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NCI/PDQ^® Health professionals: Gastrointestinal Complications (PDQ®)

National Cancer Institute
Ultima Vez Modificado: 18 de julio del 2012

TABLE OF CONTENTS

• Overview

• Constipation
  • Etiology of Constipation
  • Causes of Constipation
  • Assessment of Constipation
  • Management of Constipation
  • Medical Agents for Constipation
  • Current Clinical Trials

• Impaction
  • Etiology of Impaction
  • Signs and Symptoms of Impaction
  • Assessment of Impaction
  • Treatment of Impaction
  • Current Clinical Trials

• Large or Small Bowel Obstruction
  • Etiology of Bowel Obstruction
  • Assessment and Diagnosis of Bowel Obstruction
  • Treatment of Acute Bowel Obstruction
  • Management of Chronic, Malignant Bowel Obstruction
  • Current Clinical Trials

• Diarrhea
  • Etiology of Diarrhea
  • Assessment
  • Management
    • Uncomplicated symptoms
      • Probiotics
    • Complicated symptoms
  • Current Clinical Trials

• Radiation Enteritis
  • Etiology
  • Acute Radiation Enteritis
    • Diagnosis
    • Assessment
    • Medical management
    • The role of nutrition
  • Chronic Radiation Enteritis
    • Diagnosis
    • Treatment
    • Prevention

• Changes to This Summary (07/18/2012)

• Questions or Comments About This Summary

• About This PDQ® Summary
  • Purpose of This Summary
  • Reviewers and Updates
  • Levels of Evidence
  • Permission to Use This Summary
  • Disclaimer
  • Contact Us

• Get More Information From NCI

Overview

Gastrointestinal complications (constipation, impaction, bowel obstruction, diarrhea, and radiation enteritis) are common problems for oncology patients. The growth and spread of cancer, as well as its treatment, contribute to these conditions.

Constipation is the slow movement of feces through the large intestine that results in the passage of dry, hard stool. This can result in discomfort or pain. 1 The longer the transit time of stool in the large intestine, the greater the fluid absorption and the drier and harder the stool becomes.

Inactivity, immobility, or physical and social impediments (particularly inconvenient bathroom availability) can contribute to constipation. Depression and anxiety caused by cancer treatment or cancer pain can lead to constipation. Perhaps the most common causes of constipation are inadequate fluid intake and pain medications; however, these causes are manageable.

Constipation may be annoying and uncomfortable, but fecal impaction can be life-threatening. Impaction refers to the accumulation of dry, hardened feces in the rectum or colon. The patient with a fecal impaction may present with circulatory, cardiac, or respiratory symptoms rather than with gastrointestinal symptoms. 2 If the fecal impaction is not recognized, the signs and symptoms may progress and result in death.

In contrast to constipation or impaction, an intestinal obstruction is a partial or complete occlusion of the bowel lumen by a process other than fecal impaction. Intestinal obstructions can be classified by three means: the type of obstruction, the obstructing mechanism, and the part of the bowel involved.

Structural disorders, such as intraluminal and extraluminal bowel lesions caused by primary or metastatic tumor, postoperative adhesions, volvulus of the bowel, or incarcerated hernia, affect peristalsis and the maintenance of normal bowel function. These disorders can lead to total or partial obstruction of the bowel. Patients who have colostomies are at special risk of developing constipation. If stool is not passed on a regular basis (once a day to several times a day), further investigation is warranted. A partial or complete blockage may have occurred, particularly if no flatus has been passed. 3

Diarrhea can occur throughout the continuum of cancer care, and the effects can be physically and emotionally devastating. Although less prevalent than constipation, diarrhea remains a significant symptom burden for people with cancer. Diarrhea can alter dietary patterns, trigger dehydration, create electrolyte imbalance, impair function, cause fatigue, impair skin integrity, limit activity, and in some cases, be life-threatening. Furthermore, diarrhea can lead to increased caregiver burden. Specific definitions of diarrhea vary widely. Acute diarrhea is generally considered to be an abnormal increase in stool liquid that lasts more than 4 days but less than 2 weeks. Another definition suggests that diarrhea is an increase in stool liquidity (>300 mL of stool) and frequency (the passage of more than three unformed stools) during a 24-hour period. 4 Diarrhea is considered chronic when it persists longer than 2 months.

Radiation enteritis is a functional disorder of the large and small bowel that occurs during or after a course of radiation therapy to the abdomen, pelvis, or rectum.

The large and small bowel are very sensitive to ionizing radiation. Although the probability of tumor control increases with the radiation dose, so does the damage to normal tissues. Acute side effects to the intestines occur at approximately 10 Gy. Because curative doses for many abdominal or pelvic tumors range between 50 and 75 Gy, enteritis is likely to occur. 5

In this summary, unless otherwise stated, evidence and practice issues as they relate to adults are discussed. The evidence and application to practice related to children may differ significantly from information related to adults. When specific information about the care of children is available, it is summarized under its own heading.

