Diverticulitis 101: Symptoms, Causes, and Treatment

Medically reviewed by Judith Marcin, MD on November 3, 2017Written by Laura Persons

Overview

While it was rare before the 20th century, diverticular disease is now one of the most common health problems in the Western world. It’s a group of conditions that affect the digestive tract. Diverticulitis is the most serious type of diverticular disease (1).

Read on to learn all about diverticulitis, including causes, symptoms, treatment, and how your diet affects your risk of developing this condition.

What is diverticulitis?

Formations called diverticula are key components of diverticulitis. Diverticula are pouches that occur along your digestive tract, most often in your colon (large intestine).

These pouches form when weak spots in the intestinal wall balloon outward. When these pouches become inflamed, or bacteria gather in them and cause an infection, you have diverticulitis.

Diverticulitis often requires treatment because it typically causes symptoms and can lead to serious health complications.

Diverticulitis vs. diverticulosis

Diverticula themselves can be harmless. If you have diverticula that aren’t infected or inflamed, you have diverticulosis. This condition typically causes no symptoms and doesn’t need treatment.

If diverticulosis does cause symptoms, it’s called symptomatic uncomplicated diverticular disease (SUDD). This condition causes symptoms similar to those of irritable bowel syndrome, such as abdominal pain and bloating.

The good news for people with diverticulosis is that only 10 to 20 percent of people with this condition progress to SUDD. And of those, about 4 percent get acute diverticulitis (2, 3).

In addition, it typically takes about 7 years for this progression to diverticulitis to occur. And of the 4 percent of people with diverticulitis, only 15 percent have complications (2, 4).

Disease progression

If you have an episode of diverticulitis, it can recur as an acute, or short-term, problem. However, that’s not a definite.

According to one study, in those who have had one episode, around 39 percent of individuals have another acute attack within five years (5).

And another study found that the first attack is typically the worst one. This may be because scar tissue builds up in the diverticula and helps prevent future perforations. So, if your first episode was mild, you have a good chance of avoiding serious complications (5).

But for some, diverticulitis can progress into a chronic, or long-term, problem. For these people, the condition can be much more serious. Surgery to remove the diseased tissue is generally considered (6).

Who’s at risk?

While there are several risk factors for diverticulitis, the key risk factor is age. The older you get, the higher your risk of developing this condition.

Diverticulosis, the precursor to diverticulitis, is very common in older adults, especially those over 60. In people over age 70, 60 percent have diverticulosis, while 75 percent of people 80 years and older have the condition (2, 7, 8).

However, young people have their own level of risk. A study found that the younger you are when receiving a diagnosis of diverticulosis, the higher your risk is of the condition progressing to diverticulitis (9).

SUMMARY: Diverticulosis is a common digestive disorder, especially among older adults. Diverticulitis happens when the diverticula become inflamed. This is less common than diverticulosis but more concerning, because it typically causes symptoms and, in some cases, can lead to serious complications and long-term health problems.

What causes it?

Doctors don’t think one thing in particular leads to diverticulitis.

They do agree that the root cause of the condition is fecal matter blocking the opening of diverticula, which leads to inflammation and infection. However, they think the reasons for that blockage can vary from person to person (3, 10).

Multiple factors seem to lead to diverticulitis. Researchers’ opinions on these factors have changed over the years. For instance, constipation is no longer considered a risk factor (11).

Today, recent research supports several risk factors:

