Diverticulitis

What Is Diverticulitis? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Ashley Welch
By Medically Reviewed by 
Reviewed:
Medically Reviewed

Diverticulitis is an infectious inflammatory condition that occurs in a diverticula, a thinned-out portion of the colon.

The condition is a form of colitis, an inflammatory bowel disease (IBD); it can be serious and require surgery if it isn’t caught quickly and treated.

Signs and Symptoms of Diverticulitis

While diverticulosis doesn’t present symptoms, there are clear warning signs of diverticulitis, the inflamed form of the condition, including:

Although many of these symptoms overlap with other gastrointestinal problems, including peptic ulcers and irritable bowel syndrome, consult your doctor if you have any of these symptoms and the risk factors apply to you.

What Does Diverticulitis Pain Feel Like?

During the digestive process, the colon (also called the large intestine or large bowel) is responsible for absorbing liquid from food and breaking down any remaining material to move it to the rectum. The rectum acts as a storage space for this waste, and its muscles help your body remove stool through the anus.

The sigmoid colon is the S-shaped lower section of your colon, which links the descending colon to your rectum. In Western countries, most diverticula develop in this area of the colon.

When diverticulosis becomes inflamed and progresses to diverticulitis, you may feel persistent pain in the area of the sigmoid colon — the lower left part of your abdomen — and potentially develop fever and chills.

The pain can come on suddenly and severely, or it may increase in severity over a period of days. It can also fluctuate in intensity.

Ultimately, the degree of pain you experience from a flare-up of diverticulitis depends on the severity of your infection and whether it is localized, caused by an abscess (pus pocket), or has spread throughout the abdomen.

Advanced Symptoms of Diverticulitis

If you experience any of these advanced symptoms, a diverticulitis complication may have developed:

  • Fever over 100 degrees F (38 degrees C)
  • Worsening or severe abdominal pain
  • Inability to tolerate fluids
  • Feeling light-headed, dizzy, or showing other signs of low blood pressure.

If you have any of these symptoms, get in touch with your doctor as soon as possible.

Common Questions & Answers

What foods trigger diverticulitis?
No specific foods are known to trigger diverticulitis, but a low-fiber, high-animal-fat diet may increase your risk. Contrary to a once-popular belief, nuts, popcorn, and seeds don’t cause diverticulitis
Can diverticulitis pain radiate to the back?
Symptoms of diverticulitis include nausea, vomiting, abdominal pain, fever, and constipation or diarrhea. Pain often affects the lower left side of the abdomen, but it can radiate to the back, legs, groin, and side as well.
Can diverticulitis heal itself?
Very mild diverticulitis may improve on its own without treatment. But even the mildest symptoms may require an antibiotic and over-the-counter pain relievers to treat the infection and inflammation, respectively.
What is the best treatment for diverticulitis?
Your doctor may recommend oral antibiotics, pain relievers, and a liquid diet until your bowel heals. Slowly increasing your fiber intake can also improve symptoms. Severe or complicated diverticulitis may require hospitalization or surgery to treat an abscess, repair a rupture in the bowel wall, or remove diseased parts of the intestines.
What drinks should you avoid with diverticulitis?
Drinking plenty of fluids can soften your stool, making it easier to pass. Aim for 6 to 8 cups of fluid per day. This can include water, tea, coffee, and fruit juice. Avoid carbonated drinks, which can cause bloating or gas and worsen symptoms of diverticulitis.

Causes and Risk Factors of Diverticulitis

Diverticula form when the inner soft-tissue layer of the intestine passes through the outer muscular layer, forming a pocket or pouchlike, marble-size bulge. This happens most often where the muscles of the intestine are weakest, particularly in the sigmoid colon.

It’s unclear why diverticula form, but they’re linked with these factors:

Aging People older than 40 are more likely to be diagnosed with diverticulitis.

Obesity A body mass index of 30 or over means you’re obese.

Smoking People who smoke cigarettes are more likely to get diverticulitis.

Inactivity Vigorous exercise appears to ward off diverticulitis. Regularly aim for 150 minutes of moderate-intensity aerobic exercise (such as brisk walking) each week.

Certain medications Steroids, opioids, and nonsteroidal anti-inflammatory drugs (NSAIDs) increase the risk of diverticulitis.

Can Nuts and Seeds Increase Your Risk of Diverticulitis?

This theory explains why, for decades, doctors advised people with diverticulosis (the presence of diverticula) not to eat nuts, seeds, or popcorn, which they believed could block the openings of the diverticula and lead to flare-ups of diverticulitis.

But research has never proved that these foods lead to diverticulitis, so doctors no longer warn their patients away from such foods.

Can a Low-Fiber Diet Cause Diverticula to Form?

Research suggests that the link between a low-fiber diet and an increased risk of diverticulitis is simply that — a link without a causal relationship, at least for now.