References:

1. Culhane B: Constipation. In: Yasko J, ed.: Guidelines for Cancer Care: Symptom Management. Reston, Va: Reston Publishing Company, Inc., 1983, pp 184-7. [PUBMED Abstract]
2. Wright BA, Staats DO: The geriatric implications of fecal impaction. Nurse Pract 11 (10): 53-8, 60, 64-6, 1986. [PUBMED Abstract]
3. Hampton BG, Bryant RA, eds.: Ostomies and Continent Diversions: Nursing Management. St. Louis, Mo: Mosby Year Book, Inc., 1992. [PUBMED Abstract]
4. Tuchmann L, Engelking C: Cancer-related diarrhea. In: Gates RA, Fink RM, eds.: Oncology Nursing Secrets. 2nd ed. Philadelphia, Pa: Hanley and Belfus, 2001, pp 310-22. [PUBMED Abstract]
5. Perez CA, Brady LW, eds.: Principles and Practice of Radiation Oncology. 3rd ed. Philadelphia, Pa: Lippincott-Raven Publishers, 1998. [PUBMED Abstract]

Constipation

Etiology of Constipation

Common factors that contribute to the development of constipation in the general population are diet, altered bowel habits, inadequate fluid intake, and lack of exercise. Constipation can be a presenting symptom of cancer, or it can occur later as a side effect of a growing tumor or treatment of the tumor. For patients with cancer, additional causative factors are the tumor itself, cancer-related problems, the effects of drug therapy for cancer or for cancer pain, and other concurrent processes such as organ failure, decreased mobility, and depression. 1 Physiologic factors include inadequate oral intake, dehydration, inadequate intake of dietary fiber, or organ failure. Any or all of these factors can occur because of the disease process, aging, debilitation, or treatment. (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ® summary on Nausea and Vomiting for more information.)

Causes of Constipation

Medications
• Chemotherapy (e.g., any agent that can cause autonomic nervous system changes such as vinca alkaloids, oxaliplatins, taxanes, and thalidomide).*
• Opioids or sedatives.
• Anticholinergic preparations (e.g., gastrointestinal antispasmodics, antiparkinsonism agents, and antidepressants).
• Phenothiazines.
• Calcium- and aluminum-based antacids.
• Diuretics.
• Vitamin supplements (e.g., iron and calcium).
• Tranquilizers and sleeping medications.
• General anesthesia and pudendal blocks.

Diet
• Inadequate fluid intake.*

Altered bowel habits
• Repeatedly ignoring defecation reflex.
• Excessive use of laxatives and/or enemas.

Prolonged immobility* and/or inadequate exercise
• Spinal cord injury or compression, fractures, fatigue, weakness, or inactivity (including bedrest).
• Intolerance with respiratory or cardiac problems.

Bowel disorders
• Irritable colon, diverticulitis, or tumor.*

Neuromuscular disorders (disruption of innervation leads to atony of the bowel)
• Neurological lesions (cerebral tumors).
• Spinal cord injury or compression.*
• Paraplegia.
• Cerebrovascular accident with paresis.
• Weak abdominal muscles.

Metabolic disorders
• Hypothyroidism and lead poisoning.
• Uremia.*
• Dehydration.*
• Hypercalcemia.*
• Hypokalemia.
• Hyponatremia.

Depression
• Chronic illness.
• Anorexia.
• Immobility.
• Antidepressants.

Inability to increase intra-abdominal pressure
• Emphysema.
• Any neuromuscular impairment of the diaphragm or abdominal muscles.
• Massive abdominal hernias.

Atony of muscles
• Malnutrition.
• Cachexia, anemia, or carcinoma.*
• Senility.

Environmental factors
• Inability to get to the bathroom without assistance.
• Unfamiliar or hurried environment.
• Excess heat leading to dehydration.
• Change in bathroom habits (e.g., use of a bedpan).
• Lack of privacy.

Narrowing of colon lumen
• Related to scarring from radiation therapy, surgical anastomosis, or compression from growth of extrinsic tumor.

[Note: *Frequently seen in oncology patients.]

Constipation is frequently the result of autonomic neuropathy caused by the vinca alkaloids, taxanes, and thalidomide. Other drugs such as opioid analgesics or anticholinergics (antidepressants and antihistamines) may lead to constipation by causing decreased sensitivity to the defecation reflexes and decreased gut motility. Since constipation is common with the use of opioids, a bowel regimen should be initiated at the time opioids are prescribed and continued for as long as the patient takes opioids. Opioids produce varying degrees of constipation, suggesting a dose-related phenomenon. One study suggests that clinicians should not base laxative prescribing on the opioid dose, but rather should titrate the laxative according to bowel function. Lower doses of opioids or weaker opioids, such as codeine, are just as likely to cause constipation. 2 (Refer to the Side Effects of Opioids section in the PDQ® summary on Pain for more information.)

