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Understanding Ulcerative Colitis (UC)

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Ulcerative Colitis (UC) - What Is It?

What is UC?

Ulcerative colitis is a chronic, or long lasting, disease that causes inflammation—irritation or swelling—and sores called ulcers on the inner lining of the large intestine.


Ulcerative colitis is a chronic inflammatory disease of the gastrointestinal (GI) tract, called inflammatory bowel disease (IBD). Crohn's disease and microscopic colitis are the other common IBDs. Ulcerative colitis most often begins gradually and can become worse over time. Symptoms can be mild to severe. Most people have periods of remission—times when symptoms disappear—that can last for weeks or years. The goal of care is to keep people in remission long term.

Ulcerative colitis is a chronic, meaning not curable, Inflammatory Bowel Disease (IBD) affecting only large intestine (considered the colon and rectum). The disease causes inflammation and ulceration of the lining of the large intestine. This inflammation can cause tiny open sores to form on the surface of the lining which damages the tissue.


What is the large intestine?

The large intestine is part of the GI tract, a series of hollow organs joined in a long, twisting tube from the mouth to the anus—an opening through which stool leaves the body. The last part of the GI tract, called the lower GI tract, consists of the large intestine—which includes the appendix, cecum, colon, and rectum—and anus. The intestines are sometimes called the bowel.

The large intestine is about 5 feet long in adults and absorbs water and any remaining nutrients from partially digested food passed from the small intestine. The large intestine changes waste from liquid to a solid matter called stool. Stool passes from the colon to the rectum. The rectum is located between the lower, or sigmoid, colon and the anus. The rectum stores stool prior to a bowel movement, when stool moves from the rectum to the anus and out of a person's body.


What causes ulcerative colitis?

The exact cause of ulcerative colitis is unknown. Researchers believe the following factors may play a role in causing ulcerative colitis: #1. overactive intestinal immune system (an autoimmune disorder), #2. genes and #3. environment. It is important to note that a significant amount of research data tends to be more congruent with, or suggestive of, factor #1 compared to #2 or #3.

Overactive intestinal immune system: Scientists believe one cause of ulcerative colitis may be an abnormal immune reaction in the intestine. In short, the majority of research points to UC as an autoimmune disorder. Normally, the immune system protects the body from infection by identifying and destroying bacteria, viruses, and other potentially harmful foreign substances. Researchers believe bacteria or viruses can mistakenly trigger the immune system to attack the inner lining of the large intestine. This immune system response causes the inflammation, leading to symptoms.


Genes: Ulcerative colitis sometimes runs in families. Research studies have shown that certain abnormal genes may appear in people with UC. However, researchers have not been able to show a clear link between the abnormal genes and ulcerative colitis.


Environment: Some studies suggest that certain things (poorly-defined triggers) in the environment may increase the risk of someone already predisposed to developing UC to develop the condition. However, these studies are very controversial, and overall chance of this actually occurring is extremely low.

Who is more likely to develop ulcerative colitis?

Ulcerative colitis can occur in people of any age. However, it is more likely to develop in people: between the ages of 15 and 30, older than 60, who have a family member with IBD and/or are of Jewish descent.


What are the signs and symptoms of ulcerative colitis?

The most common signs and symptoms of ulcerative colitis are diarrhea with blood or pus and abdominal discomfort. Other signs and symptoms include: an urgent need to have a bowel movement, feeling tired, nausea or loss of appetite, weight loss, fever and   anemia—a condition in which the body has fewer red blood cells than normal.

Less common symptoms include: joint pain or soreness, eye irritation, certain rashes.


The symptoms a person experiences can vary depending on the severity of inflammation and where it occurs in the intestine. When symptoms first appear, most people with ulcerative colitis have mild to moderate symptoms and ~10% of people have severe symptoms, such as frequent, bloody bowel movements; fevers; and severe abdominal cramping


How is ulcerative colitis diagnosed?

A health care provider diagnoses ulcerative colitis with the following: medical and family history, physical exam, lab tests and endoscopies of the large intestine The health care provider may perform a series of medical tests to rule out other bowel disorders, such as irritable bowel syndrome, Crohn's disease, or celiac disease, that may cause symptoms similar to those of UC.

  • Medical and Family History: Taking a medical and family history can help the health care provider diagnose ulcerative colitis and understand a patient's symptoms. The health care provider will also ask the patient about current and past medical conditions and medications.

  • Physical Exam: A physical exam may help diagnose UC. During a physical exam, the health care provider most often: checks for abdominal distension (swelling), listens to sounds within the abdomen and/or taps on the abdomen to check tenderness and pain.

