Gastroenterology is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, sometimes referred to as the GI tract, which includes the esophagus, stomach, small intestine and large intestine as well as the accessory organs of digestion which include the pancreas, gallbladder, and liver. The digestive system functions to move material through the GI tract via peristalsis, break down that material via digestion, absorb nutrients for use throughout the body, and remove waste from the body via defecation. Physicians who specialize in the medical specialty of gastroenterology are called gastroenterologists or sometimes GI doctors. Some of the most common conditions managed by gastroenterologists include gastroesophageal reflux disease, gastrointestinal bleeding, irritable bowel syndrome, inflammatory bowel disease (IBD) which includes Crohn's disease and ulcerative colitis, peptic ulcer disease, gallbladder and biliary tract disease, hepatitis, pancreatitis, colitis, colon polyps and cancer, nutritional problems, and many more.
Colonoscopy or coloscopy is a medical procedure involving the endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a CCD camera or a fiber optic camera, which is mounted on a flexible tube and passed through the anus.
An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical device, which is used to look deep into the body by way of openings such as the mouth or anus. A typical endoscope applies several modern technologies including optics, ergonomics, precision mechanics, electronics, and software engineering. With an endoscope, it is possible to observe lesions that cannot be detected by X-ray, making it useful in medical diagnosis. Endoscopes use tubes which are only a few millimeters thick to transfer illumination in one direction and high-resolution images in real time in the other direction, resulting in minimally invasive surgeries. It is used to examine the internal organs like the throat or esophagus. Specialized instruments are named after their target organ. Examples include the cystoscope (bladder), nephroscope (kidney), bronchoscope (bronchus), arthroscope (joints) and colonoscope (colon), and laparoscope. They can be used to examine visually and diagnose, or assist in surgery such as an arthroscopy.
Esophagogastroduodenoscopy (EGD) or oesophagogastroduodenoscopy (OGD), also called by various other names, is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract down to the duodenum. It is considered a minimally invasive procedure since it does not require an incision into one of the major body cavities and does not require any significant recovery after the procedure. However, a sore throat is common.
Endoscopic retrograde cholangiopancreatography (ERCP) is a technique that combines the use of endoscopy and fluoroscopy to diagnose and treat certain problems of the biliary or pancreatic ductal systems. It is primarily performed by highly skilled and specialty trained gastroenterologists. Through the endoscope, the physician can see the inside of the stomach and duodenum, and inject a contrast medium into the ducts in the biliary tree and pancreas so they can be seen on radiographs.
Mallory–Weiss syndrome or gastro-esophageal laceration syndrome refers to bleeding from a laceration in the mucosa at the junction of the stomach and esophagus. This is usually caused by severe vomiting because of alcoholism or bulimia, but can be caused by any condition which causes violent vomiting and retching such as food poisoning. The syndrome presents with hematemesis. The laceration is sometimes referred to as a Mallory–Weiss tear.
Percutaneous endoscopic gastrostomy (PEG) is an endoscopic medical procedure in which a tube is passed into a patient's stomach through the abdominal wall, most commonly to provide a means of feeding when oral intake is not adequate. This provides enteral nutrition despite bypassing the mouth; enteral nutrition is generally preferable to parenteral nutrition. The PEG procedure is an alternative to open surgical gastrostomy insertion, and does not require a general anesthetic; mild sedation is typically used. PEG tubes may also be extended into the small intestine by passing a jejunal extension tube through the PEG tube and into the jejunum via the pylorus.
Endoscopic ultrasound (EUS) or echo-endoscopy is a medical procedure in which endoscopy is combined with ultrasound to obtain images of the internal organs in the chest, abdomen and colon. It can be used to visualize the walls of these organs, or to look at adjacent structures. Combined with Doppler imaging, nearby blood vessels can also be evaluated.
Endoscopic foreign body retrieval refers to the removal of ingested objects from the esophagus, stomach and duodenum by endoscopic techniques. It does not involve surgery, but rather encompasses a variety of techniques employed through the gastroscope for grasping foreign bodies, manipulating them, and removing them while protecting the esophagus and trachea. It is of particular importance with children, people with mental illness, and prison inmates as these groups have a high rate of foreign body ingestion.
