Gallstones are solid deposits that form within the gallbladder or biliary tract when substances in bile precipitate and crystallise. Most gallstones are composed predominantly of cholesterol, while others are pigment stones containing calcium salts and bilirubin-related compounds. Gallstones can remain asymptomatic for years and may be discovered incidentally during imaging performed for another reason. Symptoms generally occur when a stone obstructs bile flow, particularly at the gallbladder outlet or common bile duct. The presence of stones without symptoms is therefore different clinically from symptomatic gallstone disease.
Gallstone formation involves changes in bile composition, gallbladder motility and the physical conditions that allow crystals to form and grow. Cholesterol stones are associated with bile that contains more cholesterol than can remain solubilised, whereas pigment stones are associated with processes that increase bilirubin availability or alter biliary chemistry. Risk is influenced by factors including age, sex, obesity, rapid weight loss, pregnancy, certain metabolic conditions and particular disorders affecting red blood cells or the biliary system. The traditional mnemonic involving several “F” characteristics is an oversimplification and should not be treated as a diagnostic rule.
Many people with Gallstones have no symptoms. Asymptomatic stones generally do not cause the characteristic episodes of biliary pain and may require no treatment unless particular circumstances increase risk. Symptomatic gallstones can produce biliary colic, typically characterised by steady pain in the right upper abdomen or epigastrium that may radiate to the back or right shoulder. Episodes can follow meals, particularly fatty meals, although food is not a necessary trigger. Pain commonly lasts for a sustained period rather than behaving like brief intestinal cramps and may be accompanied by nausea or vomiting.
Gallstones can cause complications when they obstruct the biliary system. A stone obstructing the cystic duct can cause acute cholecystitis, while a stone entering the common bile duct can cause obstructive jaundice and potentially cholangitis. A stone obstructing the pancreatic duct outflow or ampullary region can contribute to acute pancreatitis. Gallstone ileus is a rarer complication in which a large stone enters the intestine through an abnormal fistula and causes bowel obstruction. These complications differ substantially in severity and treatment requirements from uncomplicated symptomatic gallstones.
Diagnosis of Gallstones commonly uses abdominal ultrasound because it can detect gallstones and assess the gallbladder without ionising radiation. Blood tests can identify evidence of inflammation, liver dysfunction or biliary obstruction but may be normal in uncomplicated biliary colic. If a common bile duct stone is suspected, additional imaging such as magnetic resonance cholangiopancreatography or endoscopic ultrasound may be used. Endoscopic retrograde cholangiopancreatography is primarily a therapeutic procedure for removing accessible bile-duct stones rather than a routine first-line diagnostic test.
Treatment of symptomatic Gallstones depends on symptoms, complications and patient circumstances. Laparoscopic cholecystectomy, removal of the gallbladder using minimally invasive surgery, is a standard treatment for recurrent symptomatic gallbladder stones and many gallstone complications. If stones are present in the common bile duct, endoscopic removal may be required, often followed by gallbladder surgery to prevent recurrence. Dietary modification may reduce symptoms in some people while awaiting definitive treatment, but it does not remove existing stones. Dissolution therapy with bile acids has limited applicability and is not a general substitute for surgery.
Gallstones can remain silent or produce recurrent episodes over months or years. The distinction between biliary colic and acute Cholecystitis is clinically important. Biliary colic generally results from transient obstruction and often resolves when the stone moves, whereas cholecystitis involves persistent cystic-duct obstruction and inflammation of the gallbladder. Persistent right-upper-quadrant pain, fever, tenderness and inflammatory findings are more suggestive of cholecystitis than uncomplicated biliary colic. Jaundice raises concern for obstruction of the common bile duct or another hepatobiliary disorder rather than an isolated gallbladder stone.
Gallstones are common throughout the world, but prevalence varies with genetics, diet, metabolic factors and population characteristics. Increased obesity and metabolic disease have contributed to gallstone risk in many populations, while rapid weight loss can also promote stone formation because of changes in bile composition and gallbladder emptying. Gallstones should not be confused with biliary sludge, which consists of microscopic particulate material in bile and can precede stone formation. Nor does the presence of gallstones automatically establish that abdominal pain is caused by them; incidental stones are common, so symptoms and imaging findings must be correlated carefully.
