Diverticulitis vs. Ulcerative Colitis: What Are the Differences?

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Diverticulitis and ulcerative colitis may have similar symptoms, but they are different conditions. One of the main differences between diverticulitis and ulcerative colitis is that diverticulitis is a form of diverticular disease, while ulcerative colitis is a type of inflammatory bowel disease (IBD).

Both conditions can affect the large intestine (the colon and rectum). Diverticulitis occurs when bulges in weakened areas of the lining of the colon (called diverticula) become infected.

Ulcerative colitis is an immune-mediated disease that causes ulcers (holes) in the large intestine. People have can both conditions at the same time, but they have different causes.

Learn more about the differences between ulcerative colitis and diverticulitis. Make sure to see a healthcare professional for a diagnosis so you can receive the proper treatment. 

Man having abdominal pain or cramping

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Symptoms

Symptoms of different digestive conditions can be similar. That’s why it’s important to work with a healthcare professional to ensure that the cause of the symptoms is found and diagnosed properly.

Ulcerative Colitis

The signs and symptoms of ulcerative colitis are primarily located in the digestive system. However, there can also be symptoms that are located in other body systems or parts of the body. These can include:

  • Blood in the stool
  • Crampy abdominal pain
  • Diarrhea
  • Fatigue
  • Fecal incontinence
  • Fever
  • Mucus in the stool
  • Urgent need to move the bowels
  • Using the bathroom at night
  • Weight loss

Diverticulitis

Diverticulitis is when diverticulosis (the presence of outward bulges in the lining of the digestive system) is complicated by an infection. An infection in the diverticula can cause symptoms in the digestive tract such as:

  • Abdominal cramping
  • Abdominal pain
  • Blood in the stool
  • Change in bowel habits (new constipation or diarrhea)

A Change in Bowel Habits

Diarrhea or constipation are common and usually go away in a few days. However, when either stools that are too loose or too hard continue for three days or more, it might be called a change in bowel habits.

When these changes happen over and over or go on for a long period of time, it could mean that there is a problem that needs attention. That’s why it is important to discuss stools with a healthcare professional.

Causes

The causes of ulcerative colitis and diverticulitis are quite different.

Ulcerative Colitis

The causes of ulcerative colitis are not well understood. It is thought to possibly be a combination of two factors: genetics and environment.

More than 200 genes have been found that are connected to IBD, but not everyone who has these genes goes on to develop ulcerative colitis or the other forms of IBD—Crohn’s disease or indeterminate colitis.

Additionally, one or more external—environmental—factors affect the immune system and/or the makeup of the bacteria in the digestive system. The result is a series of events that occurs in the body leading the immune system to attack the large intestine.

Diverticulitis

It’s thought that constipation or a lack of dietary fiber may cause diverticula that form in the colon. Without enough fiber, stool can become hard and not move through the colon easily, causing constipation.

Constipation causes too much pressure in the colon, leading to a weakening of the colon wall. Once the wall is weakened, it could lead to bulges in some spots (the diverticula).

The diverticula become infected, causing diverticulitis. It’s not clear what exactly causes the infection, but it could be caused by bacteria normally found in the stool. This bacteria may get caught in a diverticulum and grow there.

It’s also thought that some people may have ongoing inflammation, leading to diverticulitis that doesn’t get better with treatment.

Diagnosis

Some of the tests used to diagnose ulcerative colitis or diverticulitis will be the same, but there are also key differences.

Ulcerative Colitis

A colonoscopy with biopsy is generally used in the diagnosis of all forms of IBD. A flexible tube with a light and a camera on the end is put into the large intestine through the rectum. The doctor can see the inside of the colon and choose where to take samples of small pieces of tissue (biopsies). The biopsies are then tested in a lab.

Other tests might also be used during the process of diagnosing ulcerative colitis. These help determine whether there is another reason for the symptoms, such as a bacterial infection. These tests might include:

  • Barium enema: A series of X-rays after an enema containing contrast media is given
  • Computed tomography enterography (CTE): A CT scan using X-rays and contrast media to get detailed images of the digestive system
  • Magnetic resonance enterography (MRE): Detailed images taken by magnetic resonance imaging (using strong magnets rather than X-rays) and contrast media
  • Fecal calprotectin: Testing a stool sample for a protein found in inflammatory white blood cells
  • Sigmoidoscopy: Uses a flexible tube with a camera to see the last third of the colon
  • Upper gastrointestinal series: An X-ray series of the esophagus, stomach, and first part of the small intestine using contrast media

Diverticulitis

Diverticulitis may cause symptoms that need to be investigated. A doctor may suspect diverticulitis if diverticular disease has been found in the past. However, tests may be done to ensure that symptoms like bleeding and abdominal pain are diagnosed correctly.

