Anorectal Dysfunction in Constipated Women With Anorexia Nervosa

Anorectal Dysfunction in Constipated Women With Anorexia Nervosa GIUSEPPE CHIARIONI, MD; GABRIO BASSOTTI, MD, PHD; ANTONELLA MONSIGNORI; MONICA MENEGOTTI; LARA SALANDINI; GIORGIO DI MATTEO, MD; hALO AND WILLIAM

E. WHITEHEAD,

MD;

PHD

• Objective: To evaluate anorectal and colonic function in a group of patients with anorexia nervosa complaining of chronic constipation. • Patients and Methods: Twelvewomen (age range, 19-29 years) meeting the criteria for anorexia nervosa and complaining of chronic constipation were recruited for the study. A group of 12 healthy women served as controls. Colonic transit time was measured by a radiopaque marker technique. Anorectal manometry and a test of rectal sensation were carried out with use of standard techniques to measure pelvic floor dysfunction. A subgroup of 8 patients was retested after an adequate refeeding program was completed.

• Results: Eight (66.7%) of 12 patients with anorexia nervosa had slow colonic transit times, while 5 (41.7%) had pelvic floor dysfunction. Colonic transit time normalized in the 8 patients who completed the 4-week refeeding program. However, pelvic floor dysfunction did not normalize in these patients. • Conclusions: Patients with anorexia nervosa who complain of constipation have anorectal motor abnormalities. Delayed colonic transit time is probably due to abnormal eating behavior. Mayo Clin Proc. 2000;75:1015-1019

M

ost patients with eating disorders complain of constipation as a frequent and disabling symptom.P This is particularly common in anorexia nervosa, in which up to 90% of patients complain of constipation, bloating, or both. Anorexia nervosa affects 2% to 5% of high school- and college-aged women' and has severe morbidity and mortality (mostly suicide and malnutrition). The disease is characterized by fear of fatness, and constipation and bloating may aggravate this fear. However, it is unclear whether constipation in these patients is attributable to a pathophysiological abnormality, perhaps related to the primary disorder, or whether it represents a distorted perception of body function, as is believed for other symptoms in this condition." To date, constipation in anorexia nervosa has been investigated in only 2 studies, one that evaluated gastrointestinal transit by means of radiopaque markers and lactulose breath tests,' and the other that explored anorectal function

with use of manometric techniques," The results of these studies were divergent, so it is unknown whether constipation in women with anorexia nervosa is a real phenomenon or is mostly due to an altered self-reporting of the symptom. We found no report of the effects of refeeding on physiologic parameters in the same patients studied initially. The aim of the present study was therefore to assess colonic transit time and anorectal manometric variables in a group of anorexia nervosa patients complaining of constipation as a disabling symptom. Most patients were restudied after a 4-week refeeding treatment program. PATIENTS AND METHODS

Patients and Controls Twelve women with anorexia nervosa (age range, 19-29 years) were recruited for the study. The diagnosis of anorexia nervosa was made according to the criteria of the American Psychiatric Association.' The patients were referred by psychiatrists for severe malnutrition, and all complained of chronic constipation, which they perceived as a disabling symptom. All patients also took at least 1 laxative dose per week. Constipation was defined as fewer than 2 bowel movements per week for at least 9 months. Straining in at least 1 of 4 defecations or lumpy or hard stools in at least 1 of 4 defecations were also present; the patients thus met the diagnostic criteria for functional constipation according to Rome II classification." No patient had organic causes responsible for constipation or previous abdominal surgery, except appendectomy. Three patients were taking

From the Division of Gastroenterological Rehabilitation. Valeggio sui Mincio Hospital. University of Verona Medical School. Verona. Italy (G.C.• M.M., L.S.• I.V.); Gastrointestinal Motility Laboratory, Gastrointestinal and Hepatology Section, Department of Clinical and Experimental Medicine. University of Perugia Medical School (G.B.), and Nutrition and Diabetology Unit, Perugia General Hospital (A.M., G.o.). Perugia, Italy; and UNC Center for Functional Gastrointestinal and Motility Disorders. Division of Digestive Diseases and Nutrition. Department of Medicine. University of North Carolina at Chapel Hill. Chapel Hill (G.B.• W.E.W.). Address reprint requests and correspondence to Gabrio Bassetti, MD. PhD, Sezione di Gastroenterologia ed Epatologia, Via Enrico Dal Pozzo, 06100 Perugia, Italy (e-mail: [email protected]). Mayo Clin Proc. 2000;75:1015-1019

