Hard, pebble-like gallstones may range in size from a grain of sand to a golf ball. A person could have one large gallstone or lots of smaller ones inside their gallbladder.

Gallstones affect about 10–15% of the United States population, which equates to nearly 25 million people. About 25% of the roughly 1 million people who receive a gallstone diagnosis each year require treatment, which is typically some type of surgery. The medical term for gallstones is cholelithiasis.

A person with gallstones does not typically notice any symptoms unless the gallstones cause complications. For example, in some people, gallstones may block the bile ducts, which can lead to issues with the liver, gallbladder, or pancreas.

People may experience a gallbladder attack if gallstones cause a blockage in their bile ducts. During a gallbladder attack, a person experiences pain in the upper right of the abdomen.

This article explores some possible gallstone sizes and shapes, treatment options, tips for prevention, and when to contact a doctor.

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Gallstones are hard, pebble- or stone-like masses that develop in a person’s gallbladder. They are typically composed of cholesterol or bilirubin. Gallstones can range in color from black or dark blue to yellow-green. Bilirubin causes gallstones to appear darker, and cholesterol causes them to appear lighter.

Sizes can range from about a grain of sand to around the size of a golf ball.

Experts suggest that abdominal ultrasound scans of a person’s upper right quadrant are the best diagnostic tests for gallstones. A healthcare professional may be able to use an ultrasound scan to detect a gallstone as small as 2 millimeters (mm) in diameter.

Following an ultrasound scan, a healthcare professional may order magnetic resonance cholangiopancreatography followed by an endoscopic retrograde cholangiopancreatogram (ERCP) to confirm diagnosis, depending on the location of the stones.

Gallstones may also appear in regular CT or MRI scans. Also, gallstones with high calcium content may show up during a routine plain-film X-ray.

Gallstones do not typically require treatment if they do not cause any symptoms. Doctors may recommend treatment if they cause symptoms or lead to complications that need addressing.

In most cases, doctors recommend surgical treatment for gallstones, in which the surgeon removes the entire gallbladder. Healthcare professionals refer to this procedure as a cholecystectomy. There are two types of cholecystectomy: open and laparoscopic.

Typically, doctors recommend laparoscopic cholecystectomy, which often has a short recovery time of about 1 week. A person may even be able to go home on the same day as the procedure.

A doctor may recommend an open cholecystectomy when a person’s gallbladder is severely infected, inflamed, or scarred as a result of other surgical procedures. Open cholecystectomy is a more invasive procedure that may require a person to stay in hospital for about 1 week, and it may take around 1 month to recover.

If a person is not a candidate for surgery, a doctor may suggest other treatment methods that may include:

  • ERCP: During an ERCP, a healthcare professional may remove any gallstones stuck in the bile ducts.
  • Shockwave lithotripsy: This rare procedure uses sound waves to break up larger gallstones causing a blockage. Healthcare professionals sometimes use it in conjunction with medications such as ursodiol.
  • Oral dissolution therapy: A healthcare professional may recommend medications that contain bile acids, such as ursodiol, which helps break up gallstones.

A person may not be able to prevent all gallstones from forming. If a doctor removes a person’s gallstones, they often recur after roughly 1 year.

Steps a person can take to help prevent gallstone development may include:

If a gallstone causes a blockage in the bile ducts, it can cause a gallbladder attack. If this occurs, a person will likely experience pain in the upper right of their abdomen. Gallbladder attacks typically occur following a heavy meal and may last a few hours.

If a person experiences the following symptoms during or after a gallbladder attack, they should contact a doctor as soon as possible:

These symptoms could indicate a potentially serious issue with the liver, gallbladder, or pancreas. However, other conditions can also cause similar symptoms. A healthcare professional can identify the cause of these symptoms and recommend appropriate treatment options.

Gallstones may range in size from a grain of sand to the size of a golf ball. They resemble small stones, and may appear black, dark blue, or yellow-green in color, depending on whether they contain bilirubin or cholesterol.

For many people, gallstones may not cause symptoms. However, they may cause a blockage in the bile ducts, which can cause upper right abdomen pain, particularly following heavy meals. If they cause a larger blockage, they may cause more serious complications in the liver, pancreas, or gallbladder.

A person should talk with a doctor for further information about gallstones and their treatment.