Some of the tests used might be:

  • Barium enema
  • Computed tomography (CT) scan
  • Colonoscopy
  • Sigmoidoscopy
  • Stool sample to check for bacterial or parasitic infection

Treatment

One of the reasons that the correct diagnosis is essential is because the treatments for ulcerative colitis versus those for diverticulitis are quite different.

Ulcerative Colitis

The treatments for ulcerative colitis include lifestyle changes, over-the-counter (OTC) medications, complementary therapies, prescription drugs, and surgery. Some of the most commonly used medications include:

  • 5-aminosalicylates (5-ASA): Such as sulfasalazine and Asacol HD (mesalamine)
  • Corticosteroids: Such as prednisone
  • Biologics: Such as infliximab, adalimumab, ustekinumab, and golimumab
  • Immunosuppressants: Such as azathioprine and mercaptopurine
  • JAK-inhibitors: Such as Xeljanz (tofacitinib)

Lifestyle changes can include altering your diet and quitting smoking. Complementary therapies may include yoga, acupuncture, and probiotics.

Surgery to remove the intestine, with either the placement of an ileostomy or a j-pouch, is another form of treatment for complicated ulcerative colitis. More types of treatments might be used to treat either the disease or its effects on other parts of the body.

Diverticulitis

The treatment for diverticulitis may occur either at home or in the hospital. Which treatments are used will depend on the severity of the symptoms. Antibiotics may be given as first-line therapy, either orally or through an IV in the hospital.

Diverticulitis can lead to complications in about 12% of cases. Other treatments, including medications or surgery, might also be needed if there is a high fever, an inability to eat or drink, a high white blood cell count, or sepsis.

More treatments are being studied for diverticulitis, including Asacol HD (mesalamine), Xifaxan (rifaximin), and probiotics, although these are not yet proven to help.

Prevention

Ulcerative Colitis

It’s not well understood what causes ulcerative colitis. For that reason, there’s not a lot of information about how to avoid the disease. However, for those at risk, it may be worth talking to a physician about how to live a healthy lifestyle and avoid potential triggers.

Preventing complications from ulcerative colitis can include making sure the disease is under control. Staying on a treatment plan and seeing a gastroenterologist on a regular basis will be important in managing symptoms.

Diverticulitis

It may not be possible to avoid developing diverticular disease, and not much is known about prevention. However, a high-fiber diet may be recommended once diverticula are present in order to avoid diverticulitis.

Other prevention methods that might be recommended include drinking more water and getting the right amount of exercise. It might also be recommended to avoid eating red meat.

People who have diverticular disease may also be told to avoid certain medications that are known to cause bleeding in the digestive system in some people. This may include aspirin, cyclooxygenase inhibitors (cox inhibitors), and nonsteroidal anti-inflammatory drugs (NSAIDs).

Summary

Ulcerative colitis and diverticulitis both affect the colon and can cause abdominal pain, cramping, and blood in the stool, but they are different in many ways. Both have causes that are not fully determined. A colonoscopy and imaging may be used in diagnosis for each condition.

Treatment options for ulcerative colitis include medications, lifestyle changes, and possibly surgery. Treatment for acute diverticulitis often includes antibiotics.

A Word From Verywell

Living with digestive disease may mean paying more attention to diet, stress, and medical care. Seeing a doctor on a regular basis will be important in avoiding a flare-up of the condition or other complications. Keeping on track with medications will also be key to managing the condition well and avoiding symptoms flaring back up again.

For both diverticular disease and ulcerative colitis, diet will be important. Changing one’s diet is not easy, which is why working with a dietitian will be helpful. Having both conditions will mean taking care to live the best quality of life possible.

Frequently Asked Questions

  • Is diverticulitis a type of IBD?

    Diverticulitis is not a form of IBD, but people can have both diverticular disease and a form of IBD at the same time. People with ulcerative colitis, however, may be less likely to develop diverticula because of scarring in their colon.

  • What foods are good for diverticulitis and ulcerative colitis?

    A diet as high in fiber as can be tolerated is recommended for both diverticulitis and ulcerative colitis in remission. When ulcerative colitis is flaring, it will be important to work with a dietitian to find foods that won’t contribute to symptoms.

    This means drinking enough water and eating as well rounded of a diet as possible, while avoiding foods that might contribute to diarrhea. Every person with IBD is different, but avoiding fried foods, fatty foods, and spicy foods might be a place to start.

  • How does stress affect digestive health?

    Stress does not cause bowel diseases, however stress can contribute to an increase in symptoms. Stress-relieving techniques are often recommended for people who live with a bowel disorder. This can include mindfulness, meditation, therapy, or other lifestyle changes. Many people with IBD try various different techniques to find the best ways to keep a lid on their stress.

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