Constipation
Charles A. Ternent, M.D., FACS, FASCRS
The Colon & Rectal Clinic of Fort Lauderdale
Fort Lauderdale, Florida
Definition: Constipation encompasses symptoms of infrequent and difficult evacuation. [1] The diagnostic criteria for functional constipation according to the Rome III consensus include two or more of the following symptoms; straining, lumpy or hard stools, sensation of incomplete evacuation, sensation of anorectal obstruction and manual maneuvers to facilitate defecation more than 25 percent of the time, and less than three unassisted defecations per week. These symptoms need to be present for at least three days per month during the previous three months with symptom onset at least six months prior to diagnosis. Loose stools must be rarely present without the use of laxatives and there must be insufficient criteria for irritable bowel syndrome (IBS). [2] The Rome III diagnostic criteria for IBS include abdominal pain or discomfort at least three days per month in the previous 3 months (symptom onset more than 3 months prior to diagnosis) with two or more features: improvement with defecation, onset associated with a change in frequency of stool and/or change in the form of stool. Subclassification into constipation predominant IBS (IBS-C) based on the Rome III criteria also requires the presence of Bristol Stool Form Scale types 1 and 2. [2]
Evaluation: A history and physical examination is initially carried out in order to identify “alarm signs and symptoms” such as a family history of colorectal cancer, anemia, heme-positive stools or hemochezia which would require endoscopic evaluation. [3,4] A history and physical examination can also identify dietary, endocrine, metabolic and other physiologic causes of constipation. [5] Selective use of bloodwork to rule out hypothyroidism and hypercalcemia may also be helpful. Furthermore, an adequate history with emphasis on the evacuatory process may help to delineate a slow transit constipation problem from one of outlet obstruction. Both can coexist in the same patient and irritable bowel syndrome can mask as slow transit or obstructed defecation and may be difficult to consistently sort out with a history and physical exam alone. A digital rectal examination may help to identify the presence of an anorectal mass or stricture, paradoxical puborectalis activity, rectocele or rectal intussuception which may be associated with obstructed defecation. Sigmoidoscopy may be helpful as well. However, evidence in the literature is lacking to support the routine use of blood work, radiographic studies or endoscopy in patients with constipation without alarm symptoms according to a systematic review by Rao and coworkers. [6]
Anorectal physiology testing and colon transit studies may help to classify the etiology of refractory chronic constipation into slow transit, outlet obstruction types and normal transit constipation or constipation predominant irritable bowel syndrome. The balloon expulsion test has been used as a screening test for pelvic floor dyssynergia (PFD). Prospective data on balloon expulsion testing has a high specificity and negative predictive value in ruling out PFD. [7] Anorectal manometry and anal canal plug EMG analysis showing lack of relaxation of the external anal sphincter at strain may help to confirm PFD. Presence of the rectoanal inhibitory reflex using the balloon distention test helps to rule out the presence of Hirshprung’s disease. Defecography is useful in identifying sources of outlet obstruction such as rectal intussuception, paradoxical puborectalis activity and rectocele. [8] A colon transit study using ingestion of radioopaque markers may help to document slow transit constipation. Colon transit analysis may also document normal transit in patients with constipation symptoms. Thereby raising suspicion for the presence of constipation predominant IBS.
