Constipation is a common problem for any individual with a colon, both those with an intact anus and those with colostomies. Constipation is rarely a problem with ileostomates. This article will discuss basic colonic function, methods of evaluation and treatment options.
Normal Bowel Function
Bowel function has characteristics we can measure and subjective components. From a frequency range, 90% of people with a colon will have a range of 3 bowel movements per day to a movement every 3 days. In 1999, an international group of physicians met in Rome and described a set of criteria listed in Table 1. Constipation is common and a major medical complaint in the United States. It results in approximately 2.5 million medical visits each year, supports a huge pharmaceutical sector, often results in a poor quality of life for patients but is rarely associated with life-threatening problems. Constipation is one of many functional bowel disorders whose symptoms greatly overlap. The most recent surveys in the United States were collected in 1987 and calculated that constipation occurred in 2-28% of women. It was 5-10 times more common in women than men. Constipation can be due to causes listed in Table 2 or have no identifiable cause (idiopathic constipation).
A patient's history is important, but can be difficult and time consuming for a medical provider to obtain. Detailed information about bowel habits is necessary and should include frequency, consistency, timing of and difficulty with bowel movements. Accurate information is often better obtained if the patient keeps a log. The age of onset may suggest a problem the patient is born with (Hirschsprung's disease) or a condition that the patient develops. Other symptoms may suggest an illness associated with constipation (Table 2). Medications, including laxatives, and metabolic and endocrinologic conditions are known to affect bowel function. Previous operations may result in anatomic abnormalities which should be pursed. The evaluation process is directed at identifying causes that will respond to specific therapy.
The provider should conduct a complete examination to exclude an underlying illness. Special attention should be directed at the abdomen and perineum. The abdomen should be observed for the protuberant shape associated with excessive retained stool, surgical scars, hernias, or the location, size, and characteristics of any stoma. The perineal examination is helpful to eliminate anatomic causes of constipation (eg. tumors, fissures [tears], or anal narrowing). Evidence of fecal soiling can be appreciated from examining the patient's underwear or perianal area. A rectal examination or digitations of a colostomy demonstrates the presence and consistence of stool and the function of the anorectal muscles. To complete the examination, anoscopy, proctoscopy, or other endoscopic examination of the distal intestinal tract are performed to exclude pathology such as tumors, inflammatory bowel disease, or prolapse.
If the history and physical examination fail to identify an etiology for the constipation, additional studies are indicated. An anatomic study of the colon, either colonoscopy or barium enema, excludes an anatomic cause for the constipation(e.g. stricture or an obstructing lesion from a cancer). To access objectively the rate at which material moves through the colon a transit study can be performed. Several types of transit studies are available. One of the simplist involves taking a capsule of markers by mouth and obtaining abdominal x-rays to document the progress of markers through the colon. I usually have the patient take a marker capsule (Konsyl pharmaceuticals, Ft. Worth, TX) on Sunday night and obtain an abdominal x-ray on Monday, Wednesday, and Friday (Figure 1). The capsule contains 24 markers. Normal people will pass 80% of the markers by day 3. The number of markers on the x-ray and their distribution in the colon helps decide how slow the colon is and if certain portions are not working. Other variations of the test involve the numbers of capsules injested and the number and timing of x-rays. Other tests to evaluate intestinal function include an upper gastrointestinal contrast study(UGI), oral cecal transit using a breath hydrogen test, and scintographuc nuclear medicine studies. With the UGI and small bowel follow-through, the patient ingests liquid barium and x-rays are obtained as the contrast material moves through the intestine. The study can identify abnormalities of the stomach and small intestine and can demonstrate the speed at which thick liquids move. In the breath hydrogen test, the patient is given a fermentable non absorbed material like sorbitol by mouth. When the sorbitol reaches the patient's cecum (first part of the large intestine), the colonic bacteria metabolize the sorbitol and prodice hydrogen gas which is absorbed from the cecum, and expelled out the lungs. By measuring the level of hydrogen gas in a patient's breath, one can determine how long it took for the sorbitol to go from the mouth to the cecum. An important component of bowel movements in patients without a stoma in the function of the rectum and anus. Several tests are available to evaluate the anus and rectum. Manometry uses catheters to measure the pressure and reflexes of the anal and rectal muscles. In some diseases like Hirschsprung's disease rectal reflexes are absent. Balloon expulsion is a simple functional test of rectal or outlet function. The provider places a balloon into the rectum and inflates to a specific volume, uisually about 60 cc. The balloon acts like a piece of stool. The patient is then asked to expel the balloon like they would with a bowel movement. If the patient's anus and rectum work normally, they should be able to expel the balloon. Inability to pass the balloon suggests outlet obstruction. With cenedefecography, thick contrast material (that acts like artifical stool) is inserted into the rectum and distal colon. The patient is then asked to sit on a special commode and expel the contrast while video x-ray pictures are taken. The x-ray pictures show how the rectum is functioning during a bowel movement. Anatomic or functional abnormalities of defecation are demonstrated. If the evaluation fails to identify a cause of constipation the patient is considered to have idiopathic constipation. The studies described above help determine whether just the colon is involved (idiopathic colonic inertia), the anus and rectum are the problem (outlet obstruction) or there are problems with both.