Other diseases, such as diabetes (with autonomic neuropathy) and hypothyroidism, may cause constipation. Metabolic disorders, such as hypokalemia and hypercalcemia, also predispose cancer patients to developing constipation. Once these disorders are corrected, constipation should subside. 1

Assessment of Constipation

A normal bowel pattern is having at least three stools per week and no more than three per day; however, these criteria may be inappropriate for cancer patients. 1 3 Constipation should be viewed as a subjective symptom involving the complaints of decreased frequency with incomplete passage of dry, hard stool. A thorough history of the patient's bowel pattern, dietary changes, and medications, along with a physical examination, can identify possible causes of constipation. The evaluation should also include assessment of associated symptoms such as distention, flatus, cramping, or rectal fullness. A digital rectal examination should always be done to rule out fecal impaction at the level of the rectum. A test for occult blood will be helpful in determining a possible intraluminal lesion. A thorough examination of the gastrointestinal tract is necessary if cancer is suspected. 4

The following questions may provide a useful assessment guide:

1. What is normal for the patient (frequency, amount, and timing)?
2. When was the last bowel movement? What was the amount, consistency, and color? Was blood passed with it?
3. Has the patient been having any abdominal discomfort, cramping, nausea or vomiting, pain, excessive gas, or rectal fullness?
4. Does the patient regularly use laxatives or enemas? What does the patient usually do to relieve constipation? Does it usually work?
5. What type of diet does the patient follow? How much and what type of fluids are taken on a regular basis?
6. What medication (dose and frequency) is the patient taking?
7. Is this symptom a recent change?
8. How many times a day is flatus passed?

Physical assessment will determine the presence or absence of bowel sounds, flatus, or abdominal distention. Patients with colostomies should also be assessed for constipation. Dietary habits, fluid intake, activity levels, and use of opioids in these patients should be assessed. Irrigation of the colostomy should be monitored for proper technique.

Management of Constipation

Comprehensive management of constipation includes prevention (if possible), elimination of causative factors, and judicious use of laxatives. Some patients can be encouraged to increase dietary fiber (fruits; green, leafy vegetables; 100% whole-grain cereals and breads; and bran) and to increase fluid intake to one-half ounce per pound of body weight daily (if not contraindicated by renal or heart disease). (Refer to the PDQ® summary on Nutrition in Cancer Care for more information.) A study that involved geriatric patients compared the efficacy, cost, and ease of administration of a natural laxative mixture (raisins, currants, prunes, figs, dates, and prune concentrate) with protocols using stool softeners, lactulose, and other laxatives. Results indicated lower costs, more natural and regular bowel movements, and increased ease of administration with natural laxatives. Even though generalization from these findings was limited by small sample size, additional exploration of natural laxatives in cancer patient populations might be useful. 5 A program for prevention of constipation in cancer patients is described below.

Assessment:
• Establish the patient's normal bowel pattern and habits (time of day for normal bowel movement, consistency, color, and amount).
• Explore the patient's level of understanding and compliance relating to exercise level, mobility, and diet (fluid, fruit, and fiber intake).
• Determine normal or usual use of laxatives, stimulants, or enemas.
• Determine laboratory values, specifically looking at platelet count.
• Conduct a physical assessment of the rectum (or stoma) to rule out impaction.

Commonly used interventions:
• Record bowel movements daily.
• Encourage patient to increase fluid intake, with a goal of drinking eight 8-oz (240-mL) glasses of fluid daily unless contraindicated.
• Encourage regular exercise, including abdominal exercises in bed or moving from bed to chair if the patient is not ambulatory.
• Encourage adequate fiber intake. Experts recommend that:
  • Healthy adults consume 20 g to 35 g of fiber per day (average consumption is 11 g).
  • Children and adolescents consume the number of grams of fiber equal to their age plus 5for example, a 10-year-old should consume 15 g of fiber per day (10 + 5). This guideline applies until age 18 years; at that time, the adult recommendations should be followed.

    While there are no specific fiber recommendations for cancer patients, they should also be encouraged to eat more high-fiber foods such as fruits (e.g., raisins, prunes, peaches, and apples), vegetables (e.g., squash, broccoli, carrots, and celery), and 100% whole-grain cereals, breads, and bran. Increased fiber intake must be accompanied by increased fluid intake, or constipation may result. High fiber intake is contraindicated in patients at increased risk for bowel obstruction, such as those with a history of bowel obstruction or status postcolostomy.

• Provide a warm or hot drink approximately one-half hour before time of patient's usual defecation.
• Provide privacy and quiet time at the patient's usual or planned time for defecation.
• Provide toilet or bedside commode and appropriate assistive devices; avoid bedpan use whenever possible.

