Ulcerative colitis (UC) is a long-term disease of the large intestine or colon. While the condition itself is not fatal, it can cause life threatening complications in rare instances.

UC is a type of inflammatory bowel disease (IBD). It may affect as many as 907,000 people in the United States, according to the Crohn’s & Colitis Foundation (CCF) advocacy group.

In this article, we look at the potential complications of UC. We also cover the symptoms of each complication to help people with UC detect serious problems early and get urgent care where necessary.

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Although UC is a lifelong condition, it is not usually life threatening.

There is no cure for UC, but treatments can help prevent flare-ups or episodes of symptoms. Treatment can also allow people to achieve and maintain symptom-free periods known as remission.

However, UC can increase a person’s risk of developing severe complications, especially if the disease does not respond to treatment.

A person with UC may have a higher risk of the following health problems:

Toxic megacolon

Although it is rare, doctors consider toxic megacolon the most serious complication of IBD.

Toxic megacolon occurs when inflammation of the colon causes it to enlarge. This enlargement prevents the colon from contracting correctly, resulting in a buildup of gas.

As the colon swells with gas, it is increasingly likely to burst. If the colon bursts, it can release harmful bacteria and toxins into the bloodstream.

Symptoms

Symptoms of toxic megacolon include:

Without prompt treatment, toxic megacolon can cause the following life threatening complications:

  • perforation of the colon, which is a hole or tear in the colon
  • bleeding and blood loss
  • sepsis
  • shock

Signs of shock include:

  • a weak pulse
  • clammy skin
  • dilated pupils
  • confusion
  • rapid or shallow breathing

Perforation of the colon

Long-term inflammation and ulcers in the colon can weaken the intestinal wall. Over time, these weaknesses may develop into a perforation.

A perforation can allow bacteria and other intestinal contents to leak out into the abdomen, causing a serious condition called peritonitis.

Peritonitis is the inflammation of the peritoneum, the lining of the abdomen. This condition may cause the abdomen to fill with fluid. It can also lead to blood poisoning and sepsis, which is a whole-body inflammatory response to infection.

One in three people who develop sepsis dies from the condition.

Symptoms

Knowing the symptoms of a perforated colon is vital to help prevent peritonitis and sepsis. According to the Sepsis Alliance, these may include:

  • severe stomach pain
  • nausea
  • vomiting
  • chills
  • fever

A perforated colon is a medical emergency that usually requires surgery to repair the hole in the intestines.

People who experience sepsis also require urgent treatment with antibiotics and fluids.

Colorectal cancer

According to the CFF, between 5 and 8% of people with UC will develop colorectal cancer within 20 years of their diagnosis.

The increased risk of developing colorectal cancer is most likely to affect people with severe UC and those who have had symptoms for 8 to 10 years.

People who have not received treatment for UC also have a higher risk of colorectal cancer.

People with these risk factors are more likely to develop dysplasia, where abnormal cells are present in the lining of the colon or rectum. These abnormal cells may become cancerous over time.

The CFF recommends people with UC take the following steps to reduce their risk of colorectal cancer:

  • having a colonoscopy every 1 to 2 years
  • visiting a gastroenterologist at least once a year
  • discussing symptoms and concerns during regular checkups
  • continuing to take their prescribed medications even if they feel better
  • notifying a doctor if a family member develops colorectal cancer
  • exercising regularly
  • eating a balanced diet

Symptoms

A person with colorectal cancer may experience one or more of the following symptoms:

  • diarrhea or constipation that lasts more than a few days
  • a constant feeling of needing to empty the bowels
  • rectal bleeding with bright red blood
  • dark stools
  • abdominal pain or cramping
  • weakness and fatigue
  • unexplained weight loss

Blood clots

Numerous studies have shown that people with IBD have an increased risk of blood clot formation or thrombosis.

When a blood clot blocks a vein in a limb, this is called deep vein thrombosis (DVT). Sometimes, part of the clot can break away and travel to the lungs, which is a potentially fatal complication called a pulmonary embolism.

According to a 2015 study, people with IBD have a risk of thrombosis up to three times higher than that of a person who does not have IBD.

Doctors do not know exactly why IBD increases the risk of these blood clots. However, chronic inflammation may trigger a chemical reaction that thickens the blood, increasing the likelihood of clots forming.

According to a 2015 review, the following factors may also increase the risk of blood clots in people with IBD:

Symptoms

The symptoms of DVT include:

  • swelling and tenderness in a limb
  • a limb that is warm to the touch
  • skin discoloration

Symptoms of a pulmonary embolism include:

  • rapid heart rate
  • sudden shortness of breath
  • sharp chest pain that worsens with deep breathing
  • a cough with bloody mucus

Anyone who experiences any of the above symptoms should seek emergency medical attention.

Primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a condition that involves inflammation and damage to the bile ducts. The bile ducts transport digestive enzymes from the liver into the digestive system.

PSC affects about 3% of people with IBD. It generally only occurs when the bowel disease is extensive.

PSC is a lifelong disease that typically progresses slowly. It also increases the risk of some potentially life threatening complications.

Symptoms

Common symptoms of PSC include:

  • fatigue
  • depression
  • jaundice, a yellowing of the eyes and skin
  • intense itching, especially on the palms of the hands or soles of the feet
  • chills
  • fever

In the later stages of PSC, a person may experience the following complications, which can indicate severe liver disease:

ConditionDescriptionSymptoms
variceal bleedingbleeding from the veins in the esophagus (food pipe)anemia
• vomiting blood
• black stools
ascitesfluid in the abdomen• abdominal pain and discomfort
• difficulty breathing
hernias
hepatic encephalopathybrain changes due to harmful levels of toxins in the blood• confusion
• forgetfulness
• personality or mood changes
• poor concentration
• changes in sleep patterns
• slow movement
• seizures
• slurred speech

A person who experiences any of the above symptoms should seek urgent medical attention. Severe liver disease can be life threatening.

Although doctors do not usually classify UC as a life threatening disease, having this condition can increase the risk of more severe health complications.

Knowing the symptoms of UC complications can better equip people to detect any changes in their health.

Early recognition of these symptoms can allow people with suspected complications to seek treatment without delay.

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