Constipation and Incomplete Bowel Emptying

Reviewed by: HU Medical Review Board | Last reviewed: December 2023

Constipation is a problem many people experience. Constipation refers to difficult and infrequent bowel movements. For people with inflammatory bowel disease (IBD), constipation is complicated by other gastrointestinal (GI) symptoms.1

What is constipation?

Constipation occurs with a wide variety of medical conditions, including GI disorders. It is common in people with both active and inactive IBD. Around 15 percent of people in the United States experience constipation. Women and older people are more likely to be affected.1

Symptoms of constipation include:1-3

  • Fewer than 3 bowel movements per week
  • Hard or lumpy stools
  • Straining to have a bowel movement
  • Abdominal bloating and nausea
  • Pain and abdominal cramps
  • Excessive gas
  • Feeling unable to empty your bowels completely

Constipation and IBD

Diarrhea, cramps, abdominal pain, and rectal bleeding are common symptoms of IBD. People with ulcerative colitis (UC) and Crohn’s disease can also have constipation.2,3

Constipation can occur with either UC or Crohn’s disease, but it is more common in UC. In one study of people with UC, women were 3 times more likely than men to have constipation.2,3

Constipation in UC is often seen in people with active left-sided colitis. Left-sided colitis is inflammation from the rectum (the area of the colon closest to the anus) up through the entire left side of the colon.4,5

Older people with a type of UC called ulcerative proctitis are especially prone to constipation. Proctitis is inflammation of the rectum. This inflammation interferes with the normal passage of stool.4,6

What is tenesmus?

Tenesmus is a symptom similar to constipation. With tenesmus, you feel like you need to have a bowel movement but cannot. Tenesmus is common in people with UC that involves the lower end of the colon. This type of UC is called proctosigmoiditis.7

What causes constipation?

Constipation is very common and can occur at any age. There are many different causes.Things that can contribute to constipation include:1,3,5

  • Slow movement of food through the digestive tract
  • Abnormal absorption of fluids in the colon
  • Low-fiber diet
  • Not drinking enough fluids
  • Side effects of medicines you take
  • Damage to the anal muscles from childbirth or surgery

What medicines cause constipation?

Constipation is a common side effect of prescription drugs. Here are some common drugs that can increase the risk of constipation:1

  • Antidepressants
  • Allergy drugs
  • Narcotics
  • Iron supplements
  • Pain relievers
  • Calcium channel blockers
  • Bismuth (such as in Pepto-Bismol® or Kaopectate®)

What causes constipation in IBD?

Inflammation in the GI tract contributes to constipation in IBD. Inflammation alters normal nerve and muscle function in the colon. This dysfunction slows down the movement of food through the GI tract. As stool builds up in the colon, it can dry out and worsen constipation. IBD can also cause scarring that narrows part of your intestine.5

Pelvic muscle function is another factor in constipation with IBD. Being able to relax your anal muscles is necessary for regular bowel movements. If these muscles do not relax, normal bowel movements are not possible. This can lead to straining and incomplete bowel emptying.5

How is constipation diagnosed?

Doctors diagnose constipation based on symptoms. Experts do not recommend routine abdominal X-rays or CT scans to diagnose constipation. But these tests may be used to rule out other problems.2

Evaluation of constipation may include:2

When should I be concerned?

Complications of IBD can interfere with normal bowel movements. Talk to your doctor if you notice a sudden onset of new or severe bowel symptoms. This could be a sign of a more serious problem.8

Bowel obstruction and toxic megacolon are life-threatening IBD complications. A bowel obstruction blocks the flow of stool through the GI tract. Toxic megacolon is an enlargement of the colon and can lead to a hole in the colon.8

The following symptoms could be a sign of a serious problem:9

  • Weight loss
  • Bleeding
  • Frequent or severe diarrhea
  • Fevers
  • Nighttime symptoms

How is constipation with IBD treated?

There is no single cure for constipation. Your symptoms and treatment will vary depending on whether you have active symptoms related to IBD. In addition to managing your underlying IBD, your doctor may recommend the following:5,9

  • Diet changes
  • Fiber supplements
  • Increased fluid intake
  • Exercise
  • Medicine
  • Pelvic floor therapy

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