Diverticulosis vs. Diverticulitis

Diverticulosis is a condition in which small, bulging pouches (diverticula) develop in the lining of the intestines. Diverticulitis occurs when those pouches become inflamed or infected. Both are known as diverticular diseases.

A main difference between diverticulosis and diverticulitis is that diverticulosis doesn’t usually cause symptoms. Diverticulitis, on the other hand, causes persistent abdominal pain, usually on the lower left side of the abdomen. It can also cause nausea, vomiting, constipation, diarrhea, and fever.

Diverticulosis requires no treatment, but dietary changes may be recommended. Treatment for diverticulitis depends on the severity of the symptoms.

This article explains the difference between diverticulosis and diverticulitis. It also discusses how both are diagnosed and treated, as well as how to prevent diverticulosis from becoming diverticulitis.

What Causes Diverticulosis and Diverticulitis?

As people get older, the wall of the colon (large intestine) might weaken in some spots. This is a normal, common occurrence that can cause pockets to form in the colon wall. These pockets bulge outward through the wall of the colon.

A single one of these pockets is called a diverticulum; more than one is called diverticula. The condition of having diverticula is called diverticulosis. Diverticula can occur anywhere in the small or large intestines.

The exact cause of diverticulosis is unclear.

Low-Fiber Diet

The leading theory is a low-fiber diet may lead to the formation of diverticula in this way:

1. A low-fiber diet can cause constipation, which is when stool is hard to pass or is passed only infrequently.
2. Constipation could cause the intestinal walls to be put under too much pressure.
3. The tension causes sections of the colon to become weak and to develop pockets (diverticula).

Inflammation and Infection

Diverticulitis is a complication of diverticulosis. It occurs when one or more of the diverticula becomes infected or inflamed.

It’s not well understood why this happens. Stool normally contains a certain amount of bacteria. One theory is that the stool, and the bacteria in it, may enter into the diverticula. Once there, the bacteria may lead to an infection. 

A second theory is that diverticulitis is an inflammatory condition. Inflammation in the diverticula may lead to the symptoms. A small percentage of patients have what is known as smoldering diverticulitis. Their symptoms don’t respond to treatments and cause ongoing problems.

Risk Factors

Research suggests genes may play a role in the development of diverticular disease. Lifestyle factors that may increase your risk include: 

• Eating a diet low in fiber and high in red meat
• Lack of physical activity
• Obesity
• Smoking
• Taking anti-inflammatory medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or steroids
  

Having diverticulosis is the primary risk factor for developing diverticulitis. Other factors include:

• Autoimmune diseases
• Bacteria or stool becoming trapped in diverticula
• Changes to the intestinal microbiome
• Connective tissue, muscle, or nerve problems in the colon

Diverticulosis vs. Diverticulitis: Symptoms

Diverticulosis is typically asymptomatic. Sometimes, though, people with diverticulosis experience mild and chronic symptoms that include:

• Bloating
• Constipation
• Diarrhea
• Lower abdominal cramps
• Mild abdominal pain or discomfort

Diverticulitis symptoms, on the other hand, can be severe. Symptoms of diverticulitis tend to come on suddenly and include:

• Abdominal cramping
• Abdominal pain
• Blood in the stool
• Change in bowel habits
• Constipation
• Diarrhea
• Fever and chills
• Nausea
• Vomiting

Diverticulitis pain is typically acute and severe. However, in some people, the pain is mild at first and worsens over several days. 

Complications

About 12% of people with diverticular disease develop complications in the intestinal tract. These can include:

• An abscess (pocket of pus)
• Fistula (an abnormal connection between two body cavities)
• Obstruction (a blockage in the colon)
• Perforation (an opening in the colon)
  

Diverticulitis can also cause complications outside the colon including leukocytosis (a high number of white blood cells) and sepsis (a whole-body reaction to infection).

Thankfully, most people with diverticulosis won’t develop diverticulitis or other complications.

How Are Diverticulitis and Diverticulosis Diagnosed?

Since diverticulosis does not usually cause symptoms, it often goes undiagnosed. Sometimes diverticulosis is found during tests for another condition or during a routine colonoscopy.

Diverticulitis is diagnosed based on symptoms and imaging tests, including:

• Angiography
• Barium enema
• Colonoscopy
• Computed tomography (CT) scan
• Sigmoidoscopy
  

Your healthcare provider may also take blood work or stool samples to rule out other conditions.

Treating Diverticulosis and Diverticulitis

Diverticulosis is not usually treated because there are no symptoms. If found, your doctor may recommend some changes to your diet to avoid constipation.

Dietary changes for diverticulosis include:

• Adding more fiber to your diet
• Limiting red meat
• Eating more fruits, vegetables, nuts, seeds, beans, and legumes
• Replacing low-fiber foods, like white bread and white rice, with whole grains

For diverticulosis with symptoms, your healthcare provider may recommend taking fiber supplements or probiotics. In some cases, prescription medications may be needed.

Diverticulitis Treatments

Uncomplicated diverticulitis is usually treated with a combination of the following:

• Antibiotics, given either orally or through an IV
• A clear-liquid diet or IV fluids for a few days
• Pain-relieving medications, such as antispasmodics or acetaminophen

Diverticulitis with complications may require hospitalization. Depending on the complication, surgery may be needed to:

• Clear a bowel obstruction
• Drain an abscess
• Remove large diverticula
• Repair a fistula or intestinal perforation
  

Other potential diverticulitis treatments being investigated include:  

•  Asacol (mesalamine), an anti-inflammatory used to treat ulcerative colitis, may help prevent a recurrence of diverticulitis. However, the current research is unclear about this.
• Limosilactobacillus reuteri is a probiotic may help treat diverticulitis. Research suggests L. reuteri may work by improving intestinal motility and suppressing immune system responses.
• Xifaxan (rifaximin), an oral antibiotic, was found to be highly effective in relieving mild forms of diverticulitis and uncomplicated diverticular disease. Three rounds of treatment are typically required.

More research is needed before these treatments are recommended for treating diverticulitis.

Can You Prevent Diverticulitis or Diverticulosis?

Diverticular disease is common. It may or may not be avoidable.

Preventing constipation and straining while having a bowel movement may help prevent diverticulosis and diverticulitis.

General recommendations for avoiding constipation include:

• Drink plenty of water
• Eat enough dietary fiber or take fiber supplements
• Get daily exercise
• Maintain a healthy weight or lose weight if overweight or obese
• Quit smoking (if applicable)

Avoiding Diverticulitis

These same methods are used to prevent diverticulosis from becoming diverticulitis.

People with diverticulosis are also advised to avoid red meat, which research shows increases the risk of diverticulitis.

People with diverticular disease should avoid medications associated with digestive tract bleeding. These include:

• Aspirin, unless prescribed for heart attack or stroke prevention
• Cyclooxygenase inhibitors (COX inhibitors)
• NSAIDs

Summary

Diverticulosis is a condition of having pouches in the wall of the colon. If these pouches become inflamed, it becomes diverticulitis. Diverticulosis may not have any symptoms, while diverticulitis could cause pain and blood in the stool. The causes of both are unclear.

Treatment often isn't needed for diverticulosis, although a diet higher in fiber is recommended to prevent constipation. Diverticulitis may require treatment with antibiotics. It can lead to several complications.