Diverticulitis happens when small pouches that form in the lining of your digestive system become inflamed or infected. These pouches, called diverticula, develop most often in the lower part of the large intestine. When they get irritated, they cause pain, fever, and digestive problems. The condition is common in older adults, but it can happen at any age.
What Is Diverticulitis And What Causes It?
Diverticulitis is the inflammation or infection of diverticula. Diverticula are small, bulging pouches that can form in the lining of your digestive tract. Most people with diverticula never have any symptoms. That condition is called diverticulosis. It only becomes diverticulitis when the pouches get inflamed or infected.
The exact cause of inflammation is not fully understood. What researchers do know is that it involves a combination of factors. Stool or bacteria can get trapped inside a diverticulum. This can lead to swelling, infection, and sometimes a small tear in the pouch. The body’s immune response to this irritation is what causes the symptoms.
Age is a major factor. The risk of developing diverticula increases after age 40. By age 60, about half of all people have diverticula. But only about 4 to 15 percent of people with diverticula ever develop diverticulitis. So having the pouches does not mean you will get sick from them.
How Do Diverticula Form?
The colon is a muscular tube. It moves stool toward the rectum by contracting. When the colon has to work harder against hard stool, the pressure inside it rises. Over time, that pressure pushes weak spots in the colon wall outward. Those weak spots are where blood vessels enter the muscle layer. The result is a small pouch.
A low-fiber diet is the main reason stool becomes hard and difficult to pass. Fiber absorbs water and softens stool. It also adds bulk, which helps the colon move stool more easily. Without enough fiber, the colon has to squeeze harder. That extra pressure likely contributes to pouch formation.
This does not mean everyone with a low-fiber diet will get diverticula. Genetics, gut bacteria, and other lifestyle factors also play a role. But the fiber connection is one of the most consistent findings in research on this condition.
What Are the Symptoms of Diverticulitis?
The most common symptom is sudden pain on the left side of the lower belly. This pain is often constant and can last for days. It may get worse when you move, cough, or eat. Some people describe it as sharp or cramping.
Other symptoms include:
- Fever and chills
- Nausea and vomiting
- Bloating and gas
- Constipation or diarrhea
- Loss of appetite
Some people have mild symptoms that go away on their own. Others develop severe infections that require medical treatment. If you have sudden belly pain with fever, you should see a doctor. Untreated diverticulitis can lead to complications.
Right-sided pain is less common but can happen, especially in people of Asian descent. In those cases, the diverticula form more often on the right side of the colon. This can make it harder to tell apart from appendicitis.
How Is Diverticulitis Diagnosed?
Doctors start with a physical exam and your medical history. They press on your belly to check for tenderness. They may also check your temperature and order blood tests to look for signs of infection.
A CT scan is the most common way to confirm diverticulitis. It can show inflamed pouches, thickening of the colon wall, and any complications like abscesses. CT scans are very accurate for this diagnosis. They also help rule out other conditions that cause similar pain, like appendicitis or ovarian cysts.
Doctors usually avoid colonoscopy during an active flare. The procedure involves inflating the colon, which can worsen inflammation or even cause a perforation. If you need a colonoscopy to check for other issues, it is typically done after the infection has healed, usually six to eight weeks later.
What Are the Treatment Options?
Treatment depends on how severe the infection is. Mild cases may only need rest, a liquid diet for a few days, and oral antibiotics. The liquid diet gives your colon a break so the inflammation can settle down. As symptoms improve, you slowly add soft foods back in.
Antibiotics were once standard for all cases. But newer research suggests that some mild cases may heal without them. The body can sometimes fight off the infection on its own. Your doctor will decide based on your symptoms, overall health, and risk factors.
Severe cases may require hospital care. This includes intravenous antibiotics, fluids, and possibly drainage of an abscess. Surgery is needed in some situations. This includes cases where antibiotics do not work, the colon has a perforation, or a fistula forms between the colon and another organ.
Surgery usually involves removing the affected part of the colon. For some people, this is an emergency procedure. For others, it is planned after the infection clears to prevent future episodes. The decision to have surgery depends on how often flares happen and how severe they are.