Another approach, shown below in two parts, is adapted from the MD Anderson Cancer Center practice consensus algorithm for the prevention and management of opioid-induced constipation. [Note: Copyright 2008 The University of Texas MD Anderson Cancer Center]

MD Anderson Cancer Center Algorithm for the Prevention of Opioid-induced Constipation
• Unless there are existing alterations in bowel patterns (e.g., bowel obstruction or diarrhea), all patients receiving opioids should be started on a laxative bowel regimen and receive education for bowel management.
  1. Stimulant laxative plus stool softener (e.g., Senokot-S [senna 8.6 mg plus docusate 50 mg]), two tablets per day and titrate up (maximum nine tablets per day).
  2. Ensure adequate fluids, dietary fiber, and exercise, if feasible.
  3. Prune juice followed by warm beverage may be considered.

MD Anderson Cancer Center Algorithm for the Management of Opioid-induced Constipation
1. Assess potential cause of constipation (e.g., recent opioid dose increase, use of other constipating medications, or new bowel obstruction).
2. Increase Senokot-S (or senna and docusate tablets, if using separately), and add one or both of the following:
   1. Milk of magnesia oral concentrate (1170/5 mL), 10 mL by mouth 2 to 4 times per day.
   2. Polyethylene glycol (MiraLAX), 17 g in 8-oz beverage daily.

3. If no response to above, perform digital rectal examination to rule out low impaction. Continue above steps AND:
   1. If impacted, disimpact manually if stool is soft. If not, soften with mineral oil fleets enema before disimpaction. Follow up with milk of molasses enemas until clear with no formed stools.
   2. Consider use of rescue analgesics before disimpaction.
   3. If not impacted on rectal examination, patient may still have higher level impaction; if history is appropriate, consider abdominal imaging and/or administer milk of molasses enema with magnesium citrate 8 oz by mouth. Consider bowel management consult.

4. If patient is neutropenic or thrombocytopenic, arrange for bowel management consult.

• Start one of the following regimens if the patient has not had a stool in 3 days or on the first day that any patient starts taking drugs associated with constipation:
  • Stool softeners (e.g., docusate sodium, one to two capsules per day). For opioid-related constipation, stool softeners should be used in combination with a stimulant laxative. Bulk-producing agents are not recommended in a regimen used to counteract the bowel effects of opioids.
  • Two tablets of a senna preparation twice daily.
  • One bisacodyl tablet at bedtime.
  • Milk of magnesia, 30 to 45 mL, if a bowel movement is not achieved in 24 hours after other methods are instituted.

• If the amount of stool is still inadequate, increase stool softeners up to six capsules per day or a senna preparation (e.g., Senokot) gradually to a maximum of eight tablets (four tablets twice a day); bisacodyl may be increased gradually to three tablets.
• If the amount of stool is still inadequate, a glycerin or bisacodyl suppository or enema (phosphate/biphosphate, oil retention, or tap water) should be used with caution, especially in patients with neutropenia or thrombocytopenia.

Medical management includes the administration of saline or chemical laxatives, suppositories, enemas, or agents that increase bulk.

Rectal agents should be avoided in cancer patients at risk for thrombocytopenia, leukopenia, and/or mucositis from cancer and its treatment. In the immunocompromised patient, no manipulation of the anus should occur, that is, no rectal examinations, no suppositories, and no enemas. These actions can lead to the development of anal fissures or abscesses, which are portals of entry for infection. Also, the stoma of a patient with neutropenia should not be manipulated.

Medical Agents for Constipation

Bulk producers
• Bulk producers are natural or semisynthetic polysaccharide and cellulose. They work with the body's natural processes to hold water in the intestinal tract, soften the stool, and increase the frequency of the passage of stool. Bulk producers are not recommended for use in a regimen to counteract the bowel effects of opioids.
• Onset: 12 to 24 hours (may be delayed up to 72 hours).
• Caution: Patients should take with two full 8-oz (240-mL) glasses of water and maintain adequate hydration to avoid the risk of developing a bowel obstruction. Avoid administering psyllium with salicylates, nitrofurantoin, and digitalis because psyllium decreases the actions of these drugs. Avoid use if intestinal obstruction is suspected.
• Use: Effective in managing irritable bowel syndrome.
• Drugs and dosages:
  • Methylcellulose (Cologel): 5 to 20 cc 3 times per day with water.
  • Barley malt extract (Maltsupex): Four tablets with meals and at bedtime or 2 tbsp powder or liquid 2 times per day for 3 to 4 days, then 1 to 2 tbsp at bedtime.
  • Psyllium: Varies from 1 tbsp to one packet, depending on brand, 1 to 3 times per day.

Saline laxatives
• The high osmolarity of the compounds in saline laxatives attracts water into the lumen of the intestines. The fluid accumulation alters the stool consistency, distends the bowel, and induces peristaltic movement. Cramps may occur.
• Onset: 0.5 to 3 hours.
• Caution: Repeated use can alter fluid and electrolyte balance. Avoid magnesium-containing laxatives in patients with renal dysfunction. Avoid sodium-containing laxatives in patients with edema, congestive heart failure, megacolon, or hypertension.
• Use: Mostly as a bowel preparation to clear the bowels for rectal or bowel examinations.
• Drugs and dosages:
  • Magnesium sulfate: 15 g in a glass of water.
  • Milk of magnesia: 10 to 20 cc if concentrated, 15 to 30 cc if regular.
  • Magnesium citrate: 240 cc.
  • Sodium phosphate: 4 to 8 g dissolved in water.
  • Monobasic and dibasic sodium phosphate (Fleet Phospho-soda): 20 to 40 mL mixed with 4 oz cold water.

