A gallstone is a small pebble that develops in the gallbladder often as a result of sediment from the bile. The medical term for a gallstone is a cholelith and the process of gallstone formation and the presence of gallstones in the gallbladder is known as cholelithiasis.
There are some less common types of gallstones that do not develop within the gallbladder but rather in the bile ducts (medical term : choledocholithiasis). Many gallstones exit the gallbladder and pass out with the bile. It often goes unnoticed. At times however, the gallstone may get stuck in the narrow neck of the gallbladder or within the bile duct itself.
There are two types of gallstones – cholesterol or pigment. A third type known as a mixed stone is a combination of a cholesterol and pigment stone. Although the most common type of gallstone is a cholesterol stone, it does contain some characteristics of a pigment stone. A gallstone made purely of cholesterol is rare.
Cholesterol stones are a pale yellow in color but due to the components of a pigment stone, it appears darker yellow to a brownish-yellow. Pigment stones are generally brown or black – brown stones tend to form in the bile duct while black stones develop in the gallbladder.
Read more on the Types of Gallstones, its color, composition, quantity, size and location.
Signs and Symptoms of Gallstones
Gallstones may remain silent (asymptomatic). Very small stones or biliary sludge may pass out unnoticed. Large stones are usually trapped in the gallbladder and remain unnoticed until it leads to complications. However, the small to medium sized stones can cause the typical gallstone symptoms as it gets stuck in the bile duct (cystic or common bile) on its way out with bile.
The most common symptoms reported in symptomatic gallstones is gallstone pain (biliary colic). The pain is severe and episodic and tends to aggravate at certain times, like after a meal. If the gallstone passes out of the bile duct, the pain may resolve spontaneously.
Other signs and symptoms of gallstones include :
Gallstones can lead to a number of complications that may affect the liver, pancreas or intestines. The clinical features of these complications may add to the presentation.
Read more on the Symptoms of Gallstones.
Causes of Gallstones
Cholesterol stones, which are the most common type of gallstones, form when the cholesterol levels in the bile exceeds its solubilizing capacity. This means the the bile is no longer able to hold cholesterol in suspension and it precipitates. With time the sediments aggregate to form stones.
Pigment stones are more frequently linked to infections and biliary stasis (impaired outflow of bile). It is associated with large amounts of unconjugated bilirubin in the blood.
Advancing age is one of the main risk factors in both types of gallstones. Previously it was believed that obese middle-aged Caucasian women (fat, female, forties, fertile, fair) were the highest risk group but with time a number of other risk factors were attributed to the likelihood of developing gallstones.
Read more on the Causes of Gallstones, contributing and risk factors.
Prevention of Gallstones
Understanding and identifying the risk factors for gallstone formation is one of the key components of prevention. However, it does not mean that every person with these risk factors will develop gallstones. Generally, a single episode of symptomatic gallstones warrants the surgical removal of the gallbladder (cholecystectomy) in order to prevent a recurrence. This surgery however may be delayed until there is one or more recurrence and depends on the type of gallstone.
The link between diet and gallstone formation is inconclusive but avoiding fatty foods, dairy and meat may be useful in preventing gallstones. With high triglyceride levels being one of the risk factors of developing the more common type of gallstone, cholesterol stones, a triglyceride diet and proper management of hyperlipidemia should be considered. Obesity should also be targeted with proper medical weight loss.
Read more on the Gallstones Diet for dietary management and prevention of gallstones and foods to avoid.
Treatment of Gallstones
Proper diagnosis of gallstones with blood tests, imaging techniques like an x-ray, CT scan or HIDA, as well as endoscopic investigation is necessary before medical or surgical intervention is considered.
Read more on Gallbladder Tests.
Treatment of gallstones may involve one or more of the following measures :
- Bile acid drugs like chenodiol or ursodiol helps to “dissolve” cholesterol stones.
- Fragmentation of stones (“blasting”) using sound shock waves is known as lithotripsy. However a cholescystectomy may still be advisable and lithotripsy may therefore be unnecessary.
Read more on Gallstones Treatment for information on different therapeutic options.
Article reviewed by Dr. Greg. Last updated on December 1, 2010