintigraphically is not always clear (30). Two different sonographic techniques have been developed to quantify gastric emptying. With one (31), the volume of the entire stomach is determined at regular intervals after a liquid meal, by sampling cross-sections at multiple sites. However, volume determination is difficult because of the complex configuration of the stomach, and the unavoidable presence of gas in the fundus and superimposed viscera. The technique may also be difficult to perform in obese subjects. In addition, it is very time consuming and requires a skilled, experienced operator. Solid meals can be visualized sonographically, but inhomogeneities and gas may make reliable quantification impossible.
With the use of the second sonographic technique (32), changes in volume contained in the antrum, as indicated by the cross-sectional area, are measured before and after the ingestion of a nutrient liquid. The emptying time is defined as the time point at which the antral volume has returned to its preprandial value.
A new technique for acquiring three-dimensional ultrasonograms, which makes use of a magnetic position sensor system interfaced to an ultrasound scanner, may be valuable for the assessment of the intragastric distribution and emptying of a liquid meal (33). The contractile activity of the antropyloroduodenal segment and the movement of liquid gastric contents can be visualized simultaneously and threedimensionally using duplex sonography (34).
At the time being, however, the sonographic techniques as well as more sophisticated techniques such as electrical impedance epigastrography (35), electrical impedance tomography (36,37), high speed impedance tomography (38), magnetic resonance imaging (39) and echoplanar magnetic resonance imaging (40) may be useful in the research setting but cannot be recommended as tools to record gastric emptying in clinical practice.
Manometric studies to assess gastric motor activity are, in most cases, of little help in the workup of patients with epigastric fullness. Only lumen-obliterating contractions are recorded, ie, the contractions occurring in the distal antrum and the pylorus. Moreover, antral motility shows a wide variation of patterns, even in healthy individuals.
The Barostat can be useful for assessing the tonic activity of the fundus, which, when high, may interfere with the adaptive relaxation that occurs physiologically in response to a meal, and, when low, may contribute to delayed emptying (41,42). The Barostat can also be valuable for the detection of an increased visceral sensitivity to gastric distention, which may underlie symptoms of dyspepsia in patients with normal adaptive relaxation of the fundus and normal antral motor activity (43). Therapeutic consequences to be drawn from the recognition of such disorders have not yet been established.

CONCLUSIONS
A rational diagnostic approach to a patient complaining of epigastric fullness is needed to reveal the underlying disorder or disease in due time and thus to enable an adequate, targeted therapy. The clinical impression based on symptoms is unreliable and cannot distinguish function disorders and benign disease from severe conditions.