Gallstones

Gallstones are crystal-like deposits that form in the gallbladder - a small organ under the liver that stores bile (a fluid used by the digestive system).

The stones may stay in the gallbladder and cause no symptoms, or they may irritate the gallbladder wall or block gallbladder ducts, resulting in infection, inflammation and upper abdominal pain. It is possible for the infection to spread to the liver or pancreas. Treatment can range from pain relief to surgery.

In New Zealand, the proportion of the population with gallstones may be as high as 20%.

Causes

The gallbladder is part of the digestive system. It is a pear-shaped, sac-like structure approximately 8 cm long and 2.5 cm wide, located alongside the stomach and attached to the lower surface of the liver. The function of the gallbladder is to concentrate, store, and excrete bile ( a fluid that helps in the digestion of fat).

gastrointestinal tract gallbladder

Bile has several components including cholesterol, bile salts, and bile pigments (eg: bilirubin). Gallstones are thought to develop because of an imbalance in the chemical composition of bile inside the gallbladder, such as when the levels of cholesterol or bilirubin in the bile become too high. The excess cholesterol or bile forms crystals, which eventually form stones.

The two main types of gallstones are:

• Cholesterol gallstones: The majority of all gallstones are cholesterol stones. The amount of cholesterol that can dissolve in bile depends on how much bile salt it contains. Too much cholesterol, or too little bile salt, tends to cause cholesterol stones to form in the gallbladder.
• Pigment gallstones: These stones are formed by calcium and bilirubin when there is an excess of bilirubin in the gallbladder. Pigment stones tend to form in patients with certain blood or liver disorders.

Risk factors

The risk of developing gallstones tends to increase with age (especially after age 40 years) and they're more common among people of European ethnicity than Maori, Pacific or Asian New Zealanders.

Women develop gallstones more commonly than men and at a younger age, and there is frequently a family history of the disease.

Other factors that increase the risk of developing gallstones include:

• Being overweight or obese – particularly when the extra weight is carried around the waist
• Eating a high-fat, low-fibre diet
• Having diabetes
• Having high blood cholesterol levels
• Heavy drinking
• Smoking.

As pregnancy and contraceptive pills can slow down gallbladder activity, women who have had multiple pregnancies or long-term contraceptive pill use are at higher risk of developing gallstones.

Signs and symptoms

Gallstones vary greatly in size. Some people may form one large stone, whereas others may have hundreds of tiny stones. Most commonly, gallstones are 5–10 mm in diameter.

Most people with gallstones do not experience any symptoms. If symptoms are present, the most common early sign of gallstones is upper abdominal pain. This pain usually occurs in the upper right side of the abdomen, is often sudden and severe, and may radiate to the chest, back, or the area between the shoulders. Other symptoms that may occur include:

• Indigestion
• Nausea or vomiting
• Jaundice (the yellow appearance of skin and the whites of eyes caused by bilirubin build-up in the blood) when gallstones block the passage of bile
• Light-coloured stools.

The abdominal pain associated with gallstones is referred to as biliary colic. This type of pain is commonly set off by eating fatty foods and often occurs in the middle of the night. The symptoms experienced may be so severe that people need to seek immediate medical attention.

When infection of the gallbladder is present it is possible to also experience low-grade fever, sweats, and chills.

Diagnosis

If gallstones are suspected, it is important to consult a doctor for an accurate diagnosis and treatment. The doctor will look for signs of jaundice and will assess the abdomen for swelling and pain. Blood tests are usually performed to check the function of the liver and pancreas and to rule out other conditions that may be causing the symptoms.

The most common test used to definitively diagnose gallstones is an abdominal ultrasound scan to create pictures of the gallbladder, which are then analysed to look for signs of gallstones.

An endoscopic ultrasound (EUS) is a procedure that can help identify smaller stones that may be missed by an abdominal ultrasound. A thin, flexible tube (endoscope) is passed through the mouth and into the digestive tract, to provide a precise image of the gallbladder and nearby tissues.

If it is suspected that gallstones are blocking the ducts, then a test called endoscopic retrograde cholangiopancreatography (ERCP) may be performed. This test involves inserting an endoscope with a light and camera at its tip through the mouth into the digestive tract. A special dye is injected through the endoscope into the bile ducts allowing the outline of the ducts to be highlighted. Gallstones found in the ducts can sometimes be removed during the ERCP procedure.

Other specialised scans or x-rays are sometimes used to confirm the diagnosis and highlight the location of the gallstones.

Treatment

In general, treatment will depend on the frequency and severity of the symptoms experienced. Because it is possible that people who experience biliary colic will not experience a further episode, your doctor may advise a wait and see approach.

If attacks are occasional and mild, they may be able to be managed with pain-relieving medications, applying heat to the affected area, resting and taking sips of water. Reducing the amount of fat in your diet and maintaining a healthy body weight may also be beneficial. If attacks are frequent or severe surgery is usually recommended.

Surgery

Cholecystectomy is the surgical removal of the gallbladder and is a common and routine procedure. It may be recommended when the symptoms of gallstones are problematic. If there is infection or acute inflammation of the gallbladder, this may need to be treated with antibiotics before the gallbladder can be removed.

The gallbladder is not essential to live or to digest food. When the gallbladder is removed, bile is still produced by the liver and flows directly into the small intestine.

The two cholecystectomy techniques are:

Open cholecystectomy

This is the "traditional" but now-a-days less common surgical technique for removing the gallbladder and is performed under a general anaesthetic. A single incision is made below the rib cage. Through the incision, the surgeon can view the area and remove the gallbladder.

Laparoscopic cholecystectomy

Laparoscopic cholecystectomy is also performed under general anaesthetic but is less invasive and much more commonly used than the open cholecystectomy technique. It has a faster recovery time and a shorter hospital stay (usually just one night). A telescope-like instrument (a laparoscope) is inserted through one incision (allowing the surgeon to view the inside of the abdominal cavity on a television monitor) and surgical instruments are inserted through other incisions. The gallbladder is located and removed through an incision in the belly button.

Surgery risks and complications

As with any surgery, there are possible risks and complications which you should discuss with your doctor before surgery. These include:

• Anaesthetic complications
• Bleeding
• Wound infection
• Injury to or leakage from the bile duct
• Discomfort or numbness around the area of incision
• Jaundice.

Medication

For small gallstones that don't contain calcium, it may be possible to dissolve them by taking ursodeoxycholic acid tablets. However, ursodeoxycholic acid tablets are not often recommended because they are not always effective, need to be taken for a long time (up to 2 years), and gallstones are likely to form again once treatment is stopped. They are usually used for people who are unable to undergo surgery. Occasionally, they may be used to prevent gallstones in people at high risk of developing them.

References

Chapman, B.A., et al. (2003). Gallstone prevalence in Christchurch: risk factors and clinical significance. N Z Med J. 2000;113(1104):46–8.
Mayo Clinic (2019). Gallstones (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/gallstones/symptoms-causes/syc-20354214 [Accessed: 23/08/19]
NHS (2015). Gallstones (Web Page). Redditch: National Health Service (NHS)
England. https://www.nhs.uk/conditions/gallstones/ [Accessed: 23/08/19]
O’Toole, M.T. (Ed.) (2017). Cholelithiasis. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis: Elsevier.
O’Toole, M.T. (Ed.) (2017). Choledocholithiasis. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis: Elsevier.
Stringer, M.D., et al. (2013). Gallstones in New Zealand: composition, risk factors and ethnic differences. ANZ J Surg. 2013 Jul;83(7-8):575–80.

Last Reviewed – September 2019

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