Medically Reviewed By William C. Lloyd III, MD, FACS
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What is diverticulitis?

Diverticulitis is inflammation or infection of diverticula. Diverticula, or colonic diverticula are small pouches or sacs that form in weak spots of the large intestine—the colon. Diverticula can form anywhere in the large intestine, but they’re most commonly found in the colon, closest to the rectum in the section called the sigmoid colon. Diverticula extend out from the intestinal wall. They can impede the normal flow of digestive material through the colon.

The condition of having diverticula is commonly called diverticular disease or diverticulosis. (Some experts use the term diverticular disease only if diverticula cause symptoms.) In most cases, diverticulosis does not cause symptoms or problems. However, diverticula can rupture—or perforate—leading to inflammation or infection. This is diverticulitis, or a diverticulitis attack. It happens in less than 5% of people with diverticulosis. Diverticulitis symptoms can include abdominal pain, fever, nausea, vomiting, and rectal bleeding.

The exact cause of diverticular disease is not known. Genetic and environmental factors affect whether a person develops diverticulosis, but do not appear to play a role in diverticulitis.

Experts used to believe eating foods with indigestible components caused diverticulitis. This included nuts, fruits with small seeds, and whole seeds, like popcorn or sesame seeds. However, recent research suggests people who frequently consume these foods are not more likely to develop diverticulitis. As a result, doctors no longer recommend a particular diverticulitis diet or avoiding these foods across the board.

Diverticulitis pain and other symptoms can be mild or severe. But you should always take diverticulitis seriously. It can result in potentially life-threatening complications, such as peritonitis, an infection of the entire abdominal cavity. Diverticulitis surgery may be necessary if complications develop or if conservative treatment is not effective.

If you have diverticular disease, seek immediate medical care if you have symptoms of diverticulitis.

What’s the difference between diverticulosis and diverticulitis?

Diverticula (the sacs) alone don’t often cause significant symptoms. When symptoms do occur—cramping, constipation, bloating, diarrhea—they are not usually attributed to diverticulosis. Most people with diverticulosis do not know they have it.

However, if the diverticula become red, inflamed or infected, the condition is diverticulitis. (The suffix ‘itis’ means inflammation.) Abdominal pain is much more pronounced with diverticulitis. You may experience fever and chills along with digestive symptoms.

  • Diverticulosis is the digestive condition of having tiny pouches, or diverticula, in the wall of the large intestine. These sacs can be the size of a pea or larger. Diverticula can hinder the normal flow of digestive material through the colon to the rectum.
  • Diverticulitis is the digestive condition of an inflamed or infected diverticulum (single pouch). Diverticulitis is a complication of diverticulosis.

Is diverticulitis serious?

While the presence of a diverticulum—the small intestinal pouch—is usually not dangerous, inflammation or infection of it is a serious condition. In the United States, about 200,000 people a year are hospitalized for diverticulitis and associated diverticular bleeding.

Diverticulitis can result in potentially life-threatening complications, such as peritonitis—an infection of the entire abdominal cavity—and sepsis. In severe cases of diverticulitis, the infected part of the colon may be removed resulting in a temporary colostomy.

Repeated bouts of diverticulitis can also affect your quality of life. The condition can be quite painful, and it takes several days or weeks to recover. Some people develop chronic diverticulitis with persistent abdominal pain.

What are the signs and symptoms of diverticulitis?

There usually are no diverticular disease symptoms or signs of diverticular disease. In fact, many people do not know they have diverticula until they have an imaging test for another reason. CT scan, MRI, ultrasound, and colonoscopy can reveal diverticula.

Some people with diverticular disease experience mild cramping, bloating or constipation. If diverticulosis pain occurs, it is usually mild as well.

Diverticulitis, on the other hand, typically causes noticeable symptoms. The most common symptoms of diverticulitis are:

  • Abdominal pain or tenderness, which usually occurs in the lower left side and is sudden and severe. However, left lower quadrant pain can be a diverticulitis symptom; this pain can be mild and start gradually, getting worse with time.

Diverticulitis can lead to potentially life-threatening complications. Seek immediate medical care for symptoms of diverticulitis.

What causes diverticulitis?

Diverticulitis can occur when a diverticulum tears, leading to inflammation and infection. It is possible the diverticulum can become inflamed in the absence of a tear.

Doctors don’t know exactly what causes diverticulitis, but there are several theories, including:

  • Stool (feces) that becomes trapped in the diverticulum carries pathogenic bacteria that start an infection.
  • Dried bits of fecal matter (fecalith) in the diverticulum tear the wall of the diverticulum leading to infection.
  • Reduced blood supply in the diverticular wall leads to inflammation.

