What is diverticulosis and diverticulitis?

Diverticulosis and diverticulitis are two conditions that occur in your large intestine (also called your colon). Together they are known as diverticular disease. Both share the common feature of diverticula. Diverticula are one or more pockets or bulges that form in the wall of your colon.

Diverticula are like expanded areas or bubbles that form when you fill the inner tube of a bike tire with too much air. The increase in pressure from too much air being pumped into the inner tube causes the bubble to form where the rubber is the weakest. Similarly, an increase in pressure inside the colon causes pockets or bulges (diverticula) to form in weakened areas of your colon’s walls.

Diverticula can range from pea-size to much larger. Although they can form anywhere in the inner lining of your colon, they are most commonly found in your lower left-side, in the S-shaped segment of your colon called the sigmoid colon.

What’s the difference between diverticulosis and diverticulitis?

Diverticulosis is simply the presence of these tiny bulges or pockets (diverticula) in your colon. They usually don’t cause any symptoms or need to be treated. However, diverticulosis can lead to diverticulitis.

Diverticulitis is inflammation (swelling) and infection in one or more diverticula. You may feel pain, nausea, fever and have other symptoms. This is a much more serious and potentially dangerous condition.

How common is diverticulosis?

Diverticulosis is very common in Western populations and occurs in 10% of people over age 40 and in 50% of people over age 60. The rate of diverticulosis increases with age, and it affects almost everyone over age 80.

Who is most likely to get diverticulosis and diverticulitis?

You are at increased risk of diverticular disease (diverticulosis or diverticulitis) if you:

  • Are over 40 years of age.
  • Are male.
  • Are overweight.
  • Eat a low-fiber diet. You don’t eat a lot of fruits, vegetables, beans and legumes, breads and grains or nuts.
  • Eat a diet high in fat and red meat.
  • Don’t exercise.
  • Take nonsteroidal anti-inflammatory drugs (NSAIDs), like aspirin, ibuprofen (Advil®, Motrin®) and naproxen (Aleve®); steroids; or opioids.
  • Smoke.

What causes diverticulosis and diverticulitis?

Scientists aren’t really sure what causes diverticulosis, but they think it’s caused by not eating enough fiber. Not eating enough fiber causes a buildup of waste (constipation) in your colon. Constipation puts extra strain on the walls of the colon. This increased pressure causes the little pockets — the diverticula — to form in weak areas in your colon.

Again, scientists aren’t sure what causes diverticulitis, but they think the infection starts due to the bacteria in stool that gets pushed into the diverticula. Another theory is that the walls of the diverticula itself erode from the increased pressure on the colon walls.

What are the symptoms of diverticulosis?

Usually diverticulosis does not cause any troublesome symptoms. However, some people report:

  • Tenderness over the affected area.
  • Mild abdominal cramps.
  • Swelling or bloating.
  • Constipation.

Keep in mind that having one or more of these symptoms doesn’t mean you have diverticulosis. These symptoms are common symptoms of other gastrointestinal disorders such as irritable bowel syndrome, celiac disease, inflammatory bowel disease, appendicitis, gallstones and stomach ulcers.

What are the symptoms of diverticulitis?

The symptoms of diverticulitis include:

  • Pain, tenderness or sensitivity in the left lower side of your abdomen. Pain can start out mild and increase over several days or come on suddenly. (Pain is the most common symptom.)
  • Fever.
  • Nausea and/or vomiting.
  • Chills.
  • Cramps in the lower abdomen.
  • Constipation or diarrhea (less common).
  • Rectal bleeding.

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