Colonic diverticular disease: pathophysiology and clinical picture

Colonic diverticulosis is the most frequent structural abnormality of the large bowel, although it was a rarity before the 20th century. Lifestyle changes in westernized societies with reduced fiber diet are supposed to be the main cause for its high prevalence nowadays. In African countries, where staple diet is rich in fiber, diverticulosis remains very infrequent. Prevalence increases with ageing too. A fiber-deficient diet and subsequent reduction in bowel content volume would lead to increased intraluminal pressures and colonic segmentation, thus promoting diverticula formation. Animal and human studies have shown increased intracolonic pressures in patients with diverticulosis. Alterations in colonic muscle properties, collagen metabolism and in the interactions of the extracellular matrix components may play a role in remodelling the gut wall in diverticular disease. At least one fourth of patients with diverticulosis will develop symptoms, sometimes overlapping with irritable bowel syndrome, but 10-25% will suffer diverticulitis and 3-5% diverticular bleeding. Conservative medical management is usually sufficient in the first episode of diverticulitis, but surgical treatment is generally advocated in recurrences. Diverticular bleeding is a major cause of lower digestive haemorrhage, but generally self-limited. With the application of therapeutic endoscopic and angiographic methods, emergency surgery can often be avoided.