What is Diverticulitis?

Introduction to Diverticulitis 

Diverticulosis and diverticulitis are closely related diseases of the large intestine. Diverticulosis is relatively chronic and is usually asymptomatic. On the other hand, diverticulitis is a complicated condition that usually develops in acute episodes (flares) and can cause troublesome symptoms such as fever, pain in the abdomen, nausea, vomiting, and bloating. It is common in old age and people with obesity and a sedentary lifestyle. It should be treated promptly because if left untreated, it can lead to serious complications.

What is Diverticulitis?

Diverticulosis is characterized by the formation of pocket-like protrusions from the walls of the intestine. These pockets are called diverticula. Due to their sac-like structure, diverticula can get clogged with fecal matter and get inflamed, infected, and even perforated. Inflammation of the diverticula is called diverticulitis.

This can happen through any part of the gut but mostly develops in the sigmoid colon (the left lower part of the large intestine). As the person gets older, the walls of the intestine get weaker, making it vulnerable to diverticulosis and diverticulitis.

Who Develops Diverticulitis?

Anyone can develop diverticulitis, but there are some risk factors that play a major role in its development. These are:

  • Age (above 40 years)
  • Male sex
  • Having a history of diverticulosis
  • Obesity
  • Sedentary lifestyle (lack of exercise or physical work)
  • Consumption of a low-fiber diet
  • Smoking
  • Chronic constipation
  • NSAIDs use
  • Corticosteroids use
  • Opioids use

Diverticulitis and diverticulosis are considered to be diseases of Western countries as these are much more common in Europe and America, while Asian and African countries are not affected much by these diseases. About half of people in the United Kingdom have diverticula by the time they are 50 years old. Nearly 7 in 10 people have diverticula by the time they are about 80 years old. Both genetics and diet play a role in the development of the condition, as Western people usually consume a low-fiber diet.

What are the Symptoms of Diverticulitis?

The spectrum of symptoms ranges from absolutely no symptoms to perforation of the gut wall.

Diverticulosis is usually asymptomatic. However, some patients may experience symptoms such as pain (mild and intermittent), mostly on the left side of the abdomen, as it affects the left colon predominantly. There may be bloating and constipation.

However, as diverticulitis is an inflammatory condition, the patient develops a high-grade fever, nausea, vomiting, constipation (or less commonly diarrhea), and, in rare cases, bleeding through the rectum. Pain in diverticulitis increases in intensity and occurs constantly (severe and continuous), contrary to that in diverticulosis, which is mild and intermittent.

How Does Diet Play a Role in Developing the Condition?

As we have talked about the factors that put you at risk of acquiring diverticulitis/diverticulosis, constipation plays a major culprit role here. Let us briefly discuss various modifications in our daily dietary routine that can have obvious positive impacts on our general health, but more specifically against diverticulosis/diverticulitis. The foremost important thing in this regard is the fiber component, followed by the concept of resistant starch and prebiotics.

Dietary fibers are compounds that the body cannot digest, nor do they have a caloric value. Fiber absorbs water in the intestine, making your stools soft and easy to pass. This decreases the shear pressure on weaker walls of the gut and prevents the formation of the pockets/protrusions that might have formed otherwise due to the impaction of hard stools.

It has also been observed that people who consume a high-fiber diet (25-30 grams a day) are 40% less vulnerable to the development of diverticular disease than people who have less dietary fiber in their meals.

What are Other Conditions that Have Similar Symptoms? (Differential Diagnosis)

  • IBS (Irritable bowel syndrome)
  • IBD (inflammatory bowel disease)
  • Bowel cancer

Your doctor takes your history by asking you a series of questions that will guide you toward a set of diseases with the same spectrum of symptoms. Further in the process, laboratory and radiological investigations will confirm your diagnosis.

How is the Diagnosis Confirmed?

