Diverticulitis

Diverticulitis is inflammation of small pouches that bulge out through weak spots in the colon wall. While these pouches are common as we age, when they become inflamed or infected, they can cause sudden, severe pain and other serious symptoms that require medical attention.

Table of contents

• What is diverticulitis and how common is it?
• Types of diverticulitis
• Symptoms and warning signs
• What causes diverticulitis?
• Who is more likely to develop diverticulitis?
• How is diverticulitis diagnosed?
• Treatment options
• Possible complications
• Prevention and lifestyle changes

What is diverticulitis and how common is it?

Diverticulitis is inflammation of irregular bulging pouches in the wall of the large intestine. These pouches are called diverticula (multiple pouches) or diverticulum (a single pouch). When you have these pouches but they don’t cause problems, the condition is called diverticulosis^[1].

Diverticula are quite common, especially as people get older. More than 30% of U.S. adults between the ages of 50 and 59 and more than 70% of those older than age 80 have diverticulosis. The pouches form mostly in the lower part of the colon, called the sigmoid colon^[3].

Most people with diverticula never have symptoms or problems. However, less than 5% of people with diverticulosis develop diverticulitis. In the United States, about 200,000 people are hospitalized for diverticulitis each year^[3].

Diverticulitis occurs when one or more pouches become inflamed. Inflammation is immune system activity that increases blood flow and fluids to a site in the body and delivers disease-fighting cells. Inflammation of diverticula can cause severe pain, fever, nausea and changes in your stool habits^[1].

• Large intestine (colon)
• Sigmoid colon

Types of diverticulitis

Healthcare providers classify diverticulitis in different ways based on how it develops and whether complications occur^[2].

Acute diverticulitis means that it comes on suddenly and goes away shortly with treatment. This is how diverticulitis begins for most people. However, some people have recurring episodes of diverticulitis. An acute attack may come on more suddenly and cause sharp, severe pain^[2].

Chronic diverticulitis develops when some people have multiple episodes of the condition with ongoing inflammation. This may happen because an acute episode didn’t heal completely, or it may be related to another chronic condition in your colon. A chronic flare-up may build up over a few days^[2].

Uncomplicated diverticulitis is the most common type. Inflammation and possible infection are the extent of the problem, and it heals easily with the right treatment^[2].

Complicated diverticulitis occurs when the inflammation begins to cause secondary problems. For example, severe acute inflammation may cause a diverticulum to rupture. Chronic inflammation may cause scarring^[2].

Symptoms and warning signs

A common symptom of diverticulitis is pain in the area below the chest called the abdomen. Most often, pain is in the lower left abdomen. However, in people of Asian descent, it’s more common to have diverticulosis in the first part of the colon, which can cause pain in the upper right abdomen^[2].

The pain from diverticulitis is usually sudden and intense. You should be able to locate it in the precise spot where your diverticulum has become inflamed. It may feel sharp and penetrating or have a burning quality. The pain is usually moderate to severe and may be constant and last several days^[2].

Other symptoms of diverticulitis may include^[2]:

• Fever
• Nausea and vomiting
• Distended or swollen abdomen
• Constipation or, less commonly, diarrhea
• Rectal bleeding or passing mucus from your bottom
• Lack of appetite

You should seek urgent medical care if you have blood or mucus in your stool, tummy pain that’s getting worse or doesn’t go away, a high temperature, if you feel hot or shivery, if you keep being sick and cannot keep fluid down, or if you have diarrhea for more than 7 days or are being sick for more than 2 days^[5].

Call emergency services immediately if you or someone you care for has severe tummy pain and is vomiting, has a swollen tummy, or cannot pass stool or gas; is bleeding heavily from the bottom; or is acting confused, has pale or blotchy skin, has a very high or low temperature, or is breathless or breathing rapidly—these could all be signs of sepsis, a life-threatening condition^[5].

What causes diverticulitis?

Inflammation in your diverticula often involves a tear in the lining and infection, though it’s not always clear which came first. Diverticula make hiding places for bacteria to multiply. This might happen if, for example, some stool gets stuck in one of them^[2].

Researchers aren’t sure exactly what causes diverticulosis and diverticulitis. Studies appear to show that diverticulosis became more common in the 20th century and is more common in Western nations including North America, Europe, and Australia. It is less common in Asia and very uncommon in Africa. This led to the theory that the low-fiber diet common in Western nations may be important^[15].

Several factors may play a role in causing or increasing the risk for these conditions^[4]:

• Genetics—certain genes may make some people more likely to develop the conditions
• Diets low in fiber and high in red meat
• Lack of physical activity
• Taking certain medicines, such as nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids
• Having obesity
• Smoking

Researchers are also looking at other possible factors that may play a role, including bacteria or stool getting caught in a pouch in your colon and changes in the microbiome in the intestines. Your microbiome is made up of the bacteria and other organisms in your intestines^[4].

Who is more likely to develop diverticulitis?

People are more likely to develop diverticulosis and diverticulitis as they age. Diverticulosis occurs in about 40% to 60% of people by age 60. Among people younger than age 50, diverticulitis is more common in men than in women. However, among people ages 50 and older, diverticulitis is more common in women^[3].

Once you’ve had diverticulitis, you have a 20% chance of getting it again^[2].

Research suggests that, in the United States, diverticulitis is more common in white Americans than in other groups, and diverticular bleeding is more common in Black Americans than in other groups^[3].

There may also be genetic causes. People in Asian countries generally develop diverticulosis in the first section of the colon, while Western people develop it in the last third of the colon^[15].

How is diverticulitis diagnosed?

During the physical exam, your healthcare professional will gently touch different parts of the abdomen to learn where you have pain or tenderness. An exam may also include a pelvic exam to test for disease of the female reproductive organs^[8].

