Introduction

INTRODUCTION

The gastrointestinal tract has a myriad of functions, such as digestion, absorption and excretion, as well as the synthesis of an array of hormones, growth factors and cytokines. In addi tion, a complex enteric nervous system has evolved to control its function and communicate with the central and peripheral nervous systems. Finally , as the gastrointestinal tract contains the largest sources of foreign antigens to which the body is exposed, it houses well-developed arms of both the innate and acquired immune systems. Therefore, it is not surprising that malfunction or infection of this complex organ results in a wide spectrum of pathology . However, its importance in disease pathogenesis is matched only by its inaccessibility to traditional examination. Few discoveries in medicine have contributed more to the practice of gastroenterology than the development of diagnostic and therapeutic endoscopy . Although spectacular advances in radiology have occurr ed recently with the intro duction of multislice spiral computed tomography (CT) and magnetic resonance imaging (MRI), the ability to take tar geted mucosal biopsies remains a unique strength of endos copy . Historically , radiological techniques were required to image areas of jejunum and ileum inaccessible to the stan dard endoscope; ho wever, the introduction of both capsule endoscopy and single-/double-balloon enteroscopy allows both diagnostic and therapeutic access to the entire gastro intestinal tract. Image enhancement with techniques such as chromoendoscopy , magnifica tion endoscopy and narrow band imaging allows increased resolution a t the mucosal level and increases diagnostic yield. Endoscopic ultrasound (EUS) can examine all layers of the intestinal wall as well as extraintestinal structures. Finally , experimental techniques such as confocal Harold Horace Hopkins , 1918–1994, Professor of Applied Optics, The University of Reading, Reading, UK. laser endomicroscopy give resolution at a level compatible with standard histology . The advances in the diagnostic accuracy of endoscopy lend themselves to disease surveillance for specific patient groups as well as population screening for gastrointesti - - nal malignancy . Likewise, there has been a rapid expansion in the therapeutic capability of endoscopy with both luminal and extraintestinal surgery being performed via endoscopic access. As in all areas of interventional practice, competent endoscopists must match a thorough grounding in anatomy and physiology with a clear understanding of the capabilities and limitations of the rapidly advancing techniques a vailable. Perhaps most importantly they must appreciate all aspects of patient care, including preprocedural management, commu - nication before and during the procedure and the manage - ment of endoscopic complications. This chapter aims to guide the reader through these areas in addition to introducing the breadth of procedur es that are currently performed. -

The indications for diagnostic and therapeutic endoscopic • procedures including endoscopic ultrasound The recognition and management of complications • Novel techniques for endoscoping the small bowel • Advances in diagnostic ability •