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)
Aug. 31, 2013

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