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Constipation as a Symptom of Multiple Sclerosis

What Causes Constipation in People with MS?


Updated May 01, 2014

Multiple Sclerosis Symptoms: Constipation

Ever feel like this?

Garry Hunter / Getty Images

As a symptom of multiple sclerosis (MS), constipation is really a bummer. It can be chronic, rather than coming and going. You can spend days existing with a feeling of “not rightness.” It can get painful. It is also not really something that many of us feel comfortable talking about, so we silently suffer with the problem, rather than getting the sympathy and help that we need.

Among the amazing array of symptoms associated with MS, constipation has to be one of the biggest “dignity thieves.”

However, it is important that you seek help for this problem. Waiting it out is a bad idea, as this could lead to damage to your rectum or impaction. It is possible that the treatment will be easy, such as changing medications or increasing water intake.

What Does It Feel Like?

OK, we have all been constipated and know what it feels like. However, there is a more precise definition than just “I can’t go.” It includes:
  • Having two or fewer bowel movements per week
  • Feeling like you have not eliminated the entire bowel movement at least 25% of the time
  • Straining to have a bowel movement at least 25% of the time
  • Having a lumpy or hard stool at least 25% of the time

How Common Is It?

It is difficult to say how many people with MS experience constipation, as it tends to be underreported. This is probably due to many factors, such as patients not connecting this symptom to MS, so not reporting it to their neurologists; patients being focused on more dramatic symptoms during their neurologist visits; patient being too embarrassed to report constipation to their doctors. However, it is estimated that between 50% to 75% of people with MS experience constipation at some point. It is the most common bowel problem experienced by people with MS.

What Causes It?

Two ingredients comprise a healthy, regular bowel movements:
  1. The stool must keep moving through the intestines
  2. There must be enough water in the stool

These are really interrelated things. When the stool slows down on its journey through the bowels (especially the colon, the last part of the large intestine), water is absorbed to make the stool solid. When it slows down too much, too much water is absorbed by the colon and the stool becomes hard and difficult to pass.

Constipation in MS can be caused by any of the following factors (or a combination):

Neurological Damage: As mentioned, stool must keep moving. In people with MS, lesions may prevent the brain from accurately receiving or transmitting signals that control conscious attempts to have a bowel movement. In other words, you may not be receiving the signal that you “have to go,” or you are unable to effectively relax and push as needed to have a bowel movement. The involuntary movements that keep the stool moving through the lower parts of the digestive tract may also be impaired. Again, these problems are compounded by the stool being too hard to pass easily, due to prolonged time in the colon.

Limited Physical Activity: An important component of intestinal motility (the movement of digested food through the intestines) is physical activity, such as walking. Many of us are unable to move around and walk much, due to weakness, spasticity, sensory ataxia or fatigue.

Side Effect of Medications: Constipation is a side effect of many of the medications that people with MS take to control symptoms. These include:

  • Antidepressants, especially tricyclic antidepressants, including: Amitriptyline (Elavil, Endep), Desipramine (Norpramin), Doxepin (Sinequan), Imipramine (Tofranil-PM), nortriptyline (Pamelor)
  • Painkillers, especially those containing morphine or codeine, as well as other narcotics, such as Tramadol
  • Medications for bladder dysfunction or diarrhea, called anticholinergics, including: Propantheline (Norpanth, Pro-Banthine), Tolterodine (Detrol tablets and Detrol LA extended-release capsules), Dicyclomine (Bentyl)
  • Medications for spasticity, including Baclofen (Lioresal) and Tizanidine (Zanaflex)

Not Drinking Enough Water: I know that I am guilty of cutting back on the water to prevent some of my bladder-related symptoms, especially nocturia. Some people with MS also reduce fluid intake when they are going out or traveling, as getting to a restroom may be difficult. I cannot say it enough: It is important that you drink plenty of water and other fluids throughout the day if you have MS. Besides leading to constipation, people with MS also have a higher tendency towards urinary tract infections.

How Severe Can It Get?

Constipation that is not managed can result in fecal impaction, which happens when constipation is so severe that the entire rectum becomes filled with a large, hard ball of stool. In these cases, manual disimpaction is needed (a doctor or a nurse removes the blockage manually).

My Experience

I don’t really have a gruesome or funny story about my bouts with constipation. For me, constipation comes and goes. I make a point to drink extra water when I skip a day of bowel movements, as well as increase my dietary fiber and eat fruits and vegetables. Like I said, nothing that insightful (or fun) from my experiences. Sorry.


Randall T. Shapiro. Managing the Symptoms of Multiple Sclerosis (5th ed.). New York: Demos Medical Publishing, 2007.

The Multiple Sclerosis Resource Centre. Constipation.

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