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.
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.
The following questions may provide a useful assessment guide:
- What is normal for the patient (frequency, amount, and timing)?
- When was the last bowel movement? What was the amount, consistency, and color? Was blood passed with it?
- Has the patient been having any abdominal discomfort, cramping, nausea or vomiting, pain, excessive gas, or rectal fullness?
- Does the patient regularly use laxatives or enemas? What does the patient usually do to relieve constipation? Does it usually work?
- What type of diet does the patient follow? How much and what type of fluids are taken on a regular basis?
- What medication (dose and frequency) is the patient taking?
- Is this symptom a recent change?
- 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. A program for prevention of constipation in cancer patients is described below.