Ischemic colitis and rectal bleeding

Both pages describe inflammation that starts with blood flow, not with a swollen vein. ahem has not examined anyone and does not provide hospital care. Bright red bleeding with a bowel movement, as the hemorrhoid pages describe it, is on internal and external hemorrhoids.

Mayo Clinic dates its ischemic colitis page November 7, 2024. Opened October 30, 2026, it says blood flow to part of the large intestine is temporarily reduced, so cells in the colon do not get enough oxygen. It also calls this colonic ischemia. Any part of the colon can be affected. Pain on the left side of the belly is the common pattern. The page says ischemic colitis can be hard to diagnose because it can be confused with other digestive problems.

Cleveland Clinic lists a last update of November 29, 2022. Opened October 30, 2026, it says ischemic colitis is inflammation in the colon caused by reduced blood flow, and that it mainly affects the inner lining, usually in one section. It separates this from ulcerative colitis and Crohn's disease, which it says begin in the colon tissue itself. Ischemic colitis, on that page, begins in the circulation. The ulcerative colitis symptom list, including diarrhea counts, is on ulcerative colitis and rectal bleeding.

Mayo Clinic's symptom list, opened October 30, 2026, is pain, tenderness, or cramping in the belly, which can start suddenly or over time; bright red or maroon blood in the stool or, at times, passage of blood alone without stool; a feeling of urgency to move the bowels; diarrhea; and nausea. The color words, bright red or maroon, and the blood-without-stool line are Mayo Clinic's.

Cleveland Clinic's symptom list is:

• Abdominal pain and cramping.
• Abdominal swelling and tenderness.
• Diarrhea and an urgency to pass stool.
• Bloody stool.
• Low fever.
• Nausea or loss of appetite.

Low fever is on Cleveland Clinic's list. It is not on Mayo Clinic's symptom list. Bloody stool is Cleveland Clinic's wording. The bright red or maroon description was not copied onto it. Left-sided pain with fever is also how the diverticular pages describe diverticulitis. That guide is about pouches in the colon wall, on diverticular disease and bleeding. Black or tarry stool, which the upper-tract pages describe, is on black or tarry stool.

Mayo Clinic says ischemic colitis happens mostly in adults older than age 60, and that it is more common in women. It says ischemic colitis in a young adult may be a sign of a blood-clotting issue or of inflammation of the blood vessels, which it calls vasculitis. The risk of serious complications is higher when symptoms are on the right side of the belly. That pattern is less common. People with right-sided colitis, on this page, tend to have more underlying conditions, such as high blood pressure, atrial fibrillation, and kidney disease, more often need surgery, and have a higher risk of death. Mayo Clinic does not print a percentage for that higher risk.

Cleveland Clinic says it most commonly affects people older than 60 who have a history of arterial disease. Its other risk lines include type 2 diabetes, kidney failure and dialysis, low blood pressure, peripheral artery disease, blood clotting disorders, chronic constipation with fecal impaction, and cocaine use. Heavy exercise such as marathon running is on Mayo Clinic's risk list, as something that can reduce blood flow to the colon. Cleveland Clinic's outlook section also names strenuous exercise, which it calls runner's colitis, and says staying well hydrated can help an endurance athlete.

Mayo Clinic says certain medicines can lead to ischemic colitis, though this is rare. The list includes some heart and migraine medicines, hormone medicines such as estrogen and birth control, antibiotics, pseudoephedrine, opioids, cocaine and methamphetamine, certain medicines for irritable bowel syndrome, and chemotherapy medicines. Cleveland Clinic says the arteries that supply the colon are sensitive to drugs that constrict blood vessels, and that a clinician may stop medicines that contribute. Stopping a medicine belongs with that clinician.

Mayo Clinic says ischemic colitis usually gets better on its own within 2 to 3 days. In more serious cases it names tissue death, also called gangrene, a hole in the intestine or persistent bleeding, and a bowel obstruction it calls an ischemic stricture. It says most people who have ischemic colitis recover quickly and may never have another episode.

Cleveland Clinic says most people with acute ischemic colitis, 75 percent, have a relatively mild and short case that affects only the mucous lining in one segment, and that most recover fully with conservative treatment. A smaller group needs surgery. It says people with complications and with heart or kidney disease are more at risk of unfavorable outcomes and death, about 40 percent, and that the risk is not from ischemic colitis alone. It also says ischemic colitis after abdominal aortic aneurysm repair occurs in 2 percent to 3 percent of those operations, and that the mortality rate among that group is 50 percent. The 75 percent, the about 40 percent, and the 2 percent to 3 percent with a 50 percent mortality line are Cleveland Clinic's, last updated November 29, 2022 and opened October 30, 2026. They were not folded into Mayo Clinic's 2 to 3 days.

Cleveland Clinic says severe or complicated cases need emergency surgery, and that most cases are managed with intravenous fluids, antibiotics, and bowel rest. During that rest it describes no food at first, then a liquid diet, and it says to avoid foods high in fiber for that recovery period. Mayo Clinic says a person may need medicine or surgery if the colon has been damaged, and that most often ischemic colitis heals on its own. The fiber figure used for hemorrhoids is a different page and was not copied here.