Evaluation of the Diagnostic Role of Enteroscopy in Small Intestinal Diseases at Al-Rajhi University Hospital

The small bowel is vital for digestion and absorption and is located between the stomach and large bowel. Because of its anatomical position, the small bowel was originally thought to be a "blind area" beyond the reach of ordinary endoscopic examination, leading to difficulty in diagnosing smallbowel disease.

Diseases that affect the intestinal wall are called enteropathies and can be associated with chronic diarrhea, which clinically presents in that group of patients as malabsorption syndrome and can be divided into:

1. Autoimmune causes: They include celiac disease, Crohn's disease, and other autoimmune enteropathies that affect one or several areas of the intestine.
2. Drugs: Of the antihypertensive, especially olmesartan, NSAIDs, immunosuppressant, such as azathioprine, methotrexate as well as the checkpoint inhibitors, such as nivolumab
3. Radiotherapy (RT): Up to 20% of the patients exposed to RT can develop intestinal damage; it typically occurs between 1 and 6 years, post-exposure, and is dose-dependent, usually presenting when the dose exceeds5000 cGy (centi-Gray).
4. Infectious causes: They include tropical sprue, SIBO, giardiasis, Whipple's disease, human immunodeficiency virus infection and associated opportunistic germs, tuberculosis, post-viral enteropathies, and lymphocytic enteritis associated with Helicobacter pylori infection.
5. Infiltrative and neoplastic disorders: They include eosinophilic enteritis, collagenous sprue, amyloidosis, T cell or B cell lymphoma associated with enteropathies, ymphoproliferative intestinal lymphoma, and some vasoactive substance-producing neuroendocrine tumors, especially gastrinomas, VIPomas, and intestinal carcinoid tumors.
6. Miscellaneous causes: They include conditions as diverse as peptic duodenitis, food allergies, malnutrition, lymphangiectasis, common variable immunodeficiency, or idiopathic sprue, which can also cause malabsorption syndrome

For detecting neoplastic and inflammatory diseases, endoscopy is a powerful tool. However, the diagnostic yield of a routine colonoscopy examination has been reported to be as low as 15%-30% even when an appropriate histopathological examination is added with multiple biopsy specimens.

Capsule endoscopy is an innovative method for diagnosing smallbowel disease. The reported positivity rate of capsule endoscopy for diagnosing smallbowel disease is approximately 45-81% with an accuracy rate of approximately 20-30%. However, biopsy is not possible using this approach, the precise lesion location cannot be determined, and endoscopic therapy is not possible, which limit its use.