Gastrointestinal Bleeding, Occult

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)

Positive FOBT or FIT test

Iron deficiency anemia

Capsule endoscopy is recommended as the initial study

Colonoscopy with or without upper endoscopy is indicated

• For all adults with positive FOBT or FIT test or iron deficiency anemia

• For those with family history of GI cancer

• For premenopausal women and younger men with GI symptoms

• 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 a small intestine source is identified, push enteroscopy, balloon-assisted enteroscopy, abdominal CT, angiography, or laparotomy are pursued, as indicated

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