Diverticular Disease of the Colon

This disease usually affects the sigmoid colon, which is in the lower left side of the abdomen.  It can also occasionally affect the rest of the bowel.

It is an extremely common condition in western society and is associated with the western style diet i.e. a low fibre diet.


  1. Small pockets protrude through the wall of the bowel.  The pocket consists of the inner lining and outer covering of the bowel wall, which have penetrated between the muscles.  The opening of the pocket or diverticulum is called the mouth.
  2. The muscle wall of the bowel becomes very thick through the bowel, and the bowel becomes narrow.


As the pressure within the bowel increases because the bowel becomes narrower, the pressure causes these pockets to protrude between the muscle bowel walls.

The Diverticular disease is extremely common and many people have these pockets without experiencing any problems whatsoever.  However, they then may develop cramping, left lower abdominal discomfort, diarrhoea and some urgency of motion.  Even watery diarrhoea can occur.  The condition affects both men and women and in western society it is occurring at an earlier earlier age.

Thus in summary Diverticular disease consists of pockets in the bowel as a result of increased pressure associated with spasm and hypertrophy of the muscle and firm stools.

When these diverticular become inflamed the condition is called Diverticulitis.

The discomfort can be quite disabling for patients.  Worse however is that when complications develop.  These complications may be:

  1. An abscess, this can cause severe pain in the central or lower left side of the abdomen.  There may be an elevated temperature with either constipation or diarrhoea.Less commonly this abscess can burst resulting in generalised inflammation of the abdominal cavity – peritonitis or local peritonitis.  Here surgery may be required in an emergency situation.
  2. Haemorrhoids.  Inflammation may damage arteries near the mouth of the pocket causing bleeding.  This bleeding can be quite heavy and require hospitalisation.  The bleeding needs to be differentiated from other causes of bleeding from the bowel, such as bowel cancer.

Other Complications

The inflammation causes organs within the abdomen to stick together leading to bowel obstruction or even a fistula – this is an abnormal communication between the bowel and such organs as the bladder or vagina.  A fistula is an abnormal communication between two structures.

What the Patient Notices

Prominent symptoms are – pain and alteration of bowel habit.  There are various combinations together with bleeding.

Other conditions, which need to be excluded, are bowel polyp and cancers.

When the patient presents to the doctor, abdominal examination and a rectal examination with a glove, then a sigmoidoscopy are all helpful steps in the investigations.  X-rays may be required particularly if there is bowel obstruction or evidence of perforation.

In the less acute case a barium enema – particularly where colonoscopy is not available, can be helpful and has a typical appearance.

Treatment of Diverticulitis can be:

  1. Dietary – in a non-acute attack as a long-term treatment.  A high fibre diet and a bulking agent reduce the pressure.  Examples of the type of food are wholemeal bread, wholegrain cereal, peas and beans etc.  This matter of diet is a complex matter and requires consultation with a General Practitioner or a dietary expert.  A type of bulking agent is Metamucil (Psyllium).
  2. Anti-spasmodic – Colofac or Buscopan are commonly used and the diarrhoea can be treated symptomatically by such agents as Lomotil.

Diverticular Disease of the Colon

What is diverticular disease?

This is a condition where the internal lining of the bowel(mucosa) bulges out through the external muscular wall. From the outside, sac-like pouches are seen bulging from the bowel wall. From the inside, the diverticula look like holes in the bowel wall.


The most common sites in Western countries are the sigmoid and left colon. In Asia and Africa, diverticular disease occurs more commonly on the right side.


Diverticulum = one sac-like protrusion (note: Having only a single diverticulum only is rare, this occurs more in younger people and tends to occur more on the right colon)

Diverticula = pleural of the word “diverticulum”, this is by far the most common finding in diverticular disease

Diverticulitis = Inflammation of the diverticulum

How common is diverticular disease?

Diverticular disease becomes more common as one gets older. About 1 in 3 people above 50 years old have diverticular disease.

What causes it?

A low-fibre diet is a major contributing factor. This is because a low-fibre diet leads to less bulky and drier stools. This makes it more difficult for the large bowel to push the stool along to the rectum to be stored. The muscle of the bowel wall has to contract harder and this increases the pressure within the colon. This then causes the inner lining of the bowel to bulge through weak points in the wall of the colon (The weak points are usually where the sites where small blood vessels that supply blood to the bowel wall enter)

Rarely, conditions which causes a weakness in the connective tissue of the bowel wall such as Ehlers-Danlos syndrome can lead to diverticular disease.