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1016 Anorectal Function in Anorexia Nervosa

antidepressant drugs (amitriptyline, desipramine) prescribed by the referring psychiatrists, and this therapy was maintained during the study. Patients were studied during hospital admission and monitored to minimize surreptitious use of laxatives or purging. Colonic transit studies and anorectal manometric investigations were carried out in the second week of the hospital admission in all 12 patients. These studies were repeated after refeeding in 8 patients who had delayed colonic transit times initially. Treatment consisted of a gradually increasing energy intake up to about 8400 kl/d. The other 4 patients with normal colonic transit refused further procedures after the basal evaluation was carried out. Twelve healthy women (age range, 21-41 years) were recruited as controls for anorectal manometry variables. All patients and controls gave informed consent for the study, and this was carried out in accordance to the local ethical guidelines. Study Methods After 1 week of hospitalization and laxative withdrawal, patients underwent colonic transit time studies." This time interval was considered necessary to minimize the influence of purging. Colonic transit time studies were done while patients were consuming a high-residue diet containing at least 15 to 20 g of fiber daily. On study day 1, patients ingested 20 radiopaque markers; on day 5, a plain x-ray abdominal film was taken. During the study, patients did not use laxatives, prokinetic agents, or enemas. Anorectal manometry and a test of rectal sensation were done with use of previously described standard techniques and instrumentation.'? Briefly, a 9-lumen, commercially available polyvinyl chloride anorectal catheter with terminal rubber balloon (Arndorfer Medical Specialties type ARM-3), connected via physiological pressure transducers (Bell & Howell type 4-327-1) to a low-compliance infusion pump (Arndorfer Medical Specialties; perfusion rate 0.5 mL/min) and to a recorder (Beckman R-611 Dynograph; paper speed, 1 mm/s), was used. After recording the rectoanal pressure profile with stepwise withdrawal (1 cml 30 s), the anal resting tone was recorded for 5 minutes with the perfusion ports on the catheter fixed at the highest pressure point obtained during 2 pull-throughs. Then the rectosphincteric inhibitory reflex was evaluated by inflating and rapidly deflating the balloon on the tip of the catheter (ie, in the rectum) with 10, 20, 30, 50, 70, and 100 mL of air. For testing the rectal sensation, a single-lumen polyvinyl chloride catheter (outer diameter, 4.1 mm) with a 7-cmlong unstretched condom tied to its tip was used. The catheter was connected to the pressure transducer, and