  • A low-fiber diet: A lack of dietary fiber has long been suspected as a risk factor, but research has had conflicting results. Nevertheless, it’s still thought by some to be related to the onset of diverticulitis (12).
  • Heredity: Diverticulitis seems to have a hereditary link. A study of siblings and twins proposes that more than 50 percent of potential risk of diverticular disease comes from genetics (13).
  • Obesity: Being obese is a clear risk factor for diverticulitis. Research has shown that obesity raises the risk of diverticulitis and bleeding, but researchers aren’t sure of the reason behind this link (14).
  • Lack of physical exercise: It’s unclear if a sedentary lifestyle is a real risk factor. However, research suggests that exercise reduces the risk of diverticular disease. People who exercise less than 30 minutes a day appear to have increased risk (15).
  • Smoking: Research shows that smoking increases the risk of symptomatic and complicated diverticular disease (16).
  • Certain medications: Regular use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) may raise your risk of diverticulitis. The use of opiates and steroids appears to raise your risk of perforation, a serious complication of diverticulitis (17, 18).
  • Lack of vitamin D: One study found that people with complicated diverticulitis may have lower levels of vitamin D in their system than people with uncomplicated diverticulosis. This study suggests that vitamin D levels seem to be related to complications of the disease, although the exact reason is unclear (12).
  • Sex: In people age 50 and younger, diverticulitis appears to be slightly more common in men than women. In people older than 50, it seems slightly more common in women (19).
SUMMARY: There are likely multiple components that lead to the formation of diverticula and increase the risk for diverticulitis. The risk factors for the condition seem to be varied.

Symptoms of diverticulitis

Unlike diverticulosis, diverticulitis often causes symptoms that range from mild to severe. These symptoms can appear suddenly, or occur slowly over a few days (20).

Common symptoms

Pain in the abdomen is the most common symptom. It typically occurs in the lower left side of the abdomen. The condition most often affects the part of the colon in that area.

The most common symptoms of diverticulitis include (8, 21):

  • abdominal pain
  • fever
  • nausea
  • vomiting
  • increased urge to urinate, urinating more often than usual, or burning sensation while urinating
  • constipation
  • diarrhea

Blood in the stool, as well as bleeding from the rectum, can occur in both diverticulosis and diverticulitis. Research reports up to 17 percent of people with chronic diverticulitis experience bleeding (3).

When to call your doctor

Call your doctor if you have mild abdominal pain that doesn’t go away after 24 hours. Call right away if your abdominal pain is worsening or if you have abdominal pain along with bleeding or more severe symptoms such as fever, nausea, vomiting, or diarrhea.

SUMMARY: Diverticulitis frequently causes symptoms, with the most common ones being pain in the lower left side of your abdomen, fever, and nausea and vomiting.

How is diverticulitis diagnosed?

Many health conditions can cause symptoms similar to those of diverticulitis. Therefore, your doctor may do several types of tests to rule out other causes.

Your doctor will ask you about your symptoms, health history, and what medications you take. They’ll also do a physical exam to check your abdomen for tenderness. They may also do a digital rectal exam to check for bleeding, pain, masses, or other problems.

Your doctor may also order other tests, such as the following (3, 21, 22):

  • blood tests to check for inflammation, anemia, or kidney or liver problems
  • imaging tests, such as an abdominal ultrasound or an abdominal CT scan, to get pictures of your gastrointestinal (GI) tract
  • urine test to check for different types of infection
  • stool test to check for GI infections such as Clostridium difficile
  • pelvic exam in women to rule out gynecologic problems
  • pregnancy test in women to rule out pregnancy
SUMMARY: The symptoms of diverticulitis can be similar to those of many other conditions, so you’re likely to take several different tests to rule out other problems and confirm whether you have diverticulitis.

Common treatments for diverticulitis

The treatment your doctor prescribes will depend on how severe your condition is.

Most cases of diverticulitis — about 75 percent of them — are uncomplicated. This means they have no other problems besides the actual inflammation or possible infection from the diverticulitis itself (8).

If you have uncomplicated diverticulitis, your doctor will likely recommend some type of treatment, possibly at home. If they’re concerned about your symptoms, they may suggest that you be hospitalized.

If you stay at home, your doctor will likely suggest that you get lots of rest and fluids as you recover from your symptoms. They’ll also want to see you for a follow-up assessment within a few days (23).

In the meantime, your doctor may prescribe or recommend treatments such as medication, a liquid diet, or a low-fiber diet.