In the past, doctors recommended patients with diverticular disease or a history of diverticulitis to avoid seeds and nuts. The thought was indigestible bits of food played a role in tearing the diverticula. A relatively recent study has cast doubt on this. The study followed large numbers of men over the course of 18 years. It found those who ate such foods were no more likely to develop diverticulitis than those who did not. The results suggested the nutritional benefit of eating nuts and seeds outweighs the risk of diverticulitis.

Genetics plays a role in the development of diverticula, but not diverticulitis. People with a certain genetic background may have vulnerable areas along connective tissues, including the colon wall, and this is where diverticula are able to form.

Studies on the possible causes of diverticular disease and the role of genetics have caused some doctors to reevaluate their dietary recommendations. If you have diverticular disease, consult with a gastroenterologist and ask about the most recent recommendations.

What are the risk factors for diverticulitis?

Many factors increase the risk of developing diverticulitis, but not all people with risk factors will get diverticulitis.

Risk factors for diverticulitis include:

  • Diet high in animal fat. Red meat has been shown to increase the risk of diverticulitis.
  • Diet low in fiber. People with diverticulosis who consume a high-fiber diet have a lower risk of developing diverticulitis. The reasoning behind this is that fiber helps regulate your digestive system; it helps soften stools making them easier to pass. Too little fiber can cause constipation and slow down the digestive system, creating hard stool that is difficult to pass. When you are constipated you strain to move your bowels. It is possible this extra pressure weakens areas of the large intestinal wall such that diverticula can form, although that has not been proven. Infection may start when hardened stool or bacteria are caught in the diverticula.
  • Regular use of aspirin or NSAIDs (nonsteroidal anti-inflammatory drugs), such as ibuprofen (Advil, Motrin, and generic versions) and naproxen (Aleve and generic). These medications can increase your risk of diverticular bleeding and diverticulitis.
  • Oral corticosteroids and opiate analgesics are strongly associated with an increased risk of diverticular perforation. These medications can slow the digestive system and cause constipation.
  • Inherited connective tissue diseases. These diseases, such as Ehlers-Danlos Syndrome (EDS), weaken connective tissue, including the walls of the colon (and other hollow organs). It’s possible the higher rate of diverticular disease in people with EDS is because diverticula form in these weakened areas. Other factors could increase the risk.
  • Older age. Your risk of developing diverticulitis increases with age. Diverticular disease affects nearly 50% of people older than 60 years.
  • Personal history of diverticulitis. The rate of diverticulitis is about 4 to 5% in people with diverticulosis, but it is much higher in people who have already experienced diverticulitis.
  • Sedentary lifestyle or occupation. Physical inactivity can cause the digestive tract to slow. Researchers think the up-and-down motion of running and jogging may decrease colonic pressure, cause food to move more quickly through the digestive tract, and stimulate defecation, all of which are associated with a lower risk of diverticular complications.
  • Smoking. People who smoke are more likely than nonsmokers to develop diverticulitis.

How do you prevent diverticulitis?

Some of the risk factors for diverticulitis are related to lifestyle habits. Fortunately, this means you can do something about them. You may be able to lower your risk of diverticulitis by:

  • Eating a diet high in fiber and low in animal fats. A high-fiber diet does not reduce the risk of having diverticula. But it may reduce the chances of developing diverticulitis because a high-fiber diet improves the movement of stool through the bowel.
  • Exercising regularly. High intensity or vigorous exercise may have the most benefit.
  • Maintaining a healthy body weight
  • Taking medicines that increase the risk of diverticulitis only when absolutely necessary. These medications include aspirin; NSAIDs (nonsteroidal anti-inflammatory drugs), such as ibuprofen (Advil, Motrin, and generic versions) and naproxen (Aleve and generic); oral corticosteroids; and opiate analgesics.

There has also been interest in using medicines to prevent inflammation and infection in people who have repeated diverticulitis attacks. This includes using probiotics and the medicines mesalamine (Asacol) or rifaximin (Xiafaxan). Unfortunately, research doesn’t support their routine use at this point. If you want to try probiotics, talk with your doctor about the best strategy.

If you have diverticular disease, talk with your doctor about ways to lower your risk of diverticulitis. Ask about your medicines and find out if they put you at risk. Don’t stop taking medicines without talking to your doctor.

What are the diet and nutrition tips for diverticulitis?

If you develop a mild case of diverticulitis, drink water, broth, and no-pulp fruit juices at first. Some doctors recommend a liquid-only diet, but you may be able to eat low-fiber foods as tolerated. A low-fiber diet may relieve abdominal pain by reducing stool frequency.

