Colonic transit time measurement in mentally retarded persons

A834 AGA ABSTRACTS

GASTROENTEROLOGY Vol. 118, No.4

4388 COLONIC TRANSIT TIME MEASUREMENT IN MENTALLY RETARDED PERSONS. Danny A. De Looze, Myriam A. Van Winckel, Jan Meireleire, Roland P. Beke, Koen J. Mortele, Martine M. De Vos, Univ Hosp, Gent, Belgium; MPI Gielsbos, Gierle, Belgium. Introduction. In persons with mental retardation constipation is a frequent problem, often difficult to treat. The underlying mechanism is unclear and more information about the pathophysiology can be obtained by studying colonic transit time (CIT) in these patients. Aims. The aim of this study was to determine total and segmental CIT s in a group of at random selected persons with moderate to severe mental retardation. Methods. Fifty-eight persons with an IQ < 50 (mean age 36 y, range 17-68 y) were randomly selected from an institution for the mentally retarded with 250 residents. Informed consent was obtained from the parents. Inclusion criteria were: age> 16 y, no swallowing disorders and no scoliosis. All patients received 20 g fibre and 2 liter of fluid daily during the study period. Those with constipation (i.e. less than 3 stools/week) underwent a bowel preparation with polyethylene glycol prior to the CIT measurement. The control group existed of 32 unconstipated healthy volunteers (mean age 34 y, range 21-75 y). CIT was measured after administration of radiopaque markers: 10 daily during 6 days, followed by a plain abdominal X-ray at day 7. The segmental and total CIT s were calculated as the number of markers in each segment multiplied by 2,4. Results. Total and segmental CIT s are summarized in the table. Total and rectosigmoidal CIT were significantly longer in the patient group, compared to controls. Upper normal value for total CIT was 59 h (mean + 2SD). Twenty-eight patients (48 %) had a total CIT above this threshold. Conclusion. Nearly half of the patients with moderate to severe mental retardation have a prolonged total CIT. This is mainly due to prolongation of the rectosigmoidal transit time, suggesting an outlet type of constipation. This could be explained by inadequate central perception of rectal distension resulting in deferal of defecation.

RightCn leftCn Rectosigmoidal en TotalCn

normals

mental retardation

6.5 h(0- 36) 7.3 h(0- 26) 11 h(0- 38) 25 h(0- 69)

16h(0-101) 14h(0-110) 34h(0-101) 64h(0-153)

P< 0,02 PNS P < 0,0001 P< 0,00001

Values expressed inhours (h), mean and range. Statistics. Mann-Whitney Utest

4389 SECONDARY SMOOTH MUSCLE DEGENERATION WITH INCLUSION BODIES IN SLOW TRANSIT CONSTIPATION. Charles H. Knowles, Carole D. Nickols, Mark Scott, Ricardo Brandt de Oliveira, Leila Chimelli, Roger Feakins, Norman S. Williams, Joanne E. Martin, Royal London Hosp, London, United Kingdom; Faculty de Medicine de Ribeiro Preto, Ribeiro Preto, Brazil. Background and aims: Slow transit constipation (STC) is a disorder of intestinal motility of unknown aetiology. Myopathies, including those characterised by the finding of inclusion bodies have been described in enteric disorders. We identified inclusions present in STC patients, and tested whether these were a primary or secondary finding. Patients and methods: Systematic, blinded, dual observer qualitative and quantitative analysis of colonic and ileal tissue from patients with STC (n = 36) compared with selected control populations (n = 101). Results: Round or ovoid (4-22\\m diameter) amphophilic inclusions increased in normals with ageing (r, = 0.05, p < 0.02). Inclusions were a more frequent finding in patients with idiopathic STC compared with age matched controls or patients with rectal evacuation disorders: ileum (33% vs. 9%), ascending (50% vs. 19%, P < 0.05), and sigmoid colon (43% vs, 20%), and were very frequent in the sigmoid (71%) of patients with STC arising after pelvic surgery. The number of inclusions per unit area was significantly higher in patients with STC (p < 0.001). Inclusions were found in all Chagas' patients, but not with aganglionosis, It was not possible to determine inclusion body composition with a wide range of conventional or immunostains. Conclusions: An inclusion body myopathy is identifiable in patients with STC, and may arise secondary to denervation,

4390 THREE-DIMENSIONAL COMPUTER MODELING OF STIMULATED PROPAGATING CONTRACTIONS IN HUMAN COLON USING CIRCUMFERENTIAL ELECTRODES. Peter Z. Rachev, Martin P. Mintchev, Kenneth L. Bowes, Dept of Electrical Engineering, Univ of Calgary, Calgary, AB, Canada; Dept of Surg, Univ of Alberta, Edmonton, AB, Canada. Background. Three-dimensional parametric external modeling of the human colon can describe contractions that are artificially invoked by circumferential sets of electrodes. Synchronization of electrical stimulating patterns applied to these sets implanted along a colonic segment is crucial for real-time microprocessor-controlled recreation of impaired colonic motility. Aim. The aim of the study is to quantify enforced movement of colonic content in terms of real-time contractions and distensions of the colonic wall using parametric model of the human colon and relative

