The endoscope is the basic diagnostic tool for the gastroenterologist. It is a tube which can enter into the intestinal lumen either from the mouth or from the rectum and perform a number of diagnostic and therapeutic functions. There have been tremendous improvements in the design and the functioning of the endoscope over the last decade. The initial endoscopes were a rigid metal pipe which was inserted through the mouth and the extended neck of the patient like the sword trick performed by the magicians. The scopes are now much more refined and create minimal discomfort for the patient.
The first flexible endoscope to be developed by the german scientist Hirchowitz This scope was further improved and in the present form it enters through the mouth goes into the esophagus stomach and first and second part of the duodenum. The maximum reach of the upper GI endosope is till the third part of duodenum and it cannot go beyond. With the help of the upper GI scope one can visualize this entire area for any lesion like ulcers or tumors. The main indications for upper GI endoscopy is for the evaluation of symptoms like acid reflux, pain abdomen, gas and bloating. It is also used for the detection of esophageal, gastric and duodenal cancers, management of GI bleeding, treatment of esophageal and gastric strictures, and the management of esophageal varices. It can be used to take biopsies from any lesion that is detected during endoscopy. Upper GI endoscopy can also be used for a number of therapeutic procedures like banding of esophageal varices, dilatation of strictures and achalasia cardia, management of upper GI bleeding with a number of modalities like argon plasma coagulation, clip application and heater probe. Removal of polyps and tumors by hot or cold snare and procedures line endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD).
Colonoscopy is the second most commonly done GI procedure. Its primary use in the western world is to screen for colonic polyps. However in India it is used as a diagnostic tool for the management of pain abdomen, abdominal lumps, lower GI bleeding, constipation, diarrhoea, alteration in bowel habits etc. The therapeutic indications of colonoscopy are : the management of GI bleeding with application of clips or coagulation, removal of polyps (Polypectomy) and removal of tumors (EMR, ESD).
Enteroscopy is the visualization of the small bowel with the enteroscope which is available in three forms 1. The single balloon scope 2. The double balloon endoscope or 3. The spiral enteroscope. The primary indication of enteroscopy is the management of GI bleeding, it is also used for the detection of polyps and tumors causing obstruction, detection of ulcers and strictures in conditions like crohns disease and small intestinal lymphoma. Generally enteroscopy is preceded by capsule endoscopy which is a non invasive test and involves swallowing of the wireless capsule which sends signals into the wireless recorder attached to the patient externally. Once a lesion is found, enteroscopy is performed to either take biopsies or to remove the lesion completely.
ERCP (Endoscopic Retrograde Cholangio Pancreatography) as the name signifies is a endoscopic procedure used to access the bile duct and the pancreatic duct. With the advent of better imaging procedures, diagnostic ERCP has largely been given up and the procedure is now used only for therapeutic purposes. Bile duct ERCP is used for the removal of stones, stenting of benign and malignant strictures (including placement of metallic stents in malignancies and stenting of post liver transplant strictures), Bile duct brush cytology and biopsy can also be obtained by ERCP. Similarly pancreatic ERCP is used for sampling of pancreatic duct lesions, and for placing stents in pancreatic duct. Spyglass cholangioscopy is a new scope to visualize the bile duct and pancreatic duct directly. This scope is passed through the ERCP scope and passed into the bile and pancreatic duct. It can visualize lesions in both the ducts as well as take tissue samples.
Ultrasound is a procedure done for the visualization of the abdominal organs however in abdominal ultrasound, the sound waves have to traverse through skin, fat, bone and muscle before reaching the abdominal organ. In order to make ultrasound more accurate, the endoscopic ultrasound (EUS) was designed which has the ultrasound probe attached to the tip of the ultrasound which is then inserted into the intestine thus minimizing the distance of the probe from the organ of interest. There are two types of EUS scopes, the radial and the linear. EUS is not only a good diagnostic tool, it is now used for a number of therapeutic procedures as well like FNA and biopsy of lesions, drainage of pseudocysts, drainage of bile and pancreatic ducts, injection of alcohol for pain relief, placement of markers in tumors etc.
Endoscopy has been a game changer technology for gastroenterology. Over the last 2 decades the scope design has become such that the procedure is increasingly comfortable to the patient and we are now moving towards no sedation endoscopy. The procedure is now risk free with minimal chance of infections.