Functional Disorders

Functional disorders are those in which the bowel looks normal but doesn’t work properly. They are the most common problems affecting the colon and rectum, and include constipation and irritable bowel syndrome (IBS). The primary causes for functional disorders include:

  • Eating a diet low in fiber
  • Not getting enough exercise
  • Traveling or other changes in routine
  • Eating large amounts of dairy products
  • Being stressed
  • Resisting the urge to have a bowel movement
  • Resisting the urge to have bowel movements due to pain from hemorrhoids
  • Overusing laxatives (stool softeners) that, over time, weaken the bowel muscles
  • Taking antacid medicines containing calcium or aluminum
  • Taking certain medicines (especially antidepressants, iron pills, and strong pain medicines such as narcotics)
  • Being pregnant

Constipation

Constipation is the difficult passage of stools (bowel movements) or the infrequent (less than three times a week) or incomplete passage of stools. Constipation is usually caused by inadequate "roughage" or fiber in the diet, or a disruption of the regular routine or diet. Constipation causes a person to strain during a bowel movement. It might include small, hard stools, and sometimes causes anal problems such as fissures and hemorrhoids. Constipation is rarely the sign of a more serious medical condition.

What causes constipation?

To understand what causes constipation, it helps to know how the large intestine works. The large intestine removes most of the water from stool and changes it to a solid waste. The large intestine then moves the stool through the rectum and anus as a bowel movement.

Constipation occurs when stool passes through the large intestine too slowly. When stool stays in the large intestine too long, the intestine removes too much water, and the stool becomes hard and dry.

Some lifestyle habits that may cause constipation include

  • changing your normal diet, exercise, or travel habits
  • ignoring the urge to have a bowel movement
  • feeling a lot of stress
  • eating a low-fiber diet
  • not drinking enough liquids
  • taking calcium or iron supplements
  • taking medicines such as painkillers with codeine; diuretics, also known as water pills; medicine for depression; and some antacid

Some medical conditions that may cause constipation include

  • pregnancy or having given birth
  • problems with the muscles and nerves in the intestine, rectum, or anus
  • irritable bowel syndrome, a condition in which the nerves that control the muscles in the intestine don’t function correctly; the intestine becomes sensitive to food, stool, gas, and stress
  • diabetes, a condition in which a person has high blood sugar, also called hyperglycemia, because the body cannot use blood glucose, or blood sugar, for energy
  • hypothyroidism, a condition in which the thyroid gland does not produce enough hormone to meet the body’s needs and many of the body’s functions slow down

Treatment

Treatment of constipation includes increasing the amount of fiber you eat, exercising regularly, and moving your bowels when you have the urge (resisting the urge causes constipation). If these treatment methods don’t work, laxatives are a temporary solution. Note that the overuse of laxatives can actually aggravate symptoms of constipation. Always follow the package instructions on the laxative medicine, as well as the advice of your doctor.

Irritable bowel syndrome (IBS)

Irritable bowel syndrome (also called spastic colon, irritable colon, or nervous stomach) is a condition in which the colon muscle contracts more readily than in people without IBS. A number of factors can trigger IBS including certain foods, medicines, and emotional stress. Symptoms of IBS include abdominal pain and cramps, excess gas, bloating, and a change in bowel habits such as harder, looser, or more urgent stools than normal. Often people with IBS have alternating constipation and diarrhea.

As many as 20 percent of the adult population, or one in five Americans, have symptoms of IBS, making it one of the most common disorders diagnosed by doctors. It occurs more often in women than in men, and it begins before the age of 35 in about 50 percent of people.

What are the symptoms of IBS?

Abdominal pain, bloating, and discomfort are the main symptoms of IBS. However, symptoms can vary from person to person. Some people have constipation, which means hard, difficult-to-pass, or infrequent bowel movements. Often these people report straining and cramping when trying to have a bowel movement but cannot eliminate any stool, or they are able to eliminate only a small amount. If they are able to have a bowel movement, there may be mucus in it, which is a fluid that moistens and protect passages in the digestive system. Some people with IBS experience diarrhea, which is frequent, loose, watery, stools. People with diarrhea frequently feel an urgent and uncontrollable need to have a bowel movement. Other people with IBS alternate between constipation and diarrhea. Sometimes people find that their symptoms subside for a few months and then return, while others report a constant worsening of symptoms over time.

What causes IBS?

Researchers have yet to discover any specific cause for IBS. One theory is that people who suffer from IBS have a colon, or large intestine, that is particularly sensitive and reactive to certain foods and stress. The immune system, which fights infection, may also be involved.

