Gastroenterology, a specialty of internal medicine, is the formal study of the GI tract from the oesophagus* to the rectum. Major strides have been made in the field both in terms of technological advances and understanding of the interplay of human microbiomes on health and disease.
*Technically the mouth is also the domain of GI guys, but pathology of the oral cavity is typically managed by ENTs
The most significant technologic advance in gastroenterology was endoscopy. AJ Desormeaux, a French physician, has been called the father of endoscopy for inventing a cystoscope* which he used in 1853 to perform chemical cauterization. Later developments in endoscopy in the early 20th century included rigid sigmoidoscopes and laparoscopes, which have improved to the point of allowing minimally invasive (“keyhole”) surgery. The first flexible (fiber optic) endoscope was invented in 1957, which was followed by improvements in lighting, miniaturization of cameras to improve image quality, and of tools to allow biopsies of suspected lesions.
capsule endoscopy images at different levels of GI tract
*No mean feat when one considers that it preceded electricity and the invention of lightbulbs.
The latest development in endoscopy are “pill cams” (capsule endoscopes), invented in the late 1990s by GJ Iddan, an Israeli engineer, and cleared by the FDA for use in humans in 2001. These clever devices are swallowed and take pictures during their entire transit through the GI tract and transmit them to an external monitoring and recording system, allowing identification of premalignant conditions, cancer, and inflammatory bowel disease (see top image).
Advances in microbiology have also impacted on gastroenterology. In 2005, Barry Marshall and Robin Warren received the Nobel Prize in Medicine for their discovery in the early 1980s that the spirochaete-like bacterium, Helicobacter pylori (see bottom image, a silver stained gastric biopsy) cause gastritis and gastric ulcers. Later work by others linked non-cardia gastric cancer and MALTomas (a type of lymphoma) to colonization of the stomach by H pylori.
High-power light microscopy of gastric tissue
A second advance in microbiology has led to improved management of infection by Clostridium difficile, the most common cause of pseudomembranous colitis, and notoriously resistant to “big guns” antibiotics. Recently, fecal transplants of bacteria normally present in the native microbiome, popularly termed probiotics, including bacteria (Lactobacillus and Bifidobacterium) and a yeast (Saccharomyces boulardii) were assessed in a meta-analysis and shown to significant reduce the risk of developing C difficile-associated diarrhoea, a major cause of in-hospital morbidity.