John R. Mathias

Nausea, Vomiting, and Abdominal Pain After Roux-en-Y Anastomosis: Motility of the Jejunal Limb++++++

The Roux-en-Y anastomosis is a surgical procedure performed to divert the pancreaticobiliary juices from the gastric pouch in patients who have alkaline reflux gastritis or esophagitis, or both, that develop after vagotomy and Billroth I or II operations. After the Roux-en-Y procedure the inflammation subsides but is often replaced by a characteristic group of symptoms--chronic abdominal pain, nausea, and vomiting worsened by eating. Using a semiconductor recording probe, we investigated the Roux limb in 7 subjects who were fasted and then fed (liquid and solid meals). In the fasted state the migrating motor complex was either completely absent or grossly disrupted. Only 1 subject converted to a fed-state motility pattern in the Roux limb after a liquid meal (Osmolite), and all 7 subjects failed to convert to a fed state after a solid meal. These studies suggest that the Roux-en-Y syndrome of pain, nausea, and vomiting is secondary to a defect in motor function and that the Roux limb is acting as an area of functional obstruction.

Effects of domperidone in patients with chronic unexplained upper gastrointestinal symptoms: A double-blind, placebo-controlled study

The effects of domperidone, a peripherally acting dopamine antagonist, were compared with those of placebo in a double-blind randomized study in 16 patients with idiopathic gastric stasis, chronic symptoms of “nonulcer dyspepsia” (including nausea, vomiting, and abdominal pain), and altered gastroduodenal motility. Patients received either domperidone or placebo orally (20 mg before meals and at bedtime) for six weeks. Symptoms were assessed by daily diaries kept by the patients for two weeks while receiving no medication for their gastrointestinal complaints (baseline), and throughout the six-week treatment phase. Studies of gastric emptying of a radiolabeled solid-phase meal were performed at baseline and six weeks after treatment. All patients had delayed gastric emptying at baseline, defined as a half-emptying time of more than mean +1 sd (from studies of normal controls). An 18- to 24-hr recording of gastroduodenal motor function during fasting was also performed at baseline and after six weeks of either domperidone or placebo treatment. After six weeks of treatment, the symptom scores significantly improved in the domperidone group (P<0.05), but not in the placebo group. Gastroduodenal motor activity was unchanged from baseline recordings after six weeks. Solid-phase gastric emptying also showed no improvement in either the domperidone or placebo group of patients. Although domperidone therapy had no significant effect on motility, it appears to be an effective drug for the treatment of the symptoms of nonulcer dyspepsia.

Myoelectric effects of Clostridium difficile: motility-altering factors distinct from its cytotoxin and enterotoxin in rabbits.

Clostridium difficile is a bacterium that causes antibiotic-associated pseudomembraneous enterocolitis. This bacterium produces a cytotoxin that induces tissue culture assay positivity and an enterotoxin that causes in vivo mucosal injury. In previous studies we have described two altered myoelectric patterns in response to certain diarrheagenic organisms in an in vivo rabbit model. The first pattern was called the migrating action potential complex and is associated with noninvasive agents; the second pattern was called repetitive bursts of action potentials and is characteristic of invasive or cytolytic agents. In this study, we evaluated the effects of purified cytotoxin (2.5-3.75 micrograms) and enterotoxin (140 micrograms) from C. difficile on the myoelectric activity in isolated ileal loops in New Zealand White rabbits. These observations in myoelectric activity were correlated with the results of similar studies by using the crude culture filtrates from C. difficile, or the products of Amicon XM50 filtration of its culture supernatant resulting in a high molecular weight product (0.3 mg protein/ml) and a low molecular weight product (0.57 mg protein/ml). Monopolar silver-silver chloride electrodes were used to record all myoelectric activity for an 8-h period. The animals were then killed, and tissue obtained from the ileal loops was histologically evaluated. Crude culture filtrates of C. difficile induced 7.0 migrating action potential complexes/hour and 6.8 repetitive bursts of action potentials/hour. Saline controls induced no migrating action potential complexes and 0.1 repetitive bursts of action potentials/hour. The high molecular weight filtration product obtained from the culture supernatant of C. difficile induced significantly more repetitive bursts of action potentials (41.1/h) than all agents studied. The purified cytotoxin or enterotoxin induced no migrating action potential complex activity and minimal repetitive bursts of action potential activity (0.9/h and 0.6/h, respectively). These values were not different from the saline controls; however, only the enterotoxin and the high molecular weight filtration product caused mucosal damage. These studies suggest that C. difficile produces a heat-labile substance or substances that alter the motility of the small intestine independent of the proteins responsible for in vivo tissue damage and cytotoxin assay positivity.