Low-fiber foods include:

  • Baked, broiled or poached fish or chicken
  • Fruit with peel removed
  • Low-fiber cereal
  • Low-lactose dairy products or dairy alternatives
  • Refined grains like white bread, rice and pasta
  • Vegetables that are peeled and cooked

After 2 to 4 days of a low-fiber diet, gradually increase the amount of fiber in your diet. Aim for 5 to 15 grams of fiber a day until you reach the recommended amount of about 25 to 30 grams of daily dietary fiber. Dietary fiber reduces the risk of diverticulitis. Whole grains, fruits and vegetables are examples of dietary fiber.

Severe diverticulitis flare

Diet tips for a more severe flare of diverticulitis are different. You may not be able to eat or drink anything for several days. In those cases, hospitalization is necessary. To avoid dehydration, you will receive fluids (and antibiotics) intravenously. When you are well enough to go home, your care team will give you specific diet and nutrition instructions.

As with mild flares, you will gradually increase the amount of fiber in your diet.

How do you diagnose diverticulitis?

To diagnose diverticulitis, your doctor will ask about your symptoms, your health history, and any medications and supplements you take. During a physical exam, your doctor will likely check your abdomen to see if you have tenderness. A digital rectal exam is a screening exam your doctor may use to check for pain, masses, rectal bleeding and other problems.

These tests can also determine if you have diverticulitis:

  • Barium enema: This X-ray procedure examines your colon. After a barium mixture is slowly instilled into the colon, a radiologic technologist takes a series of X-rays. A barium enema is a lower GI (gastrointestinal tract) series.
  • Blood tests. A high white blood cell count is a sign of infection.
  • Colonoscopy: This imaging procedure examines the lining of your colon and rectum using a thin, flexible instrument called a colonoscope. The camera on the colonoscope transmits pictures of the inside of your colon to a video screen.
  • CT (computed tomography) scan: This imaging test uses X-rays and a computer to make layered images of a body area, in this case your colon. CT scans provide more detail than regular X-rays.
  • Video capsule endoscopy: With this noninvasive imaging test, you swallow a vitamin-sized capsule that contains a camera. The camera takes photos as it travels through your digestive tract including images of the colon wall.

How is diverticulitis treated?

For mild diverticulitis, the standard treatment is antibiotic therapy combined with a liquid diet. The liquid diet helps the intestine heal. Plus, you may not feel well enough to eat solid foods. If you do, eat small amounts of low-fiber foods, which will reduce stool frequency. After 2 to 5 days, you can gradually increase the amount of fiber in your diet. For these uncomplicated cases, your doctor may keep you at home during treatment.

Try these at-home remedies for diverticulitis:

  • Acetaminophen (Tylenol) for pain relief
  • Breathe slowly and as deeply as possible
  • Rest, which will promote healing throughout your body
  • Warm (not hot) heating pad on your belly for cramps and pain

For severe diverticulitis, treatment requires hospitalization due to the risk of complications. Do not consume anything by mouth. Treatment involves intravenous (IV) fluids and antibiotics, and possibly abscess drainage. If this treatment does not work, surgery may be necessary to remove the affected part of the colon or perform other procedures, such as repairing a fistula or tear in the bowel wall.

When is diverticulitis surgery necessary?

Diverticulitis surgery may be necessary if complications develop or if antibiotics cannot clear the infection or relieve diverticulitis symptoms (pain, fever, chills, nausea). Surgery may also be an option if you have had repeated uncomplicated attacks.

The types of surgeries that may be necessary include:

  • Colon resection, or colectomy, which involves removing a section of the large intestine. The doctor either connects the two ends or makes a stoma for a temporary colostomy bag.
  • Fistula repair, which is similar to colectomy, but also includes repair of the organ on the other side of the fistula—often a neighboring loop of bowel.
  • Abdominal surgery to clean the infection out of the abdominal cavity if peritonitis develops.

When should you see a doctor for diverticulitis?

You should see a doctor for any signs of diverticulitis due to the risk of life-threatening complications, such as spread of infection. If you have been recovering at home on your own or under a doctor’s care, follow up promptly with your doctor if:

  • Your fever does not subside with antibiotics.
  • Your symptoms worsen instead of improve.
  • You develop signs of peritonitis, including abdominal pain, bloating, loss of appetite, and inability to pass stool or even gas.

If you cannot reach your doctor or nurse, go to an urgent care or your hospital’s emergency department for medical care.

What are the potential complications of diverticulitis?