Stimulant laxatives
• Stimulant laxatives increase motor activity of the bowels by direct action on the intestines.
• Onset: 6 to 10 hours.
• Caution: Prolonged use of these drugs causes laxative dependency and loss of normal bowel function. Prolonged use of danthron discolors rectal mucosa and discolors alkaline urine red. Bisacodyl must be excreted in bile to be active and is not effective with biliary obstruction or diversion. Avoid bisacodyl with known or suspected ulcerative lesions of the colon. These medications may cause cramping.
• Drug interactions: Avoid taking bisacodyl within 1 hour of taking antacids, milk, or cimetidine because they cause premature dissolving of the enteric coating, which results in gastric or duodenal stimulation. There is an increased absorption of danthron when it is given with docusate.
• Use: To evacuate bowel for rectal or bowel examinations. Most of the stimulant laxatives act on the colon.
• Drugs and dosages:
  • Danthron: 37.5 to 150 mg with evening meal or 1 hour after evening meal.
  • Calcium salts of sennosides: 12 to 24 mg at bedtime; senna: Senolax, Seneson, or Black-Draught (two tablets); Senokot (two tablets or 1015 cc at bedtime).
  • Bisacodyl: 10 to 15 mg swallowed whole, not chewed, or a 10-mg suppository.

Lubricant laxatives
• Lubricant laxatives lubricate intestinal mucosa and soften stool.
• Caution: Administer on empty stomach at bedtime. Mineral oil prevents absorption of oil-soluble vitamins and drugs. With older patients, aspiration potential suggests that mineral oil should be avoided because it can cause lipid pneumonitis. It can interfere with postoperative healing of anorectal surgery. Avoid giving with docusate sodium. Docusate sodium causes increased systemic absorption of mineral oil.
• Use: Prophylactically to prevent straining in patients for whom straining would be dangerous.
• Drugs and dosages:
  • Mineral oil: 5 to 30 cc at bedtime.

Fecal softeners
• Fecal softeners promote water retention in the fecal mass, thus softening the stool. Up to 3 days may pass before an effect is noted. Stool softeners and emollient laxatives are of limited use because of colonic resorption of water from the forming stool.
• Fecal softeners should not be used as the sole regimen but may be useful given in combination with stimulant laxatives.
• Caution: May increase the systemic absorption of mineral oil when administered together.
• Use: Prophylactically to prevent straining. Most beneficial when stool is hard.
• Drugs and dosages:
  • Docusate sodium: 50 to 240 mg taken with a full glass of water.
  • Docusate calcium: 240 mg each day until bowel movement is normal.
  • Docusate potassium: 100 to 300 mg each day until bowel movement is normal; should increase daily fluid intake.
  • Poloxamer 188: 188 mg (480 mg at bedtime).

Lactulose (Cholac, Cephulac)
• Lactulose is a synthetic disaccharide that passes to the colon undigested. When it is broken down in the colon, it produces lactic acid, formic acid, acetic acid, and carbon dioxide. These products increase the osmotic pressure, thus increasing the amount of water held in the stool, which softens the stool and increases the frequency of passage.
• Onset: 24 to 48 hours.
• Caution: Excessive amounts may cause diarrhea with electrolyte losses. Avoid giving to patients with acute abdomen, fecal impaction, or obstruction.
• Dosage: 15 to 30 cc each day (contains 1020 g of lactulose).

Polyethylene glycol and electrolytes (Golytely, Colyte)
• Five packets are mixed with 1 gallon (3.785 L) of tap water and contain the following: polyethylene glycol (227.1 g), sodium chloride (5.53 g), potassium chloride (2.82 g), sodium bicarbonate (6.36 g), and sodium sulfate (anhydrous, 21.5 g). Do not add flavorings. Serve chilled to improve palatability. Can be stored up to 48 hours in the refrigerator.
• Use: To clear bowel with minimal water and sodium loss or gain.

