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What Is diverticulitis?

Diverticulitis is a relatively common condition, but not all doctors are familiar with the symptoms and treatment. To start understanding it yourself, you’ll need a big-picture glimpse of your digestive system—specifically the colon.

Also known as the large intestine, the colon is a tube-shaped organ between the small intestine and the rectum. It’s thought that when the muscles in the colon spasm, small sacs called diverticula begin to form on the wall of the intestine. People who have multiple sacs (or pouches) in their colon have diverticulosis; when these sacs become inflamed or infected, the condition is called diverticulitis.

Diverticulitis is the inflammation of diverticula, which range in size from about 1/10 of an inch to more than an inch. Although these sacs can develop anywhere in the colon, they often form in the sigmoid colon, near the rectum. (The inflammation of these diverticula is called sigmoid diverticulitis.)

The odds of developing diverticula increase with age. It’s thought that about one in three adults under the age of 50 have diverticulitis, along with more than half of those who are over the age of 60. But experts also suspect that more than 95% of people with diverticulosis will never develop diverticulitis.

Signs and symptoms of diverticulitis

When bacteria from the colon work their way into a sac, the diverticula can become infected or inflamed. One of the most common diverticulitis symptoms is abdominal pain (often on the left side of the stomach), which can be mild and sporadic or chronic and constant. Others can include:

  • Abdominal pain (usually on the left side)
  • Bleeding
  • Chills
  • Constipation
  • Cramping
  • Diarrhea
  • Fever
  • Nausea
  • Tearing of the colon
  • Vomiting

Each year, about 200,000 people in the United States are hospitalized for diverticulitis. Some of the complications that can arise include perforations (a small tear in the pouch in the colon), an abscess (a pus-filled area outside the colon wall that can cause pain, fever, and nausea), or a fistula (an abnormal “tunnel” that develops between two organs; for example, the colon and the bladder).


What causes diverticulitis?

Experts still aren’t sure what, exactly, triggers diverticulitis. It’s thought that diverticula are formed by spasms that take place in the colon; this extra pressure may cause weaker parts of the intestinal wall to bulge out. Other potential causes include obesity, smoking, and using non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen.

In the 1960s, experts theorized that eating a low-fiber diet could cause diverticula, but recent studies have questioned that assumption. In fact, one 2012 study in the journal Gastroenterology found that a high-fiber diet was associated with an increased risk of diverticulosis. Currently, the American Gastroenterological Association (AGA) suggests that people with diverticulitis eat a fiber-rich diet or take fiber supplements, but admits that the recommendation is based on a “very low quality of evidence.”

One thing that seems to be true: Diverticulitis is on the rise. A 2007 study in the Canadian Journal of Gastroenterology and Hepatology found a jump in the number of hospitalizations for diverticular disease (which includes diverticulitis) in Ontario, Canada over a 14-year-period from 94 out of 10,000 people in 1988 to 105 per 100,000 in 2002.

How is diverticulitis diagnosed?

Doctors typically diagnose diverticulitis by using a CT (computerized tomography) scan to take X-ray images of your gastrointestinal tract. They can also use a test called a lower GI series, or barium enema—in which doctors insert a tube into the anus and fill the large intestine with a liquid called barium, which helps them see the large intestine more easily on an X-ray—to identify any sacs that may be in your colon. Lastly, doctors may perform a colonoscopy, a test that uses a tube outfitted with a light and camera to see the inside of the colon. A colonoscopy can help a doctor spot diverticula or other growths, like colon cancer.


Diverticulitis treatment

If your symptoms are mild, your doctor may tell you to rest and follow a liquid diet for a few days. It’s also possible that you’ll be prescribed antibiotics, although there’s some evidence that suggests you may not need them. While antibiotics have been used to treat diverticulitis in the past, experts are starting to suspect that inflammation may play a bigger role than an infection. Currently, the AGA says that doctors should use antibiotics “selectively, rather than routinely” in people with mild cases of diverticulitis.

If your symptoms are severe—or if you’re experiencing complications like an abscess or a fistula—you may need to stay in the hospital, where doctors can give you intravenous (IV) antibiotics. You may also need to steer clear of food and drinks for a few days, and your doctor may decide to feed you with an IV mixture of the vitamins and minerals you’d normally consume in meals. If you develop an abscess—which may occur in up to 16% of people who have diverticulitis—a doctor will typically drain it in the hospital; doctors can also perform surgery to repair a perforation (i.e., a tear or hole) or fistula.

Diverticulosis and diverticulitis medications

If you have diverticulitis, your doctor may recommend some of the following medications:

  1. Ciprofloxacin: an antibiotic that’s used to treat certain bacterial infections. Although it’s unclear whether antibiotics are necessary for people who have mild diverticulitis, your doctor may prescribe you an oral course of ciprofloxacin.
  2. Mesalamine: an anti-inflammatory medication typically used to treat ulcerative colitis symptoms. If you have diverticulosis, taking this medicine may help reduce symptoms like stomach pain.
  3. Rifaximin: an antibiotic that’s used to treat traveler’s diarrhea and irritable bowel syndrome. It’s thought that taking this medication may also help quell some diverticulosis symptoms.

Is diverticulitis curable?

Once a sac forms in the colon, it doesn’t go away. Diverticulitis treatment, therefore, is aimed at limiting symptoms caused by the sacs. Experts aren’t sure if diverticulitis can be prevented. And although eating a high-fiber diet might lessen a person’s chances of developing diverticulitis, more research is needed.

It’s also thought that people who exercise, avoid cigarettes, and maintain a healthy weight are less likely to develop diverticulitis than those who are more sedentary or overweight. As for people who have already had diverticulitis, it’s unclear whether medication can prevent an attack from occurring again.


Is there a diverticulitis diet?

If you have diverticulitis, it’s possible that eating a high-fiber diet may help ward off another attack. But according to the AGA, the evidence supporting this recommendation is weak—nor is it known whether eating more fiber-rich foods or taking fiber supplements will yield the same results. In general, people should aim to eat about 14 grams of fiber for every 1,000 calories they take in. Some high-fiber foods include navy beans, peas, and oat bran.

Decades ago, experts believed that people who had diverticular disease should try to avoid eating seeds, nuts, corn, and popcorn, which were thought to get caught in the diverticula and cause inflammation or damage to the interior of the colon, but the AGA no longer recommends this. After surveying more than 47,000 men over an 18-year period, researchers writing in the Journal of the American Medical Association in 2008 reported that they found no link between eating seeds and developing diverticulitis. Now, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says that nuts and seeds (including those found in tomatoes, raspberries, and cucumbers) are also safe to eat.

Lastly, experts are currently studying whether probiotics—“good bacteria” that are found in supplements and in certain foods, like yogurt—can help prevent diverticulitis. Talk to your doctor before taking any new supplements or medications.