Inflammatory bowel disease.

Inflammatory bowel disease (IBD) comprises a group of idiopathic diseases of the intestine characterized by chronic inflammation of the bowel with periods of exacerbation and remission. The 2 major categories of IBD are ulcerative colitis and Crohn's disease, and each disease is distinct both clinically and histologically. The exact cause of IBD remains unknown, but several theories have been proposed. Primary care physicians are frequently confronted with the initial diagnosis and management of patients with IBD, and medical treatment options have rapidly expanded in recent years. This article reviews the epidemiology and pathogenesis of IBD; its clinical presentations and complications, which are essential to understanding this complex disease; and the available treatment options.