Opioid antagonists (naloxone, methylnaltrexone)
• Caution: Administer only if other drugs have failed.
• Subcutaneous methylnaltrexone, 0.15 mg per kilogram of body weight, can be administered daily or every other day to treat opioid-induced constipation. In a study of palliative care patients, including those with cancer and noncancer etiologies, approximately one-half of patients defecated within 4 hours of receiving the injection, with 30% of patients having a bowel movement within the first 30 minutes.
• In two studies of palliative care patientsone a single-dose trial and the other a 2-week every-other-day-dose trialthere was no evidence of withdrawal or other central effects of the opioid, and pain scores remained unchanged. 6 7
• Caution: This drug is contraindicated in patients with bowel obstruction.
• The most common side effects are dizziness, nausea, abdominal pain, flatulence, and diarrhea.
• A study of prolonged-released naloxone in an oxycodone:naloxone ratio of 2:1 (average results of 40:20 mg, 60:30 mg, and 80:40 mg oxycodone:naloxone combination relative to placebo) demonstrated improved bowel function without reversal of analgesia. 8

Current Clinical Trials

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about constipation, impaction, and bowel obstruction that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References:

1. Portenoy RK: Constipation in the cancer patient: causes and management. Med Clin North Am 71 (2): 303-11, 1987. [PUBMED Abstract]
2. Bennett M, Cresswell H: Factors influencing constipation in advanced cancer patients: a prospective study of opioid dose, dantron dose and physical functioning. Palliat Med 17 (5): 418-22, 2003. [PUBMED Abstract]
3. McShane RE, McLane AM: Constipation. Consensual and empirical validation. Nurs Clin North Am 20 (4): 801-8, 1985. [PUBMED Abstract]
4. Bruera E, Suarez-Almazor M, Velasco A, et al.: The assessment of constipation in terminal cancer patients admitted to a palliative care unit: a retrospective review. J Pain Symptom Manage 9 (8): 515-9, 1994. [PUBMED Abstract]
5. Beverley L, Travis I: Constipation: proposed natural laxative mixtures. J Gerontol Nurs 18 (10): 5-12, 1992. [PUBMED Abstract]
6. Thomas J, Karver S, Cooney GA, et al.: Methylnaltrexone for opioid-induced constipation in advanced illness. N Engl J Med 358 (22): 2332-43, 2008. [PUBMED Abstract]
7. Portenoy RK, Thomas J, Moehl Boatwright ML, et al.: Subcutaneous methylnaltrexone for the treatment of opioid-induced constipation in patients with advanced illness: a double-blind, randomized, parallel group, dose-ranging study. J Pain Symptom Manage 35 (5): 458-68, 2008. [PUBMED Abstract]
8. Meissner W, Leyendecker P, Mueller-Lissner S, et al.: A randomised controlled trial with prolonged-release oral oxycodone and naloxone to prevent and reverse opioid-induced constipation. Eur J Pain 13 (1): 56-64, 2009. [PUBMED Abstract]

Impaction

Etiology of Impaction

Five major factors precipitate impaction:

• Opioid analgesics.
• Prolonged inactivity.
• Dietary alterations.
• Psychiatric illness.
• Chronic use of drugs for constipation. 1

Laxatives used to decrease constipation are the drugs that contribute most to the development of constipation and impaction. Repeated and escalating dosing of laxatives renders the colon less sensitive to its intrinsic reflexes stimulated by distention. (Refer to the Etiology of Constipation section of this summary for causes of constipation that may lead to impaction.)

Signs and Symptoms of Impaction

The patient may exhibit symptoms similar to constipation or present with symptoms unrelated to the gastrointestinal system. If the impaction presses on the sacral nerves, the patient may experience back pain. If the impaction presses on the ureters, bladder, or urethra, urinary symptoms can develop. These symptoms include increased or decreased frequency or urgency of urination, or urinary retention.

When abdominal distention occurs, movement of the diaphragm is compromised, leading to insufficient aeration with subsequent hypoxia and left ventricular dysfunction. Hypoxia can, in turn, precipitate angina or tachycardia. If the vasovagal response is stimulated by the pressure of impaction, the patient may become dizzy and hypotensive.

Movement of stool around the impaction may result in diarrhea, which can be explosive. Coughing or activities that increase intra-abdominal pressure may cause leakage of stool. The leakage may be accompanied by nausea, vomiting, abdominal pain, and dehydration and is virtually diagnostic of the condition. Thus, the patient with an impaction may present in an acutely confused and disoriented state, with signs of tachycardia, diaphoresis, fever, elevated or low blood pressure, and/or abdominal fullness or rigidity.

Assessment of Impaction

Assessment includes the questions discussed previously for the patient with constipation. (Refer to the Assessment of Constipation section of this summary for the list of questions.) Additional assessment includes auscultation of bowel sounds to determine if they are present, absent, hyperactive, or hypoactive. The abdomen should be inspected for distention and gently palpated for any masses, rigidity, or tenderness. A rectal examination will determine the presence of stool in the rectum or sigmoid colon. An abdominal x-ray (flat and upright) would show loss of haustral markings, gas patterns reflecting gross amounts of stool, and dilatation proximal to the impaction. 2

If a diagnosis of fecal impaction is uncertain, a laboratory workup can rule out other problems. A complete blood cell count, appropriate blood chemistries, chest x-ray, and an electrocardiogram can be performed. If the patient has become dehydrated, the blood urea nitrogen, creatinine, and serum osmolality will be elevated. There may be an elevation of the hemoglobin and hematocrit indicating hemoconcentration. The white blood cell (WBC) count may be slightly elevated in the presence of a fever. If the WBC count is extremely elevated and the patient is exhibiting a high fever and abdominal pain, an obstruction, perforation, infection, or inflammatory process must be ruled out. With marked distention of the cecum (diameter 12 cm), there is a risk of bowel perforation.

