HOW ARE CD & UC DIFFERENT

When thinking about diagnosis and testing, it is helpful to think about some of the differences between Ulcerative Colitis and Crohn’s disease:

Ulcerative Colitis

• Affects the colon (large intestine), always involving the rectum and extending upwards from there.
• Each patient differs in terms of how far up through the colon the colitis extends.

Crohn’s disease

• Crohn’s goes “from gum to bum.” It affects the entire digestive tract, including the esophagus, stomach, both the small and large intestines, and/or rectum.
• There can be normal areas interspersed with areas that are affected (inflammed).
• Some people have disease that affects the upper gut, which includes the esophagus, stomach and early part of the small intestine.
• Some have both small and large intestine involvement and others only have disease in the large intestine or small intestine.

COMPARING CD & UC

There are similarities and differences between Crohn's Disease and Ulcerative Colitis.

Besides affecting different areas of the gastrointestinal tract, other characteristics of Crohn's disease and ulcerative colitis that may differ include: symptoms, the effect of surgery, treatment options, complications or extra-intestinal manifestations and impact of smoking.

These characteristics are summarized in the table below:

	Crohn's Disease	Ulcerative Colitis
Occurrence	More females than males All ages, peak onset 15-35 years	Similar for females and males All ages, usual onset 15-45 years
Symptoms	Diarrhea, fever, sores in the mouth and around the anus, abdominal pain and cramps, anemia, fatigue, loss of appetite, weight loss	Bloody diarrhea, mild fever, abdominal pain and cramps, anemia, fatigue, loss of appetite, weight loss
Terminal ileum involvement	Common	Never
Colon involvement	Common	Always
Rectum involvement	Common	Always
Peri-anal disease	Common	Never
Distribution of disease	Patchy areas of inflammation	Continuous areas of inflammation but can be patchy once treated
Endoscopic findings	Deep and snake-like ulcers	Diffuse ulceration
Depth of inflammation	May be transmural, extending through the entire thickness of the wall of an organ or cavity deep into tissues	Shallow, mucosal
Fistulas between organs	Common	Never
Stenosis	Common	Never
Granulomas on biopsy	Common	Never
Effect of surgery	Often return following removal of affected parts. Decreased likelihood of pregnancy.	Usually cured by removal of colon (colectomy). Decreased likelihood of pregnancy after ileoanal pouch.
Treatment options	Drug treatment (corticosteroids, immune modifiers, biologic therapies). Exclusive formula diet in children. Surgery (repair fistulas, remove obstruction, resection, and anastomosis).	Drug treatment (5-aminosalicylates, sulfasalazine, corticosteroids, immune modifiers, biologic therapies). Surgery (rectum/colon removal) with creation of an internal pouch (ileoanal pouch).
Cure	No existing cures. Maintenance therapy is used to reduce the chance of relapse.	Through colectomy only. Maintenance therapy is used to reduce the chance of relapse.
Bowel complications	Blockage of intestine due to swelling or formation of scar tissue. Abscesses, sores, or fistulas. Malnutrition. Colon cancer	Bleeding from ulcerations. Perforation (rupture) of the bowel. Malnutrition. Colon cancer
Extra-intestinal disease	Osteoporosis. Liver inflammation (primary sclerosing cholangitis). Blood clots. Pain and swelling in the joints (arthritis). Growth failure (in children). Mental Illness	Liver inflammation (primary sclerosing cholangitis). Blood clots. Eye inflammation (iritis). Pain and swelling in the joints (arthritis). Mental illness.
Smoking	Higher risk of acquiring for smokers	Higher risk of acquiring for ex-smokers
Mortality risk	Increased risk of colorectal cancer and overall mortality. Increased risk of lymphoma and skin cancer (due to treatments).	Increased risk of colorectal cancer. Uncertain change in mortality risk. Increased risk of lymphoma and skin cancer (due to treatments).