Nonoperative management of constipation: Conservative management is the initial treatment of choice for patients with constipation symptoms. [9] A high fiber diet (25 gm / day) has been shown to increase stool frequency in constipated patients. The addition of 1.5 to 2 liters of fluid per day to a high fiber diet has been shown to improve stool frequency further in a randomized clinical trial of constipated patients. The use of psyllium and lactulose has been shown to improve symptoms of constipation according to a systematic review of the literature. [10] Furthermore, a British prospective non-randomized study found that the isphagula husk was a better therapy for patients with constipation than lactulose or other laxatives. [11] The use of various laxatives including senna, bysicodyl, sodium docusate and milk of magnesia for chronic constipation has been evaluated by a metanalysis of 11 large controlled studies with findings of a slight and not statistically significant increase in the stool frequency and stool weight when compared to placebo. [12] Polyethylene glycol, tegaserod maleate and lubiprostone have been independently shown to be effective in the treatment of constipation by prospective randomized clinical trials. [13-15] Patients with PFD and documented paradoxical puborectalis activity benefit from therapy with neuromuscular retraining or biofeedback as primary treatment in order to learn adequate relaxation of the puborectalis muscle with straining. [16] A recently published randomized controlled trial showed that instrumented biofeedback was more effective than diazepam or placebo for the treatment of pelvic floor dyssynergia-type constipation. [17]
Surgical management of constipation: Surgical approaches to chronic constipation should only be entertained after conservative medical management has failed and after thorough preoperative workup. The treatment of choice for documented refractory slow transit constipation based on non-randomized data is a subtotal colectomy with ileorectal anastomosis (STC-IRA). [18] Success rates for STC-IRA for chronic refractory slow transit constipation vary between 89 and 100 percent in patients that have been preoperatively worked up with anorectal physiology tests and colon transit studies. [18] Success rates for subtotal colectomy without complete preoperative physiologic work up and for segmental colectomy for slow transit constipation are low and should be avoided. Similarly, patients with documented normal transit constipation need to be identified and treated conservatively. Patients with combined slow transit constipation and pelvic outlet obstruction such as PFD, anismus or paradoxical puborectalis as well as symptomatic refractory retaining rectoceles and rectal intussuception benefit from STC-IRA and repair or treatment of the outlet obstruction causing pathology. [19-23]
Surgical management of obstructed defecation includes the repair of non-emptying rectoceles, usually greater than 4 cm in size and those benefiting from posterior vaginal pressure. [24] Surgical repair of a symptomatic refractory rectocele can be performed via transvaginal, transanal or transperineal techniques. Transvaginal and transanal techniques appear to have similar functional results, but further data is needed with regards to the transperineal route and the use of mesh. [25-26] Transanal stapled repair of rectoceles and intussuception has been recently studied in a prospective non-randomized fashion with significant improvement in obstruction symptoms. Long-term studies as well as studies comparing the various modalities are needed. [27-28]
References:
1. Brandt LJ, Schoenfeld P, Prather CM, et al. An evidence based approach to the management of chronic constipation in North America : American College of Gastroenterology Task Force. 2005;100:S1-S4.
2. Longstreth GF, Thompson WG, Chey WD, et al. Functional bowel disorders. Gastroenterol 2006;130:1480-1491.
3. Stewart WF, Liberman JN, Sandler RS, et al. Epidemiology of constipation (EPOC) study in the United States : relation of clinical subtypes to sociodemographic features. Am J Gastro 1999;94:3530-3540.
4. Drossman DA, Corazziari E, Talley NJ, et al. Functional bowel disorders in Rome II: the Functional Gastrointestinal Disorders: diagnosis, pathophysiology, and treatment: a multinational consensus. Senior editor: Drossman DA, 2nd ed. 2000;352-97.
5. Thornton MJ, Lubowski DZ. An overview in Complex anorectal disorders: investigation and management. Editors: Wexner SD, Zbar AP, Pescatori M. Springer-Verlag London Limited 2005:412-428.
6. Rao SS, Ozturk R, Laine L. Clinical utility of diagnostic tests for constipation in adults: a systematic review. Am J Gastroenterol 2005;100(7):1605-15.
7. Minguez M, Herreros B, et al. Predictive value of the balloon expulsion test for excluding the diagnosis of pelvic floor dyssynergia in constipation. Gastroenterology 2004;126(1):57-62.
8. Dobben AC, Wiersma TG, et al. Prospective assessment of interobserver agreement for defecography in fecal incontinence. Am J Roentgenol 2005;185(5):1166-72.
