Diverticulitis 101: Symptoms, Treatment, & what to eat.

Our content is not intended nor recommended as a substitute for medical advice by your doctor. Use for informational purposes only.

What are diverticula, diverticular disease, and diverticulitis?

  • Diverticula are small sacs or pouches that project to the outside through weak points in your colon wall (see the image below).
  • Diverticular disease (diverticulosis): the presence of diverticular in the colon (common on the descending and sigmoid colon (on the left side).
  • Acute diverticulitis: is the inflammation of the diverticula with bleeding, fever, and abdominal pain. Some cases of acute diverticulitis may become complicated (Massive bleeding or perforation of the colon).

File:Ds00070 an01934 im00887 divert s gif.webp - Wikimedia Commons

How common are diverticular disease and diverticulitis?

Diverticular disease (the presence of diverticula without inflammation) is widespread and commonly has no symptoms.

The risk of getting diverticular disease increases with age:

  • Diverticular disease is more common in western industrialized countries such as Europe and the USA.
  • Less than 20% of people under the age of 40 have the diverticular disease (reference).
  • Asians
  • More than 60% of people over 60 have diverticular disease.
  • Approximately 95% of people with diverticular disease have sigmoid colon diverticula (The last part of the colon in the lower left abdomen).
  • Only 4% to 15% of people with the diverticular disease will develop diverticulitis.
  • Also, about 5% to 15% will have bleeding from the diverticula. One-third of them will have massive bleeding.

What is the cause of diverticular disease and acute diverticulitis?

Diverticula develop as projections of the natural weak areas of the walls of your colon. Age, race, and genetics play a significant role in developing diverticular diseases.

However, Researchers identified several dietary and lifestyle factors that contribute to the development of diverticula. In addition, abnormal motility and increased pressure inside the colon also play a role.

Common risk factors include (reference):

  • High intake of red meat.
  • High-fat diet.
  • A diet that is low in fibers. (NOTE: Nuts and popcorn are NOT associated with an increased risk of diverticulosis).
  • Lack of physical activity (especially vigorous exercise).
  • Overweight and obesity.
  • Smoking.

Eventually, vessels in the weak diverticular wall may burst and cause significant bleeding. Also, an infection may occur, leading to acute diverticulitis.


  • Asymptomatic: 70% to  80% of patients with diverticular disease have no symptoms.
  • Abdominal pain: The most common symptom of acute diverticulitis. It is usually in the left lower abdomen. However, The pain can occur anywhere in the abdomen.
  • Fever.
  • Nausea, loss of appetite (anorexia).
  • Vomiting may also occur in severe cases. 
  • Blood in the stool or frank bleeding per rectum (blood without a stool).
  • Abdominal rigidity and severe tenderness.
  • A sense of painful (tender) mass.
  • Signs of low blood pressure (due to massive bleeding): dizziness, fainting. 
  • Symptoms of acute intestinal obstruction may occur during the attack, such as severe abdominal distension, persistent vomiting, and constipation.

Complications of acute diverticulitis:

  • Abscess formation: The inflamed diverticula may turn into a pocket of pus (abscess). The symptoms of a diverticular abscess are the same as acute diverticulitis.
  • Perforation (rupture): The diverticulum may burst due to its weak walls and inflammation. The rupture often causes severe abdominal pain and tenderness.
  • Intestinal obstruction: during an attack of diverticulitis, partial colon obstruction may occur with symptoms such as vomiting, distension, and constipation.
  • Fistula formation: A tubular tract may develop between the colon and another abdominal organ due to the rupture. Fistulas most commonly involve the urinary bladder.
  • Septicemia and septic shock: Rupture may cause a spread of the severe infection. The infection may reach the circulation and leads to life-threatening, very low blood pressure (septic shock).
  • Massive bleeding: bleeding from the diverticula can occur with or without the presence of inflammation (acute diverticulitis).

How are diverticulosis and diverticulitis diagnosed?

Your doctor will diagnose diverticulitis based on history (symptoms), signs, imaging, and lab tests.

The most commonly used tests for diverticulitis are:

  • Abdominal ultrasound
  • Abdominal CT
  • Abdominal Magnetic resonance imaging (MRI).
  • Checking for anemia (Hemoglobin levels).
  • Checking for infection and inflammations (white blood cell count and C-reactive Protein).
  • And others.

Treatment of acute diverticulitis.

Most patients with acute diverticulitis respond to medical treatments without the need for hospital admission.

Your doctor will evaluate the severity of your condition and put the management plan accordingly.

Uncomplicated acute diverticulitis is managed as follows:

A. Diet for acute diverticulitis (3 stages):

  • Bowel Rest(liquid diet): Your doctor may instruct you on a fluid-only diet to rest the bowel for a few days.
  • Very low-fiber (low-residue) diet: Once your symptoms improve, Your doctor will allow eating small amounts of very diets that don’t form a bulk inside the intestine.
  • After the symptoms resolve, you can safely return to the high-fiber diet. In addition, a high-fiber diet decreases the risk of recurrence of acute diverticulitis.

Examples of liquid diet for acute diverticulitis:

  • Water
  • Clear broths (not soup).
  • Jell-O
  • Clean pulp-free fruit juice such as cranberry and apple juice.
  • Popsicles.,

Examples of low-fiber diet:

  • Eggs, Fish, and poultry.
  • Milk, yogurt, and cheese.
  • White rice.
  • Pasta and noodles.
  • Canned or cooked fruits (without skin or seeds) and vegetables.
  • Refined white bread.

Examples of high-fiber diet:

  • Whole grains.
  • Fruits.
  • Vegetables.
  • Legumes, including lentils and nuts.

B. Pain control.

Acute diverticulitis often presents with abdominal pain and/or fever. Your doctor will evaluate the severity of pain and prescribe analgesic medications such as paracetamol or ketorolac.

C. Antibiotics

Your doctor may prescribe antibiotics for the treatment of diverticulitis. However, if your condition is mild, antibiotics may not have a role.

D. Treatment of severe/complicated acute diverticulitis.

Severe or complicated acute diverticulitis often requires admission to the hospital, intravenous antibiotics, and analgesia. In extreme cases, surgery may be needed to:

  • Treat complications such as bowel abscess, fistula, or obstruction.
  • Multiple episodes of uncomplicated diverticulitis.
  • Weak immune system causing severe, recurrent, or complicated diverticulitis.

The surgeon often resects the affected part of the colon to prevent recurrence or complications.