Scientists long believed that lack of fiber could increase the risk of diverticulosis, but research suggests that’s not necessarily the case.

How Is Diverticulitis Diagnosed?

If you are experiencing any of the symptoms of diverticulitis, your doctor will likely take the following actions:

  • Gather information about your full medical history, including preexisting conditions and risk factors
  • Examine your abdomen to check for tenderness
  • Perform a rectal exam to check for rectal bleeding
  • Perform a blood test to check your white blood cells and determine if you have an infection
  • Order a diagnostic test to get a picture of your colon and determine if diverticula are present and whether they are inflamed or infected

The most common test used to diagnose diverticulitis is a CT scan. A CT scan uses both X-rays and computer technology to create three-dimensional images of your colon.

Prognosis of Diverticulitis

While some people with diverticulitis will require intravenous antibiotics or even surgery, many can be treated at home.

If you experience increasing pain, fever, or an inability to tolerate fluids, you may need to be hospitalized, as these symptoms may indicate diverticulitis complications.

Your doctor may recommend hospitalization if you have the following characteristics or symptoms:

  • You are older.
  • You are unable to take oral fluids.
  • You have other existing health conditions.
  • The inflammation or infection you are experiencing is particularly severe.

Duration of Diverticulitis

With home treatments, symptoms of diverticulitis usually clear up within 7 to 10 days. Your doctor will likely schedule several follow-up visits to assess your condition.

Treatment and Medication Options for Diverticulitis

If you are generally in good health and the inflammation or infection you are experiencing is not severe, your doctor will likely proceed with nonsurgical, at-home treatments for diverticulitis.

Diet Options

For mild cases, doctors prescribe a light or low-residue diet. Sometimes a clear liquid diet for a few days is required to treat diverticulitis. This allows your digestive tract to rest and begin healing and will also keep you hydrated.

Foods and drinks to consume might include:

  • Clear broths
  • Clear soups
  • Juices without pulp, such as apple juice
  • Plain gelatin
  • Ice chips
  • Water
  • Tea without milk

As you begin to feel better, you can start reintroducing foods into your diet, including:

  • Canned or cooked fruit and vegetables with no skin or seeds
  • Eggs, fish, and poultry
  • White bread
  • Low-fiber cereal
  • Milk, yogurt, and cheese
  • White rice, pasta, and noodles

Medication Options

In the past, oral antibiotics were considered the first line of therapy for uncomplicated diverticulitis. Recent guidance from the American College of Physicians states that most cases can be treated without antibiotics.

For most patients, bowel rest and a liquid diet should be enough to manage uncomplicated diverticulitis.

The guidance states that doctors may prescribe antibiotics for some patients, including those who are immunocompromised or medically frail.

These broad-spectrum antibiotics are commonly used:

OTC pain relievers used to treat diverticulitis include Tylenol (acetaminophen). Narcotics are not recommended because they can increase pressure in the colon.

Surgery Options

If you have two or more acute attacks that were not treated with surgery, you may need surgery.

In more complicated cases of diverticulitis — an abscess or gross peritonitis (a leakage or hole in the intestines) you will need surgery to remove the diseased part of your colon. Primary bowel resection, which reconnects the healthy sections of your colon after removing the diseased part, is one option. A bowel resection with colostomy is another option.

Alternative and Complementary Therapies

There is very little evidence that alternative therapies and complementary supplements are useful treatments for diverticulitis. Glutamine (an amino acid that aids in digestion), fish oil (high in omega-3 fatty acids), flaxseed, and probiotics (which help maintain intestinal health), have all been studied as treatment options, but the results have been inconclusive.

You should always consult with your doctor before adding a new supplement to your diet, particularly if you have diverticulitis or other health conditions.

Prevention of Diverticulitis

To prevent diverticulitis, consider the following:

  • Exercise regularly
  • Stay hydrated
  • Avoid smoking

It’s also recommended to eat a diet high in fiber. Fiber-rich foods like whole grains, fruits, and vegetables soften stool and help it pass more easily.

Just keep in mind that there is such a thing as too much fiber. Aim for 14 grams of fiber per 1,000 calories.

Complications of Diverticulitis

Left untreated, diverticulitis can lead to life-threatening illness.

About 25 percent of people with diverticulitis develop complications. Some of these include:

  • Abscess
  • Fistula
  • Peritonitis
  • Rectal bleeding
  • Intestinal obstruction

As with many diseases, age is a risk factor for diverticulitis complications, but simply having one attack can put you at about a 50 percent risk of having a second in 5 to 10 years.

You can help prevent diverticulitis complications by maintaining a healthy weight, eating enough fiber, not smoking, exercising regularly, and visiting the doctor on a regular basis.

Research and Statistics: How Many People Have Diverticulitis?

Even though diverticulosis is harmless and usually doesn’t cause any symptoms, some research suggests people with this condition have a 10 to 25 percent lifetime risk of developing diverticulitis.

