Gastroenterology — Find Specialists & Top Hospitals Worldwide | MyMedicPlus

Gastroenterology is the branch of internal medicine concerned with the structure, function, diseases, and diagnosis of the gastrointestinal (GI) tract and accessory digestive organs. The GI system encompasses the oesophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (colon), rectum, and anus — collectively spanning approximately 9 metres of digestive organ — as well as the liver, gallbladder, bile ducts, and pancreas. Gastroenterologists are the primary specialists for digestive health across this entire system.

What distinguishes gastroenterology from other internal medicine subspecialties is the central role of endoscopy — visual examination of the digestive tract using flexible cameras called endoscopes — as both a diagnostic and therapeutic tool. Gastroenterologists use upper endoscopy (gastroscopy) to visualise and treat the oesophagus, stomach, and duodenum, and colonoscopy to examine the colon and terminal ileum. Advanced therapeutic endoscopy, practised by endoscopic subspecialists, allows removal of large polyps, treatment of bleeding, dilation of strictures, and drainage of cysts — all without surgery.

Gastroenterology has several subspecialties. Hepatology — the study and treatment of liver, gallbladder, and biliary tract diseases — is closely related and often practised by gastroenterologists with additional hepatology training. Inflammatory bowel disease (IBD) specialists focus exclusively on Crohn disease and ulcerative colitis. Motility specialists address oesophageal, gastric, and colonic motor disorders. Advanced endoscopic specialists and therapeutic endoscopists perform complex procedures including endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), and advanced polypectomy. Paediatric gastroenterology addresses digestive conditions from infancy through adolescence.

Gastroenterologists diagnose and manage a broad range of conditions affecting the digestive system:

• Gastro-oesophageal reflux disease (GERD): Chronic reflux of stomach acid into the oesophagus causing heartburn, regurgitation, and potential complications including oesophagitis, stricture, and Barrett oesophagus (a precancerous change).
• Peptic ulcer disease: Ulcers in the stomach (gastric ulcer) or duodenum (duodenal ulcer) caused by Helicobacter pylori infection or non-steroidal anti-inflammatory drug (NSAID) use.
• Inflammatory bowel disease (IBD): Crohn disease (transmural inflammation that can affect any part of the GI tract from mouth to anus, causing strictures, fistulas, and abscesses) and ulcerative colitis (continuous mucosal inflammation limited to the colon, causing bloody diarrhoea).
• Irritable bowel syndrome (IBS): Functional gut disorder characterised by abdominal pain, bloating, and altered bowel habits (diarrhoea, constipation, or mixed) without identifiable structural or biochemical abnormality.
• Coeliac disease: Immune-mediated enteropathy triggered by gluten ingestion causing villous atrophy in the small intestine, malabsorption, diarrhoea, and nutrient deficiencies; managed with strict lifelong gluten-free diet.
• Colorectal cancer and polyps: Adenomatous polyps are premalignant lesions identified and removed during colonoscopy; colorectal cancer is the third most common cancer worldwide and the second leading cause of cancer death — screening from age 45 is recommended.
• Gastrointestinal bleeding: Upper GI bleeding (haematemesis, melaena) from peptic ulcers, oesophageal varices, or vascular lesions; lower GI bleeding (haematochezia) from diverticulosis, angiodysplasia, or colorectal cancer.
• Liver diseases: Non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease, viral hepatitis (B and C), cirrhosis, and hepatocellular carcinoma (managed jointly with hepatologists).
• Pancreatitis: Acute pancreatitis (sudden inflammation, often from gallstones or alcohol) and chronic pancreatitis (progressive fibrosis leading to exocrine and endocrine insufficiency).
• Motility disorders: Achalasia (failure of oesophageal lower sphincter relaxation), gastroparesis (delayed gastric emptying), and chronic constipation or slow transit disorders.
• Microscopic colitis: Collagenous or lymphocytic colitis causing chronic watery diarrhoea with a normal-appearing colon on endoscopy but diagnostic changes on biopsy.

Gastroenterologists are defined by their expertise in endoscopic diagnosis and treatment:

