What are the causes of obscure Gastrointestinal (GI) bleeding?

From the Guidelines

Obscure Gastrointestinal (GI) bleeding is most commonly caused by lesions that are overlooked in the esophagus, stomach, and colon during initial workup, or lesions in the small intestine that are difficult to visualize with conventional endoscopy and radiologic imaging.

Causes of Obscure GI Bleeding

• Lesions in the small intestine, such as angioectasias, neoplasms, and Meckel's diverticulum
• Overlooked lesions in the upper GI tract, including:
  • Cameron’s erosions in large hiatal hernias
  • Fundic varices
  • Peptic ulcer disease
  • Dieulafoy’s lesion
  • Gastric antral vascular ectasia
• Lesions missed during colonoscopy, including:
  • Angioectasias
  • Neoplasms As noted by the American Gastroenterological Association 1, these lesions can be difficult to detect and may require additional testing, such as video capsule endoscopy or CT enterography, to identify the source of bleeding. According to a study published in the Journal of the American College of Radiology 1, nonvariceal upper GI bleeding is a common cause of obscure GI bleeding, and peptic ulcer disease is the most common cause of nonvariceal upper GI bleeding. Another study published in the same journal 1 highlights the potential usefulness of CT enterography in detecting small bowel sources of GI bleeding, although its sensitivity is generally lower than that of capsule endoscopy.

From the Research

Causes of Obscure Gastrointestinal (GI) Bleeding

The causes of obscure GI bleeding can be varied and may include:

• Bleeding from the small intestine, which is a common cause of obscure GI bleeding 2
• Lesions in the gastrointestinal tract, which can cause occult gastrointestinal bleeding 2
• Gastrointestinal tract malignancy, which should be considered in patients with iron-deficiency anemia (IDA) 2
• Other entities that should be considered as part of the differential diagnosis in patients with obscure-overt GI bleeding 3

Diagnostic Approach

The diagnostic approach to obscure GI bleeding typically involves:

• Endoscopic evaluation of the entire bowel, including esophagogastroduodenoscopy and colonoscopy with endoscopic evaluation of the terminal ileum 3, 4
• Radiographic techniques, such as capsule endoscopy, double balloon enteroscopy, CT, and MRI 4, 5
• Abdominal computed tomography, angiography, and radionuclide scanning may also be used 5
• Diagnostic algorithms and treatment options may vary depending on the type and location of the bleeding lesion 6

Challenges in Diagnosis

The diagnosis and management of patients with obscure GI bleeding can be challenging due to:

• The difficulty in exactly identifying the site and nature of the underlying source of bleeding 5
• The difficulty in applying effective and durable diagnostic approaches, with no single technique emerging as the most efficient way to evaluate obscure GI bleeding 5