| Digestive disease | |
|---|---|
 | |
| Organs of thegastrointestinal tract | |
| Specialty | Gastroenterology  |
Gastrointestinal diseases (abbrev.GI diseases orGI illnesses) refer to diseases involving thegastrointestinal tract, namely theesophagus,stomach,small intestine,large intestine andrectum; and theaccessory organs of digestion, theliver,gallbladder, andpancreas.
The oral cavity is part of the gastrointestinal system and as such the presence of alterations in this district can be the first sign of both systemic and gastrointestinal diseases.[1] By far the most common oral conditions areplaque-induced diseases (e.g.,gingivitis,periodontitis,dental caries). Oral symptoms can be similar to lesions occurring elsewhere in the digestive tract, with a pattern of swelling, inflammation, ulcers, and fissures. If these signs are present, then patients are more likely to also have anal and esophageal lesions and experience other extra-intestinal disease manifestations.[2] Some diseases which involve other parts of the GI tract can manifest in the mouth, alone or in combination, including:
Oesophageal diseases include a spectrum of disorders affecting theoesophagus. The most common condition of the oesophagus in Western countries isgastroesophageal reflux disease,[4] which in chronic forms is thought to result in changes to theepithelium of the oesophagus, known asBarrett's oesophagus.[5]: 863–865
Acute disease might includeinfections such asoesophagitis, trauma caused by the ingestion of corrosive substances, or rupture ofveins such asoesophageal varices,Boerhaave syndrome orMallory-Weiss tears. Chronic diseases might includecongenital diseases such asZenker's diverticulum andesophageal webbing, andoesophageal motility disorders including thenutcracker oesophagus,achalasia,diffuse oesophageal spasm, andoesophageal stricture.[5]: 853, 863–868
Oesophageal disease may result in asore throat,throwing up blood, difficultyswallowing orvomiting. Chronic or congenital diseases might be investigated usingbarium swallows,endoscopy andbiopsy, whereas acute diseases such as reflux may be investigated and diagnosed based onsymptoms and amedical history alone.[5]: 863–867
Gastric diseases refer to diseases affecting thestomach. Inflammation of the stomach by infection from any cause is calledgastritis, and when including other parts of the gastrointestinal tract calledgastroenteritis. When gastritis persists in a chronic state, it is associated with several diseases, includingatrophic gastritis,pyloric stenosis, andgastric cancer. Another common condition isgastric ulceration,peptic ulcers. Ulceration erodes thegastric mucosa, which protects the tissue of the stomach from the stomach acids. Peptic ulcers are most commonly caused by a bacterialHelicobacter pyloriinfection.[5]Epstein–Barr virus infection is another factor to induce gastric cancer.[6][7]
As well as peptic ulcers,vomiting blood may result from abnormal arteries or veins that have ruptured, includingDieulafoy's lesion andGastric antral vascular ectasia. Congenital disorders of the stomach includepernicious anaemia, in which a targetedimmune response againstparietal cells results in an inability to absorbvitamin B12. Other common symptoms that stomach disease might cause includeindigestion ordyspepsia,vomiting, and in chronic disease, digestive problems leading to forms ofmalnutrition.[5]: 850–853 In addition to routine tests, anendoscopy might be used to examine or take abiopsy from the stomach.[5]: 848
Thesmall andlarge intestines may be affected byinfectious, autoimmune, and physiological states. Inflammation of the intestines is calledenterocolitis, which may lead todiarrhea.
