Constipation

Constipation facts

• Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week.
  
• Constipation usually is caused by the slow movement of stool through the colon.
  
• There are many causes of constipation including medications, poor bowel habits, low fiber diets, abuse of laxatives, hormonal disorders, and diseases primarily of other parts of the body that also affect the colon.
  
• The two disorders limited to the colon that cause constipation are colonic inertia and pelvic floor dysfunction.
  
• Medical evaluation for the cause of constipation should be done when constipation is of sudden onset, severe, worsening, associated with other worrisome symptoms such as loss of weight, or is not responding to simple, safe treatments.
  
• Medical evaluation of constipation may include a history, physical examination, blood tests, abdominal X-rays, barium enema, colonic transit studies, defecography, ano-rectal motility studies, and colonic motility studies.
  
• The goal of therapy for constipation is one bowel movement every two to three days without straining.
  
• Treatment of constipation may include dietary fiber, non-stimulant laxatives, stimulant laxatives, enemas, suppositories, biofeedback training, and surgery.
  
• Stimulant laxatives should be used as a last resort because of the possibility that they may permanently damage the colon and worsen constipation.
  
• Most herbal laxatives contain stimulant-type laxatives and should be used, if at all, as a last resort.

What is constipation?

Constipation means different things to different people. For many people, it simply means infrequent stools. For others, however, constipation means hard stools, difficulty passing stools (straining), or a sense of incomplete emptying after a bowel movement. The cause of each of these "types" of constipation probably is different, and the approach to each should be tailored to the specific type of constipation.
Constipation also can alternate with diarrhea. This pattern commonly occurs as part of the irritable bowel syndrome (IBS). At the extreme end of the constipation spectrum is fecal impaction, a condition in which stool hardens in the rectum and prevents the passage of any stool.
The number of bowel movements generally decreases with age. Ninety-five percent of adults have bowel movements between three and 21 times per week, and this would be considered normal. The most common pattern is one bowel movement a day, but this pattern is seen in less than 50% of people. Moreover, most people are irregular and do not have bowel movements every day or the same number of bowel movements each day.
Medically speaking, constipation usually is defined as fewer than three bowel movements per week. Severe constipation is defined as less than one bowel movement per week. There is no medical reason to have a bowel movement every day. Going without a bowel movement for two or three days does not cause physical discomfort, only mental distress for some people. Contrary to popular belief, there is no evidence that "toxins" accumulate when bowel movements are infrequent or that constipation leads to cancer.
It is important to distinguish acute (recent onset) constipation from chronic (long duration) constipation. Acute constipation requires urgent assessment because a serious medical illness may be the underlying cause (for example, tumors of the colon). Constipation also requires an immediate assessment if it is accompanied by worrisome symptoms such as rectal bleeding, abdominal pain and cramps, nausea and vomiting, and involuntary loss of weight. In contrast, the evaluation of chronic constipation may not be urgent, particularly if simple measures bring relief.

What causes constipation?

Theoretically, constipation can be caused by the slow passage of digesting food through any part of the intestine. More than 95% of the time, however, the slowing occurs in the colon.

Medications that cause constipation

A frequently over-looked cause of constipation is medications. The most common offending medications include:

• Narcotic pain medications such as codeine (for example, Tylenol #3), oxycodone (for example, Percocet), and hydromorphone (Dilaudid);
  
• Antidepressants such as amitriptyline (Elavil) and imipramine (Tofranil)
  
• Anticonvulsants such as phenytoin (Dilantin) and carbamazepine (Tegretol)
  
• Iron supplements
  
• Calcium channel blocking drugs such as diltiazem (Cardizem) and nifedipine (Procardia)
  
• Aluminum-containing antacids such as Amphojel and Basaljel

In addition to the medications listed above, there are many others that can cause constipation. Simple measures (for example, increasing dietary fiber) for treating the constipation caused by medications are often are effective, and discontinuing the medication is not necessary. If simple measures don't work, it may be possible to substitute a less constipating medication. For example, a nonsteroidal antiinflammatory drug (for example, ibuprofen) may be substituted for narcotic pain medications. Additionally, one of the newer and less constipating anti-depressant medications [for example, fluoxetine (Prozac)] may be substituted for amitriptyline and imipramine.