What causes constipation and how is it treated?

What causes constipation and how is it treated?

By Christopher J. Carlson, MD
Gastroenterologist

People often fear the worst about constipation.  Constipation is very common and only rarely signifies something serious.  Just because the average person has a bowel movement daily doesn’t mean you have to—if normal for you is every 3, 5, or 7 days that is okay so long as it’s not adversely affecting your life. In many cases, people with constipation struggle with it all their lives and are looking to be certain nothing more serious is going on and for a way to treat their symptoms.  Even in people with relatively new onset of constipation, there usually is a simple solution.  It is certainly reasonable to have your constipation assessed but in the absence of other warning signs for more serious disease, additional testing related to constipation is not always essential.

What are the causes of constipation?

Colonic inertia

  • Most cases of constipation are caused by colonic inertia, which is simply a slow moving colon.  Different people are made differently, and the muscles and nerves that are supposed to act in concert to push stool along just work a little slower in people with constipation.  In such cases, if we could look at the colon under the microscope it would look normal but if we took an x-ray of how quickly it pushed stool through, it would on average move things along more slowly.

Pelvic floor dysfunction

  • If we were to cut you in half just above the waist, like the magician box trick, and look down into your pelvis, we’d see a whole bunch of muscles that make a basket in the pelvis and hold everything above in place.  This basket of muscles is called the pelvic floor, and works along with the rectum in a coordinated effort to let you have a bowel movement.  In some cases, this coordination is disrupted so that while the colon is moving stool through just fine, when you go to pass it, you end up straining and little comes out or it takes a long time to force stool out.  Some factors can contribute to pelvic floor dysfunction (such as a traumatic vaginal delivery).

Mechanical obstruction

  • Usually if this is a factor, onset is somewhat abrupt and continues until relieved.  Fortunately this is relatively rare but because such obstructions can be caused by scar tissue or cancer and because if unrelieved they could result in continued colon dilation, perforation, and grave illness, this always needs to be considered. 

Other more rare causes

  • Other possible and much more rare causes of constipation would include neuropathy (nerves to the colon are impaired), myopathy (muscle issue), or Hirschsprung’s (a congenital nerve issue). These typically present in a more dramatic fashion.

How is constipation treated?

Treatment of chronic constipation is in most cases straightforward and is treated similarly at the beginning, with the exception of mechanical obstruction (where treatment typically involves an endoscopic procedure or surgery to remove the obstruction). Most involve increasing fiber in the diet and if this is ineffective, taking gentle laxatives that are safe for long term use.  There are several newer, designer laxatives on the market; however some of the simpler laxatives are safe, reliably effective if taken properly, and cheaper.  Finally, people often think that increasing water consumption will help with constipation however as the concentration of contents in the colon always equals that in the blood and this is very tightly regulated, adding water alone will do little to improve the situation. 

You can talk to your doctor about a safe long term solution.

Comments
Anney John
This is a good post on constipation, thanks for sharing information.
11/14/2013 4:01:10 AM
Christopher J. Carlson, MD | Gastroenterologist
The short answer is yes, but not really pinworms. Parasites are pretty interesting, in part because we don't see that much of them in the United States, and they can do some fascinating things in the gut and elsewhere in our bodies.

A few things come to mind:

A classic and the best example of a parasite causing constipation is Trypanosoma cruzi, a parasite delivered by various bug species (classically the Reduviid bug) that might happen to defecate during their blood meals. This parasite can go on to cause Chagas disease, which among affecting other organs can have gastrointestinal manifestations. Afflicted patients may develop increasing constipation that progresses to severe constipation and megacolon-- a large, ineffectively moving colon. This disease is typically found in Latin America.

Some common parasites like Enterobius (pinworm) and Trichuria trichuris (whipworm) have been implicated in causing rectal prolapse, where the rectum sort of folds over on itself and protrudes out from the anal canal. This can result in a blockage with inability to pass stool. This typically results when worm burden is very high, and the worms can then be seen on the rectum itself. The exact mechanism is not well understood.

Also, parasites like Ascaris lumbricoides can form large masses of worms that can form a bowel obstruction with resulting decreased stool passage, although this blockage typically occurs in the small bowel.

Finally, there are rare cases of colon obstruction being caused by a common Southeast Asia parasite called Schistosomiasis.

However a low burden of pinworms, as is typically seen, should not result in constipation.
11/6/2013 1:45:40 PM
James
Hi Christopher, i've never read a post that so efficiently covers so much. You mention the main causes of constipation but I am curious... can a parasitic infection also cause constipation? A close friend of mine has experienced constipation for a few years now and just recently was diagnosed with pin worms which hes had symptoms for since the constipation started. Could the two be related?
11/1/2013 12:32:37 PM
Leave comment



 Security code