Abscess: A collection of pus (infection) that is enclosed in an organ or other tissue in the body. In Crohn's disease, abscesses are seen in the intestines or in between the intestines and other organs. They are treated with a combination of antibiotics and surgical drainage.

Aminosalicylates: A group of medications sometimes called 5-ASAs that work against inflammation by releasing an anti-inflammatory medication inside the intestinal tract. They work by topical action.

Anal fissure: A superficial tear in the skin lining the anus or the mucosa, which can cause bleeding and pain. 

Anemia: A condition marked by low numbers of red blood cells, which carry oxygen. There are multiple causes of anemia, which include extreme fatigue, weakness, shortness of breath, dizziness or fainting, feeling cold and sadness or depression.

Anus: The opening to the outside of the body at the end of the anal canal.

Appliance: A plastic bag that is attached to an opening through the skin of the abdomen to collect waste from an ostomy.

Biologic therapies: Biologic therapies or biologics are medications that are made from a living organism or a living cell. Unlike most medications that although taken to treat one symptom, affect the whole body, biologic therapies are comprised of protein molecules engineered to target specific cells or other molecules.

Biopsy: The surgical removal of a tissue sample for examination under a microscope. Biopsies are most often done to confirm or establish a diagnosis.

Bowel: The small and large intestine.

Burrill Crohn: In 1932, along with Leon Ginzburg, M.D. and Gordon Oppenheimer, M.D., two other physicians, Dr. Burrill Crohn published the first article in the Journal of the American Medical Association describing the condition that is now known as “Crohn’s disease.”

Clinical trials: Research studies, conducted with patients, which test the effectiveness and safety of a new medical treatment, drug or device. The purpose of a clinical trial in IBD is new and improved methods of treating the disease. Clinical trials make it possible to apply the latest scientific and technological advances to patient care. They usually involve placebos and both patient and physician are unaware of which treatment the patient is receiving.

Colectomy: A procedure that surgically removes either the entire colon or part of it.

Colitis: An inflammation of the colon .

Colon: The section of the large intestine that extends from the cecum to the rectum and is responsible for removing water from digested food and converting it into a solid form (stool).

Colonoscope: A long, flexible device fitted with a light and small lens that is used to examine the lining of the colon and rectum.

Colonoscopy: A test using a colonoscope to examine the inside of the colon and rectum. Used to diagnose, guide therapy and monitor patients with IBD, colonoscopy allows the lining of the colon to be visually well-inspected, and also permits biopsies to be taken to assess inflammation, other abnormal areas and screen for colon cancer.

Colorectal cancer: A term that most often refers to cancer of the colon and cancer of the rectum. It also includes cancer of the anus.

Colostomy: A surgical procedure that allows stool to leave the body when large parts of bowel have been removed or there is a blockage in the intestine. An opening is made in the abdomen, and the colon is attached to the abdominal wall.

Constipation: A condition that is marked by the infrequent, difficult or incomplete passage of stools. Constipation means different things to each patient.

Crohn's disease: One type of the inflammatory bowel diseases, Crohn's disease can affect any part of the digestive tract from the mouth to the anus. It most frequently affects the lower part of the small intestine, called the ileum.

Crohn’s colitis: Crohn’s disease affecting the colon.

C-reactive protein (CRP): A protein in the blood that increases with inflammation. The test is used to measure activity of Crohn's disease or the response to treatment.

CT (computerized tomography) scan: Also known as a computerized axial tomography (CAT) scan, a CT scan creates pictures of structures inside the body using a computer and X-ray imaging. It is very helpful in identifying abscesses.

Diarrhea: A condition marked by frequent bowel movements that are abnormally soft and loose in consistency.

Digestive system: The system of organs that breaks down and absorbs food and is comprised of the mouth, esophagus, stomach, small intestine, large intestine, rectum and anus.

Diverticulitis: An inflammation or infection of the diverticula (small outpouchings) along the inner lining of the large intestine.

Duodenum: The first part of the small intestine, which extends from the end of the stomach to the jejunum, the second part of the small intestine.

Dysplasia: Abnormal areas of the tissues of the intestines, often precursors to cancer.

Edematous: Swelling due to fluid accumulation.