What trouble can diverticular disease cause?

The majority of people(70%) with diverticular disease do not have any symptoms from it. Some complain of  abdominal pain and cramps, bloating, diarrhoea, altered bowel habit and other bowel symptoms.

Diverticulitis can occur in about 20% of  all people with diverticular disease. The symptoms are usually of abdominal pain on the left side and fever.  This occurs when one of the diverticulum become blocked by hard stools and become inflamed (similar to appendicitis – although the treatment in most cases is the opposite ie with antibiotics alone and not surgery). The vast majority (75%) will have an uncomplicated course and settle within a few days of treatment (see below). Less than a third of patients will go on to develop more episodes of diverticulitis.

Rarely as a complication of diverticulitis:

  1. The diverticulum that is inflamed can burst causing either an abscess (this can be treated with antibiotics and drainage) or peritonitis (if widespread this would need to be treated with antibiotics AND surgery).
  2. A fistula can form – this means there is a communication between the bowel and another organ (skin, bladder, uterus/vagina, other parts of the bowel)

Uncommonly, diverticular disease can also lead cause heavy bleeding when the wall of the blood vessel next to it is eroded. This settles spontaneously without requiring any surgery in the vast majority of patients.

Even more rarely, it can cause the bowel to narrow leading to a partial bowel obstruction.

Differential diagnoses to consider – What other conditions can mimic symptoms of diverticular disease?

Bowel cancer (link to that section)

Irritable bowel syndrome – up to 30% of patients with diverticular disease have irritable bowel syndrome

Inflammatory bowel disease – Crohn’s disease (in the elderly, there is an association between diverticular disease and Crohn’s disease) and ulcerative colitis



Diverticular disease is often found as an incidental finding during a colonoscopy.

If someone presents with the first attack of diverticulitis or bleeding, a colonoscopy is recommended in particular to exclude bowel cancer. This is generally done after the bleeding has stopped or the attack of diverticulitis has completely settled to reduce the risk of perforation.

An alternative test would be a Barium enema but this does not allow one to the mucosa as well and would not allow biopsies to be taken if there were anything suspicious.

In an attack of severe diverticulitis, a CT scan of the abdomen with contrast is recommended to look for any abscesses.

Treatment of diverticular disease

To prevent worsening of diverticular disease, a high-fibre diet is recommended along with adequate water consumption in order to produce soft bulky stools.


Oral antibiotics for mild cases eg Keflex AND Flagyl; Augmentin DuoForte; Flagyl AND cotrimoxazole if allergic to penicillin

In severe cases, the patient would need to be admitted to hospital. Intravenous antibiotics would be required. The bowel is rested by fasting the patient and intravenous fluids is given. A low residue diet is commenced once the patient has improved clinically (ie. fever settles, pain lessens and inflammatory markers such as white cell count go down)

Elective Surgery is generally indicated if (i) there have been more than 2 attacks of diverticulitis (ii) there has been a complication during/from the episode of diverticulitis eg localized perforation, fistula (iii) there is concern that a cancer cannot be completely excluded

Emergency surgery is indicated for complications of diverticulitis such as

  1. there is generalized peritonitis from perforation
  2. bowel obstruction
  3. an abscess that cannot be drained under CT or ultrasound guidance

Diverticular abscess

This is best managed usually with either a CT or ultrasound-guided drainage of the abscess

Diverticular bleeding

This is generally managed with close observation in hospital given the risk of massive bleeding. If the patient is on medications that thin the blood (eg aspirin, Plavix, Asasantin, warfarin) – these would need to be stopped. Sometimes,  blood transfusion may be necessary.

If the bleeding continues, a red cell scan or CT scan may be necessary to localize where the bleeding is coming from. Interestingly, despite diverticula being much more common in the left side, the bleeding site is usually on the right colon. If an active bleeding vessel is found, urgent embolization of the blood vessel (blocking the bleeding blood vessel with coils or glue to stop the bleeding) via angiogram may be needed or if that expertise is not available – an urgent colonoscopy may be needed. Rarely, surgery may need to be carried out.