The primary distinction between an endoscopy and an enteroscopy lies in the area of the digestive tract they examine. Both procedures utilize a flexible tube with a camera (endoscope); however, an endoscopy typically investigates the upper gastrointestinal tract, including the esophagus, stomach, and duodenum. In contrast, an enteroscopy focuses specifically on visualizing the small intestine, which is deeper within the digestive system and more challenging to access. Enteroscopy becomes necessary when other diagnostic tests like endoscopy or colonoscopy fail to yield clear results or when there's a suspected issue in the small intestine.