• Upper endoscopy (oesophagogastroduodenoscopy, OGD/EGD): Flexible camera examination of the oesophagus, stomach, and duodenum under sedation; used to diagnose GERD complications, peptic ulcers, gastritis, coeliac disease (duodenal biopsy), and early upper GI cancer; allows therapeutic interventions including haemostasis and stricture dilation.
• Colonoscopy: Examination of the entire colon and terminal ileum with a flexible colonoscope; the gold standard for colorectal cancer screening, polyp removal (polypectomy), IBD assessment, and investigation of bleeding or altered bowel habits.
• Flexible sigmoidoscopy: Shorter version of colonoscopy examining the rectum and sigmoid colon; used for surveillance of distal IBD and as an alternative screening tool.
• Endoscopic retrograde cholangiopancreatography (ERCP): Combines endoscopy and fluoroscopy to diagnose and treat disorders of the bile duct and pancreatic duct, including gallstone removal, stricture dilation, and stent placement for bile duct obstruction.
• Endoscopic ultrasound (EUS): Endoscope with an integrated ultrasound transducer providing high-resolution imaging of the GI tract wall layers and adjacent structures (pancreas, liver, lymph nodes, mediastinum); used for staging of GI cancers and fine-needle aspiration of pancreatic masses, cysts, and enlarged lymph nodes.
• Capsule endoscopy: Patient swallows a small wireless camera capsule that photographs the entire small bowel as it passes through; used to investigate obscure GI bleeding, suspected Crohn disease of the small intestine, and small bowel tumours.
• Liver biopsy: Percutaneous or transjugular needle biopsy of liver tissue for histological assessment of fibrosis stage, inflammation, and diagnosis of specific liver diseases.
• Oesophageal manometry: Measures pressure and motor function of the oesophagus and lower oesophageal sphincter to diagnose achalasia, diffuse oesophageal spasm, and other motility disorders.
• Helicobacter pylori testing: Non-invasive urea breath test or stool antigen test to confirm active H. pylori infection; crucial before and after eradication treatment to confirm cure.

Many GI symptoms — heartburn, bloating, or occasional diarrhoea — are managed effectively by primary care physicians without specialist referral. However, specific clinical features warrant gastroenterology evaluation.

Seek urgent gastroenterology evaluation for: rectal bleeding or blood mixed in stool, which may indicate colorectal cancer, IBD, or haemorrhage from vascular lesions; new or worsening difficulty swallowing (dysphagia) — particularly if it is progressive and associated with weight loss, which may indicate oesophageal cancer; jaundice (yellow skin and eyes) suggesting acute liver disease, bile duct obstruction, or pancreatic cancer; acute abdominal pain with elevated liver enzymes, suggesting biliary obstruction or pancreatitis; and unexplained significant weight loss with any digestive symptom.

Routine gastroenterology referral is appropriate for: heartburn symptoms not adequately controlled with twice-daily proton pump inhibitors; unexplained iron deficiency anaemia (requiring upper and lower endoscopy to identify a source); change in bowel habits lasting more than 6 weeks in an adult, particularly after age 50; chronic diarrhoea (more than 4 weeks) to distinguish functional from inflammatory or malabsorptive causes; abdominal pain not explained by GP investigations; and all adults aged 45 and above for colorectal cancer screening discussion — earlier if there is a family history of colorectal cancer or polyps (screening should begin 10 years before the youngest affected relative).

The training pathway to becoming a gastroenterologist in the USA begins with a 4-year medical degree (MD or DO), followed by a 3-year internal medicine residency. After obtaining ABIM internal medicine board certification, physicians complete a 2–3 year gastroenterology fellowship covering the full range of GI diseases and gaining hands-on endoscopy training. ACGME-accredited programmes require fellows to perform a minimum number of upper endoscopies, colonoscopies, and other procedures before independent competency is achieved — typically 200 colonoscopies minimum to reach adequate adenoma detection and cecal intubation rates.

Board certification in gastroenterology is conferred by the American Board of Internal Medicine (ABIM) through a subspecialty examination. Recertification every 10 years requires continuing medical education and assessment.

Subspecialty fellowships are available for advanced endoscopy (1–2 additional years, covering ERCP, EUS, and complex endoscopic resection), hepatology (1–2 years, leading to separate ABIM hepatology certification), motility (1 year), and IBD. Hepatologists who complete a transplant hepatology fellowship earn additional certification for managing liver transplant patients. In the UK, gastroenterologists train through a 4-year specialty training programme (ST3–6) within the JRCPTB, leading to CCT in Gastroenterology and Hepatology, with subspecialty certificates in advanced endoscopy, hepatology, or IBD available through the British Society of Gastroenterology (BSG).

Your primary care physician is the appropriate first point of contact for most digestive symptoms and will refer to a gastroenterologist when specialist assessment or endoscopy is indicated. Verify board certification through the ABIM. For specific advanced procedures such as ERCP, EUS-guided tumour biopsy, or complex endoscopic mucosal resection, seek a gastroenterologist with specific advanced endoscopy fellowship training and high procedural volume, as complication rates are inversely related to operator experience.

For IBD care, seek a gastroenterologist who manages a large IBD population and has access to the full range of biologic therapies — including TNF inhibitors (infliximab, adalimumab), IL-12/23 inhibitors (ustekinumab), IL-23 inhibitors (risankizumab, mirikizumab), and integrin antagonists (vedolizumab) — as treatment algorithms are complex and evolving rapidly.

For your first appointment, bring any prior endoscopy reports, barium swallow or CT scan results, blood tests (including liver function, full blood count, and inflammatory markers), and a symptom diary documenting frequency, severity, triggers, and associated factors. Note any family history of colorectal cancer, polyps, IBD, or coeliac disease, as this significantly affects screening recommendations and diagnostic priorities.