  • Lab Tests: A health care provider may order lab tests to help diagnose ulcerative colitis, including blood and stool tests.

  • Blood tests: A blood test involves drawing blood at a health care provider's office or a lab. A lab technologist will analyze the blood sample. A health care provider may use blood tests to look for: anemia, inflammation or infection somewhere in the body, markers that show ongoing inflammation and/or low albumin, or protein—common in patients with severe ulcerative colitis.

  • Stool tests: A stool test is the analysis of a sample of stool. A health care provider will give the patient a container for catching and storing the stool at home. The patient returns the sample to the health care provider or to a lab. A lab technologist will analyze the stool sample. Health care providers commonly order stool tests to rule out other causes of GI diseases, such as infection.

  • Endoscopies of the Large Intestine: Endoscopies of the large intestine are the most accurate methods for diagnosing ulcerative colitis and ruling out other possible conditions, such as Crohn's, diverticular disease, or cancer. Endoscopies of the large intestine include colonoscopy and flexible sigmoidoscopy procedures.

    • Colonoscopy: CLICK HERE for a comprehensive understanding of colonoscopies

    • Flexible sigmoidoscopyCLICK HERE for a full understanding of flexible sigmoidoscopies.


How is ulcerative colitis treated?

  • A GI doctor usually treats UC with medications, infusion therapies, and/or surgery (if necessary). 

  • Which treatment a person needs depends on the severity of the disease and the symptoms.

  • Each person experiences ulcerative colitis differently, so health care providers adjust treatments to improve the person's symptoms and induce, or bring about, remission.

  • Surgery: Some people will need surgery to treat their ulcerative colitis when they have: colon cancer, dysplasia (precancerous cells in the colon), complications that are life threatening, such as megacolon or bleeding, no improvement in symptoms or condition despite treatment, continued dependency on steroids and/or side effects from meds that threaten their health.

What are the complications of ulcerative colitis?

Complications of ulcerative colitis can include:

  • Rectal bleeding—when ulcers in the intestinal lining open and bleed. Rectal bleeding can cause anemia, which health care providers can treat with diet changes and iron supplements. People who have a large amount of bleeding in the intestine over a short period of time may require surgery to stop the bleeding. Severe bleeding is a rare complication of ulcerative colitis.

  • ​Dehydration and malabsorbtion, which occur when the large intestine is unable to absorb fluids and nutrients because of diarrhea and inflammation. Some people may need IV fluids to replace lost nutrients and fluids.

  • Osteoporosis—the loss of bone. Osteopenia—low bone density.

  • Inflammation in other areas of the body e.g., joints, eyes, skin and liver.

  • Megacolon—a serious complication that occurs when inflammation spreads to the deep tissue layers of the large intestine. The large intestine swells and stops working. Megacolon can be a life-threatening complication and typically requires surgery. This is a rare complication of UC.

Ulcerative Colitis and Colon Cancer

People with ulcerative colitis may be more likely to develop colon cancer when: UC affects the entire colon, a person has ulcerative colitis for at least 8 years, inflammation is ongoing, people also have primary sclerosing cholangitis, a condition that affects the liver and/or a person is male


People who receive ongoing treatment and remain in remission may reduce their chances of developing colon cancer.


People with ulcerative colitis should talk with their health care provider about how often they should get screened for colon cancer. Screening can include colonoscopy with biopsies or a special dye spray called chromoendoscopy.


Health care providers may recommend colonoscopy every 1 to 3 years for people with ulcerative colitis who have: the disease in 33%+ of their colon and/or have had ulcerative colitis for 8 years.


Such screening does not reduce a person's chances of developing colon cancer. Instead, screening can help diagnose cancer early and improve chances for recovery. 

How is UC treated?
What causes UC?
How is UC diagnosed?
UC signs & symptom
Who is most prone to UC?
What's the large intestine?
Potential Complications of UC
Ulcerative Colitis Treatment Atlanta
Relation to colon cancer
UC vs. Crohns difference?

What's The Difference Between UC and Crohn's Disease?

Crohn's disease can affect any part of the gastrointestinal tract, from the mouth to the anus. The inflammation of Crohn's disease can be patchy and noncontinuous and can deeply penetrate into the bowel wall. Even if the affected part of a Crohn's disease bowel is removed, the disease may recur.

Ulcerative colitis differs in that it affects only the colon. The inflammation does not go past the inner layer of the bowel wall. Ulcerative colitis can be limited to the rectum or can extend further up the large bowel. In some cases, it can affect the entire colon. The inflammation of ulcerative colitis is continuous, not patchy. UC can be completely cured by surgical removal of the colon and rectum.

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