IBD
See Inflammatory Bowel Disease (IBD).

IBS
See Irritable Bowel Syndrome (IBS).

Ileal
(IL-ee-ul)
Related to the ileum, the lowest end of the small intestine.

Ileal Pouch
See Ileoanal Reservoir.

Ileitis
See Crohn's Disease.

Ileoanal Anastomosis
See Ileoanal Pull-Through.

Ileoanal Pull-Through
An operation to remove the colon and inner lining of the rectum. The outer muscle of the rectum is not touched. The bottom end of the small intestine (ileum) is pulled through the remaining rectum and joined to the anus. Stool can be passed normally. Also called ileoanal anastomosis.

Ileoanal Reservoir
An operation to remove the colon, upper rectum, and part of the lower rectum. An internal pouch is created from the remaining intestine to hold stool. The operation may be done in two stages. The pouch may also be called a J-pouch or W-pouch.

Ileocecal Valve
A valve that connects the lower part of the small intestine and the upper part of the large intestine (ileum and cecum). Controls the flow of fluid in the intestines and prevents backflow.

lleocolitis
Irritation of the lower part of the small intestine (ileum) and colon.

Ileostomy
An operation that makes it possible for stool to leave the body after the colon and rectum are removed. The surgeon makes an opening in the abdomen and attaches the bottom of the small intestine (ileum) to it.

Ileum
The lower end of the small intestine.

Impaction
The trapping of an object in a body passage. Examples are stones in the bile duct or hardened stool in the colon.

Imperforate Anus
A birth defect in which the anal canal fails to develop. The condition is treated with an operation.

Indigestion
Poor digestion. Symptoms include heartburn, nausea, bloating, and gas. Also called dyspepsia.

Infectious Diarrhea
Diarrhea caused by infection from bacteria, viruses, or parasites. See also Travelers' Diarrhea and Gastroenteritis.

Infectious Gastroenteritis
See Gastroenteritis.

Inflammatory Bowel Disease (IBD)
Long-lasting problems that cause irritation and ulcers in the GI tract. The most common disorders are ulcerative colitis and Crohn's disease.

Inguinal Hernia
A small part of the large or small intestine or bladder that pushes into the groin. May cause pain and feelings of pressure or burning in the groin. Often requires surgery.

Intestines
See Large Intestine and Small Intestine. Also called gut.

Intestinal Flora
The bacteria, yeasts, and fungi that grow normally in the intestines.

Intestinal Mucosa
The surface lining of the intestines where the cells absorb nutrients.

Intestinal Pseudo-Obstruction
A disorder that causes symptoms of blockage, but no actual blockage. Causes constipation, vomiting, and pain. See also Obstruction.

Intolerance
Allergy to a food, drug, or other substance.

Intussusception
A rare disorder. A part of the intestines folds into another part of the intestines, causing blockage. Most common in infants. Can be treated with an operation.

Iron Overload Disease
See Hemochromatosis.

Irritable Bowel Syndrome (IBS)
A disorder that comes and goes. Nerves that control the muscles in the GI tract are too active. The GI tract becomes sensitive to food, stool, gas, and stress. Causes abdominal pain, bloating, and constipation or diarrhea. Also called spastic colon or mucous colitis.

Ischemic Colitis
Decreased blood flow to the colon. Causes fever, pain, and bloody diarrhea.