 
  • Normal motility, or movement, may not be present in the colon of a person who has IBS. It can be spasmodic or can even stop working temporarily. Spasms are sudden strong muscle contractions that come and go.
  • The lining of the colon called the epithelium, which is affected by the immune and nervous systems, regulates the flow of fluids in and out of the colon. In IBS, the epithelium appears to work properly. However, when the contents inside the colon move too quickly, the colon loses its ability to absorb fluids. The result is too much fluid in the stool. In other people, the movement inside the colon is too slow, which causes extra fluid to be absorbed. As a result, a person develops constipation.
  • A person’s colon may respond strongly to stimuli such as certain foods or stress that would not bother most people.
  • Recent research has reported that serotonin is linked with normal gastrointestinal (GI) functioning. Serotonin is a neurotransmitter, or chemical, that delivers messages from one part of your body to another. Ninety-five percent of the serotonin in your body is located in the GI tract, and the other 5 percent is found in the brain. Cells that line the inside of the bowel work as transporters and carry the serotonin out of the GI tract. People with IBS, however, have diminished receptor activity, causing abnormal levels of serotonin to exist in the GI tract. As a result, they experience problems with bowel movement, motility, and sensation—having more sensitive pain receptors in their GI tract.
  • Researchers have reported that IBS may be caused by a bacterial infection in the gastrointestinal tract. Studies show that people who have had gastroenteritis sometimes develop IBS, otherwise called post-infectious IBS.
  • Researchers have also found very mild celiac disease in some people with symptoms similar to IBS. People with celiac disease cannot digest gluten, a substance found in wheat, rye, and barley. People with celiac disease cannot eat these foods without becoming very sick because their immune system responds by damaging the small intestine. A blood test can determine whether celiac disease may be present.

How is IBS diagnosed?

If you think you have IBS, seeing your doctor is the first step. IBS is generally diagnosed on the basis of a complete medical history that includes a careful description of symptoms and a physical examination.

There is no specific test for IBS, although diagnostic tests may be performed to rule out other problems. These tests may include stool sample testing, blood tests, and x rays. Typically, a doctor will perform a sigmoidoscopy, or colonoscopy, which allows the doctor to look inside the colon. This is done by inserting a small, flexible tube with a camera on the end of it through the anus. The camera then transfers the images of your colon onto a large screen for the doctor to see the lining the colon.

If your test results are negative, the doctor may diagnose IBS based on your symptoms, including how often you have had abdominal pain or discomfort during the past year, when the pain starts and stops in relation to bowel function, and how your bowel frequency and stool consistency have changed. Many doctors refer to a list of specific symptoms that must be present to make a diagnosis of IBS.

What is the treatment for IBS?

Treatment includes avoiding caffeine, increasing fiber in the diet, monitoring which foods trigger IBS (and avoiding these foods), minimizing stress or learning different ways to cope with stress, and sometimes taking medicines as prescribed by your health care provider.

Unfortunately, many people suffer from IBS for a long time before seeking medical treatment. Up to 70 percent of people suffering from IBS are not receiving medical care for their symptoms. No cure has been found for IBS, but many options are available to treat the symptoms. Your doctor will give you the best treatments for your particular symptoms and encourage you to manage stress and make changes to your diet.

Medications are an important part of relieving symptoms. Your doctor may suggest fiber supplements or laxatives for constipation or medicines to decrease diarrhea, such as loperamide (Imodium). An antispasmodic may be prescribed, which helps to control colon muscle spasms and reduce abdominal pain. Antidepressants may relieve some symptoms. However, both antispasmodics and antidepressants can worsen constipation.

With any medication, even over-the-counter medications such as laxatives and fiber supplements, it is important to follow your doctor’s instructions. Some people report a worsening in abdominal bloating and gas from increased fiber intake, and laxatives can be habit forming if they are used too frequently.

Medications affect people differently, and no one medication or combination of medications will work for everyone with IBS. You will need to work with your doctor to find the best combination of medicine, diet, counseling, and support to control your symptoms.

How does stress affect IBS?

Stress—feeling mentally or emotionally tense, troubled, angry, or overwhelmed—can stimulate colon spasms in people with IBS. The colon has many nerves that connect it to the brain. Like the heart and the lungs, the colon is partly controlled by the autonomic nervous system, which responds to stress. These nerves control the normal contractions of the colon and cause abdominal discomfort at stressful times. People often experience cramps or “butterflies” when they are nervous or upset. In people with IBS, the colon can be overly responsive to even slight conflict or stress. Stress makes the mind more aware of the sensations that arise in the colon, making the person perceive these sensations as unpleasant.

Some evidence suggests that IBS is affected by the immune system, which fights infection in the body. The immune system is affected by stress. For all these reasons, stress management is an important part of treatment for IBS. Stress management options include

  • stress reduction (relaxation) training and relaxation therapies such as meditation
  • counseling and support
  • regular exercise such as walking or yoga
  • changes to the stressful situations in your life
  • adequate sleep

Conditions We Treat