Colonoscopic image showing the presence of small pockets within the bowel wall

Diverticular disease of the colon consists of three related conditions that involve development of small sacs or pockets in the wall of the colon.

This is a condition that affects a great number of adults, especially those above the age of 50. It is thought that nearly half of the population older than 50 years in the developed world suffers the problem on different degrees and all persons have diverticula when they are 80 or older.

The diverticulitis disease is benign in its nature and many people do not have symptoms but in some occasion symptoms or complications may arise. Possible symptoms might include the following:

  • Diverticulosis (confirmed presence of diverticula with none or little symptoms)
  • Diverticular bleeding
  • Diverticulitis (infection and swelling of the diverticula).


Diverticulosis is the formation of numerous small pockets, or diverticula, in the inside lining of the bowel. Diverticula, which can range from a pea-size to a much larger size, are formed by increased pressure on weakened spots of the
intestinal walls by gas, waste, or liquid. Diverticula can form while straining during a bowel movement, especially during constipation. They are most common in the lower portion of the large intestine (called the sigmoid colon).

Diverticulosis is very common and occurs in 10% of people aged 40 or more and in 50% of people above the age of 60. Most people will have no or few symptoms from diverticula.

Complications can occur in about 20% of people with diverticulosis. One of these complications is rectal bleeding, called diverticular bleeding, and another is diverticular infection, called diverticulitis.

Colonoscopic image showing the presence of small pockets within the bowel wall

Diverticular Bleeding

Hemorrhoids and diverticular disease of the colon are, in that order, the most frequent conditions causing bleeding of the rectum. Patients having bleeding alone or coupled with motions are advised to consult with their doctors. Diverticular bleeding occurs through chronic injury to the small blood vessels that are next to the diverticula. The patients notice that blood, normally red and fresh looking, is mixed with faeces. In other occasions, normally a greater amount of blood is coming out not mixed with faeces. Only severe cases of bleeding may require surgery, but recurrent blood loss makes surgery an advisable option.


Diverticulitis occurs when there is inflammation and infection in one or more diverticula. This usually happens when outpunchings become blocked with waste, allowing bacteria to build up, causing infection.

Symptoms of Diverticulosis

Diverticulosis on its own does not cause any major symptoms. Patients suffering from it may complaint of occasional left side abdominal discomfort, or constipation.

Symptoms of Diverticulitis

Diverticulitis or infection and inflammation of diverticula are a more serious condition that needs medical advice and treatment.  It can occur suddenly and without warning or as subtle discomfort that builds up. It may be a recurring problem.

Symptoms of diverticulitis include:

  • Alternating diarrhea with constipation.
  • Painful cramps or tenderness in the lower abdomen or in the lower left quadrant.
  • Chills or fever.

How Is Diverticulosis Diagnosed?

Because people with diverticulosis do not have any symptoms, it is usually found through tests ordered for an unrelated reason. The standard test to diagnose it is a Colonoscopy, (a flexible tube with a camera that allows the internal vision of the colon). The procedure is done under sedation and therefor the discomfort is minimal.

How Is Diverticulitis Diagnosed?

If you are having the symptoms of diverticulitis, you need to see your doctor.

Your doctor will ask questions about your medical history (such as bowel habits, symptoms, diet, and current medications) and perform a physical exam, possibly including a digital rectal exam.

One or more diagnostic tests may be ordered. Tests may include X-rays, CT scanning, ultrasound testing, a sigmoidoscopy, colonoscopy, and blood tests to look for signs of infection or the extent of bleeding.

In people with rapid, heavy rectal bleeding, the doctor may perform a procedure called angiography to locate the source of the bleeding.

How Is Diverticulosis Treated?

People who have diverticulosis without symptoms or complications do not need specific treatment, yet it is important to adopt a high-fiber diet to prevent the further formation of diverticula.

Laxatives should not be used to treat diverticulosis and enemas should also be avoided or used infrequently.

What Are the Complications of Diverticulitis?

Serious complications can occur as a result of diverticulitis. Most of them are the result of the development of a tear or perforation of the intestinal wall. If this occurs, intestinal waste material can leak out of the intestines and into the surrounding abdominal cavity causing the following problems:

  • Peritonitis (a painful infection of the abdominal cavity)
  • Abscesses (“walled off” infections in the abdomen) and fistulae when the abscess opens up to the surface or another cavity.
  • Obstruction (blockages of the intestine)


  • Hospital admission is required for people with diverticulitis when:
    • Pain cannot be managed with usual pain killers.
    • Hydration cannot be easily maintained with oral fluids, or oral antibiotics cannot be tolerated.
    • The person is frail or has a significant comorbidity that is likely to complicate their recovery, particularly if they are immunocompromised.
    • There is rectal bleeding that may require transfusion.
    • Perforation and peritonitis occur.
    • An intra-abdominal abscess or fistula develops.
    • Symptoms persist after 48 hours despite conservative management at home.
  • For people treated at home:
    • Broad-spectrum antibiotics should be prescribed to cover anaerobes and Gram-negative rods, e.g. co-amoxiclav or a combination of ciprofloxacin and metronidazole (if allergic to penicillin). Antibiotic treatment should last for at least 7 days.
    • Paracetamol should be used for pain.
    • Recommend clear liquids only; gradually reintroduce solid food as symptoms improve over 2-3 days.
    • Review within 48 hours or sooner if symptoms deteriorate. Hospital admission should be arranged if symptoms persist or deteriorate.
    • Mesalazine has been shown to be more effective in improving the severity of symptoms, bowel habit, and in preventing symptomatic recurrence of diverticulitis, than antibiotics alone.


  • Most patients admitted with acute diverticulitis will respond to conservative treatment, but 15-30% will need surgery.
  • The indications for surgery are:
    • Purulent or faecal peritonitis
    • Uncontrolled sepsis
    • Fistula
    • Obstruction
    • Inability to exclude carcinoma
  • Free perforation with generalized peritonitis, although uncommon, carries a high mortality rate (up to 35%) and needs urgent surgical intervention.
  • Risk of recurrent symptoms after an attack of acute diverticulitis is about one in three. Recurrent attacks are less likely to respond to medical treatment and have a high mortality rate. Although often recommended, recent evidence indicates that prophylactic resection has little impact in preventing subsequent complications, as most patients who need urgent surgery have no history of diverticular disease.
  • For emergency surgery, a recent multicentre randomised controlled trial found that a one-stage procedure (primary anastomosis) significantly reduced rates of postoperative peritonitis and emergency re-operation compared with a two-stage procedure (formation of an end colostomy with oversewing of the rectal stump – Hartmann’s procedure).