Gastrointestinal Bleeding, Occult

For further information, see CMDT Part 15-07: Gastrointestinal Bleeding

Key Features

• 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

• Positive FOBT or FIT test

• Iron deficiency anemia

Diagnosis

• 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

• 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