Medication

To treat any infection, your doctor may prescribe antibiotics, such as metronidazole (Flagyl, Flagyl ER) or amoxicillin. Newer research indicates that antibiotics aren’t always needed or helpful for uncomplicated diverticulitis. Your doctor will decide whether they’re a good treatment option for you (6, 8).

Your doctor may also suggest over-the-counter pain medications, such as acetaminophen (Tylenol), to ease your discomfort.

A short-term clear liquid diet

Your doctor may suggest that you have only clear liquids for a few days. This diet can give your digestive system a rest while you recover (6, 23).

A low-fiber diet

As your symptoms improve, or if your symptoms were very mild to begin with, your doctor may recommend a low-fiber diet while your digestive system is recovering (24).

Follow-up care

Your doctor may recommend that you have a colonoscopy six to eight weeks after your first episode of diverticulitis. This test can help confirm that the episode wasn’t related to other problems (25).

SUMMARY: Many cases of diverticulitis are uncomplicated and require only at-home treatment. This may include antibiotics, a clear liquid diet, and a slow reintroduction to fiber in the diet.

Negative effects of diverticulitis

About 25 percent of people with diverticulitis develop complications during acute episodes. The more complications that occur, the more serious the condition becomes. Symptoms that are more likely to occur with complicated diverticulitis include fever, bleeding from the rectum, blood in the stool, nausea, and vomiting (8).

If you have complicated diverticulitis, you’ll likely need to be admitted to the hospital for treatment. You’ll probably be given fluids and antibiotics into your vein through an IV.

The rest of your treatment will depend on the type of complications you have.

Possible diverticulitis complications

The complications caused by diverticulitis can be very serious and even life-threatening. They often require procedures or surgery. The more common complications are listed below.

Perforation and peritonitis: Diverticulitis typically causes tiny perforations in the diverticula. In severe cases, these ruptures can grow larger and spill the colon’s contents into the peritoneal (abdominal) cavity.

This can lead to peritonitis, which is inflammation and infection within the abdominal cavity. Symptoms can include abdominal pain, fever, nausea, vomiting, and rigid abdominal muscles (3, 26).

Treatment for peritonitis is emergency surgery to remove the damaged part of the colon and clean out the abdominal cavity. Removing the damaged intestine is known as a large bowel (colon) resection, or a colectomy.

With this procedure, the diseased tissue is removed, and the healthy parts of the colon are reattached. If the colon can’t be reattached, the end of it is redirected to the outside of your body and attached to a colostomy bag. A colostomy can be temporary or permanent (8).

Abscess and phlegmon: An abscess is an infected pocket that’s filled with pus. A phlegmon is an infected area within tissue that’s less defined than an abscess.

Abscesses and phlegmons can form along the wall of the colon. Symptoms can include fever, abdominal pain, nausea, and vomiting.

Treatment for abscesses and phlegmons can include antibiotics. In more serious cases, surgery may be done to remove the affected tissue (3).

In some cases, abscesses can also be treated using percutaneous drainage. With this treatment, a tube is inserted through your skin and into the abscess to allow the pus to drain (3, 6).

Fistula: A fistula is an abnormal connection between two organs, or between an organ and the skin. A fistula caused by diverticulitis typically connects the colon with the bladder, the vagina, or the small intestine.

Symptoms depend on the type of fistula. Symptoms can include painful urination and abnormal vaginal discharge. Usually fistulas require surgery to repair the fistula and surrounding tissue and remove the affected section of the colon (27).

Intestinal obstruction: Obstructions, or blockages, of the colon can occur if a stricture forms. A stricture is a severe narrowing of the colon due to inflammation or scarring. This narrowing can block the passage of stool.

Symptoms can include abdominal pain and bloating, vomiting, and severe constipation. An intestinal obstruction is typically treated with surgery to remove the affected part of the colon (8, 24, 28).

SUMMARY: Complicated diverticulitis can lead to life-threatening complications. Surgery is often recommended as treatment.