The first priotity is to treat any underlying condition. Hypothyroidism responds to treatment with thyroid hormone (Synthyroid) and Hirschsprung's disease is treated surgically with a pullthrough procedure. Patients felt to have idiopathic constipation should receive an adequate trial of medical therapy. The mainstay of therapy is diet. It should include at least 14 grams of crude fiber per day with adequate hydration. The type of fiber is less important than getting the patient to take it. All bulking agents (Table 3) working by increasing the volume and water content of stool. Therefore adequate fluid intake is important. Symptoms of bloating or abdominal cramps are diminished in the fiber therapy is started at low amounts and increased gradually. Exercise has many health benefits and regular vigorous activity assists in bowel function. If the bulking agents fail to relieve symptoms, other agents or techniques may be tried. Simple dietary additions such as prunes or juices should be tried. Many of the products we use for more serious constipation are modified from bowel cleansing preparations originally designed for surgery or colonoscopy (Table 4). For example polyethylene glycol solutions (Miralax, Braintree Laboratories or Glycolax, Reed and Carnick) or sodium phosphate tablets (Visacol) have been helpful in patients unresponsive to fiber. Tegaserod (Zelnorm, Novartis) is a drug that is approved to treat women with constipation symptoms associated with irritable bowel syndrome. Stimulate laxatives also have a role in refractory patients. Daily use is avoided unless absolutely necessary. The lowest amount necessary is used and varying the medication may be helpful. SennaPrompt (Konsyl Pharmaceuticals, Fort Worth, TX) is a capsule that contains fiber with a lose dose of sennacot. Enemas may also assist in bowel training to attempt to empty the colon at regular intervals. The goal in treating constipated patients is reduction of symptoms and improvement in life style. If this goal cannot be achieved safely with medication, a surgical option merits consideration.
The patient with persistent symptoms despite an adequate evaluation and course of medical therapy may benefit from surgical therapy. It is difficult to decide when we have tried hard enough with medical therapy to "cure" the patient's symptoms. Operations for constipation have been looked on with disapproval by parts of the medical community. This stems in part by inadequate evaluations or misuse of surgical therapy in the past. Today we see constipated patients who suffer from a degree of disability that would not consider acceptable if their condition had a more "legimate" diagnosis. Often tyese patients dramatically respond to surgical procedures and are extremely grateful. Matching the patient with the appropriate procedure continues to be difficult. Utilization of the methods described previously assists in this decision. As in all interventional procedures, the risks must be weighed against the possible benefits. Any procedure should relieve or significantly improve the patient's symptoms and have an acceptable degree of risk. The risks of a colonic resectionnare related to the anastomosis (leak, stricture) and the anesthesia required to accomplish the procedure. The potential risks of an anorectal procedure are incontinence or failure to improve symptoms.
In patients with slow colonic transit or colonic inertia, the most successful procedure has been total abdominal colectomy and ileorectal anastomosis. The technique uses an end-to-end anastomosis with either a circular intralumenal stapler or a one or two-layered hand-sewn anastomosis at the level of the sacral promontory. This area of the rectum has a good blood supply and leaves an adequate rectal reservoir. The reported experience with this procedure is summarized in Table 4. Ninety percent of the patients were female and the patients averaged 36 years of age. The reported success rate (averaging 90 %) has been good. The numbers in most of the series are small; reflecting the reluctance of surgeons to offer this procedure. An advantage of this procedure is that surgeons perform it frequently for other reasons and its morbidity and mortality are low. After the procedure, the bowel frequency averages 1-3 bowel movements per day with good control. Pikarsky and colleagues from Cleveland Clinic Florida reviewed the long term results of colectomy for constipation in 30 of their patients. After more than 8 years of follow up, all patients felt that their outcome was excellent. They averaged 2.5 bowel movements per day. Two of the patients were taking antidiarrheal medication, one patient needed laxatives, and one patient needed enemas. FitzHarris and colleagues from the University of Minnesota, studied quality of life issues with 75 constipated patients. Their study found that 81% of the patients were at least somewhat pleased with their bowel frequency, but 41% cited abdominal pain, 21% incontinence, and 46% diarrhea at least some of the time. However, 93% stated they would undergo subtotal colectomy again if given a second chance.
