What is small bowel endoscopy?

Small Bowel Endoscopy: Types, Applications, and Clinical Utility

Small bowel endoscopy refers to various endoscopic techniques that allow visualization and examination of the small intestine, with capsule endoscopy being the preferred first-line examination due to its non-invasive nature, excellent safety profile, and ability to visualize the entire small bowel mucosa. 1

Types of Small Bowel Endoscopy

Video Capsule Endoscopy (VCE)

• Description: A swallowable, pill-sized camera that captures images as it passes through the digestive tract
• Procedure:
  • Patient swallows the capsule after a 12-hour fast
  • Capsule is propelled through the GI tract via peristalsis
  • Images are transmitted to a recording device worn by the patient
  • Capsule is naturally excreted 2
• Advantages:
  • Non-invasive and well-tolerated by patients
  • Can visualize the entire small bowel mucosa
  • No sedation required
  • High diagnostic yield compared to radiological methods 3
• Limitations:
  • Cannot take biopsies or perform therapeutic interventions
  • Risk of capsule retention in patients with strictures
  • Cannot precisely localize lesions
  • Requires adequate bowel preparation 4

Device-Assisted Enteroscopy (DAE)

• Types: Double-balloon, single-balloon, or spiral enteroscopy 3
• Applications:
  • Complementary to capsule endoscopy
  • Allows for tissue sampling and therapeutic interventions
  • Used to confirm and treat lesions identified by capsule endoscopy 1
• Limitations:
  • Invasive procedure
  • Requires sedation
  • Limited depth of insertion in some cases 3

Push Enteroscopy

• Description: Extension of standard upper endoscopy using a longer endoscope
• Applications:
  • Obtaining jejunal biopsies for rare causes of diarrhea
  • Evaluating proximal small bowel lesions 3

Clinical Applications

Obscure Gastrointestinal Bleeding/Iron Deficiency Anemia

• Capsule endoscopy is recommended as first-line examination for suspected small bowel bleeding 1
• Should be performed within 48 hours of overt bleeding episode to maximize diagnostic yield 1
• Common findings include:
  • Vascular malformations (most common)
  • Small bowel tumors
  • Ulcers 4
• Device-assisted enteroscopy is recommended to confirm and treat lesions identified by capsule endoscopy 1

Crohn's Disease

• Capsule endoscopy recommended in patients with suspected Crohn's disease and negative ileocolonoscopy 1
• Patency capsule should be used before capsule endoscopy in patients with established Crohn's disease to reduce retention risk 1
• Can help assess small bowel involvement and disease extent 5

Small Bowel Tumors and Polyposis Syndromes

• Capsule endoscopy suggested for surveillance in patients with polyposis syndromes 3
• Can detect small bowel neoplasms missed by other imaging modalities 3

Celiac Disease

• Not recommended for initial diagnosis of celiac disease
• May help demonstrate villous atrophy in patients unable/unwilling to undergo gastroscopy with duodenal biopsy 3
• Useful in patients with celiac disease who have unexplained symptoms despite appropriate treatment 3

Chronic Diarrhea

• Push enteroscopy may be valuable for obtaining jejunal biopsies in rare causes of diarrhea 3
• Capsule endoscopy not recommended for chronic diarrhea without evidence of abnormal biomarkers 3

Diagnostic Algorithm

1. Initial Assessment:

   • For suspected small bowel pathology, consider non-invasive imaging first (MR enterography preferred over CT due to lower radiation exposure) 3

2. First-Line Small Bowel Examination:

   • Capsule endoscopy is recommended as first-line examination for suspected small bowel bleeding and iron deficiency anemia 1
   • For Crohn's disease with negative ileocolonoscopy, capsule endoscopy is the initial diagnostic modality 1

3. Follow-up Testing:

   • If capsule endoscopy identifies lesions requiring biopsy or treatment, proceed to device-assisted enteroscopy 1
   • If capsule endoscopy is negative but clinical suspicion remains high, consider device-assisted enteroscopy or alternative imaging 3

Important Considerations and Precautions

• Contraindications for capsule endoscopy:

  • Known or suspected GI obstruction unless intestinal patency is proven
  • Swallowing disorders
  • Pregnancy (relative contraindication) 5

• Risk of capsule retention:

  • Main complication of capsule endoscopy
  • Use patency capsule in high-risk patients (Crohn's disease, prior abdominal surgery, radiation enteritis) 1

• Bowel preparation:

  • Adequate bowel preparation is essential for optimal visualization
  • Poor preparation can lead to missed lesions 4

• Limitations in localization:

  • Capsule endoscopy has limited ability to precisely localize lesions
  • Complementary imaging may be needed for localization prior to intervention 4

By understanding the various types and applications of small bowel endoscopy, clinicians can select the most appropriate technique based on the clinical scenario to optimize diagnostic yield and patient outcomes.