Gallbladder & Gallstones

Gallstones are small, pebble-like substances that develop in the gallbladder. An estimated 20.5 million people in the United States have gallstones. Women are two to three times more likely than men to have them. In fact, 10 to 30 percent of women develop gallstones in their lifetime.

There are two types of gallstones. Between 70 and 80 percent are cholesterol gallstones, which are made up mostly of cholesterol. The remaining 20 to 30 percent are black- or brown-pigment gallstones, which have a much lower cholesterol content and are primarily made of bilirubin (a component of bile made by the liver).

Causes of gallstones

Gallstones form when the liquid (the bile) stored in the gallbladder hardens into stones. This hardening occurs when there is too much cholesterol or bilirubin in the bile or when the gallbladder doesn't empty as it should. It's not known why these imbalances occur. Diet may play a role: For instance, eating a diet high in cholesterol and fat and low in fiber may increase the risk of gallstones.

Risk factors for the development of cholesterol gallstones include

  • a genetic predisposition (particularly in people of Pima Indian or Scandinavian ancestry)
  • age (older than age 50)
  • obesity
  • pregnancy
  • use of medications such as postmenopausal estrogen, oral contraceptives, or the antibiotic ceftriaxone (Rocephin)
  • prolonged intravenous feeding
  • rapid weight loss
  • diseases of the terminal ileum (the last portion of the small intestine, which is responsible for reabsorption of bile acids from the bowel into the blood)

A 2008 study suggested that a deficiency of magnesium—an essential mineral found in green vegetables, fish, whole grains, legumes, seeds, and nuts—might be a risk factor as well.

People with hemolytic anemia or a bacterial infection inside the bile ducts are at risk for pigment gallstones.

Symptoms of gallstones

Between 70 and 80 percent of gallstones produce no symptoms and are discovered by accident during an imaging test for another health problem. There is a 1 to 4 percent chance each year that a symptom-free gallstone will begin to cause symptoms.

The most common cause of symptoms is gallstone migration. When gallstones migrate, they can obstruct the gallbladder neck (the narrow portion between the gallbladder and the beginning of the cystic duct), the cystic duct, or the common bile duct. The resulting increased pressure inside the gallbladder produces sharp pain in the right upper portion of the abdomen. Intermittent episodes of such pain, due to obstruction and spontaneous release (when the gallstone dislodges), are called biliary colic.

When stones migrate from the gallbladder into the common bile duct, they can cause partial or complete obstruction of bile flow. Signs and symptoms of bile duct obstruction are intermittent abdominal pain, jaundice (yellow discoloration of the skin and eyes), and cholangitis (inflammation of the bile ducts).

Gallstones that lodge in the major duodenal papilla (a small elevation in the second portion of the duodenum, where both the common bile duct and the pancreatic duct openings are located) can cause acute pancreatitis (inflammation of the pancreas), with abdominal pain, nausea, and vomiting.

If the obstruction persists, a condition called acute cholecystitis may develop. In this condition, rising pressure inside the gallbladder leads to decreased blood flow to the gallbladder wall, inflammation, bacterial infection, and, in some cases, a hole in the wall of the gallbladder (perforation). Symptoms of acute cholecystitis include severe pain, fever, nausea, and vomiting. The pain is located below the bottom edge of the right rib cage and often spreads to the back, right shoulder, or right side of the neck.

Publication Review By: H. Franklin Herlong, M.D.

Published: 25 Mar 2011

Last Modified: 05 Jan 2015