Mayo Clin Proc, October 2000, Vol 75

pressures were recorded at a paper speed of 0.25 mm/s. The balloon was placed with its distal portion about 5 em from the anal margin and inflated by handheld syringe with 50mL increments of air every 60 seconds until the maximum rectal tolerable volume was reached. Finally, all patients and controls were asked to expel (in a seated position) a 50-mL water-filled balloon inserted into the rectum. Data Analysis For colonic transit time, the total number of radiopaque markers still present in the colon was counted at day 5 and expressed as a percentage. The normal upper limit for our laboratory is 20% or less of ingested markers still present at day 5. For anorectal manometry and the test of rectal sensation, the following parameters were taken into account: (1) maximum basal pressure of the anal sphincter, defined as the mean of the highest resting pressures recorded from each of the 4 ports during 2 pull-throughs"; (2) minimum relaxation volume, defined as the lowest rectal balloon distention that elicited a rectoanal inhibitory reflex, a drop in pressure more than 5 mm Hg I2. 13; (3) defecatory sensation threshold, defined as the lowest volume at which the first desire to defecate was reported by the patient!"; (4) maximum rectal tolerable volume, defined as the maximum volume of air that could be infused into the rectal balloon until an intolerable urge to defecate, pain, or expulsion of the balloon itself caused the patient to request termination of the procedure"; and (5) response to straining, evaluated by observing whether straining to defecate caused a decrease in intra-anal pressure (normal response) or a paradoxical increase in intra-anal pressure (dyssynergia). 16 Statistical Analysis This was carried out with use of nonparametric tests, adopting the Mann-Whitney U test, the Wilcoxon rank sum test, and the X2 test, where appropriate. Values of P<.05 were chosen for rejection of the null hypothesis. Data are presented as mean ± SO. RESULTS Table I shows overall demographic, clinical, and manometric data of the 12 anorexia nervosa patients who participated in the first part of the study. Comparison with manometric data obtained in controls revealed that significant differences were found concerning resting anal pressure (50.6±19.1 mm Hg in patients vs 83.1±24.4 mm Hg in controls; P=.003); threshold for urge to defecate (l21±86.5 mL in patients vs 58.3±19.5 mL in controls; P=.Ol); and pelvic floor dyssynergia (41.7% in patients vs 0% in con-

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Anorectal Function in Anorexia Nervosa 1017

Table I. Demographic, Clinical, and Manometric Variables in 12 Anorexic Patients Complaining of Chronic Constipation and in 12 Controls*

Age (y) Weight (kg) BMI (kg/m") No. (%) who complained of constipation No. (%) with slow CTT Resting anal pressure (mm Hg) MRV(mL) Defecatory threshold (mL) MRTV (mL) No. (%) with dyssynergia

P value

Patients

Controls

23.7±3.2 35.7±2.8 13.1±1.6

26.2±4.3 48.2±2 22.4±1.8

.08 <.05 <.05

12/12 (100) 8/12 (66.7) 50.6±19.1 14±5 121±86.5 342±1l8 5/12 (41.7)

0/12 (0)

<.05

83.1±24.4 12±5 58.3±19.5 262±64 0/12 (0)

.003 .09 .01 .10 <.05

*All

values are mean ± SD unless indicated otherwise. BMI = body mass index; CTT = colonic transit time; MRTV = maximum rectal tolerable volume; MRV = minimum relaxation volume.

trols; P<.05); the other manometric variables were not significantly different. Of the 3 patients taking antidepressant drugs, 2 had normal colonic transit times, and 1 had slow transit time. All 5 patients with pelvic floor dyssynergia were unable to expel the balloon, whereas this was accomplished by the remaining patients and all controls. Table 2 shows clinical and manometric variables in the 8 patients with delayed colonic transit times who were restudied after the 4-week refeeding program was completed. Analysis of these data showed that the clinical variables improved, with an average gain in body weight of 8.4 kg and a body mass index that reached the lower limit of normal values for the Italian population. No statistical differences were found in manometric variables before or after refeeding, whereas colonic transit time normalized in all 8 patients. DISCUSSION Patients with anorexia nervosa may display motor abnormalities of the upper gut, including delayed gastric emptying. 17- 19 Many patients also complain of debilitating constipation, but it is unclear whether this complaint is due to a gastrointestinal pathophysiological process or represents a manifestation of distorted bodily perception. Unfortunately, the available data are few. Kamal et aP studied the overall delay in gastrointestinal transit time in 8 patients with anorexia nervosa compared with controls. Analysis of individual patients revealed slow colonic transit time in only 50% of these patients. No anorectal manometric tests were performed. Another study by Chun et al" in 13 patients with anorexia nervosa showed that, despite complaints of severe constipation, colonic transit time was normal or returned to normal in most

