Christopher N. Andrews, MD, Gastroenterology Fellow, Faculty of Medicine, University of Calgary, Calgary, AB.
Eldon A. Shaffer, MD, FRCPC, Professor of Medicine, Division of Gastroenterology, Faculty of Medicine, University of Calgary, Calgary, AB.

Introduction
Diverticular disease of the colon (or diverticulosis) is an anatomical description of saccular outpouchings of mucosa through the wall of the colon. It is very common in the Western world, and its prevalence is rising. This paper will briefly review the epidemiology and pathophysiology of diverticular disease, followed by a focus on the diagnosis and management of the two most common complications of the disease: diverticulitis and diverticular bleeding.

Epidemiology
The true prevalence of diverticulosis is unknown, but autopsy reports suggest that up to half of patients over 60 years are affected.¹ The frequency increases with age and is much higher in developed societies in which fibre intake is lower. In the Western world, the most commonly affected site in the colon is the sigmoid colon, sometimes with more proximal involvement.² However, in Asian countries diverticulae tend to be right-sided (in the ascending colon) and fewer in number. The reason for this difference is unknown.

Pathophysiology
The colon is made up of circumferential and longitudinal (taenia coli) muscle layers, which act in unison to propel stool towards the rectum.

Nariman Malik, BSc

Diverticular disease of the colon had been a rare clinical entity before the twentieth century. Currently, diverticulosis is the most common condition affecting the intestine.¹ The incidence of diverticular disease increases with age from approximately 9% in those younger than 50 to 50% in those over the age of 70.² Diverticular disease is almost exclusively seen in populations that consume low fibre diets such as those common in Western society. Interestingly, these conditions are less common in vegetarians than in non-vegetarians. There is no associated risk with smoking, caffeine, or alcohol use.³

A diverticulum is defined as a sac-like protrusion of the colonic wall. Colonic diverticuli are formed by the herniation of the mucosa and submucosa through the muscularis mucosa. They tend to develop at points where the vasa recta penetrates the circular muscle layer.

Diverticular disease is a spectrum of diseases that encompass three clinical multi-faceted conditions: diverticulosis, diverticulitis, and diverticular bleeding. Each condition has a unique set of presenting symptoms and an individualized course of management (see Table 1).