Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ Key Features ++ Essentials of Diagnosis ++ Hematochezia usually present Ten percent of cases of hematochezia are due to upper gastrointestinal source Stable patients can be evaluated by colonoscopy Massive active bleeding calls for evaluation with sigmoidoscopy, upper endoscopy, angiography, or nuclear bleeding scan ++ General Considerations ++ Lower GI bleeding defined as that arising below the ligament of Treitz, ie, small intestine or colon; up to 95% of cases derive from the colon Lower tract bleeding 33% less common than upper tract bleeding Tends to have a more benign course Is less likely to present with shock or orthostasis (< 20%) or to require transfusions (< 40%) Spontaneous cessation in > 75%; hospital mortality in < 4% Most common causes in patients < 50 years Infectious colitis Anorectal disease Inflammatory bowel disease Most common causes in patients > 50 years Diverticulosis (over 50% of cases) Angioectasias (5%) Neoplasms (polyps or carcinoma) (7%) Ischemia Radiation-induced proctitis Solitary rectal ulcer Nonsteroidal anti-inflammatory drug (NSAID)-induced ulcers Small bowel diverticula Colonic varices Risk of lower GI bleeding is increased in patients taking Aspirin Nonaspirin anti-platelet agents Nonsteroidal anti-inflammatory drugs (NSAIDs) Diverticular bleeding Acute, painless, large-volume maroon or bright red hematochezia occurs in 3–5% of patients with diverticulosis, often associated with the use of NSAIDs Bleeding more commonly originates on the right side > 95% require less than 4 units of blood transfusion Bleeding subsides spontaneously in 80% but may recur in up to 25% of patients Angioectasias Painless bleeding ranging from melena or hematochezia to occult blood loss Bleeding most commonly originates in the cecum and ascending colon Causes: congenital; hereditary hemorrhagic telangiectasia; autoimmune disorders, typically scleroderma Neoplasms: benign polyps and carcinoma cause chronic occult blood loss or intermittent anorectal hematochezia Anorectal disease Small amounts of bright red blood noted on the toilet paper, streaking of the stool, or dripping into the toilet bowl Clinically significant blood loss can sometimes occur Ischemic colitis Hematochezia or bloody diarrhea associated with mild cramps In most cases, bleeding is mild and self-limited ++ Demographics ++ Diverticular bleeding is more common in patients > 50 years Angiodysplasia bleeding is more common in patients > 70 years and with chronic kidney disease Ischemic colitis is most commonly seen In older patients due to atherosclerotic disease—postoperatively after ileoaortic or abdominal aortic aneurysm surgery In younger patients due to vasculitis, coagulation disorders, estrogen therapy, and long-distance running ++ Clinical Findings ++ Symptoms and Signs ++ Brown stools mixed or streaked with blood suggest rectosigmoid or anal source Painless large-volume bleeding suggests diverticular bleeding Maroon stools suggest a right colon or small intestine source Black stools (melena) suggest a source proximal to the ligament of Treitz, but dark maroon stools arising from small intestine or right colon may be misinterpreted as "melena" Bright red blood per rectum occurs uncommonly with upper tract bleeding and almost always in the setting ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessMedicine 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessMedicine Full Site: One-Year Individual Subscription $995 USD Buy Now View All Subscription Options