Diagnosis of Constipation
A diagnosis of constipation involves at least two of the following symptoms for 12 weeks (not necessarily consecutive weeks) during the past 12 months. Symptoms include the following:
- Fewer than three bowel movements per week
- Hard stool
- Straining during bowel movements
- Sensation of incomplete evacuation or intestinal blockage
Physical examination often includes a digital rectal exam (DRE). In DRE, the physician inserts a lubricated, gloved finger into the patient's rectum to detect tenderness, blockage (e.g., colorectal polyp), or blood.
Diagnostic tests that may be performed include the following:
- Anorectal function tests—These tests are used to evaluate the function of the anus and rectum.
- Barium enema—This tests uses x-rays and a contrast solution to view the rectum, colon, and lower portion of the small intestine.
- Colonoscopy or sigmoidoscopy—These tests involve using a flexible tube with a light and camera attached to view the inside of the colon.
- Colorectal transit study—This test evaluates how well food moves through the colon. The patient swallows capsules containing markers that are visible on x-ray and a series of x-rays is taken 3–7 days later.
- Defecography—This test uses x-rays to evaluate how well stool is eliminated through the rectum and anus.