Diverticulitis occurs when a small pouch called a diverticulum forms in the colon wall and becomes infected or inflamed. Symptoms include severe pain in the lower left abdomen, fever and chills, nausea, constipation or diarrhea, and diverticular bleeding. Left untreated, it can worsen and lead to abscesses, perforations, peritonitis, fistulas, or intestinal obstructions.

Because diverticulitis symptoms are similar to irritable bowel syndrome and colorectal cancer, it’s important to get prompt, accurate diagnosis. Your doctor may perform a digital rectal exam to check for pain, bleeding or blockage and use blood tests to look for signs of inflammation or anemia. You also may undergo flexible sigmoidoscopy, colonoscopy, lower GI, body CT, or catheter angiography to confirm a diagnosis and identify the site of any diverticular bleeding. Treatment depends on your symptoms and complications. Mild cases may be treated with rest, antibiotics and a liquid diet while more severe cases may require intravenous antibiotics or surgery.

What is diverticulitis?

Diverticulitis occurs when a small pouch, called a diverticulum, forms in the wall of the colon and becomes inflamed or infected, usually due to the presence of bacteria. These pouches can push outward, causing pain and bleeding; diverticula (more than one diverticulum) are most common in the sigmoid colon.

When diverticula are present with no symptoms of inflammation, the condition is known as diverticulosis.

The exact cause of diverticulitis is unknown, although research has linked it with obesity, lack of exercise, smoking, and certain medications including nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and steroids. Diverticulitis is more common in men than in women, and risk increases in people older than age 50.

The most common symptom of diverticulitis is severe pain in the lower left side of the abdomen. Other symptoms include:

  • fevers and chills
  • nausea or vomiting
  • constipation or diarrhea
  • diverticular bleeding

Left untreated, diverticulitis can worsen and cause complications such as abscesses, perforations, peritonitis, fistulas and intestinal obstruction.

How is diverticulitis evaluated?

Symptoms of diverticulitis are similar to those of other gastrointestinal tract conditions, including irritable bowel syndrome and colorectal cancer, so prompt, accurate diagnosis is important. Initial evaluation might include a digital rectal exam to check for pain, bleeding or a blockage in the intestine. You may also have a blood test to look for the presence of inflammation or anemia.

Other common tests include:

  • Flexible sigmoidoscopy: In this examination, a flexible tube with a tiny camera on the end called a sigmoidoscope is inserted into the rectum to view the lower colon and rectum.
  • Colonoscopy: Colonoscopy uses a lighted instrument called a colonoscope to view the ileum, rectum and the entire colon.
  • X-ray (Radiography) - Lower GI Tract: Lower gastrointestinal (GI) tract radiography, also called a lower GI or barium enema, is an x-ray examination of the large intestine, also known as the colon. This examination evaluates the right or ascending colon, the transverse colon, the left or descending colon, the sigmoid colon and the rectum. The appendix and a portion of the distal small intestine may also be included.
  • Body CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of your pelvis, abdomen or chest. You may receive an injection of contrast material so that the GI tract and abdominal organs show up clearly in the pictures.
  • Catheter angiography: This examination may be used to identify the site of diverticular bleeding.

How is diverticulitis treated?

Treatment for diverticulitis varies depending on the symptoms and complications. For mild cases, rest, oral antibiotics and a liquid diet are often prescribed. Solid food is gradually added back to the diet in a few days if symptoms ease.

A high-fiber diet or fiber supplements are often prescribed to treat the symptoms of diverticulosis. Anti-inflammatory medications and antibiotics also may be effective at reducing symptoms. For more severe cases, intravenous antibiotics and fasting for a few days may help.

Abdominal surgery with colon resection may be necessary if diverticular bleeding does not stop. Colon resection involves removal of the affected part of the colon and the joining together of the remaining ends.

Treatments for complications of diverticulitis vary. Large abscesses may need to be drained by needle and catheter (drainage tube) placement under ultrasound or CT guidance. Perforations usually require surgery to repair the tear or hole. Peritonitis and intestinal blockages require immediate surgery with possible colon resection. Fistulas can be corrected with a colon resection and removal of the fistula.

This page was reviewed on March 17, 2016


Senior patient with doctor in ER room View full size with caption

About this Site is produced by:

Please note is not a medical facility. Please contact your physician with specific medical questions or for a referral to a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database.

This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Discuss the fees associated with your prescribed procedure with your doctor, the medical facility staff and/or your insurance provider to get a better understanding of the possible charges you will incur.

Web page review process: This Web page is reviewed regularly by a physician with expertise in the medical area presented and is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic areas.

Outside links: For the convenience of our users, provides links to relevant websites., ACR and RSNA are not responsible for the content contained on the web pages found at these links.