Chronic Constipation Causes

Dr. Shrey Lakhotia, BDS

Chronic constipation causes

Constipation is characterized by infrequent stools, difficult to pass stools, or both.

Difficulty in passing stools can involve straining, discomfort, a sense of incomplete evacuation after stool passage, hard stools, increased time to pass a stool, or even the need to place a finger in the anus to help with passing stools.

Chronic Constipation is defined as the presence of constipation symptoms for at least 6 months.


The causes of chronic constipation may be either Extrinsic or Intrinsic. Lets discuss each individually.

Extrinsic Factors

Low fiber intake 

Reduced intake of dietary fiber is a common cause of constipation.

Fiber adds bulk to stools, which is needed for their proper movement through the colon. Fiber also holds moisture, which is needed to keep stools soft.

If we are not getting enough fiber, it can be corrected by simply eating more fiber rich foods, including whole wheat and whole grain products, vegetables and fruit. Another option is to take supplemental fiber.

Inadequate hydration

Water is an essential requirement for the body.

A high water content in stools is vital for proper bowel function. Stool should be around 75% water. When there is less than this, stool becomes dry, hard and difficult to pass.

Inadequate hydration can be avoided by drinking more water, and reducing consumption of diuretics like coffee, tea and other caffeinated beverages.

Reduced mobilty

This may happen as a result of declining health, hospitalization or a lifestyle with little exercise.

As a result of reduced mobility, the muscles of the body grow weaker. This includes abdominal muscles that are involved in the movement of stool through the bowel.

Reduced mobility can be overcome by looking for ways to include exercise in one’s lifestyle. Even something as simple as taking a walk each day can be helpful.

Electrolyte imbalances (hypercalcemia, hypokalamia, hypermagnesemia)

An imbalance of electrolytes in the blood can result in constipation.

Excessive calcium and a shortage of magnesium may both be contributing factors.

Since 80% of Americans don’t get enough magnesium in their diet, and since many take a calcium supplement or antacids containing calcium, an electrolyte imbalance may be more common than people realize.

Calcium constricts muscles

Since the colon is a large muscle, too much calcium in the stool can restrict bowel movement.

Magnesium not only compliments calcium as a muscle relaxant, but it also serves as an osmotic laxative, pulling additional water into the colon. Magnesium helps to make stools soft, slick and easier to pass.

A magnesium supplement may actually be one of the best answers for chronic constipation.

A Result of Other Medical Conditions

Chronic constipation may be caused by:

  • Metabolic disorders, like chronic renal failure

  • Endocrine disorders, like hypothyroidism, hyperparathyroidism and diabetes mellitus

  • Neurological disorders, including Parkinson's disease, injuries to the spinal cord, dementia, multiple sclerosis, cauda equine syndrome and various neuropathies

The first step to treat chronic constipation due to these is to treat the underlying disease first. Other steps and general measures like a fiber rich diet, better hydration and exercise may be helpful.

Psychological disorders

Psychological problems like depression, a history of abuse, stress or personality disorders can cause constipation by activating the sympathetic nervous system fight or flight response. Certain individuals react to stress with decreased contractions of the colon (peristalsis).

People with psychological problems are more likely to eat unhealthy diets, decrease physical activity, and drink less water. All these are can contribute to constipation.

Exercise, deep breathing, meditation, taking a break and massage therapy may be helpful in stress management.


Medications like aspirin, opiates, diuretics, anticholinergics, antidepressants, calcium channel blockers, NSAIDs and β-blockers may all be contributing factors to continuing constipation. This is especially a problem in older individuals. 

To avoid this, inform your physician of the problem you are having with constipation and ask if there might be an alternative less constipating medication.

Intrinsic Factors

The two categories of factors that can result in chronic constipation are:

  • Slow colon transit time (STC)
  • Pelvic floor dysfunction (PFD)

Chronic Constipation Causes 

Slow colon transit time (STC)

This condition is not well understood. It can cause constipation problems in young women and children that does not respond to conventional treatment.

A common characteristic of Slow Colon Transit Time is less intense contractions of the colon. This can lead to bloating, discomfort in the abdomen, feces moves slower through the colon, and defecation is less frequent.

As stool spends more time in the large intestine, more water is extracted from the stool. This results in stool that is small and hard, and is generally not large enough to provide enough pressure on the rectum to trigger the reflex to defecate.

When the cause is slow transit time, the best pharmacological answer for chronic constipation is as follows:

  • Take a bulk forming agent like bran or psyllium to

  • Take an osmotic agent or stool softener, like docusate, PEG or lactulose
    Magnesium, an excellent osmotic agent, helps by pulling water into the colon. This serves to soften and bulk up stool. A magnesium supplement may be taken as an ongoing osmotic agent

  • Take a stimulant laxative, like senna or bisacodyl

  • For extreme or resistant cases, add one of newer agents like 5-HT4 agonist or chloride channel activators

Pelvic floor dysfunction (PFD)

In pelvic floor dysfunction, also called anismus or dyssynergic dysfunction, there is ineffective coordination among the muscles of the pelvic floor, abdominal, rectal, and anal sphincter in the process of defecation. 

There is:

  • Impaired sensation in the rectal area
  • Decreased pressure from lumen in the anal canal
  • Pelvic floor muscles are lax

The above have been shown to cause chronic constipation, especially in women and the elderly.

While one is defecating, there can be an involuntary contracting of the muscles that encircle the rectum and anus. This closes off the rectum and anus, making it difficult to completely empty out. 

The following can distort the normal functions of the pelvic floor:

  • Rectal prolapse (the protrusion of rectal tissue through the anal opening)
  • Rectocele (the out-pouching of the rectum)
  • Damage to the perineal area, which can be caused by sacral nerve injury or traumatic childbirth

For chronic constipation caused by pelvic floor dysfunction, biofeedback is the best solution. 

It helps in retraining the sensation and control of the anorectum and pelvic floor, which in turn helps to eliminate paradoxical contractions during the process of defecation.

Conclusion, Chronic Constipation Causes

In conclusion, there can be many chronic constipation causes. 

These need to be identified to help with proper treatment. 

Of course, there are general measures for managing chronic constipation, like:

  • Increasing fiber in diet

  • Avoiding dehydration

  • Exercising regularly

  • Dealing with stress

  • Taking a magnesium supplement 
  • Note: 

As with any over-the-counter remedy, talk with your doctor before starting on a magnesium supplement.

Supplemental magnesium may interfere with certain prescription medications. Those with kidney disease should not take a magnesium supplement unless instructed to do so by their doctor.

(Return from Chronic Constipation Causes to Cause of Constipation)

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