Constipation is caused by the slowed transit of stool . Under normal circumstances, water is pulled from the stool as it passes through the large intestine. Slowed transit of stool allows the large intestine to pull more water from the stool, resulting in the hard, dry stools and associated difficult passage of stools that characterize constipation.
Low fiber diet is most common cause of constipation, other common causes of constipation are lack of physical activity or exercise, inadequate intake of fluid each day, or delay in going to the bathroom when you have the urge to defecate. Stress and travel can also contribute to constipation or other changes in bowel habits.
Other Causes of Constipation
Drugs can cause constipation. Drugs slow the transit of stool causing constipation. Here is a list of drugs known to cause constipation: Aluminum hydroxide (AMPHOGEL, ALU-CAP); Bismuth subsalicylateSome (PEPTO-BISMOL), Iron salts, anticholinergic drugs, certain antihypertensive, opioids, and many sedatives, frequently cause constipation.
Diseases and disorders can cause constipation . This may include an under active thyroid gland (hypothyroidism), high blood calcium levels (hypercalcemia), and Parkinson's disease. Other conditions, including poor blood supply to the large intestine and nerve or spinal cord injury, can also cause constipation by slowing transit.
Constipation is sometimes caused by obstruction of the large intestine . Obstruction can be caused by cancer, especially in the last portion of the large intestin. Bezoars (tightly packed collections of partially digested or undigested material) and foreign bodies can also block the intestinal tract. People who previously had abdominal surgery may develop obstruction, usually of the small intestine, because of formation of bands of fibrous tissues.
Aging is also a cause of constipation : Constipation is particularly common among older people. Age-related changes in the large intestine along with increased use of medications and reduced physical activity tend to slow the transit of stool through the large intestine. Slowed transit is particularly common during periods of illness. The rectum enlarges with age, and increased storage of stool in the rectum allows hard stool to become impacted.
Chronic pain and psychological conditions , especially depression, are common causes of acute and chronic constipation. Constipation may result from changes in the levels of certain substances in the brain, such as serotonin, that can affect the intestinal tract.