How your diet affects diverticulitis

Diet plays a role in your digestive health, there’s no doubt about that. What role it plays in the prevention and management of diverticulitis, however, is less clear.

In the past, you may have heard about a “diverticulitis diet.” That diet recommended eating certain foods, such as those high in fiber, and avoiding specific foods, such as popcorn, nuts, and seeds.

It was thought that foods high in fiber could benefit digestion and reduce symptoms of diverticulitis, while foods such as nuts and seeds could aggravate those symptoms.

Today, the National Institutes of Health (NIH) says that eating nuts and seeds isn’t a problem, and that people with diverticulitis don’t need to avoid any particular foods. They also say that fiber can indeed be a good choice if you have diverticulitis (6, 29).

In addition to these recommendations, today’s research supports other dietary suggestions for people at risk of diverticulitis, and for people who already have the condition.

For people at risk of diverticulitis

Does diet affect your risk of getting diverticulitis in the first place? Although we may want a definitive answer, today’s research only shows that it might. And much of the focus of that research has been on fiber intake.

Fiber: Research results on the role of fiber in diverticulitis has had conflicting results. Some studies have indicated that a high-fiber diet doesn’t reduce risk for diverticulosis, but others have shown otherwise. It’s also not clear how much fiber is needed to be beneficial (30).

Researchers have studied the so-called “Western” diet, which is high in fat and sugar and low in fiber. Compared to a diet high in fruits, vegetables, and whole grains — a high-fiber diet — the Western diet was shown to increase the risk of diverticulitis (31).

One study showed that people who are vegetarians and eat a high-fiber diet have a lower risk of hospital admission and death from diverticular disease than meat-eaters do (32).

Despite the current fiber research, you might want to follow a high-fiber diet anyway. It’s been shown to have many health benefits, even for people not at risk of diverticulitis.

Some fiber and fiber supplements can cause bloating and abdominal discomfort. Talk to your doctor about which type of fiber is best for you.

For people with diverticulitis

As for whether diet affects the symptoms of someone with diverticulitis, the general consensus is that it does. Factors to consider include:

Fiber: While it’s not clear that a high-fiber diet can reduce the risk of diverticulitis, it’s more likely that it can help reduce symptoms of diverticular disease (10).

Vitamin D: One study found that people with complicated diverticulitis who were hospitalized had lower levels of vitamin D than people with uncomplicated diverticulosis (12).

Another study found that people who live in areas that get less sun have an increased risk of hospital admissions from diverticulitis. Sunlight enables your body to make vitamin D (33).

These studies seem to indicate that higher levels of vitamin D reduce the risk of diverticular complications. The exact role that vitamin D plays in relation to diverticular disease isn’t clear. It’s suggested that higher levels of vitamin D may decrease inflammation.

Low-FODMAP diet: For people with irritable bowel syndrome, it can be helpful to avoid foods that are high in FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) (34).

Examples of these foods include dairy foods, certain fruits, fermented foods, onions, and garlic.

Researchers have suggested that a low-FODMAP diet could also benefit people with diverticulitis. Ask your doctor if avoiding these types of foods might be a good choice for you (34).

Probiotics: There’s questionable evidence that probiotics can help reduce diverticulitis symptoms or encourage remission. The American Gastroenterological Association doesn’t currently recommend the use of probiotics for diverticular disease (10, 25).

SUMMARY: Research isn’t definitive, but it’s likely that diet plays some role in diverticular disease. Whether you have diverticulitis or would just like to avoid getting it, it’s probably a good idea to follow a high-fiber diet.

The bottom line

While diverticulitis is an increasingly common problem in the Western world, it doesn’t pose a big risk to the health of most people who have it. Treatment for uncomplicated diverticulitis can typically be done at home, and long-term complications aren’t the norm.

However, when complications do develop, they can be very serious and can require immediate medical care, including surgery.

If you have diverticulitis or are concerned about your risk for the disease, the best thing you can do is talk with your doctor. They can make recommendations to reduce your risk of getting the disease, or help reduce your symptoms or risk of recurrence.

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