Perforated sigmoid diverticulitis and their abscesses often resolve spontaneously. However, large or unresolving abscesses may require percutaneous drainage under ultrasound or CT guidance. Perforation of a diverticular abscess into the peritoneal cavity will result in purulent peritonitis with localized tenderness becoming generalised peritonism.

The localized inflammatory process associated with a diverticulum may perforate through another epithelial surface to form a fistula. The commonest type of fistula associated with diverticular disease is a colovesical fistula resulting from perforation of a diverticulum into the bladder. Patients with colovesical fistulae may present without bowel symptoms but with recurrent urinary tract infections and/or pneumaturia.

Fistulation can occur into other organs, such as the vagina or small intestine, and occasionally enterocutaneous fistulae may occur.

Generalized peritonitis associated with diverticular disease is due to the presence of free pus, faeces, or both, within the peritoneal cavity. Faecal peritonitis occurs where there has been necrosis of the intestinal wall resulting in the leakage of faeces into the peritoneal cavity. Patients are often gravely ill with marked peritonism and septic shock.

Bleeding sometimes occurs from vessels at the neck of a diverticulum and tends to be profuse - such blood loss usually arises from a single diverticulum, most frequently situated in the right colon.

Diverticular disease cannot be held responsible for occult lower gastrointestinal bleeding leading to an iron deficiency anaemia; in these situations other causes should be sought, such as neoplasia or angiodysplasia.

Inflammatory changes with associated scarring from previous episodes of acute diverticulitis and smooth muscle hypertrophy may be sufficient to cause a complete blockage of the colonic lumen and precipitate acute large bowel obstruction. Incomplete obstruction resulting from scarring may result in a variable bowel habit and intermittent colicky abdominal pain. Stricturing as a result of diverticular disease can be indistinguishable from malignancy on radiological investigation.

Diverticulosis is detected readily by both barium enema and contrast enhanced computed tomography (CT). Double contrast barium enema will demonstrate diverticulae, any strictures present and may also be helpful in demonstrating the presence of fistulae.

In areas of severe diverticulosis it may be impossible to safely exclude small polyps or carcinomas, and a colonoscopy or flexible sigmoidoscopy is indicated if doubt exists. Double contrast barium enema is deferred in the presence of acute diverticulitis and is usually performed 4-6 weeks after the acute episode has settled.

In acute situations other imaging modalities such as CT and/or ultrasound scanning provide the mainstay of investigation.

Colonoscopy is easily performed as an outpatient procedure. It clearly demonstrates the presence of diverticulae and any other mucosal abnormalities. It is the procedure of choice when patients present with rectal bleeding or where a barium enema has failed to adequately delineate an area of the colon. Colonoscopy, however, may be difficult in the presence of extensive diverticular disease due to spasm, rigidity and the presence of the diverticulae themselves.

Computerised tomography and ultrasound scanning Contrast enhanced CT scanning is the investigation of choice in patients with acute diverticultis when the characteristic colonic wall thickening with inflammation of pericolic fat are frequently seen. In complicated cases, abscesses, extraluminal gas and extraluminal contrast may all be detected by CT scanning. Drainage of intra- abdominal abscesses under CT guidance is practiced in many units and can prevent the need for operative intervention in the acute setting. Ultrasound scanning, although less sensitive, can also demonstrate wall thickening and the presence of significant abscesses.

The average American consumes only 11 grams of the 25 to 30 grams of fiber recommended daily. Increasing fiber in our diet is fairly easy to do. Start by choosing Diverticulitis Foods whole-grain cereals and breads. Eat whole fruits instead of juices, and increase the amount of vegetables in your diet. Eat the peel on the fruits and vegetables you can tolerate. Leave the skin on potatoes when making mashed potatoes. Avoid processed foods. When having rice with dinner, choose whole-grain brown rice in lieu of the prepared Rice-a-Roni or Minute variety.

Analyze recipes for ways to increase the fiber. For example, instead of bread crumbs in meatloaf, use uncooked oats. While each change may only make the difference of a gram or two of fiber, by the end of the day you may reach your goal of 25 to 30 grams. In addition to decreasing your risk of diverticulitis, you’ll be reducing your risk of some types of cancer, heart disease and diabetes as well.

Diverticulosis of the colon is an acquired condition thought to occur as a result of disordered colonic peristalsis, leading to areas of high intra-luminal pressure that push the mucosa out through the submucosa and muscularis of the colon. This occurs at the relatively weak points at the site of entry of blood vessels through the circular muscle.

Disordered peristalsis probably results from the frequent passage of low-volume, low-residue stools. Both the circular and longitudinal muscle are characteristically hypertrophied, leading to thickening and shortening of the colon. Diverticulae and muscular hypertrophy are most commonly seen in the sigmoid colon but any part, or all of the colon may be affected.

The term diverticulosis simply describes the presence of diverticulae and no symptoms need be present. Diverticulitis describes the clinico- pathological condition associated with inflammation of diverticulae. Diverticular disease is an all-encompassing description applicable to diverticulosis and its complications.

Diverticulosis is uncommon in patients under 30 years of age, but its prevalence increases with age and by the age of 50 years up to 30 per cent of the population will have diverticulae in their colon. Men and women are equally affected.

Only 20 per cent of those with diverticulosis will ultimately develop symptoms. Diverticulosis is a ‘disease’ of Western populations, its development being strongly associated with an inadequate dietary fiber intake - it is less commonly seen in vegetarians, and is rare among rural Africans.

It is thought that environmental factors, particularly diet, play an important role in pathogenesis, although unknown genetic factors may be implicated in some individuals who develop diverticulae at a young age or who have predominantly right-sided disease.

Most patients with diverticulosis will remain asymptomatic. Patients with uncomplicated diverticular disease may present with an altered bowel habit, often associated with colicky abdominal pain, flatulence and distension. These symptoms may be indistinguishable from the irritable bowel syndrome.

Acute diverticulitis is characterized by left iliac fossa pain and is usually associated with features of acute inflammation: tachycardia, pyrexia, localized peritonism and a leucocytosis. Acute diverticulitis may be complicated by localized abscess formation resulting from a perforation of an inflamed diverticulum. Such patients may present with swinging pyrexia and a tender mass.