Gastroenterology

Gastroenterologist
Occupation
Names	Physician; Surgeon;
Occupation type	Specialty
Activity sectors	Medicine, Surgery
Description
Education required	Doctor of Medicine (M.D.); Doctor of Osteopathic medicine (D.O.); Bachelor of Medicine, Bachelor of Surgery (M.B.B.S.); Bachelor of Medicine, Bachelor of Surgery (MBChB);
Fields of; employment	Hospitals, Clinics

Gastroenterology
	Illustration of the stomach, colon and rectum.
System	Gastrointestinal
Significant diseases	Gastrointestinal cancers, Gastrointestinal bleeding, Liver cirrhosis, Gallstones, Gastroenteritis, Inflammatory bowel disease
Significant tests	Colonoscopy, Stool test, Barium swallows, Endoscopy
Specialist	Gastroenterologist
Glossary	Glossary of medicine

Gastroenterology^[1] is the branch of medicine focused on the digestive system and its disorders.

Diseases affecting the gastrointestinal tract, which include the organs from mouth into anus, along the alimentary canal, are the focus of this speciality. Physicians practicing in this field are called gastroenterologists. They have usually completed about eight years of pre-medical and medical education, a year-long internship (if this is not a part of the residency), three years of an internal medicine residency, and three years in the gastroenterology fellowship. Gastroenterologists perform a number of diagnostic and therapeutic procedures including colonoscopy, esophagogastroduodenoscopy (EGD), endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), and liver biopsy.^[2] Some gastroenterology trainees will complete a "fourth-year" (although this is often their seventh year of graduate medical education) in transplant hepatology, advanced interventional endoscopy, inflammatory bowel disease, motility, or other topics.

Advanced endoscopy, sometimes called interventional or surgical endoscopy, is a sub-specialty of gastroenterology that focuses on advanced endoscopic techniques for the treatment of pancreatic, hepatobiliary, and gastrointestinal disease. Interventional gastroenterologists typically undergo an additional year of rigorous training in advanced endoscopic techniques including endoscopic retrograde cholangiopancreatography, endoscopic ultrasound-guided diagnostic and interventional procedures, and advanced resection techniques including endoscopic mucosal resection and endoscopic submucosal dissection. Additionally, the performance of endoscopic bariatric procedures is also performed by some advanced endoscopists.

Hepatology, or hepatobiliary medicine, encompasses the study of the liver, pancreas, and biliary tree, and is traditionally considered a sub-specialty of gastroenterology, while proctology encompasses disorders of the anus, rectum, and colon and is considered a sub-specialty of general surgery.

History

Drawings of Bozzini's "Lichtleiter", an early endoscope

Citing from Egyptian papyri, John F. Nunn identified significant knowledge of gastrointestinal diseases among practicing physicians during the periods of the pharaohs. Irynakhty, of the tenth dynasty, c. 2125 B.C., was a court physician specializing in gastroenterology, sleeping, and proctology.^[3]

Among ancient Greeks, Hippocrates attributed digestion to concoction. Galen's concept of the stomach having four faculties was widely accepted up to modernity in the seventeenth century.^{[citation needed]}

Eighteenth-century:

Italian Lazzaro Spallanzani (1729–99) was among early physicians to disregard Galen's theories, and in 1780 he gave experimental proof on the action of gastric juice on foodstuffs.
In 1767, German Johann von Zimmermann wrote an important work on dysentery.
In 1777, Maximilian Stoll of Vienna described cancer of the gallbladder.^[4]^[5]

Nineteenth-century:

In 1805, Philipp Bozzini made the first attempt to observe inside the living human body using a tube he named Lichtleiter (light-guiding instrument) to examine the urinary tract, the rectum, and the pharynx. This is the earliest description of endoscopy.^[6]^[7]
Charles Emile Troisier described enlargement of lymph nodes in abdominal cancer.^[8]
In 1823, William Prout discovered that stomach juices contain hydrochloric acid.^[9]
In 1833, William Beaumont published Experiments and Observations on the Gastric Juice and the Physiology of Digestion following years of experimenting on test subject Alexis St. Martin.
In 1868, Adolf Kussmaul, a well-known German physician, developed the gastroscope. He perfected the technique on a sword swallower.
In 1871, at the society of physicians in Vienna, Carl Stoerk demonstrated an esophagoscope made of two telescopic metal tubes, initially devised by Waldenburg in 1870.
In 1876, Karl Wilhelm von Kupffer described the properties of some liver cells now called Kupffer cells.
In 1883, Hugo Kronecker and Samuel James Meltzer studied oesophageal manometry in humans.

McClendon's pH-probe

Twentieth-century:

In 1915, Jesse McClendon tested acidity of human stomach in situ.^[10]
In 1921–22, Walter Alvarez did the first electrogastrography research.^[11]
Rudolf Schindler described many important diseases involving the human digestive system during World War I in his illustrated textbook and is portrayed by some as the "father of gastroscopy". He and Georg Wolf developed a semiflexible gastroscope in 1932.
In 1932, Burrill Bernard Crohn described Crohn's disease.
In 1957, Basil Hirschowitz introduced the first prototype of a fibreoptic gastroscope.

Twenty-first century:

In 2005, Barry Marshall and Robin Warren of Australia were awarded the Nobel Prize in Physiology or Medicine for their discovery of Helicobacter pylori (1982/1983) and its role in peptic ulcer disease. James Leavitt assisted in their research, but the Nobel Prize is not awarded posthumously so he was not included in the award.

Disease classification

1. International Classification of Disease (ICD 2007)/WHO classification:

Chapter XI, Diseases of the digestive system,(K00-K93)[2]

2. MeSH subject Heading:

Gastroenterology (G02.403.776.409.405)[3]
Gastroenterological diseases(C06.405)[4]

3. National Library of Medicine Catalogue (NLM classification 2006):

Digestive system(W1)[5] Archived 2004-10-19 at the Wayback Machine