(Acute Diverticulitis; Acute Colonic Diverticulitis)



A pouch that forms in the wall of the large intestine is called a diverticulum. When this pouch becomes infected or swollen, it is called diverticulitis.


Infected pouches along the colon.
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It is not clear why the pouches form. It may be due to a constant build up of pressure when food moves too slowly through the bowel. This pressure increases and pushes along the sidewalls of the bowel creating pouches. Digested food or stool can become trapped in one of the pouches. This leads to swelling and infection.

The following may contribute to diverticulitis:

  • Low-fiber diet—Fiber softens stools and makes them pass through the bowel more easily
  • Increased pressure in the bowel from straining to pass a hard stool
  • Defects in the colon wall
  • Chronic constipation

Risk Factors

Risk Factors

This condition is more common in people who are older than 50 years of age.

Factors that increase your chance of getting diverticulitis include:

  • Eating a low-fiber diet
  • Previous episodes of diverticulitis
  • High-meat diet or high-protein diet
  • Chronic constipation
  • Smoking



Symptoms can come on suddenly. They vary depending on the degree of the infection.

Symptoms may include:

  • Abdominal pain
  • Tenderness; usually in the lower left part of the abdomen
  • Swollen and hard abdomen
  • Fever
  • Chills
  • Poor appetite
  • Nausea and vomiting
  • Diarrhea and/or constipation
  • Cramping
  • Rectal bleeding



You will be asked about your symptoms and medical history. A physical and rectal exam will be done. Finding the disease early is important. The pouch can break, releasing stool into the abdomen. This is a medical emergency that requires surgery.

Your bodily fluids and waste products may be tested. This can be done with:

  • Blood tests
  • Stool sample analysis

Images may need to be taken of your bodily structures. This can be done with:

After the inflammation subsides, other tests may be performed to examine the colon, including:



The goals of treatment are to:

  • Resolve the infection and inflammation
  • Rest the bowel
  • Prevent complications

Treatments include:


Antibiotics and other medications are given to fight the infection. Pain medications and drugs are given to decrease the abdominal pain.

You may also be given medication to help control vomiting.


For mild swelling, you can drink clear liquids for the first two to three days. For a more severe case, you will be admitted to the hospital, where fluids are given by IV. Antibiotics will also be given to you through IV.

Preventive Care

Changes in your diet can help prevent future attacks.

  • Increase the amount of fiber you eat by eating more fruits, vegetables, and whole grains
  • Supplement your diet with a fiber product, as advised by your doctor
  • Avoid laxatives and enemas
  • Avoid narcotic medications—they can slow down bowel movement and can cause constipation


Surgery to remove the section of the bowel with pouches may be advised if:

  • You have had multiple attacks during a two-year period
  • A pouch breaks and the contents spread into the abdominal cavity, which requires that the cavity be cleaned out

Surgery is also used to treat complications of diverticulitis, such as:

  • Abscess—occurs if the infected pouch fills with pus
  • Blocked bowel—scar tissue that forms and blocks movement of stool through the intestine
  • Fistula—occurs if the infection spreads and colon tissue attaches to another organ, such as the bladder, the uterus, or the vagina

When surgery is done on an elective basis, the surgeon will remove the part of the bowel that is diseased and connect the normal parts of the bowel back together.

When surgery is done on an emergency basis, the diseased part of the bowel will be removed. The healthy parts of the bowel will not be connected right away. Your bowel will need time to rest and heal. The upper part of the bowel will be attached to the abdominal wall. A port will allow waste to pass from the intestine to a bag outside of your body. If possible, the healthy bowel will be reconnected after 6-12 weeks.



The following recommendations may help prevent diverticulitis by improving the movement of stool through the bowel and decreasing constipation:

  • Eat a balanced, high-fiber diet with plenty of fruits, vegetables, and whole grains.
  • Drink plenty of water each day.
  • Exercise regularly.


American Society of Colon and Rectal Surgeons http://www.fascrs.org

National Digestive Diseases Information Clearinghouse http://digestive.niddk.nih.gov


Dietitians of Canada http://www.dietitians.ca

Health Canada http://www.hc-sc.gc.ca


Diverticular disease. American Society of Colon and Rectal Surgeons website. Available at:
Updated October 2012. Accessed September 23, 2014.

Diverticulitis. EBSCO DynaMed website. Available at:
Updated September 8, 2014. Accessed September 23, 2014.

Diverticulosis and diverticulitis. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
Updated September 19, 2013. Accessed September 23, 2014.

2/9/2012 DynaMed’s Systematic Literature Surveillance
Hjern F, Wolk A, Håkansson N. Smoking and the risk of diverticular disease in women. Br J Surg. 2011;98(7):997-1002.

Last reviewed August 2014 by Daus Mahnke, MD
Last Updated: 9/23/2014

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