Diverticulitis: Symptoms, Causes, and Treatment

Diverticulitis symptoms can occur in anyone who has a common condition called diverticulosis. Since about 60 percent of people may have diverticulosis by age 60, it is important to know the symptoms, causes, and treatment of diverticulitis.

Woman suffering from diverticulitis symptoms

Diverticulitis symptoms depend on many factors, including the location of the inflamed diverticula in the abdomen.

To understand diverticulitis, you need to understand diverticulosis, so let’s start there. Diverticulosis is a very common bowel condition. It usually occurs in the last part of your colon, called your sigmoid colon. A pouch of the inner lining of your colon pushes inward  through a weak area of the muscular layer of your colon. The pouch is called a diverticulum. [1-3]

These pouches are very common and cause the condition called diverticulosis. Diverticulosis increases with age. By age 60, about 60 percent of people will have this condition. [1] Luckily, most people with diverticulosis never know that have it because they never have symptoms. [1-3]

Diverticular Disease

If a person with diverticulosis does develop symptoms, it is called having diverticular disease. Some people with diverticulosis may complain of lower belly pain, bloating, or changes in bowel habits. Rarely, a blood vessel inside a diverticulum can rupture and cause bleeding. [1-3]

A diverticulum may also become swollen and irritated. This causes the condition called diverticulitis. Diverticulitis causes symptoms like pain and fever, and it can lead to dangerous complications that require surgery. Diverticulitis probably occurs in less than five percent of people with diverticulosis, but that still amounts to about 200,000 people being hospitalized for diverticulitis every year in the United States. [1]

What Causes Diverticulosis and Diverticulitis?

Diverticulosis increases with age and may be linked to a diet low in fiber, although some recent research no longer supports this theory. You may be at higher risk for diverticulosis if you:

  • Take medications called NSAIDs (over-the-counter NSAIDs include aspirin, ibuprofen, and naproxen) or steroids
  • Don’t get enough exercise
  • Are overweight
  • Smoke cigarettes [1]

Doctors used to think that diverticulitis occurred when a seed or a piece of a nut or popcorn got stuck in a diverticulum. That has been disproven. The cause may be bacteria from your colon that get stuck in the diverticulum and cause inflammation or infection. Another possible cause is a small hole (perforation) that breaks through a diverticulum and causes an infection just outside the wall of the colon. [1-3]

Symptoms of Diverticulitis

Diverticulitis symptoms may start suddenly or they may build up over a few days. They include:

  • Pain in the lower left side of your belly (abdomen) that may be severe
  • Tenderness in the left lower abdomen
  • Constipation or diarrhea
  • Fever and chills
  • Nausea or vomiting [1-3]

Diagnosis and Treatment of Diverticulitis

Your doctor can usually diagnose diverticulitis just by the symptoms if you are known to have diverticulosis. Diverticulosis may have been discovered during a routine colonoscopy or an abdominal imaging study if you had abdominal pain or rectal bleeding. [1-3]

If your doctor is not sure, the best way to diagnose diverticulitis is with a CT scan imaging study. After the symptoms of diverticulitis go away, your doctor may want to take a look into your colon with a scope (colonoscopy) to confirm the diagnosis and rule out any other problems. [2,3]

Treatment of diverticulitis depends on how severe the infection is. A mild infection may clear up with just rest and a liquid diet at home. If you have fever, or your symptoms don’t get better is a day or two, your doctor will probably add antibiotics. If you have severe pain and high fever, you may need to be in the hospital on intravenous antibiotics. You may need to avoid all foods and liquids until the infection subsides. [1-3]

Complications of diverticulitis include a collection of pus in your abdomen or colon (abscess), a perforation of your colon, infection that spreads through your abdomen (peritonitis), obstruction of your colon, and an infected connection (fistula) that forms between your colon and your skin or a nearby abdominal organ, usually your bladder. [1-3]

Diverticulitis Prevention

Although the jury is out on whether a low fiber diet causes diverticulosis, a high fiber diet may help prevent diverticulitis once you have diverticulosis. Your doctor may prescribe a high fiber diet that includes foods like whole grains, fruits, beans, and other vegetables. There are no foods that you need to avoid. In some cases, your doctor may prescribe a fiber supplement. [1]

Now that you know the symptoms of diverticulitis, don’t ignore them. Untreated diverticulitis can lead to dangerous complications. If you have had diverticulitis in the past or you have been diagnosed with diverticulosis, ask your doctor about diet and lifestyle changes to help you prevent an attack of diverticulitis in the future. [1-3]



  1. NIH, Definition & Facts for Diverticular Disease
  2. Merck Manual, Diverticulitis
  3. Harvard Medical School, Diverticular Disease of the Colon

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Chris Iliades, MD

Dr. Chris Iliades is board-certified in Ear, Nose and Throat and Head and Neck Surgery from the American Board of Otolaryngology and Head and Neck Surgery. He holds a medical … Read More

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