Ischemic colitis in a young woman following colonoscopy

The colon, or large intestine, is the final segment of the digestive system. Its primary functions include absorbing water and vitamins produced by gut bacteria and transforming waste from liquid to solid to form stool. In adults, the large intestine is approximately 5 feet long and consists of four main sections:

Ulcerative colitis is a chronic inflammatory disorder of the colon characterized by continuous mucosal inflammation that typically begins in the rectum and extends proximally in a uniform pattern. Its pathogenesis involves a complex interplay of genetic predisposition, immune dysregulation, and environmental influences. These factors converge to impair the colon’s epithelial defenses and promote an exaggerated inflammatory response against luminal contents.Breakdown of the Mucosal...

Introduction
Inflammatory bowel disease, or IBD, encompasses a group of disorders characterized by chronic inflammation or ulceration of the gastrointestinal tract.
Risk Factors
The exact cause of IBD remains unclear, although it is believed to be due to a mix of genetic, environmental, microbial, and immune factors. Genetic factors are significant in determining susceptibility to IBD, with family history being a critical risk factor. Individuals with a first-degree relative who has IBD are at...

Diverticular disease involves the formation of diverticula—small sac-like outpouchings of the colonic wall—and their complications. It most commonly affects the sigmoid colon due to higher intraluminal pressure and structural vulnerability. It results from structural weakness and increased pressure in the colon, producing pseudodiverticula that may remain silent or progress to inflammation and serious complications.Structure of DiverticulaIn diverticulosis, these outpouchings are...

Crohn’s disease is a chronic, relapsing form of inflammatory bowel disease characterized by segmental, transmural inflammation that can affect any part of the gastrointestinal tract. Its pathogenesis arises from a combination of genetic susceptibility, environmental exposures, epithelial barrier dysfunction, and immune dysregulation. Together, these factors lead to an exaggerated immune response against components of the gut microbiome.Genetic and Environmental InfluencesMultiple genetic...

Various diagnostic tests are employed in the diagnostic process for Inflammatory Bowel Disease (IBD), particularly to differentiate between Crohn's disease and ulcerative colitis.
Diagnostic studies
A colonoscopy is the definitive screening test, distinguishing ulcerative colitis from other colon diseases with similar symptoms. During a colonoscopy test, inflamed mucosa with exudate ulcerations can be observed, and biopsies are taken to determine the histologic characteristics of the...