Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 15-07: Gastrointestinal Bleeding + Key Features Download Section PDF Listen +++ ++ Positive fecal occult blood test (FOBT), fecal immunochemical test (FIT), or iron deficiency anemia in an adult with no visible fecal blood loss 2–6% of patients in screening programs have a positive FOBT or FIT 2% of men and 5% of women have iron deficiency anemia In premenopausal women Most common causes: menstrual and pregnancy-associated iron loss GI blood loss in 10% No cause determined in 30–50% In men and postmenopausal women Colonic blood loss in 15–30% Upper GI blood loss in 35–55% Malignancy in 10% Most common causes Neoplasms Vascular abnormalities (angioectasias) Acid-peptic lesions Infections (nematodes [especially hookworm], tuberculosis) Medications (especially NSAIDs or aspirin) Inflammatory bowel disorder or malabsorption (celiac disease) + Clinical Findings Download Section PDF Listen +++ ++ Positive FOBT or FIT test Iron deficiency anemia + Diagnosis Download Section PDF Listen +++ ++ Colonoscopy with or without upper endoscopy is indicated For all adults with positive FOBT or FIT test or iron deficiency anemia For premenopausal women and younger men with GI symptoms For those with family history of GI cancer For women with anemia disproportionate to the estimated menstrual blood loss Colonoscopy should be done first unless upper GI tract symptoms are present Upper endoscopy indicated in patients with upper GI tract symptoms or iron deficiency anemia after nondiagnostic colonoscopy If unexplained chronic GI blood loss or iron deficiency anemia persists after upper endoscopy and colonoscopy, evaluate small intestine with capsule endoscopy If a small intestine source is identified, push enteroscopy, balloon-assisted enteroscopy, abdominal CT, angiography, or laparotomy are pursued, as indicated + Treatment Download Section PDF Listen +++ ++ Colonoscopy, upper endoscopy, and small bowel enteroscopy allow Biopsy specimens to be obtained Benign and malignant neoplasms to be excluded Vascular ectasias to be cauterized endoscopically