Can Diet Prevent Diverticulitis?
Yes, diet plays a major role in prevention. A high-fiber diet is linked to a lower risk of developing diverticula in the first place. It is also associated with fewer flares in people who already have diverticula.
Good sources of fiber include:
- Vegetables like broccoli, carrots, and leafy greens
- Fruits such as apples, pears, and berries
- Whole grains like oats, brown rice, and whole wheat bread
- Legumes including beans, lentils, and chickpeas
- Nuts and seeds
The recommended daily fiber intake is 25 grams for women and 38 grams for men. Most Americans get only about half that amount. Increasing fiber gradually and drinking plenty of water helps prevent gas and bloating.
For many years doctors told people with diverticulosis to avoid nuts, seeds, popcorn, and corn. The idea was that these foods could get stuck in the pouches and cause inflammation. Research has now shown that this is not true. There is no evidence that these foods increase the risk of diverticulitis. In fact, nuts and seeds are good sources of fiber.
What Are the Common Myths?
One of the most persistent myths is that diverticulitis is caused by eating small seeds or nuts. This has been repeated for decades. But large studies have found no link between eating these foods and developing diverticulitis. The theory made sense on the surface, but it does not hold up to evidence.
Another myth is that diverticulitis is always an emergency. Most cases are mild and can be treated at home. Only about 20 percent of cases require hospitalization. Knowing the warning signs of severe infection helps you know when to seek care.
Some people believe that once you have diverticulitis, you will always have it. This is not true either. Many people have a single episode and never have another one. Even among those who have repeat flares, the frequency varies widely.
What Lifestyle Factors Matter?
Several lifestyle factors are linked to a higher risk of diverticulitis. Smoking is one of the strongest. People who smoke are more likely to develop diverticulitis and more likely to have complications. Quitting reduces the risk over time.
Obesity is another risk factor. Higher body mass index is associated with more inflammation and more severe disease. Regular exercise, even walking, seems to protect against diverticulitis. The exact mechanism is not clear, but physical activity may help reduce inflammation and improve colon function.
Nonsteroidal anti-inflammatory drugs, or NSAIDs, are also linked to diverticulitis. These include ibuprofen, naproxen, and aspirin. These medications can irritate the lining of the colon and increase the risk of bleeding and perforation. If you have diverticulosis, it is worth talking to your doctor about safer pain relief options.
Alcohol use has a mixed relationship with diverticulitis. Heavy drinking is likely harmful, but moderate drinking does not seem to increase risk significantly. The evidence is not strong enough to make a clear recommendation beyond general moderation.
Can Diverticulitis Come Back?
Yes, it can. About 20 to 30 percent of people who have one episode of diverticulitis will have another one. The risk of recurrence is higher in people who are younger when they first get it. It is also higher in people who smoke or have obesity.
After a second episode, the chance of having more flares goes up. This is why some doctors recommend surgery after two or three episodes. But the decision is personal. Some people choose surgery after one severe episode. Others manage mild flares with lifestyle changes for years.
There is no guaranteed way to prevent recurrence. But a high-fiber diet, regular exercise, maintaining a healthy weight, and not smoking all lower the odds. These changes do not eliminate the risk, but they make a meaningful difference for most people.
Frequently Asked Questions
Is diverticulitis a serious condition?
Most cases are mild and treatable at home with rest and diet changes. But severe cases can lead to complications like abscesses, perforation, or peritonitis, which require emergency care.
Can stress cause diverticulitis?
There is no direct evidence that stress causes diverticulitis. However, stress can affect digestion and immune function, which might play a role in triggering flares in some people.
What foods should you avoid during a diverticulitis flare?
During a flare, doctors usually recommend a clear liquid diet for a few days to rest the colon. This includes broth, clear juices, and gelatin. Solid foods are added back slowly as symptoms improve.
Does diverticulitis ever go away on its own?
Some mild cases of diverticulitis can resolve without antibiotics or other treatment. But it is important to see a doctor to confirm the diagnosis and rule out complications.