Different diseases can have common presenting symptoms, so we need to choose the investigation appropriately based on factors like age, gender, history, examination, cost, and affordability. The Investigations that help to confirm diverticulitis are as follows:

  • Blood tests such as CBC (complete blood count), ESR (erythrocyte sedimentation rate), and CRP (C-reactive protein) show leukocytosis and raised ESR and CRP, which is indicative of the inflammatory process.
  • A CT-Scan of the abdomen and pelvis with oral and intravenous (IV) contrast is very helpful in the diagnosis of diverticulitis and ruling out other diseases.
  • MRI is an alternative test for pregnant women and young people, but it is costly.
  • Ultrasound abdomen and pelvis can also be done. It is easy to perform, cost-effective, and non-invasive, and it also has comparable diagnostic accuracy.
  • A Colonoscopy is where a thin tube with a camera attached to its head is inserted into your rectum, looking for some signs of diverticulitis. It is usually performed six to eight weeks after symptoms have resolved. It is also very helpful to rule out bowel cancer and inflammatory bowel disease.

How is the Condition Treated?

Mild diverticulitis can be treated at home with bowel rest, increased fluid intake, and oral antibiotics. No dietary restrictions exist in mild cases. However, a high-fiber diet should be encouraged when the flare has resolved.

Severe diverticulitis is treated by admitting the patient to a hospital. The patient is given intravenous fluids, antibiotics, and other drugs that the patient’s condition demands, such as anti-emetics and painkillers. They are advised to bed rest and take a soft diet after the resolution of their symptoms.

If there is a formation of an abscess (collection of pus), it is drained under CT or an endoscopic guided procedure. Emergency surgery may be necessary for people whose intestine has ruptured, leading to peritonitis.

How Can It Be Prevented?

Diverticulitis is a preventable disease and can be prevented by lifestyle modifications, regular exercise, avoiding smoking or alcohol use, and consuming a high-fiber diet. Dietary modification is the most important step in this regard and really plays an important role in bowel health.

Dietary Modifications:

Dietary fibers, prebiotics, and hydration are the most significant components of diet modification regarding diverticulitis. Let’s discuss them one by one here.

Dietary Fibers:

These are divided into two classes:

  • Soluble Fiber
  • Insoluble Fiber

Soluble fiber gets dissolved in water inside the gut to make a gel-like substance that binds cholesterol from the digested food and slows down the digestive process itself, leading to a beneficial steady release of glucose from the food into the blood. To explain how fiber can be good for your gut health, let’s take resistant starch as an example. Resistant starch is a soluble fiber that is highly fermentable. They are broken down by the bacteria found naturally (normal gut flora) in the gut wall to short-chain fatty acids (SCFAs), which are extremely important for gut health.

Sources of soluble fiber:

  • Oats
  • Barley
  • Seeds
  • Beans
  • Pulses

Insoluble fiber is the type that does not dissolve in water. Instead, it absorbs water to add bulk to stools, softens the stool, and helps in smooth expulsion. Sources of insoluble fiber are:

  • Pith and pips of fruit and vegetables
  • Wheat
  • Bran
  • Whole grains
  • Nuts
  • Corn

The sudden and excess fiber intake can cause wind and bloating. So, always add fiber to your diet as recommended by your doctor. If you want to safely use fiber without causing you even a little doubt, then it is better to add two types of fibers in any raw form, such as oatmeal milk or cereals, at least once a day, along with your otherwise balanced diet. The average daily requirement of fiber is 25g-30g.


There are bacteria living inside our gut that have a mutually beneficial relationship with us in the sense that only they can produce certain things that we require, such as vitamin K. Prebiotics is a fiber type that is only used by these good bacteria to help promote their growth.


Drink about 2L of fluids (8-10 cups) daily in the form of clean drinking water and fresh juices. This helps to maintain adequate hydration and counteracts constipation-causing mechanisms.

What are the Complications of Diverticulitis?

If left untreated, diverticulitis can cause some serious complications, such as:

  • Fistulas
  • Abscesses
  • Peritonitis
  • Strictures

See Also

Diverticulosis vs Diverticulitis

Foods to Avoid with Diverticulitis

High Fiber Diet for Diverticulitis

Liquid Diet for Diverticulitis – Diets Meal Plan

What Soups Can I Eat with Diverticulitis?

Can Probiotics Cause Constipation?

Can Probiotics Cause Diarrhea?

What is Obesity?

Low Residue Diet Plan

Current Version
June 15, 2023
Written By
Daniyal Haider
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