Acute conditions affecting the bowels includeinfectious diarrhea andmesenteric ischaemia. Causes ofconstipation may includefaecal impaction andbowel obstruction, which may in turn be caused byileus,intussusception,volvulus.Inflammatory bowel disease is a condition of unknown aetiology, classified as eitherCrohn's disease orulcerative colitis, that can affect the intestines and other parts of the gastrointestinal tract. Other causes of illness includeintestinal pseudoobstruction, andnecrotizing enterocolitis.[5]: 850–862, 895–903
Diseases of the intestine may causevomiting,diarrhoea orconstipation, and alteredstool, such as withblood in stool.Colonoscopy may be used to examine the large intestine, and a person's stool may be sent forculture andmicroscopy. Infectious disease may be treated with targetedantibiotics, and inflammatory bowel disease withimmunosuppression. Surgery may also be used to treat some causes of bowel obstruction.[5]: 850–862
The normal thickness of the smallintestinal wall is 3–5 mm,[8] and 1–5 mm in the large intestine.[9] Focal, irregular and asymmetrical gastrointestinal wall thickening onCT scan suggests a malignancy.[9] Segmental or diffuse gastrointestinal wall thickening is most often due to ischemic, inflammatory or infectious disease.[9] Though less common, medications such asACE inhibitors can causeangioedema and small bowel thickening.[10]
The small intestine consists of theduodenum,jejunum andileum. Inflammation of the small intestine is calledenteritis, which if localised to just part is calledduodenitis,jejunitis andileitis, respectively.Peptic ulcers are also common in the duodenum.[5]: 879–884
Chronic diseases ofmalabsorption may affect the small intestine, including the autoimmunecoeliac disease, infectivetropical sprue, and congenital or surgicalshort bowel syndrome. Other rarer diseases affecting the small intestine includeCurling's ulcer,blind loop syndrome,Milroy disease andWhipple's disease. Tumours of the small intestine includegastrointestinal stromal tumours,lipomas,hamartomas andcarcinoid syndromes.[5]: 879–887
Diseases of the small intestine may present with symptoms such asdiarrhoea,malnutrition,fatigue andweight loss. Investigations pursued may includeblood tests to monitor nutrition, such asiron levels,folate andcalcium,endoscopy andbiopsy of the duodenum, andbarium swallow. Treatments may include renutrition andantibiotics for infections.[5]: 879–887
Diseases that affect thelarge intestine may affect it in whole or in part.Appendicitis is one such disease, caused by inflammation of theappendix. Generalised inflammation of the large intestine is referred to ascolitis, which when caused by the bacteriaClostridioides difficile is referred to aspseudomembranous colitis.Diverticulitis is a common cause of abdominal pain resulting from outpouchings that particularly affect the colon.Functional colonic diseases refer to disorders without a known cause, includingirritable bowel syndrome andintestinal pseudoobstruction.Constipation may result from lifestyle factors,impaction of a rigid stool in the rectum, or inneonates,Hirschprung's disease.[5]: 913–915
Diseases affecting the large intestine may cause blood to be passed with stool, may causeconstipation, or may result inabdominal pain or a fever. Tests that specifically examine the function of the large intestine include barium swallows,abdominal x-rays, andcolonoscopy.[5]: 913–915
Diseases affecting therectum andanus are extremely common, especially in older adults.Hemorrhoids, vascular outpouchings of skin, are very common, as ispruritus ani, referring to anal itchiness. Other conditions, such asanal cancer may be associated withulcerative colitis or withsexually transmitted infections such asHIV. Inflammation of the rectum is known asproctitis, one cause of which is radiation damage associated withradiotherapy to other sites such as theprostate.Faecal incontinence can result from mechanical and neurological problems, and when associated with a lack of voluntary voiding ability is described asencopresis. Pain on passing stool may result fromanal abscesses, small inflamed nodules,anal fissures, andanal fistulas.[5]: 915–916
Rectal and anal disease may be asymptomatic, or may present with pain when passing stools,fresh blood in stool,a feeling of incomplete emptying, or pencil-thin stools. In addition to regular tests, medical tests used to investigate the anus and rectum include thedigital rectal exam andproctoscopy.[citation needed]