If the evaluation suggests an outlet problem, the surgical options have been limited. Many patients can be helped with biofeedback therapy. For those that aren't a few surgeons have performed a restotative proctocolectomy with an ileoanal anastomosis. This is a major operative procedure with significant morbidity. Its use should be reserved for very selected patients. Another option for the patient with normal colonic motility but outlet obstruction is a sigmoid colostomy.
Constipation is a major problem. An adequate evaluation can identify correctable problems, guide medical therapy, and help select the patients that would benefit from surgical therapy. If surgical therapy is indicated, good results are obtained from total colectomy and ileorectal anastomosis.
Beck DE, Jagelman DG, Fazio VW. The surgical management of idiopathic constipation. Clinics in Gastroenterology. 1987;16:143-156. Beck DE. Constipation. Current Therapy in Colon and Rectal Surgery. B.C. Decker, Inc. Publishers. 1990:339-343. Beck DE, Fazio VW, Jagelman DG, Lavery IC. Surgical management of colonic inertia. Southern Medical Journal 82:305-309, 1989. Pikarsky AJ, Singh JJ, Weiss EG, Nogueras JJ, Wexner SD. Long-term follow-up of patients undergoing colectomy for colonic inertia. Dis Colon Rectum 2001;44:179-183 FitzHarris GP, Garcia-Aguilar J, Parker SC, et al. Quality of life after subtotal colectoimy for slow-transit constipation. Dis Colon Rectum 2003;46:433-440
Table 1. Rome II Criteria for Constipation
Straining in greater than 25% of defecations Lumpy or hard stools in greater than 25% of defecations Sensation of incomplete evacuation in greater than 25% of defecations Sensation of anorectal obstruction/blockade in greater than 25% of defecation Manual maneuvers to facilitate greater than 25% of defecation Less than 3 defecations per week
Table 2. Causes of Constipation
Mechanical Obstructive: Neoplastic Postsurgical abnormalities Hernia Volvulus (twisting of colon) Functional: Irritable bowel disease Proctitis Diverticular disease Inadequate dietary fiber Pharmacologic Analgesics Parasympatholytics Phenothiazines Metalic intoxication Laxative abuse Metabolic and Endocrine Diabetes, amyloidosis, uremia. Hypokelemia, hypercalcemia, porphyria Hypothyroidism, phemochrocytoma, pregnancy Neurogenic Peripheral: Aganglionosis (Hirschsprung's disease) Ganglioneuromatosis Autonomic neuropathy Chagas' disease Central: Trauma Central nervous system disease
Table 3. Fiber preparations
Type of Fiber Trade Name Available Fiber* Bran Whole bran Psyllium MetamucilTM 3.4 g/teaspoon in 8 oz water KonsylTM 6 g/teaspoon in 8 oz water Methycellulose CitrucelTM 2 g in 8 oz water Citrucel Fiber Tablets 0.2 g/capsule Calcium polycarbophil FiberconTM 0.5 g/capsule Konsyl Fiber Tablets 0.5 g/capsule
Table 4. Laxatives
Agent Trade Name Mechanism of Action Polyethelene glycol Miralax Glycolax Osmotic laxative Lactulose Kristalose Enulose Nonabsorbed sugar that is metabolized by colonic bacteria Tegaserod Zelnorm Neuromuscular drug Magnesium citrate Nonabsorbed cation (osmotic) Sodium phosphate Fleet Phospho-soda Osmotic cathartic Visacol Extract of senna X-Prep Works predominately in the colon by an unknown mechanism Senna Prompt Bisacodyl Dulcolax Contact irritant (oral or rectal use) Castor oil Whole-gut irritant
Table 5. Selected Experience with Total Abdominal Colectomy and Ileorectal Anastomosis for Constipation
Authors Year Number of Patients Successful Outcome (%) Length of Follow-up (years) Colected series (6) 1977-85 65 66-100 0.7-5.7 Aakervall et al 1988 12 75 3.4 Beck et al 1988 14 100 1.2 Zenilman et al 1989 12 100 2 Pemberton et al 1991 38 100 Wexner et al 1991 16 94 1.2 Mahendarajah et al 1994 9 88 1.3 Piccirillo et al 1995 54 94 2.2 Redman et al 1995 34 90 7.5 Pikarsky et al 2001 30 100 8.9 FitzHarris et al 2003 75 95 3.9 Total 359