viscosity of the colonic content. Methods. Colonic content was modeled as a viscous incompressible Newtonian fluid. The colonic segment undergoing stimulation was approximated by a cylindrical pipe of arbitrary shape represented as a composition of elementary straight pipe segments of different radii. Poiseuille s theory of viscous pipe flow was applied to quantify the pressure and velocity of the content while it is being pushed down by the contractions invoked by the stimulating electrodes. Results. The simulator allowed for a real-time modeling of synchronized propulsive contractions leading to movement of content in the human colon. It made possible the optimization of the stimulating patterns applied to sets of circumferential electrodes for different types of colonic content. An average stimulating pattern was found to meet the requirements for optimal real-time open-loop microprocessor control of the human colon. The optimal timing of multi-site stimulation for movement of content with different relative viscosity was computed. Conclusion. Artificially produced movement of content in the human colon can be accomplished using real-time microprocessor control of synchronized multi-site sequential stimulation of sets of circumferentially implanted electrodes.

4391 COLONIC PRESSURE GRADIENTS IN HEALTH AND CONSTIPATION. S. N. Reddy, G. Lagmay, D. N. Reddy, P. E. Hyman, W. 1. Snape, Memorial Med Ctr, Long Beach, CA; Sriram Motility Ctr, Hyderabad; Acad Hosp, Orange, CA. Pressure gradients (PGs), in addition to propagating contractions, facilitate the transit of intraluminal contents in the colon. Here we have employed a novel technique to study PGs in the colon from motility data. Colonic motility was monitored 60 min during fasting and 120 min after a meal in 9 healthy adult subjects (4M)and II (3M) with constipation (spastic colon). Intraluminal pressure was recorded from eight segments of the colon using a GIPC Motility system. Motility Index (area under the curve) was estimated as a function of space (proximal to sigmoid colon) and time (every 5 min) resulting in a 3D pressure profile. From this, aborad (orad) PG was assumed if pressure was greater at a given site than at the adjacent two or more distal (proximal) sites. Postprandial data was normalized to one hour to correspond with fasting data. Also, the site with the highest pressure (from proximal to sigmoid colon) was traced as a function of time. RESULTS: Aborad whole colonic PGs occurred just 5 times in all healthy subjects, while orad whole colonic PGs never occurred. Neither occurred in any constipation patients. The high pressure segment tended to be within the mid colon 81:±:8% of the time in healthy subjects. It varied during fasting and shifted to the lower colon (80:':: 13%) of the time in constipation. In healthy subjects, during fasting, orad PGs occurred 30.8:'::11.7% of the time and aborad PGs 42.5:±:15.8% of the time - with no significant difference. After eating, orad PGs occurred 45.8:'::9.2% of the time, again not significantly different from aborad 46.6::':5.0%. In constipation, during fasting, orad PGs occurred 26.7::':9.2% of the time, not significantly different from 34.2::':19.2% of aborad PGs. However, after eating, the orad PGs occurred 63.3::':24.2% of time, signficantly (p<0.02) higher than aborad PGs which occurred 26.7::':22.5% of the time. The time of postprandial orad PGs was also significantly (p<0.02) higher than that of fasting orad PGs. In COLNCLUSION, a) 3D pressure profiles enable us to study movements and transit within the colon; b) healthy subjects demonstrate pressure gradients consistent with storage and absorption function of the colon in that the PGs are centered around transverse colon; and, c) unfavorable pressure gradients, combined with high pressures in the lower colon, contribute to constipation by slowing down transit. Therapeutic measures aimed at altering pressure gradients and decreasing high pressure zones in the lower colon should help alleviate constipation in patients with spastic colon.

4392 COLONIC DIVERSION FOR INTRACTABLE CONSTIPATION IN CHILDREN: COLONIC MANOMETRY GUIDES CLINICAL DECISIONS. Tsili Zangen, Carlo Di Lorenzo, Sam Zangen, Jose Cocjin, S. Naru Reddy, Alejandro F. Flores, Thanh Le, Paul E. Hyman, Children's Hosp of Orange County, Orange, CA; Acad Hosp of Pittsburgh, Pittsburgh, PA; NewtonWellesley Hosp, Newton, MA. Colonic manometry discriminates functional and behavioral causes for childhood constipation from colonic neuromuscular disease. Based on colonic manometries that showed either no contractions, or an absence of the gastrocolonic response and high amplitude propagating contractions, we recommended diverting colostomies in II children (mean age 4y, range 2-14 y, 7 male). Prior to study, all children failed medical management and had radiologic documentation of persistently dilated colons. These children had pathologic diagnoses of intestinal neuronal dysplasia (4), hypoganglionosis (2), hollow visceral myopathy (1), solitary rectal ulcer (I), and normal (3). Six months to 2.5 y following diversion we restudied all children. We used propofol and midazolam anesthesia to facilitate endoscopic placement of a manometry catheter through the anus to the ostomy. We confirmed catheter position with fluoroscopy, then studied fasting Ih, postprandial I h, and the effect of bisacodyl 0.2 mg/kg. up to 5 mg. Ten of II previously dilated diverted colons were no longer dilated. In 2 cases, abnormal motility involving the entire colon was unchanged from the initial study, and we recommended no further surgery. In 6 cases, the left colon remained abnormal, but the right colon was normal, and we recom-