Enema: Liquid injected into the rectum and colon that can be used to clear out the bowel, produce a bowel movement or deliver medication to the lower portion of the bowel.

Endoscope: An instrument used to inspect the interior of the digestive tract.

Endoscopy: A procedure in which an endoscope is passed through the mouth or the anus to examine the digestive tract.

Enterostomal therapist: An expert in the management of stomas who works with both patients and physicians.

Erythrocyte sedimentation rate test (ESR): A blood test that measures how fast red blood cells, called erythrocytes, fall to the bottom of a test tube; the higher the sedimentation rate, the greater the inflammation.

Erythema nodosum: Red, painful nodules, usually found on the front of the legs. Often accompanies active bowel inflammation.

Erythematous: The lining of the colon in mild ulcerative colitis, which is redder than normal without the delicate pattern of blood vessels.

Extraintestinal symptoms: Symptoms of IBD that occur outside the GI tract. These can include joint swelling and pain, eye inflammation and leg lesions.

Flare: The occurrence of symptoms after a period of remission.

Fistula: A common complication of Crohn’s disease, it occurs when an abnormal connection forms between two different parts of the intestine or between two internal organs.

5-Aminosalicylates: See Aminosalicylates.

Friable: The description of the lining of the colon when the surface can bleed or ooze a small amount of blood when stroked gently with a cotton swab.

Gastroenterologist: A specialist in the diagnosis and treatment of diseases of the digestive tract, stomach and intestines.

Gastrointestinal tract: The tube that runs from the mouth to the anus, which contains organs involved in the digestive process, including: the mouth, esophagus, stomach, duodenum, small intestine, large intestine, rectum, anus, liver, biliary system and pancreas.

GI tract: Gastrointestinal tract.

Granuloma: A specific finding in an area of the GI tract. When found, it indicates Crohn’s disease.

Ileitis: Inflammation of the ileum.

Ileostomy: An operation in which an opening is created in the ileum to provide a new route for stool to exit the body into an appliance.

Ileocecal valve: The opening that separates the small intestines from the colon, called the I-C valve.

Ileum: The lower part of the small intestine where the small and large intestines connect. It is the most common site of Crohn's disease.

Immune system: A group of related responses from the body that usually protect it from disease.

Immunosuppressant agents: Drugs that decrease the activity of the immune system. Immunosuppressant agents include azathioprine (Imuran) and 6-mercaptopurine (6-MP, Purinethol and Methotrexate.)

Indeterminate colitis: The diagnosis is given when thorough medical evaluation does not clearly indicate whether an individual has Crohn’s disease or ulcerative colitis. Approximately 10 percent of patients fit into this category.

Inflammation: The response of the body's tissue to injury or irritation, marked by redness, heat, swelling and pain.

Inflammatory bowel disease: The collective term used to describe ulcerative colitis, Crohn’s disease and indeterminate colitis. IBD, as the name suggests, is a disease in which some part of the bowel (esophagus, stomach, small intestine and the colon) is inflamed.

Intestine: The part of the digestive system that transports food from the stomach to the anus. The small intestine links the stomach to the large intestine and is the primary area where nutrients from food are absorbed; the large intestine (sometimes called the colon) extends from the small intestine to the anus. It is the primary area for water reabsorption and preparing stool for elimination.

Irritable bowel syndrome (IBS): Different from IBD, IBS is a very common, chronic disorder defined by a set of symptoms in which there is, typically, a change of bowel habits with abdominal pain relieved with a bowel movement. IBS-related complaints or symptoms vary greatly between individuals and can include diarrhea, abdominal cramping, bloating and/or constipation. IBS is the accurate diagnosis when a patient presents with abdominal complaints but does not, on examination, have inflammation of the intestines.

Jejunum: The section of the small intestine that comprises the first two-fifths beyond the duodenum; it is the first major part of the small bowel, called the jejunum and the further half, called the ileum. Most of the nutritional content of food is absorbed by the small bowel, which has numerous small folds to increase its surface area and permit absorption of the food.

J pouch surgery: A surgical procedure that involves removal of the colon, upper rectum and part of the lower rectum. A new rectum or “pouch” is created out of the last part of the small bowel. The end of the bowel is turned back on itself into a “J” with the bottom of the “J” attached to the anus.