Complications occur with diverticulitis about 25% of the time. All of them are serious and some are even life threatening. Potential complications include:

  • Abscess, which is a collection of pus or infected fluid. Doctors may need to drain an abscess if it is large or does not respond to antibiotics. The bacteria that caused the abscess can also enter the bloodstream and result in sepsis—a life-threatening medical emergency.
  • Bowel blockage, which can be complete or partial. A complete bowel obstruction is a medical emergency requiring surgery. Doctors may be able to correct a partial blockage without surgery.
  • Fistula, which is an abnormal connection between the intestine and nearby organs, such as the bladder. It requires surgical correction.
  • Perforation, which is a hole in the intestine allowing intestinal contents to spill into the abdominal cavity. It can cause peritonitis. This is a medical emergency. Emergency surgery is necessary to clean out the abdomen and repair or remove the hole.

Seeking medical care at the earliest signs of diverticulitis is the best way to avoid complications.

What are the different types of diverticulitis?

Diverticulitis usually refers to inflammation or infection of colonic diverticula, pouches that form in the wall of the colon. But, a diverticulum can develop anywhere along the digestive tract, from the esophagus to the colon. In fact, diverticula can form along the wall of any hollow organ.

Types of diverticulitis and diverticula include:

  • Colonic diverticulum and diverticulitis, which occur in the large bowel, or colon
  • Bladder diverticulum and diverticulitis, which occur more frequently in males and rarely cause symptoms
  • Esophageal diverticulum and diverticulitis, which occur anywhere along the esophagus from the throat to the stomach
  • Meckel’s diverticulum and diverticulitis, which occur in the small intestine and are present at birth. (Diverticulitis is a complication of the diverticulum.)

Meckel’s diverticulitis

Meckel’s diverticulitis is inflammation or infection of a congenital diverticulum in the small intestine. A Meckel’s diverticulum is present at birth, from leftover remnants of the fetal umbilical cord. It occurs in 2 to 3% of the population, but is more common in children born with defects of the umbilicus (navel), digestive tract, nervous system, and cardiovascular system. Symptoms of Meckel’s diverticulum include:

  • Abdominal pain, bloating, diarrhea or constipation, and vomiting, from bowel obstruction caused by the diverticulum
  • Belly button tenderness

Complications of Meckel’s diverticulum include:

  • Bleeding from ulcers in the small intestine, which is due to secretion of stomach acid from the diverticulum
  • Bowel obstruction
  • Diverticulitis (Meckel’s diverticulitis), which is more common in older than younger children

The prognosis for Meckel’s diverticulum is good. Most people do not know they have a Meckel’s diverticulum because it seldom causes symptoms. If symptoms or complications develop, a surgeon can remove the diverticulum and suture the ends of the small intestine together.

Esophageal Diverticulitis

Esophageal diverticulitis is inflammation or infection of a diverticulum in the esophagus. Esophageal diverticula are rare and typically diagnosed in the elderly. Esophageal diverticula can form in an area of the esophageal wall that has been weakened by another condition of the esophagus. External pressure can also cause a diverticulum. There are three areas where diverticula occur along the esophagus:

  • Back of the throat (pharyngoesophageal), known as a Zenker’s diverticulum
  • Mid-chest (mid-thoracic) diverticulum
  • Above the diaphragm (epiphrenic) diverticulum

Most people with an esophageal diverticulum do not notice symptoms. When symptoms occur, they include:

  • Cough from food stuck in the diverticulum
  • Difficulty swallowing
  • Regurgitation
  • Unexpected weight loss

People who are asymptomatic do not need treatment for an esophageal diverticulum. Zenker’s diverticulum is more likely than the other two types to cause symptoms requiring treatment, which is usually surgery to remove the defect. Nonsurgical management includes changing the way you eat. Drinking water after every bite will help move food out of the diverticulum and down the esophagus to the stomach.

A tear in the diverticulum can lead to esophageal diverticulitis, which is very rare. Only a few cases have been officially documented. Symptoms of esophageal diverticulitis include fever, chills, chest pain, and persistent difficulty swallowing. Treatment includes intravenous antibiotics and possibly surgery.

Bladder Diverticulitis

Diverticulitis of a bladder diverticulum is a rare condition, with few cases formally identified. (The bladder is considered a sterile organ, which decreases the risk of infection.) Bladder diverticula do not usually cause symptoms. However, a diverticulum may bleed causing blood in the urine (hematuria), become infected, or cause urinary retention. A perforation, or tear in the bladder diverticulum could lead to inflammation or infection.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Aug 13
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