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Gallstones

Gallbladder Calculi Form Slowly

Apr 7, 2009 Stephen Allen Christensen

Gallbladder disease caused by gallstones is common in America, particularly among diabetics, alcoholics, pregnant women, and the morbidly obese.

The gallbladder is a pear-shaped sac that lies suspended from the bottom of the liver. Its job is to store and concentrate bile that is produced by the liver.

Bile is injected through the common bile duct and into the gut when a meal is consumed. Bile has several purposes: it emulsifies fats and fat-soluble vitamins; it helps to eliminate potentially toxic compounds that have been metabolized by the liver; it creates an osmotic gradient that assists in the movement of stool through the gut.

Unfortunately, when conditions within the gallbladder are appropriate, calculi (stones) can form. These concretions are usually asymptomatic (80%), but they can be the source of problems ranging from intermittent abdominal pain to life-threatening obstruction with infection.

Types of Gallstones and Their Development

Three major types of gallstones have been identified:

Cholesterol stones: Account for at least 85% of gallstones in the Western world. They form when bile is supersaturated with cholesterol, which precipitates into crystals that eventually form stones. Various conditions may contribute to this process, including diabetes and obesity..
Black pigment stones: Composed of calcium bilirubinate and inorganic calcium salts; usually small, hard stones. Alcoholism, chronic hemolysis (breakdown of red blood cells), and older age are risk factors.
Brown pigment stones: Composed of bilirubinate and fatty acids; typically soft and oily. Infections, parasitic infestations, and chronic inflammation may predispose to these gallstones.

Gallstone Growth

Gallstones grow slowly, expanding by approximately one to two millimeters annually. Thus, it could take five to 20 years for a typical stone to become troublesome.
Biliary sludge, which may be a precursor to gallstones, often develops during periods of gallbladder stasis (e.g., fasting or pregnancy); sludge often clears when the underlying condition resolves, but it, too, can cause symptoms.

Signs and Symptoms of Gallstones

Symptoms of gallstone disease occur when a stone (or sludge) enters the duct that empties the gallbladder (the cystic duct) and causes transient or persistent obstruction.
Transient obstruction causes intermittent pain (biliary colic). This discomfort begins abruptly and often occurs in the upper right abdomen, although it can be poorly localized. The pain often radiates into the back or even into the right arm.
Biliary colic typically becomes intense within 15 to 60 minutes, lasts for up to six hours, and then slowly resolves. Nausea and vomiting are common, but fever is absent.
Biliary colic may recur for months, and full-blown obstruction may never occur. When a gallstone does lodge in the biliary ducts, it causes inflammation of the gallbladder (cholecystitis); symptoms are similar to biliary colic, but more protracted. Low-grade fever often accompanies cholecystitis.
Fatty food has not been shown to be a specific precipitating factor for biliary colic.
Complications of untreated or persistent cholecystitis—or of obstruction at the lower reaches of the bile duct—include gallbladder perforation with peritonitis; pancreatitis; cholangitis (an infection that ascends from the gut into the bile ducts and liver); jaundice; sepsis; even death.

Treatment for Symptomatic Gallstones

Obstructing gallstones (or cholecystitis caused by sludge) can be treated via:

Cholecystectomy: Gallbladder removal, mostly through a laparoscopic approach, is a safe and effective procedure for most people. Dietary restrictions are not necessary following surgery.
Medications: Cholesterol stones can sometimes be slowly dissolved by administering bile acids (i.e., ursodiol). Smaller gallstones respond more readily, and resolution may take many months. Stones often recur if treatment is not continued.
Lithotripsy: Fragmentation of stones with shock-wave lithotripsy is possible, but is not widely used due to advances in laparoscopic surgery.
Endoscopic retrograde cholangiopancreatography: Stones lodged at the bottom of the bile duct can sometimes be dislodged via endoscopy.

(From The Merck Manual, 18th Edition 2006:240-44)

The copyright of the article Gallstones in General Medicine is owned by Stephen Allen Christensen. Permission to republish Gallstones in print or online must be granted by the author in writing.