Laboratory tests may be used to rule out other conditions and make a diagnosis. These may include^[8]:

• Blood tests for signs of infection and immune-system activity
• Urine test
• Stool test
• Pregnancy test
• Liver enzyme test to rule out liver disease

A computerized tomography (CT) scan is the best way to diagnose diverticulitis. It can show inflamed diverticula, abscesses, fistulas, or other complications and helps determine the severity of the inflammation and the right treatment plan^[8].

If you haven’t had a colonoscopy within a year of experiencing symptoms, your doctor will order one for four to six weeks after your symptoms began in order to rule out the possibility of colorectal cancer, among other issues. It is important to time the colonoscopy for several weeks after symptoms to reduce the swelling of the bowel, therefore reducing the risk of bowel perforation during the procedure^[4].

Treatment options

Treatment depends on how serious the condition is and whether you have complications^[8].

Treatment for uncomplicated diverticulitis

When symptoms are mild and there are no complications, the condition is called uncomplicated diverticulitis. If your symptoms are mild, you may be treated at home^[8].

Your healthcare professional is likely to recommend a liquid diet to let your digestive tract rest and recover. When symptoms begin to improve, you can gradually increase solid food, beginning with low-fiber foods. When you’re fully recovered, you can resume a regular diet with high-fiber foods^[8].

In mild, uncomplicated diverticulitis, antibiotics may not be necessary. Recent studies have questioned their necessity, especially in mild, uncomplicated disease. However, if antibiotics are prescribed, you will need to take all of the pills even when you are feeling better^[8].

Treatment for complicated diverticulitis

If you have serious symptoms or signs of complications, you’ll likely need to be in a hospital. You may be given fluids through a vein first. You also may need medicines such as antibiotics. Broad-spectrum antibiotics covering gram-negative bacteria and anaerobic bacteria should be used in patients with complicated diverticulitis^[8].

Patients with a localized abscess (a painful, swollen, pus-filled area caused by infection) may be candidates for CT-guided percutaneous drainage, where a needle is used to drain the abscess^[13].

Surgery

If your diverticulitis doesn’t improve with treatment or if it leads to complications, you may need surgery to remove part of your colon. This procedure is called a colectomy or colon resection. Fifteen to 30 percent of patients admitted with acute diverticulitis require surgical intervention during that admission^[13].

Laparoscopic surgery results in a shorter length of stay, fewer complications, and lower in-hospital mortality compared with open surgery. When caught and treated early enough, surgeons may be able to remove just small amounts of your intestines and stitch the healthy parts together so you can eliminate normally^[13].

If diverticulitis persists for too long and too much of your colon is damaged, you may need a colostomy, where your bowel is brought out of a hole in your tummy and a bag is attached to collect your stool^[5].

Possible complications

Some people with diverticular disease may develop serious complications^[4]:

• Abscess: A painful, swollen, pus-filled area caused by infection in your bowel
• Fistula: An abnormal opening or passage between the colon and another part of the body, such as the bladder or vagina
• Intestinal obstruction: A partial or total blockage that keeps food, fluids, air, or stool from moving through your intestines
• Perforation: A hole in your colon that allows its contents to leak into the abdomen
• Peritonitis: An infection of the lining of the abdominal cavity, which can be life-threatening
• Diverticular bleeding: This happens when a small blood vessel within the wall of a pouch bursts. The bleeding may be severe and sometimes even life-threatening

These problems can sometimes be treated with antibiotics or surgery. For example, you may need surgery to drain an abscess or remove an infected part of the bowel^[5].

Prevention and lifestyle changes

If you have diverticular disease or diverticulitis, there are things you can do to reduce the risk of your symptoms getting worse in the future^[5].

Eat a high-fiber diet

A healthy diet is healthy for diverticulitis, too. Eat plenty of fiber-rich foods such as leafy greens, cooked and raw vegetables, low-glycemic fruits, whole grains, nuts and seeds. Analysis of large-scale studies has found that people with higher overall fiber intake have lower incidence of diverticulitis. The type of dietary fiber may be important, with grains, cereals, and fruits beneficial^[15].

If you haven’t already adjusted to a diet that incorporates plenty of fiber, do so gradually. Too much fiber too quickly may cause gas that could irritate your gut lining. Slowly increase how much fiber you eat if you do not eat much fiber—and make sure to also drink plenty of water^[5].

There is no evidence that avoiding nuts, corn, or popcorn decreases the risk of diverticulosis or diverticular complications such as diverticulitis. These foods can actually decrease your chances of a diverticulitis flare-up by softening your stool^[17].

Stay physically active

Regular exercise can make it easier to have bowel movements. Exercise doesn’t just build up your arm, leg, and core muscles—it also strengthens and tones the muscles in your intestines. Vigorous physical activity like jogging, swimming laps, or playing tennis or basketball is associated with a reduced risk of diverticulitis and diverticular bleeding^[16].

If you haven’t been active in a while, start with a regular walk, working your way up to 30 minutes a day. Gradually add more intensity and variety^[21].

Maintain a healthy weight

Smoking and obesity are associated with diverticular complications. If you smoke, try to quit, and maintain a healthy weight^[16].

Support healthy bowel movements

Whenever you feel the urge to have a bowel movement, make sure you do so rather than trying to hold it in. Constipation and retained stool may worsen your diverticulitis. Drink plenty of water so your stools remain soft and easy to pass^[21].

Do not take NSAIDs (such as ibuprofen) or opioid painkillers (such as codeine)—they can cause stomach problems or constipation, and increase the risk of getting a hole in your bowel. Use paracetamol for pain instead^[5].