Diverticulosis

Author, Frank W. Jackson MD
Updated 2014

Diverticulosis is a very common disorder. Diverticuli are simply pockets or balloon-like projections extending out from the bowel wall. They occur most commonly in the colon, otherwise known as the large bowel. The colon is five to six feet long, starting in the right lower abdomen by the appendix, then moving up and across the abdomen to the left side. It
then turns and ends in the rectum. Just above the rectum is a short section called the sigmoid colon. Sigmoid in Greek means S-shaped and, indeed, this portion of the colon is a bit convoluted in this manner. It is here that diverticuli almost always occur. This portion of the colon is a high pressure zone meaning the bowel contracts quite vigorously in this portion. In so doing, it regulates the passage of stool into the rectum.

How Do Diverticuli Form?

There are tiny weak points throughout the large bowel wall where small blood vessels move through. Most of the time this is not a problem. However, if the pressure within the colon is excessive and frequent, as occurs in the sigmoid colon, then there is a ballooning effect and a small pocket is pushed outward. Gradually, over many years, the pocket enlarges and
becomes thin-walled, just like a balloon does when air is continuously pumped into it. This is when trouble can start. Furthermore, these do not occur one at a time but rather can develop in large numbers.

A Disease of Civilization

Diverticulosis is a disorder of Western civilization where the fiber intake in food has been dramatically reduced over the years. Rural Africans, for instance, in many areas eat mostly a grain-vegetable diet with large amounts of fiber being consumed every day. A fiber intake of 50 grams a day or more is common. These people rarely have diverticulosis of the
colon, nor for that matter, other disorders of the colon such as polyps, cancer and irritable bowel syndrome.

So what is this fiber business? Food fiber comes from plants. None of it is digested in the small intestine. All of it reaches the colon. There are many types of fiber but they all fall into two main categories. Soluble fiber is fermented by and feeds the bacteria that live in the colon. Insoluble fiber is not fermented but does retain large amounts of water (see Introduction to Prebiotics).  Together, they create a large, bulky stool which is usually soft and easy to pass. Let me demonstrate how this high pressure in the sigmoid colon works on small, thin stool and a larger bulkier stool.

The Finger Squeeze Test

Assume that your left forefinger is a small stool and that your left wrist is a large bulky stool. Now assume that your right hand is your colon which can squeeze down at only certain maximum force.

Squeeze your left forefinger as hard as you can. It can almost hurt if you squeeze hard enough. Then squeeze your left wrist with the same force. You can generate much less pressure on the wrist. The high pressure is dissipated over the larger bulk of the wrist. Analysis: You have just proven that bulking up the stool with adequate fiber reduces pressure within the colon, which in turn, prevents diverticuli from forming or, perhaps, even preventing colon bacteria from being driven into the colon wall, causing diverticulitis.
It is the high colon pressures that result in small, hard pellet stools and constipation.

Am I at Risk for Diverticulosis?

It takes a long time to develop diverticulosis. Often, it is something a physician will discover at the time of a colonoscopy for a cancer surveillance exam. This means that most of the time diverticuli cause no problems. However, no one can be sure. So, even though the physician may not make much of colon diverticuli, which are causing no problems,
it should be a warning that the diet may be low in fiber. So anyone can get diverticulosis and anyone can have symptoms of diverticulosis and its complications.

And the Symptoms Are…

When there are just a few or even moderate number of diverticuli, there are usually no symptoms at all. However, when diverticulosis is advanced, this area of the colon can become hard and knotty, fixed and narrowed. At this time, there may be recurrent, low grade discomfort. It is usually crampy, meaning it comes and goes. When it is steady and more of
a pain than a mild discomfort, problems may be occurring.

And the Problems Are…

  • Infection and inflammation – This is called diverticulitis. Now the colon’s bacteria have moved through the thin wall of the diverticulum and caused a local infection. This can be mild and clear up on its own. Often, a period of bowel rest is required, meaning a low fiber diet. Along with this, rest at home or in bed and antibiotics may be required.
  • Abscess – If there is a serious leakage of bacteria, then a localized abscess can occur. Now the pain is much more intense and tenderness is present in the abdomen. Like it or not, surgery is often needed at this point to drain the abscess.
  • Peritonitis – If there is a perforation and an abscess does not form, then periotonitis may occur. This is a very serious problem and requires immediate surgery. Fortunately, this is uncommon.

Prevention

As noted, most diverticuli are found as an incidental finding at colonoscopy. It means that too much pressure is occurring in the lower portion of the colon. It also can mean that a complication can occur. But prevention of serious complications of diverticulosis is possible. Remember the Finger Squeeze Test above. You need to develop bulkier stools, which can lower the pressure within the colon. A High Fiber Diet is the best and really the only means of doing this in a long term manner. Visit our High Fiber Diet page for a recap of the benefits of maintaining a high fiber diet. Many people will add fiber supplements to helps create a larger, bulkier stool. Prebiotics are a more recently discovered form of soluble plant fibers.

Final Words

  • Diverticulosis is common.
  • Diverticulosis, most of the time, causes no problems.
  • Diverticulosis, however, can go into diverticulitis and other complications, none of which are good.
  • Diverticulosis and its complications can likely be prevented by getting adequate fiber in the diet or by taking fiber supplements.

Surgery

With certain medical conditions such as severe diverticulosis or extreme constipation in children, surgery may be required.