Chronic Constipation

Diagnosis

It is important to identify the cause of constipation for treatment to be appropriate and effective. A majority of constipated patients have no underlying medical condition. They have "functional constipation," which can usually be managed with self-help measures.

When chronic constipation is a side effect of another condition, it is called secondary constipation. Conditions which can cause secondary constipation include:

• Primary diseases of the colon (stricture, cancer, anal fissure, proctitis)
• Metabolic disturbances (hypercalcemia, hypothyroidism, diabetes mellitus)
• Neurologic disorders (parkinsonism, spinal cord lesions)
• Use of narcotic medications

These conditions are often associated with other symptoms and can be diagnosed by blood or other tests.

If functional constipation and other diseases have been ruled out as causes, patients may need additional tests to see if the cause may be:

• Slow-transit constipation (colonic dysmotility)
• Pelvic floor dysfunction
• Irritable bowel syndrome

Diagnostic Tests

Mayo Clinic offers a full range of gastrointestinal diagnostic studies to assess colonic functions. After obtaining a history and conducting a physical examination, Mayo doctors may use one or more of the following tests to diagnose chronic constipation.

Scope Tests

Flexible sigmoidoscopy, rigid proctoscopy and colonoscopy allow the doctor to examine all or part of the colon and rectum for bleeding, inflammation and tumors. The colonoscope can also be used to obtain tissue samples (biopsy).

Defecating Proctogram

An X-ray exam that checks the way the sigmoid colon and rectum empty stool.

Anal and Abdominal Ultrasound

Sound waves are used to image the abdomen and anal sphincter muscles.

In the GI transit test, a special camera measures the rate at which two radioactive markers travel through the digestive tract.

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GI Transit Study (Scintigraphy)

A GI transit study measures the rate at which a radioactive marker travels through the stomach, small intestine and colon. Traditional forms of the test can take five to seven days to complete. With the use of radioactive isotopes, Mayo Clinic's test is able to measure transit time in 24 to 48 hours.

Anorectal Testing

Anorectal tests can assess whether the rectum and pelvic floor muscles function appropriately during evacuation. These tests include manometry (which measures pressures), sensation, empying ability, the ability to expel a rectal balloon, and visualization of rectal evacuation by X-ray (defecography) or magnetic resonance imaging (MRI).

Colonic Motility Test

A colonic motility test is a newer test available at Mayo Clinic. A special balloon is inserted into the colon with an endoscope. A machine contracts and expands the balloon and instruments measure the colon's response. The test can help the physician decide if constipation should be treated with medications or surgery.

Hydrogen Breath Test

Used to detect lactose or fructose intolerance, which may cause abdominal pain, bloating, gas and diarrhea. When large amounts of carbohydrates, such as lactose or fructose, are incompletely digested in the intestine and pass through to the colon, hydrogen gas is produced that can be measured in exhaled breath.