patients after a weight maintenance diet lasting at least 3 weeks. Anorectal motility test results were also normal. However, the patients were studied at different intervals from the date of hospital admission, and conditions of nutrition were likely to be nonhomogeneous. The present study investigated anorexia nervosa patients in poor nutritional balance in whom constipation was a disabling symptom. The findings showed that these patients display several anorectal motor abnormalities compared with controls. These findings suggest that increased defecatory perception thresholds and altered expulsion dynamics could be the cause of constipation." In addition, 66.7% of our patients had slow colonic transit. After an adequate refeeding period, colonic transit times normalized, whereas anorectal variables remained unchanged. These results suggest that at least some patients with anorexia nervosa may have anorectal motor impairment as a cause of constipation, whereas abnormalities in colonic transit could reflect altered eating behavior, as demonstrated by the normalization of this parameter after completion of a successful refeeding program. The importance of diet and energy intake on colonic transit has been previously shown in elderly patients complaining -of constipation." Our results are at variance with those reported by Chun et al.? These discrepancies may be due to a more homogeneous nutritional status in our study and to differences in techniques. Eight of 12 patients were studied twice at programmed intervals of hospitalization, which enabled us to more accurately compare starvation to the fed condition. Constipated patients with anorexia nervosa seem to have an anorectal dysfunction similar to that described in severe chronic idiopathic constipation, which usually af-

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1018 Anorectal Function in Anorexia Nervosa

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Table 2. Clinical and Manometric Variables Before and After Refeeding Program in 8 Patients With Anorexia Nervosa and Delayed Colonic Transit*

Weight (kg) BMI(kg/m 2) Resting anal pressure (mm Hg) Defecatory threshold (mL) MRTV(mL) No. (%) with dyssynergia CTT (% retained markers)

*All values are mean CTT

Basal

After refeeding

P value

36.6±2 13±2 41.5±10 l50±92.6 4l2.5±64 1/8 (12.5) Delayed (>80)

45±2.2 l7±1.5 47±15 100±53.4 356±49.5 1/8 (12.5) Normal (5)

.06 .06 .08 .08 .09 .10 <.05

± SD unless indicated otherwise. BMI = body mass index;

= colonic transit time; MRTV = maximum rectal tolerable volume.

fects young women.P'? We cannot completely exclude cathartic damage to the colon due to the use of laxatives, but large bowel transit normalized after the refeeding program was completed. This suggests that the colon was not damaged by cathartic use. Moreover, there is no good evidence that laxatives actually damage colonic structures." In patients with chronic constipation, rectal sensation may be improved by fiber supplementation," but refeeding did not change the blunted rectal sensation in our patients. Rectal sensation has been reported to be more severely impaired in patients with rectosigmoid fecal stasis. 22,24 We cannot be certain that our patients exhibited rectosigmoid fecal stasis because the radiopaque markers technique we used is not suitable for determination of segmental colonic transit. However, rectal stasis is what would be anticipated from the paradoxical pelvic floor contractions observed during straining in our patients. In healthy volunteers, intermittent painless rectal balloon distention slows gastrointestinal transit of a solid meal." Another study showed that colonic fecal loading eventually leads to delayed gastric emptying in healthy controls." Since disturbed gastric transit has been described in patients affected by anorexia nervosa,'?"? delayed large bowel transit and anorectal dysfunction in such patients could perpetuate or contribute to altered eating behavior through reflex pathways. Colonic transit time in malnourished patients with anorexia nervosa normalized after an adequate nutritional program was completed. We have no explanation for the persisting anorectal dysfunction and its meaning. However, these findings suggest that persisting anorectal dysfunction may increase the chance of relapse of anorexia. Additional studies are needed to investigate proximal and distal gut motor activity and its relationships with food intake and symptoms in anorexia nervosa.

In conclusion, we have shown that a group of malnourished patients with anorexia nervosa who complain of chronic constipation display anorectal sensorimotor abnormalities that persist after a refeeding program of 4 weeks. This anorectal dysfunction may identify patients at risk for symptoms relapse. Slowed colonic transit was found in most of these patients. To our knowledge, this is the first longitudinal study to be reported in literature that shows normalization of this variable with diet. We confirm the impression gained from previous studies that the mainstay of the therapy in constipated patients with anorexia nervosa is refeeding. Alternative therapies for persistent constipation in such patients should be considered for nonresponders, and these therapies will most likely focus on anorectal retraining techniques.

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