Hepatic diseases refers to those affecting theliver.Hepatitis refers to inflammation of liver tissue, and may beacute orchronic. Infectiousviral hepatitis, such ashepatitis A,B andC, affect in excess of (X) million people worldwide. Liver disease may also be a result of lifestyle factors, such asfatty liver andNASH.Alcoholic liver disease may also develop as a result of chronic alcohol use, which may also causealcoholic hepatitis.Cirrhosis may develop as a result of chronichepatic fibrosis in a chronically inflamed liver, such as one affected byalcohol or viral hepatitis.[5]: 947–958
Liver abscesses are often acute conditions, with common causes beingpyogenic andamoebic. Chronic liver disease, such as cirrhosis, may be a cause ofliver failure, a state where the liver is unable to compensate for chronic damage, and unable to meet the metabolic demands of the body.In the acute setting, this may be a cause ofhepatic encephalopathy andhepatorenal syndrome. Other causes of chronic liver disease are genetic or autoimmune disease, such ashemochromatosis,Wilson's disease,autoimmune hepatitis, andprimary biliary cirrhosis.[5]: 959–963, 971
Acute liver disease rarely results in pain, but may result injaundice. Infectious liver disease may cause a fever. Chronic liver disease may result ina buildup of fluid in the abdomen,yellowing of the skin oreyes, easy bruising,immunosuppression, and feminization.[11]Portal hypertension is often present, and this may lead to the development of prominent veins in many parts of the body, such asoesophageal varices, andhaemorrhoids.[5]: 959–963, 971–973
In order to investigate liver disease, a medical history, including regarding a person'sfamily history, travel to risk-prone areas, alcohol use and food consumption, may be taken. Amedical examination may be conducted to investigate for symptoms of liver disease. Blood tests may be used, particularlyliver function tests, and other blood tests may be used to investigate the presence of the Hepatitis viruses in the blood, and ultrasound used. If ascites is present, abdominal fluid may be tested for protein levels.[5]: 921, 926–927
Pancreatic diseases that affect digestion refers to disorders affecting theexocrine pancreas, which is a part of the pancreas involved in digestion.[citation needed]
One of the most common conditions of the exocrine pancreas isacute pancreatitis, which in the majority of cases relates togallstones that have impacted in the pancreatic part of thebiliary tree, or due to acute or chronichazardous alcohol use or as a side-effect ofERCP. Other forms of pancreatitis includechronic andhereditary forms. Chronic pancreatitis may predispose topancreatic cancer and is strongly linked to alcohol use. Other rarer diseases affecting the pancreas may includepancreatic pseudocysts,exocrine pancreatic insufficiency, andpancreatic fistulas.[5]: 888–891
Pancreatic disease may present with or without symptoms. When symptoms occur, such as inacute pancreatitis, a person may experience acute-onset, severe mid-abdominal pain, nausea and vomiting. In severe cases, pancreatitis may lead to rapid blood loss andsystemic inflammatory response syndrome. When the pancreas is unable to secrete digestiveenzymes, such as with a pancreatic cancer occluding thepancreatic duct, result in jaundice. Pancreatic disease might be investigated usingabdominal x-rays,MRCP orERCP,CT scans, and through blood tests such as measurement of theamylase andlipase enzymes.[5]: 888–894
Diseases of thehepatobiliary system affect thebiliary tract (also known as thebiliary tree), which secretesbile in order to aid digestion of fats. Diseases of thegallbladder and bile ducts are commonly diet-related, and may include theformation ofgallstones that impact in the gallbladder (cholecystolithiasis) or in thecommon bile duct (choledocholithiasis).[5]: 977–978
Gallstones are a common cause of inflammation of the gallbladder, calledcholecystitis. Inflammation of thebiliary duct is calledcholangitis, which may be associated withautoimmune disease, such asprimary sclerosing cholangitis, or a result of bacterial infection, such asascending cholangitis.[5]: 977–978, 963–968
Disease of the biliary tree may cause pain in the upper right abdomen,particularly when pressed. Disease might be investigated usingultrasound orERCP, and might be treated with drugs such asantibiotics orUDCA, or by the surgicalremoval of the gallbladder.[5]: 977–979
Gastrointestinal cancer comprises specific malignant conditions of the gastrointestinal tract. In general, a significant factor in the etiology of gastrointestinal cancers appears to be excessive exposure of the digestive organs tobile acids.[12][13]
{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)