Large intestine: The large intestine extends from the small intestine to the anus and is the primary area where water is reabsorbed and stool is prepared for elimination.

Left-sided colitis: Ulcerative colitis involving the left side of the colon.

Loop ileostomy: A specific type of ostomy, which is utilized only temporarily and if often closed after healing occurs.

Megacolon: An abnormally large and swollen colon that results from severe inflammation in patients with colitis. Magacolon can be seen in several other conditions.

Molecule: The smallest particle of a substance that retains the properties of the substance and is composed of one or more atoms.

Mucosa: The inside lining of the intestines.

NOD2: The first gene associated with Crohn’s disease. The gene’s function, when normal, is to alert the cell that bacteria have broken into it, prompting the cell to produce an inflammatory response and cannot rid the cell of bacteria. Scientists recognize that NOD2 is only one of a number of genes, which are linked to IBD and which will increase our understanding of Crohn’s disease and UC.

NSAID: Non-steroidal anti-inflammatory drugs, which include medications such as Ibuprofen, Advil, Motrin, Naprosyn, Aleve, Celebrex and Vioxx. These drugs can initiate a flare.

Obstruction: A blockage that occurs in the small or large intestine, which obstructs the contents from passing through.

Ostomy: A surgical procedure in which an opening in the abdomen is created to make it possible for stool to leave the body into an appliance.

Pancolitis: Ulcerative colitis found in the entire colon.

Pathology: Tissue biopsy.

Perforation: A hole through the wall of the intestine.

Perianal: The area that surrounds the anus; the opening of the rectum to the outside of the body.

Polyp: Abnormal growths that develop on the inside wall of an organ, most commonly seen in the colon or rectum.

Proctitis: Ulcerative colitis confined to the rectum.

Proctosigmoiditis: Ulcerative colitis in much of the left side of the colon.

Pyoderma gangrenosum: Severe ulcerated skin (lesions or sores) usually on the front of the legs. A complication of colitis.

Rectum: The lower portion of the large intestine, which stores waste until it leaves through the anus.

Refractory disease: Disease that is not responding to treatment.

Remission: Disease that is controlled and is not producing symptoms.

Resection: The surgical removal of all or part of an organ.

Sigmoidoscopy: A procedure that uses a tube called a sigmoidoscope to examine the lower portion of the colon and the rectum.

Skip lesion: Areas of disease interspersed with normal areas of the small or large intestine. Usually associated with Crohn’s disease.

Small intestine: The small intestine extends from the stomach to the large intestine and is the primary area where nutrients are absorbed.

Splenic flexure: The area on the left side of the body that makes a turn from the descending colon into the transverse colon.

Steroids: Medications used to combat inflammation and suppress immune response. Steroids work quickly and dramatically but can have serious short- and long-term side effects.

Stool: Mostly solid waste from the digestive tract; feces.

Stoma: An opening through the skin in the abdomen, which is created by a surgeon during an operation (ostomy).

Stricture: The abnormal narrowing or scarring of a body passage, such as the small and large intestine.

Tenesmus: Urgency for frequent evacuation.

Terminal ileum: The end of the small intestine.

Ulcer: A break in the skin, or in the lining of the gastrointestinal (GI) tract.

Ulcerative colitis: An inflammatory bowel disease that causes inflammation in the large intestine. Ulcerative colitis shares many characteristics with Crohn's disease, but the two conditions are separate. Ulcerative colitis affects only the colon. The small bowel is not involved. Inflammation in the colon is found only superficially in the lining of the colon, but not through the whole wall, as occurs in Crohn’s disease. The extent of inflammation varies in each individual. In some, it may involve just the rectum (Iproctitis) the left side ( of variable extent) or the entire colon (pan-colitis). Symptoms depend on the extent and the severity of inflammation and include rectal bleeding and urgency to evacuate, diarrhea, abdominal cramping and joint pain/swelling, eye inflammation and skin lesions.

Upper GI series and small bowel follow-through: A series of X-rays that evaluates the esophagus, stomach and small intestine (upper GI tract).