Treatment of Impaction

The primary treatment of impaction is to hydrate and soften the stool so that it can be removed or passed. Enemas (oil retention, tap water, or hypertonic phosphate) lubricate the bowel and soften the stool. Caution must be exercised; fecal impaction can irritate the bowel wall, and enemas in excess may perforate the bowel. The patient may need to be digitally disimpacted if the stool is within reach. This is best done after administering an enema to lubricate the bowel.

Nonstimulating bowel softeners such as docusate can be used to help soften stool higher in the colon. Mineral or olive oil can be given to loosen the stool. Caution should be used when giving docusate sodium with mineral oil because there could be an increased systemic absorption of the mineral oil leading to systemic lipid granulomas. 3 Glycerin suppositories can also be used. Any laxatives that might stimulate the bowel or cause cramping should be avoided so that the bowel is not damaged further.

Current Clinical Trials

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about constipation, impaction, and bowel obstruction that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References:

1. Cefalu CA, McKnight GT, Pike JI: Treating impaction: a practical approach to an unpleasant problem. Geriatrics 36 (5): 143-6, 1981. [PUBMED Abstract]
2. Bruera E, Suarez-Almazor M, Velasco A, et al.: The assessment of constipation in terminal cancer patients admitted to a palliative care unit: a retrospective review. J Pain Symptom Manage 9 (8): 515-9, 1994. [PUBMED Abstract]
3. Brandt LJ: Gastrointestinal Disorders of the Elderly. New York, NY: Raven Press, 1984. [PUBMED Abstract]

Large or Small Bowel Obstruction

There are four types of obstruction:

1. Simple.
2. Closed-loop.
3. Strangulated.
4. Incarcerated.

A simple obstruction is blocked in one place; a closed-loop obstruction is blocked in two places. A closed-loop obstruction may develop when the bowel twists around on itself, isolating the looped section of the bowel and obstructing the portion above it. With a strangulated obstruction, there is decreased blood flow to the bowel that, if not relieved, will develop into an incarcerated obstruction, and the bowel will become necrotic.

The obstructing mechanism can be mechanical or nonmechanical. Mechanical factors can be anything that causes a narrowing of the intestinal lumen (e.g., inflammation or trauma to the bowel, neoplasms, adhesions, hernias, volvulus, or a compression from outside the intestinal tract). 1 Nonmechanical factors include those that interfere with the muscle action or innervation of the bowel: paralytic ileus, mesenteric embolus or thrombus, and hypokalemia.

Eighty percent of bowel obstructions occur in the small intestine; the other 20% occur in the colon. 2 Bowel obstructions are frequently seen in the ileum. Small bowel obstructions are caused often by adhesions or hernias, whereas large bowel obstructions are caused by carcinomas, volvulus, or diverticulitis. The presentation of obstruction will relate to whether the small or large intestine is involved.

Etiology of Bowel Obstruction

The most common malignancies that cause bowel obstruction are cancers of the colon, stomach, and ovary. Extra-abdominal cancers (such as lung and breast cancers and melanoma) can spread to the abdomen, causing bowel obstruction. 3 Patients who have had abdominal surgery or abdominal radiation are also at higher risk of developing bowel obstruction. 2 Bowel obstructions are most common during advanced stages of disease.

Assessment and Diagnosis of Bowel Obstruction

Examination of the patient will determine the presence or absence of abdominal pain, vomiting, and evidence of the passage of flatus or stool. A complete blood cell count, electrolyte panel, and urinalysis are obtained to evaluate fluid and electrolyte imbalance and/or sepsis. An elevated white blood cell count (15,00020,000/mm³) suggests bowel necrosis. Flat and upright abdominal films as well as a barium enema may be necessary to determine where the obstruction is located. While it remains controversial, an upper gastrointestinal series is contraindicated with an acutely presenting obstruction because it can cause a partial obstruction to become complete or may further complicate a total obstruction. If the patient is exhibiting dehydration, oliguria, or shock, perforation of the bowel may have occurred, and immediate medical or surgical intervention is indicated. (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ® summary on Nausea and Vomiting for more information.)

Treatment of Acute Bowel Obstruction

Careful serial examinations are necessary in the management of patients with progressive abdominal symptoms that may be due to acute bowel obstruction. The principles of supportive care in this setting include volume resuscitation, correction of electrolyte imbalances, and transfusion support (if necessary). These measures should precede or accompany decompression efforts.

