Constipation

Definition

Chronic constipation is infrequent bowel movements or difficult passage of stools that persists for several weeks or longer.

Constipation is generally described as having fewer than three bowel movements a week.

Though occasional constipation is very common, some people experience chronic constipationthat can interfere with their ability to go about their daily tasks. Chronic constipation may also cause excessive straining to have a bowel movement and other signs and symptoms.

Treatment for chronic constipation depends on the underlying cause. Though, in some cases, a cause for chronic constipation is never found.

Symptoms

Signs and symptoms of chronic constipation include:

• Passing fewer than three stools a week
• Having lumpy or hard stools
• Straining to have bowel movements
• Feeling as though there's a blockage in your rectum that prevents bowel movements
• Feeling as though you can't completely empty the stool from your rectum
• Needing help to empty your rectum, such as using your hands to press on your abdomen and using a finger to remove stool from your rectum

Constipation may be considered chronic if you've experienced two or more of these symptoms for the last three months.

When to see a doctor

Make an appointment with your doctor if you experience unexplained and persistent changes in your bowel habits.

Causes

Constipation most commonly occurs when waste or stool moves too slowly through the digestive tract, causing it to become hard and dry. Chronic constipation has many causes:

Blockages in the colon or rectum

Blockages in the colon or rectum may slow or stop stool movement. Causes include:

• Anal fissure
• Bowel obstruction
• Colon cancer
• Narrowing of the colon (bowel stricture)
• Other abdominal cancer that presses on the colon
• Rectal cancer
• Rectocele

Problems with the nerves around the colon and rectum

Neurological problems can affect the nerves that cause muscles in the colon and rectum to contract and move stool through the intestines. Causes include:

• Autonomic neuropathy
• Multiple sclerosis
• Parkinson's disease
• Spinal cord injury
• Stroke

Difficulty with the muscles involved in elimination

Problems with the pelvic muscles involved in having a bowel movement may cause chronic constipation. These problems may include:

• Inability to relax the pelvic muscles to allow for a bowel movement (anismus)
• Pelvic muscles don't coordinate relaxation and contraction correctly (dyssynergia)
• Weakened pelvic muscles

Conditions that affect hormones in the body

Hormones help balance fluids in your body. Diseases and conditions that upset the balance of hormones may lead to constipation, including:

• Diabetes
• Overactive parathyroid gland (hyperparathyroidism)
• Pregnancy
• Underactive thyroid (hypothyroidism)

Risk Factors

Factors that may increase your risk of chronic constipationinclude:

• Being an older adult
• Being a woman
• Being dehydrated
• Eating a diet that's low in fiber
• Getting little or no physical activity
• Taking certain medications, including sedatives, narcotics or certain medications to lower blood pressure

Complications

Complications of chronic constipation include:

• Swollen veins in your anus (hemorrhoids).Straining to have a bowel movement may cause swelling in the veins in and around your anus.
• Torn skin in your anus (anal fissure). A large or hard stool can cause tiny tears in the anus.
• Stool that can't be expelled (fecal impaction). Chronic constipation may cause an accumulation of hardened stool that gets stuck in your intestines.
• Intestine that protrudes from the anus (rectal prolapse).Straining to have a bowel movement can cause a small amount of the rectum to stretch and protrude from the anus.

Test and diagnosis

Tests and procedures used to diagnose chronic constipationinclude:

• Examination of the rectum and lower, or sigmoid, colon (sigmoidoscopy). In this procedure, your doctor inserts a lighted, flexible tube into your anus to examine your rectum and the lower portion of your colon.
• Examination of the rectum and entire colon (colonoscopy). This diagnostic procedure allows your doctor to examine the entire colon with a flexible, camera-equipped tube.
• Evaluation of anal sphincter muscle function (anorectal manometry). In this procedure, your doctor inserts a narrow, flexible tube into your anus and rectum and then inflates a small balloon at the tip of the tube. The device is then pulled back through the sphincter muscle. This procedure allows your doctor to measure the coordination of the muscles you use to move your bowels.
• Evaluation of how well food moves through the colon (colonic transit study). In this procedure, you'll swallow a capsule containing markers that show up on X-rays taken over several days. Your doctor will look for signs of intestinal muscle dysfunction and how well food moves through your colon.
• An X-ray of the rectum during defecation (defecography).During this procedure, your doctor inserts a soft paste made of barium into your rectum. You then pass the barium paste as you would stool. The barium shows up on X-rays and may reveal a prolapse or problems with muscle function and muscle coordination.