Double-balloon enteroscopy, also known as push-and-pull enteroscopy, is an endoscopic technique for visualization of the small bowel. It was developed by Hironori Yamamoto in 2001. It is novel in the field of diagnostic gastroenterology as it is the first endoscopic technique that allows for the entire gastrointestinal tract to be visualized in real time.
Colonic polypectomy is the removal of colorectal polyps in order to prevent them from turning cancerous.
An endoclip is a metallic mechanical device used in endoscopy in order to close two mucosal surfaces without the need for surgery and suturing. Its function is similar to a suture in gross surgical applications, as it is used to join together two disjointed surfaces, but, can be applied through the channel of an endoscope under direct visualization. Endoclips have found use in treating gastrointestinal bleeding, in preventing bleeding after therapeutic procedures such as polypectomy, and in closing gastrointestinal perforations. Many forms of endoclips exist of different shapes and sizes, including two and three prong devices, which can be administered using single use and reloadable systems, and may or may not open and close to facilitate placement.
Capsule endoscopy is a medical procedure used to record internal images of the gastrointestinal tract for use in disease diagnosis. Newer developments are also able to take biopsies and release medication at specific locations of the entire gastrointestinal tract. Unlike the more widely used endoscope, capsule endoscopy provides the ability to see the middle portion of the small intestine. It can be applied to the detection of various gastrointestinal cancers, digestive diseases, ulcers, unexplained bleedings, and general abdominal pains. After a patient swallows the capsule, it passes along the gastrointestinal tract, taking a number of images per second which are transmitted wirelessly to an array of receivers connected to a portable recording device carried by the patient. General advantages of capsule endoscopy over standard endoscopy include the minimally invasive procedure setup, ability to visualize more of the gastrointestinal tract, and lower cost of the procedure.
An esophageal food bolus obstruction is a medical emergency caused by the obstruction of the esophagus by an ingested foreign body.
An esophageal stent is a stent (tube) placed in the esophagus to keep a blocked area open so the patient can swallow soft food and liquids. They are effective in the treatment of conditions causing intrinsic esophageal obstruction or external esophageal compression. For the palliative treatment of esophageal cancer most esophageal stents are self-expandable metallic stents. For benign esophageal disease such as refractory esophageal strictures, plastic stents are available. Common complications include chest pain, overgrowth of tissue around the stent and stent migration. Esophageal stents may also be used to staunch the bleeding of esophageal varices.
Therapeutic endoscopy is the medical term for an endoscopic procedure during which treatment is carried out via the endoscope. This contrasts with diagnostic endoscopy, where the aim of the procedure is purely to visualize a part of the gastrointestinal, respiratory or urinary tract in order to aid diagnosis. In practice, a procedure which starts as a diagnostic endoscopy may become a therapeutic endoscopy depending on the findings, such as in cases of upper gastrointestinal bleeding, or the finding of polyps during colonoscopy.
An endoscopy unit refers to a dedicated area where medical procedures are performed with endoscopes, which are cameras used to visualize structures within the body, such as the digestive tract and genitourinary system. Endoscopy units may be located within a hospital, incorporated within other medical care centres, or may be stand-alone in nature.
Chromoendoscopy is a medical procedure wherein dyes are instilled into the gastrointestinal tract at the time of visualization with fibre-optic endoscopy. The purposes of chromoendoscopy is chiefly enhance the characterization of tissues, although dyes may be used for other functional purposes. The detail achieved with chromoendoscopy can often allow for identification of the tissue type or pathology based upon the pattern uncovered.
Narrow-band imaging is an imaging technique for endoscopic diagnostic medical tests, where light of specific blue and green wavelengths is used to enhance the detail of certain aspects of the surface of the mucosa. A special filter is electronically activated by a switch in the endoscope leading to the use of ambient light of wavelengths of 415 nm (blue) and 540 nm (green). Because the peak light absorption of hemoglobin occurs at these wavelengths, blood vessels will appear very dark, allowing for their improved visibility and in the improved identification of other surface structures.
Endoscopic mucosal resection is a technique used to remove cancerous or other abnormal lesions found in the digestive tract. It is one method of performing a mucosectomy.