Other research, however, finds that less than 5 percent of people with diverticulosis go on to develop diverticulitis.

In the United States, about 200,000 people are hospitalized for diverticulitis each year. About 70,000 people are hospitalized for diverticular bleeding each year.

About 50 percent of people in Western countries who experience diverticular bleeding have it in the right colon.

BIPOC Communities and Diverticulitis

Diverticulitis affects people differently, with complications and hospitalization occurring more among certain races and ethnic groups — namely Black, Hispanic, and Native Americans.

Black Americans and Diverticulitis

According to research, there were about 30 hospitalizations for diverticulitis per 100,000 Black Americans between 2000 and 2010. Diverticular bleeding was more prevalent in Black people during this 10-year period, too. This is likely due to hypertension and diabetes (both risk factors for diverticular hemorrhage), which are more common in Black Americans.

But bleeding isn't the only concern — surgery is another. Research examining the charts of 327 people with diverticulitis found that Black participants were “more likely than any other racial group to require surgery for recurrent diverticulitis after at least one medically managed hospital admission for the condition.”

Hispanic Americans and Diverticulitis

The rate of hospitalization among Hispanic Americans with diverticulitis is similar to that of Black Americans, about 32 per 100,000 cases.

Hispanic Americans are less likely to have surgery for recurrent diverticulitis, however, and they’re also less likely to have diverticular bleeding, according to research.

Native Americans and Diverticulitis

Native Americans are a smaller population, but research finds the highest prevalence of diverticulitis among this group.

It's believed that this disparity is largely due to the higher rate of diverticulitis risk factors like smoking, obesity, and physical inactivity among Native Americans.

Related Causes and Conditions of Diverticulitis

When left untreated, diverticulitis can cause complications such as a bowel obstruction, perforation, or abscess.

But conditions related to diverticulitis aren’t limited to those affecting the gastrointestinal tract. Diverticulitis has been associated with other ailments, too.

Colorectal Cancer

After hospitalization for diverticular disease, a person's risk of colorectal cancer, which affects the colon and rectum, may be elevated, according to a research paper. Indeed, the risk of this type of cancer is 40-fold higher in people with acute diverticulitis than in the general population. In general, a colonoscopy is recommended in the United States after a diverticulitis episode to identify potential colorectal cancer.

Heart Disease

One study evaluating the risk of acute coronary syndrome (ACS) in people with and without diverticular disease found that ACS was significantly higher in the group living with diverticular disease. The exact link is unknown, but chronic inflammation likely contributes to both conditions, and they have similar risk factors (obesity, inactivity, smoking, and hypertension).

Type 2 Diabetes

Type 2 diabetes, which weakens the immune system and increases the risk of infections, is another disease that can occur alongside diverticulitis, and even increase the severity of diverticulitis, research has shown.

Dementia

Incidence of diverticular disease has also been higher in people with dementia, suggesting a connection, but the exact relationship remains unclear.

Diverticulitis Resources We Love

Favorite Resources for Patient Information

American Gastroenterological Association (AGA)

The AGA describes itself as a “trusted voice in the gastrointestinal community.” The group's website is an excellent place to start if you're looking for general information on diverticulitis. Glean insights on getting tested and potential complications, and download its comprehensive patient info PDF to your phone, tablet, or computer for quick reference at your next doctor’s appointment.

Canadian Society of Intestinal Research (GI Society)

Diverticulitis can have a huge impact on your life, and it’s the GI Society’s aim to make living with this condition easier. Its website offers general information about diverticulitis as well as practical tips, such as managing diverticular disease as a young person. Read advice on recommended fiber intake and physical activity, or check out the Q&A section or videos.

American College of Gastroenterology (ACG)

The ACG is committed to enhancing patient care based on the most recent research available. On its site, you’ll learn about diverticulitis causes, treatment options, prevention, and more. It offers a wealth of multimedia resources, too. This includes podcasts, videos, brochures, and a “Find a Gastroenterologist” search tool.

Favorite Resources for Diet Advice

Mayo Clinic

Not sure what to eat with diverticulitis? While your doctor might give recommendations and tips, it can be difficult to remember everything you've heard. No worries — the Mayo Clinic does a superb job highlighting foods that are safe to eat with diverticulitis.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

We can't talk about diverticular disease without including the NIDDK. Even if you know the benefit of consuming fiber to manage diverticulosis or prevent another episode of diverticulitis, you may not know how much to eat. The NIDDK provides a breakdown of the best fiber-rich foods to consume, as well as how much to eat each day.

For more on how to add more fiber to your diet, check out our article.

Favorite Site for Online Support

Diverticulitis Support Group

Diverticulitis can be overwhelming and frustrating, so there's comfort in knowing you're not alone with this illness. Local in-person support isn’t always an option. But with an online group, you can lean on others for diet and medication advice, or simply for emotional support, anytime of the day or night.

Editorial Sources and Fact-Checking

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