Studies Used to Determine the Cause of Constipation
A physical exam may include a rectal exam with a gloved, lubricated finger to evaluate the tone of the muscle that closes off the anus (anal sphincter) and to detect tenderness, obstruction, or blood. In some cases, blood and thyroid tests may be necessary to look for thyroid disease and serum calcium or to rule out inflammatory, neoplastic, metabolic, and other systemic disorders.
Extensive testing is usually reserved for older people or those with:
- Severe symptoms
- Sudden changes in number and consistency of bowel movements
- Blood in the stool.
Additional tests that may be used to evaluate constipation include:
- Colorectal transit study
- Anorectal function tests.
Because of an increased risk of colorectal cancer in older adults, the doctor may use tests to rule out a diagnosis of cancer. These tests include:
A colorectal transit study, usually reserved for those with chronic constipation, shows how well food moves through the colon. The patient swallows capsules containing small markers that are visible on an x-ray. The movement of the markers through the colon is monitored with abdominal x-rays taken several times 3 to 7 days after the capsule is swallowed. The patient follows a high-fiber diet during the course of this test.