Electrolyte profiles within the ileoanal pouch: measurement by an in vivo equilibrium dialysis technique.

BACKGROUND: Patients with an ileoanal pouch have high rates of fluid and electrolyte loss. These improve with pouch adaptation. There is limited information concerning secretion and absorption in the stable ileoanal pouch. A new method to measure and characterize electrolytes in the ileoanal pouch is described. METHODS: Following an in vitro study, nine patients with a stable ileoanal pouch had consecutive placement of dialysis bags consisting of a semi-permeable membrane containing 5 ml of 10% dextran in normal saline into the ileoanal pouch. These were left in place for 15, 30, 60, and 120 min. After determining that 60 min was the optimal timing for measurement of electrolyte concentrations, 12 normal volunteers underwent a similar in vivo dialysis study with dialysis bags withdrawn at 60 min. Sodium, chloride, potassium, phosphorus, calcium and magnesium concentrations in the dialysis bags were compared between the two groups. RESULTS: In the in vitro and in vivo studies, the measured electrolytes reached equilibrium within 60 min. Statistically significant differences between sodium concentrations (160.9 +/- 30.2 vs. 116.8 +/- 13.8 mmol/l, respectively) and phosphorus concentrations (6.8 +/- 5.2 vs. 1.8 +/- 0.7 mg/dl, respectively) at 60 min in ileoanal pouch patients and volunteers were found (p<0.001). There were no statistical differences in the other measured electrolytes between the two groups. CONCLUSION: An in vivo dialysis technique is described for measuring electrolyte concentrations within the ileoanal pouch. Differences in sodium and phosphate concentrations may reflect incomplete adaptation of the ileoanal pouch, and are a potential explanation for increased stool frequency in these patients.

Which form of erythromycin should be used to treat gastroparesis? A pharmacokinetic analysis.

BACKGROUND: Erythromycin is a macrolide antibiotic that exhibits prokinetic effects. It has been shown to enhance antral contractility and accelerates gastric emptying rates, primarily by stimulating motilin receptors. AIM: To determine the optimal dosage form of erythromycin for use as a prokinetic agent. METHODS: Eight normal volunteers and three patients with documented gastroparesis ingested 250 mg erythromycin in tablet. suspension and intravenous forms. Serum erythromycin levels were determined at frequent intervals. These data were plotted vs. time and analysed for lag time, time to maximum concentration (tmax), maximum concentration (Cmax) and bioavailability (F). RESULTS: The absorption kinetics of the erythromycin suspension was notable for short lag times and early tmax, while lag times and tmax were delayed with the tablet form. Median lag time was 15 min for the suspension vs. 90 min for the tablet (P < 0.005). Median tmax for the suspension was 45 min vs. 180 min for the tablet (P < 0.005). A non-significant decrease in F was seen with the suspension compared to the tablet (P = 0.12). CONCLUSION: Based on the kinetic data from this study, erythromycin suspension is the ideal dosage form for administration of this drug as a prokinetic agent.

Alterations in colonic anatomy induced by chronic stimulant laxatives: the cathartic colon revisited.

Cathartic colon is a historic term for the anatomic alteration of the colon secondary to chronic stimulant laxative use. Because some have questioned whether this is a real entity, we investigated changes occurring on barium enema in patients ingesting stimulant laxatives. Our study consisted of two parts. In part 1, a retrospective review of consecutive barium enemas performed on two groups of patients with chronic constipation (group 1, stimulant laxative use [n=29]; group 2, no stimulant laxative use [n=26]) was presented to a radiologist who was blinded to the patient group. A data sheet containing classic descriptions of cathartic colon was completed for each study. Chronic stimulant laxative use was defined as stimulant laxative ingestion more than three times per week for 1 year or longer. To confirm the findings of the retrospective study, 18 consecutive patients who were chronic stimulant laxative users underwent barium enema examination, and data sheets for cathartic colon were completed by another radiologist (part 2). Colonic redundancy (group 1, 34.5%; group 2, 19.2%) and dilatation (group 1, 44.8%; group 2, 23.1%) were frequent radiographic findings in both patient groups and were not significantly different in the two groups. Loss of haustral folds, however, was a common finding in group 1 (27.6%) but was not seen in group 2 (p < 0.005). Loss of haustral markings occurred in 15 (40.5%) of the total stimulant laxative users in the two parts of the study and was seen in the left colon of 6 (40%) patients, in the right colon of 2 (13.3%) patients, in the transverse colon of 5 (33.3%) patients, and in the entire colon of 2 (13.3%) patients. Loss of haustra was seen in patients chronically ingesting bisacodyl, phenolpthalein, senna, and casanthranol. We conclude that long-term stimulant laxative use results in anatomic changes in the colon characterized by loss of haustral folds, a finding that suggests neuronal injury or damage to colonic longitudinal musculature caused by these agents.

Serum electrolyte abnormalities secondary to Fleet's Phospho-Soda colonoscopy prep. A review of three cases.

The authors report three cases of adverse reactions to commonly used lavage solutions generally believed harmless.

Improved computer analysis of solid phase gastric emptying scans.

OBJECTIVES: The solid phase gastric emptying scan (GES) is used to confirm the clinical impression of abnormal gastric emptying. There is variability in the interpretation of GES. Determination of initial lag phase of the GES and the emptying half-time (t1/2) is generally performed by curve inspection and thus may suffer from lack of objectivity. The purpose of this study was to develop a physiological model for interpretation of the GES using nonlinear curve fitting. This model resulted in computer-generated best fits for lag time and t1/2, which were analyzed in a group of patients with suspected gastroparesis. METHODS: All gastric emptying scans performed at our institution over a 3.5-yr period were studied. Raw data from these studies were analyzed by nonlinear curve fitting. Using the equation: If (x < xo, plateau, plateau * exp( - K * (x - xo))) data were best fit to a function describing a lag followed by a log linear decay. This model generated four parameters; lag, K, t1/2, and T50%. Forty patients with less than 50% emptying at 1 h (group II) were compared with 31 patients with normal emptying (group I). RESULTS: The nonlinear model resulted in better curve fitting (higher r2) in 59 of 71 studies (81%) when compared with a monoexponential decay after a lag of 0 min. Mean lag for patients in group I was 8.5 +/- 1.2 min and was 25.9 +/- 3.1 min in group II (p < 0.0005). Mean t1/2 was 31.7 +/- 1.8 min in group I and 69.7 +/- 5.0 min in group II (p < 0.007). By adding 2 SD to lag and t1/2 in group I, normal values for these parameters were 21.9 and 52.2 min, respectively. Eleven patients in group II had a prolonged lag alone, 13 had a prolonged t1/2, and 13 had prolongation of both parameters. CONCLUSIONS: A new physiological model for the interpretation of GES is presented. Individual patients with delayed gastric emptying may have increased lag times, a decreased rate of antral emptying, or both abnormalities.