When bowel obstruction is partial, decompression of the distended bowel may be attempted with nasogastric or intestinal tubes. Although use of these tubes may be successful in reducing edema, relieving fluid and gas accumulation, or decreasing the need for multiple stage procedures, 4 surgery may be necessary within 24 hours if there is complete, acute obstruction. The use of self-expandable stents to decompress complete, acute malignant bowel obstruction has been noted to decrease the frequency of unnecessary surgery by permitting staging of the disease, increasing the rate of primary anastomosis relative to colostomy, and decreasing morbidity in patients with left-sided colon and rectal malignancies. Further study is warranted, including cost analysis. 5

Management of Chronic, Malignant Bowel Obstruction

Patients with advanced cancer may have chronic, progressive bowel obstruction that is inoperable. 6 7 The most frequent causes of inoperability are extensive tumor and multiple partial obstructions. 8 9[Level of evidence: II] 10 A retrospective review evaluating surgical palliation of malignant bowel obstruction secondary to peritoneal carcinomatosis in 63 patients with nongynecological cancer used the ability to tolerate solid food at hospital discharge as the criterion for successful palliation. Multiple logistic regression analysis identified the absence of ascites and obstruction not involving the small bowel as predictors of successful surgical palliation in this population. Successful palliation was achieved in 45% of patients and was maintained in 76% of this group at a median follow-up of 78 days, for an overall success rate of 35%. Postoperative mortality was 15%, and postoperative complications occurred in 44% of patients. 11

For some patients with malignant obstructions of the gastrointestinal tract, the use of expandable metal stents may provide palliation of obstructive symptoms. Esophageal, biliary, gastroduodenal, and colorectal stents are available. 5 12 13 14 15 16 17 Stents may be placed under endoscopic guidance, with or without fluoroscopy, or by an interventional radiologist using fluoroscopy. Morbidity with stent placement may be lower than with surgery. Adequate imaging of the stricture itself and the gastrointestinal tract distal to the stricture is recommended to assess stricture length, detect multifocal disease, and determine the appropriateness of stenting. 18 19[Level of evidence: II] 20.

When neither surgery nor stenting is possible, the accumulation of the unabsorbed secretions produce nausea, vomiting, pain, and colicky activity as a consequence of the partial or complete occlusion of the lumen. In this case, a gastrostomy tube is commonly used to provide decompression of air and fluid that may be accumulating and causing visceral distention and pain. The gastrostomy tube is placed into the stomach and is attached to a drainage bag that can be easily concealed under clothing. When the valve between the gastrostomy tube and the bag is open, the patient may be able to eat or drink by mouth without creating discomfort since the food is drained directly into the bag. Dietary discretion is advised to minimize the risk of tube obstruction by solid food. If the obstruction improves, the valve can be closed and the patient may once again benefit from enteral nutrition.

Sometimes, decompression is difficult even with a gastrostomy tube in place. This problem may be caused by the accumulation of fluid, since several liters of gastrointestinal secretions may be produced per day. To relieve continuous abdominal pain, opioid analgesics via continuous subcutaneous or intravenous infusion may be necessary. Effective antispasmodics in this situation include anticholinergics (such as hyoscine butylbromide) 21 and possibly corticosteroids as well as centrally acting agents. If the bowel obstruction is thought to be functional (rather than mechanical) in origin, metoclopramide is the drug of choice because of its prokinetic effects on the bowel. For complete bowel obstruction thought to be irreversible, a trial of an antispasmodic such as hyoscyamine may decrease bowel contractions and therefore yield pain relief. Another option for management of refractory pain and/or nausea is the synthetic somatostatin analog octreotide. This agent inhibits the release of several gastrointestinal hormones and reduces gastrointestinal secretions. 22 23[Level of evidence: I] 24 Octreotide is usually given subcutaneously at 50 to 200 g 3 times per day and may reduce the nausea, vomiting, and abdominal pain of malignant bowel obstruction. For selected patients, the addition of an anticholinergic such as scopolamine may be helpful in reducing the associated painful colic of malignant bowel obstruction when octreotide alone is ineffective. When either scopolamine or octreotide is used alone, each is ineffective. 12 25 26 27 Corticosteroids are widely used in treating bowel obstruction, but empirical support is limited. 28 They may be useful as adjuvant antiemetics and analgesics in this setting, given as dexamethasone at a starting dose of 6 to 10 mg subcutaneously or intravenously 3 to 4 times per day. 12 25 (Refer to the Nausea, Vomiting, Constipation, and Bowel Obstruction in Advanced Cancer section in the PDQ® summary on Nausea and Vomiting for more information.)

Current Clinical Trials

Check NCI's list of cancer clinical trials for U.S. supportive and palliative care trials about constipation, impaction, and bowel obstruction that are now accepting participants. The list of trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References:

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3. Ripamonti C, De Conno F, Ventafridda V, et al.: Management of bowel obstruction in advanced and terminal cancer patients. Ann Oncol 4 (1): 15-21, 1993. [PUBMED Abstract]
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