New or changing symptoms often mean that additional treatment is needed to keep ulcerative colitis under control. For this reason, people who have ulcerative colitis should be in frequent contact with their physicians. Common symptoms that require a doctor's immediate attention are fever, which could indicate infection or a ruptured intestine, and heavy bleeding from the rectum. A serious, but uncommon, complication, called megacolon, results when the colon inflammation is so severe that it stops the colon's motion. Megacolon causes the abdomen to swell, which can cause vomiting or severe abdominal pain and bloating. Megacolon requires emergency treatment.