Abnormal gastroduodenal motility in children and adolescents with recurrent functional abdominal pain

To determine whether motor activity of the stomach and proximal small intestine is a factor in recurrent abdominal pain in adolescents, we prospectively investigated eight patients with recurrent abdominal pain and compared them with seven normal adolescents. All patients underwent a detailed examination to exclude other known organic causes of the pain. The gastroduodenal motor activity during fasting was studied with a semiconductor recording probe. The recordings were analyzed for periodicity, duration, and propagation velocity of the activity front of the migrating motor complex. The amplitude of the antral and duodenal contractions was also determined. The patients with recurrent abdominal pain had more frequent migrating motor complexes, but these were shorter in duration and moved more slowly down the intestine (slower propagation velocities). The patients also had high-pressure duodenal contractions that were associated with abdominal pain during the study period. These studies suggest that altered intestinal motility may be the underlying mechanism of recurrent abdominal pain in some children.

Review: pathophysiology of diarrhea caused by bacterial overgrowth of the small intestine

The bacterial overgrowth syndrome constitutes an intestinal problem involving alterations in motility and injury to the brush border and mucosa. The overgrowth of bacteria also causes secretion, malabsorption, and maldigestion. These alterations result in a clinical syndrome that manifests itself as weight loss, malabsorption of specific nutrients, and (usually) diarrhea. There are known causes of bacterial overgrowth, such as intestinal diverticuli or surgical procedures involving a vagotomy, but in our experience most cases remain idiopathic. This review evaluates the mechanisms of bacterial overgrowth, as currently understood, and specifically addresses the known causes of diarrhea that results from bacterial contamination of the small intestine.

Gastric emptying in infants with gastroesophageal reflux. Measurement with a technetium-99m-labeled semisolid meal.

AbstractIt is well established that liquid emptying occurs in the absence of motor activity of the stomach. In contrast, solid-phase emptying is controlled in part by antral peristalsis and is, therefore, a more precise indicator of gastric motility. We developed a semisolid, radionuclide gastric emptying test using rice cereal and technetium-99m-sulfur colloid to assess antral physiology in infants with vomiting. Computer-programmed mathematical models were used to determine the shape of a line that best fit our emptying data points. Linear, simple exponential [ f=2−(t/t1/2)], and power exponential

99mTc-labeled solid-phase meal: a quantitative clinical measurement of human gastric emptying.

\left[ {f = 2^{(t/t1/2)^\beta } } \right]

Effect of lidamidine hydrochloride and loperamide on gastric emptying and transit of the small intestine: A double-blind study

patterns of emptying were calculated, wheref is the fraction of the meal remaining in the stomach at time t,and t1/2 is the time when 50% of the meal has emptied and is a determinant of the shape of the curve. In infants with simple regurgitation (chalasia) and those with vomiting and failure to gain weight, we made statistical comparisons between gastric emptying patterns after analysis of the mean percentage of retained radionuclide at 120 min, calculated t1/2, and area under the curve. The coefficient of determination, R2,was calculated as an index of whether a curve provided goodness of fit to the data. Differences between groups of patients were statistically significant for all parameters of each mathematical model. However, higher coefficients of determination were noted in the power exponential model. The data suggest that the power exponential mathematical model provides the best analysis of the gastric emptying patterns for infants with chalasia and those with vomiting and failure to gain weight. We conclude that testing for significant differences between groups of infants by using exponential mathematical descriptions of gastric emptying curves would be most accurately accomplished by determining the area under the curve and the percentage of residual of a semisolid meal at 120 min.