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Blog » Diverticulosis/ Diverticulitis, what is it, and what is the difference

Diverticulosis/ Diverticulitis, what is it, and what is the difference
Diverticulosis/ Diverticulitis, what is it, and what is the difference

A very common question in my practice, I wanted to educate and illustrate to you, my reader, this common topic.

This is an important piece of knowledge in order to recognize it and prevent it. It has been called the condition or illness of the developed world.

Let me start by explaining where and how it originates.

The word diverticulum is referring to a small pocket that develops in any place of the intestines. It can be anywhere from the esophagus to the rectum, but in this instance, we will focus on the colon or large intestine.

The pocket I refer to is an area that protrudes, and that is an outpouching of the wall of the intestine that is continuous with the inside of the intestines as in the picture below.

So these pockets are called diverticuli. These usually develop in large qualtities and it is believed that they are the result of poor eating habits (particularly low fiber diet). I am sure that genetics has its part in it also, but it is an acquired condition due to the low fiber diets of the modern world. The consumption of overly processed foods are thought to be the culprit.

This is a condition most commonly seen in people over 40 years old, but I have seen it in people who are a lot younger.

It, itself, is not harmful, but it can turn into a deadly condition or situation as I will demonstrate below.

Diverticulosis is the presence of these pockets and they are usually seen during colonoscopy or other imaging like a cat scan.

Having these are not problematic as long as they do not get infected. That is when this turns into diverticulitis.

As you can tell the difference between the word is the ending. The "itis" part is what defines it as an infection.

How does this happen?

The exact mechanism is not totally understood, but it is suspected that it starts with low fiber, making the stool crumble and break into small pieces instead of staying all together. A small piece of stool falls into the pocket and stays there decomposing. Then the bacterial overgrowth and toxins cause inflammation. This inflammation then progresses to infection and irritation of the intestinal wall. The wall in the diverticulum is already thin and it gets swollen and as the pressure in the wall increases, and the infection progresses the blood supply is decreased by compression of the thin vessels in the intestinal wall.


As the blood supply in the wall is compromised, this could lead to damage to the wall and compromise the integrity, of the wall, leading to a rupture or perforation of the colon. If this happens then stool spills freely into your abdominal cavity. This would be then perforated diverticulitis. This is when things get very serious. Perforation equals peritonitis and eventually sepsis.

Peritonitis - Inflammation of the peritoneum (the lining of the abdominal cavity)

Sepsis - it is the body's severe response to infection

Up to this point, the treatment would be bowel rest and oral antibiotics. When you perforate the intestines then we are talking serious and life-threatening condition.

When perforation occurs you are in need of a hospital and intravenous antibiotics.

So let's go back to the beginning of the problems. How do you recognize it early on? Initially, diverticulitis would present as a series of symptoms that usually begins with constipation alternating with diarrhea possibly. The most common symptoms are a pain in the left lower abdomen and tenderness to the touch of the left side.

Why the left side?

Although diverticulitis can happen anywhere in the colon, the most common location is the sigmoid colon or left side colon. It is called a sigmoid because it has the shape of an S or a snake as if comes down to the rectum.

This is where most cases are seen. This is also the most common presentation.

In some instances people present with bleeding from a diverticulum and there is no infection. It is just a ruptured vessel at the base of the diverticulum that bleeds. As mentioned above, the wall of the diverticulum tends to be thinner than the rest of the colon and prone to rupture or spontaneous bleed.

When the colon ruptures, as I stated above, you have a serious problem, as stool and gas escape into the abdominal cavity and this will lead to diverticulitis and if uncontrolled then sepsis. This is an emergency and should not be taken lightly.

The body, in an effort to stop the infection, then tries to control the infection and walls off the area where the rupture occurred. Depending on how severe this was or the size of the opening and /or contamination, an abscess develops.

An abscess is a collection of pus or infection


Once there is an abscess, there is the need to control the spilling of stool, and help the body deal with this. Up to the point of infection, antibiotics alone likely stop the problem and a modification of diet and lifestyle helps prevent recurrent attacks and hopefully this level of infection.

Once the perforation occurs or abscess forms, the level of attention increases exponentially, and urgent care should be pursued.

In the past, an abscess or perforation meant direct surgery and a colostomy. Nowadays we have options as I explain below.

A colostomy is used to divert stool from the contaminated area and allow for healing to occur. This is usually reversed after about two months from the initial event.


As you see above a colostomy is when we disconnect and remove the segment of the intestine that is damaged and exteriorize the intestine so that bowel movements can happen. The distal part or the part that goes to the anus is shut until we can reconnect in the future, once the infection is gone.

Now a days we try to eliminate this step and if there is an abscess, we have the radiologist drain (place a needle and a catheter) this and then cool off the infection. After this is done and a few weeks pass, we can do a one-time operation to both, remove the damaged intestine segment, and re-establish the continuity in one operation. So no need for colostomy.

Why not do that instead of draining it? Well, if we do that in the midst of infection, the area we stitch together would break apart due to the infection and we have a bigger problem.

The key to avoiding this situation is to pay attention to your body and seek medical care at the first sign of diverticulitis (left lower abdominal pain and tenderness to touch).

If you want to try to avoid diverticulitis altogether then implement a high fiber diet and this will decrease the chances of having acute diverticulitis. Remember to also drink enough water. Fiber without water does not work well.

If you are young and/or do not have diverticulosis yet, then increase the consumption of fiber in your diet and this will help decrease the chances of ever having diverticulosis, or minimizing the number of diverticula, helping keep your intestinal health in check.

If you have any questions about this or any other topic you can email me at [javascript protected email address], or go to and message using the chat area. If you want me to write about a particular topic also you can tell us in the comments or message us and we can cover that here. Thank you for reading.