Constipation and Incomplete Bowel Emptying

Constipation is not a typical symptom of Crohn’s disease.¹ Nevertheless, constipation can be a symptom of Crohn’s disease complications.² It also can be a side effect of medications.

Constipation can be a symptom of ulcerative colitis, particularly in people with left-sided disease, where only the left side of the large intestine is inflamed.³

The medical definition of constipation is in the table below.⁴ One sign is having 3 or fewer bowel movements per week.¹ Straining, hard stool, or abdominal discomfort alone are not constipation. However, having 2 or more of these symptoms at least 25% of the time is a sign of constipation.¹Table. Diagnosis of Chronic Constipation

From: ASGE Standards of Practice Committee. Gastrointest Endosc. 2014;80:563-565.

Incomplete bowel emptying is the feeling that you need to pass stool, but your bowels are already empty. If you have this feeling with more than 25% of your bowel movements, it may be a symptom of constipation.¹ This feeling can also occur without constipation, as a symptom of inflammation in the colon or rectum. There is more information about incomplete bowel emptying at the end of this article.

What causes constipation with ulcerative colitis?

In ulcerative colitis, constipation can occur in people with early-stage disease or in people with left-sided disease. While the speed of transit is increased in the inflamed portion, it slows in the non-affected part of the intestines, which may lead to constipation.³

Strictures and anal fissures can also cause constipation, or constipation can be a side effect of medication or supplements.

A stricture is a section of the digestive tract that has become abnormally narrow. A stricture forms when connective tissue builds up within the digestive tract. When this happens, food and waste cannot pass normally.

An anal fissure is a split or tear at the end of the anal canal. Constipation can cause a fissure. A fissure can also make constipation worse. Some fissures are very painful. Having a bowel movement may feel like you are “passing shards of glass.”⁵ Consequently, you may try to delay a bowel movement, leading to constipation.⁶

You may need opioid pain relievers after surgery or for abdominal pain. You may take an iron supplement to treat anemia. These can cause constipation.

What are other causes of constipation?

Constipation can be a condition on its own, called primary constipation. Primary constipation can be caused by:⁷

• Uncoordinated pelvic muscles, leading to straining.
• Slow movement of waste through the digestive tract.
• Normal movement of waste through the digestive tract, but difficulty passing the waste out of the body.

Constipation also can be a symptom of other medical conditions, including:¹

• Depression
• Diabetes mellitus
• Hypothyroidism
• Irritable bowel syndrome
• Neurologic disorders (problems with the nerves)

How common is constipation?

Constipation is one of the most common digestive tract problems in adults. There are 2.5 million clinic visits per year for constipation.⁴ In a general population, about 12% of men and 16% of women have constipation.¹ Risk factors for constipation are:

• Female gender
• Older age
• Low-calorie, low-fiber diet
• Using several medications

How is constipation evaluated?

Your health care provider will ask questions about your constipation symptoms. Tell your provider about:^1,7,8

• Abdominal pain or cramping
• Swelling or bloating
• Nausea, vomiting
• Consistency of stool
• Use of digital manipulation (eg, a lubricated finger) to pass stool
• Pain while passing stool
• Medications and laxatives you are taking
• Typical diet or recent diet changes

These details can help your provider sort out the cause of constipation.

The physical examination will probably include an abdominal and rectal examination.¹ A colonoscopy is not a routine procedure for constipation. However, colonoscopy is useful if there are signs of an obstruction.⁴

How is constipation due to ulcerative colitis treated?

Treatment for constipation depends on the underlying cause. For constipation related to left-sided ulcerative colitis, stool bulking agents or laxatives can help.³ For constipation related to inflammatory bowel disease complications, treating the complication may improve bowel function. Small strictures can be treated with endoscopy. Surgery is used to treat large strictures. Most anal fissures heal on their own. While the fissure is healing, there are things you can do at home to ease the pain. Options include topical pain medication and a sitz bath.⁹

What causes the feeling of incomplete bowel emptying?

You may have had the feeling that you need to pass stools, but your bowels are already empty. The medical term for this is tenesmus. You may also hear it described as a feeling of “incomplete evacuation” or “incomplete bowel emptying.” You may strain when you feel this way, but pass very little stool.

Feeling this sensation is more than 25% of the time is one part of the definition of constipation.¹ However, inflammation in the rectum or colon is a more common cause.¹⁰ It is a typical symptom of Crohn’s disease, ulcerative colitis, and diversion colitis.^11,12 It also can be a symptom of a rectal stricture.^9,11