9. Voderholzer WA, Schatke W, Muhldorfer BE, et al. Clinical response to dietary fiber treatment of chronic constipation. Am J Gastroenterol 1997;92:95-98.
10. Anti M, Pignataro G, Armuzzi A, et al. Water supplementation enhances the effect of high-fiber diet on stool frequency and laxative consumption in adult patients with functional constipation. Hepatogastroenterology 1998;45:727-32.
11. Dettmar PW, Sykes J. A multi-centre, general practice comparison of ispaghula husk with lactulose and other laxatives in the treatment of simple constipation. Curr Med Res Opin 1998;14(4):227-33.
12. Ramkumar D, Rao SS. Efficacy and safety of traditional medical therapies for chronic constipation: systematic review. Am J Gastroenterol 2005;100(4):936-71.
13. Cleveland MV, Flavin DP, et al. New polyethylene glycol laxative for treatment of constipation in adults: a randomized, double-blind, placebo controlled study. South Med J 2001;94(5):478-81
14. Evans BW, Clark WK, et al. Tegaserod for the treatment of irritable bowel syndrome. The Cochrane Database of Systematic Reviews. 2006;Issue 2
15. McKeage K, Plosker GL, Siddiqui MA. Lubiprostone. Drug 2006;66(6):873-9.
16. Chiaroni G, Whitehead WE, Pezza V, et al. Biofeedback is superior to laxatives for normal transit constipation due to pelvic floor dyssynergia. Gastroenterology 2006;130(3):657-64.
17. Heymen S, Scarlett Y, Jones K, et al. Randomized, controlled trial shows biofeedback to be superior to alternative treatments for patients with pelvic floor dyssynergia-type constipation. Dis Colon Rectum 2007;50:428-441.
18. Knowles CH, Chir B, Scott M, et al. Outcome of colectomy for slow transit constipation. Ann Surg 1999;230(5):627
19. Pemberton JH, Rath DM, Ilstrup DM. Evaluation and surgical treatment of severe chronic constipation. Ann Surg 1991; 214:403–411.
20. Christiansen J, Rasmussen OO. Colectomy for severe slow-transit constipation in strictly selected patients. Scand J Gastroenterol 1996; 31:770–773.
21. Lahr SJ, Lahr CJ, Srinivasan A, et al. Operative Management of severe constipation. Am Surg 1999;65(12):1117-21.
22. Zenilman ME, Dunnegan DL, Soper
23. Nyam DC, Pemberton JH, Ilstrup DM, Rath DM. Long-term results of surgery for chronic constipation. Dis Colon Rectum 1997; 40:273–279.
24. Mellgren A, Anzen B, Nilsson BY, Johansson C, Dolk A, Gillgren P, Bremmer S, Holmstrom B. Results of rectocele repair. A prospective study. Dis Colon Rectum 1995;38:7-13.
25. Ayabaca SM, Zbar AP, Pescatori M. Anal continence after rectocele repair. Dis Colon Rectum 2002;45:63-69.
26. Watson SJ, Loder PB, Halligan S, Bartram CI, Kamm MA, Philips RK. Transperineal repair of symptomatic rectocele with Marlex mesh: a clinical, physiological, and radiological assessment of treatment. J Am Coll Surg 1996;183:257-261.
27. Corman ML, Carriero A, Hager T, Herold A, Jayne DG, Lehur PA, Lomanto D, Longo A, Mellgren AF, Nicholls J, Nystrom PO, Senagore AJ, Stuto A, Wexner SD. Consensus conference on the stapled transanal rectal resection (STARR) for disordered defaecation. Colorectal Dis. 2006 Feb;8(2):98-101.
28. Boccasanta P, Venturi M, Stuto A, Bottini C, Caviglia A, Carriero A, Mascagni D, Mauri R, Sofo L, Landolfi V. Stapled transanal rectal resection for outlet obstruction: a prospective, multicenter trial. Dis Colon Rectum 2004;47(8):1285-96; discussion 1296-7.