Gallstones Diagnosis

  • Diagnosis

    Gallstones are solid crystals that form in the gallbladder or nearby bile ducts Figure 01. Most gallstones form in the gallbladder, a small pear-shaped organ located in the upper right side of the abdomen, underneath the liver. The gallbladder stores bile, a digestive fluid that makes cholesterol, fats, and some vitamins more easily absorbed by the body.

    Click to enlarge: Anatomy of liver, gallbladder, and ducts

    Figure 01. Anatomy of liver, gallbladder, and ducts

    Cholesterol is the primary element of most gallstones, but gallstones can also form from calcium salts and bile pigments. Cholesterol is a normal component of bile, and usually remains dissolved. However, when the bile becomes oversaturated with cholesterol, small crystals form. These crystals are trapped in mucus within the gallbladder, and gradually grow. Gallstones can be as small as grains of sand or as large as golf balls.

    Gallstones are one of the most common medical conditions in the U.S. Approximately one million people in the U.S. develop gallstones each year, and as many as 500,000 operations are performed annually to remove the gallbladder, usually as a result of gallstone disease.

    Gallstones can cause serious and potentially fatal complications if left untreated.

    Gallstones occur when the liver excretes bile that is excessively rich in cholesterol. The mechanism that predisposes some people to form gallstones is not well-understood. Overproduction of cholesterol due to genetic factors, infrequent emptying of the gallbladder (as during fasting), and infection with certain bacteria have all been identified as potential causes of gallstones.

    Serious symptoms of gallstones result from blockage of the bile duct system. Blockage of the bile duct system allows bacteria to flourish, resulting in severe, potentially life-threatening infection. The infection can spread from the bile ducts to the pancreas and through the blood to other parts of the body.

    Most gallstones do not cause symptoms. It is estimated that between 10% and 20% of people over the age of 65 in the U.S. have gallstones. In the majority of cases, especially when the gallstones remain in the gallbladder, these stones cause no symptoms. As long as bile can continue to flow through its duct system, gallstones pose little danger. It is only when the gallstones cause obstructions or erode the gallbladder wall that they cause severe symptoms.

    The characteristic symptom of gallstones is sudden, irregular episodes of moderate-to-intense pain in the upper abdomen, often radiating into the right shoulder blade. The pain often begins shortly after eating, and can last from 30 minutes up to several hours. This pain cannot be relieved by changing position or taking antacids, and it may fluctuate over time. The pain may be accompanied by nausea, vomiting, and tenderness near the gallbladder, which is located in the right upper part of the abdomen.

    Symptoms of gallstones may also include fever, yellowing of the skin and eyes (jaundice), clay-colored stools, or coffee-colored urine. If you experience these symptoms, seek emergency medical care immediately. These symptoms indicate that you may have a blocked duct and/or infection. Left untreated, such a blockage can be life-threatening.

    Gallstones tend to run in families. Although the genetics are not well-understood, inheritance plays some role in development of gallstones.

    Women have a higher risk of developing gallstones than do men. Estrogen increases secretion of cholesterol in the bile and increases the risk of developing gallstones. Use of oral contraceptives, hormone replacement therapy, and pregnancy all elevate estrogen levels and increase the risk of gallstones. After menopause, estrogen production decreases, and a woman's risk of developing gallstones becomes similar to that of a man of the same age.

    The risk of developing gallstones increases with age. Before adolescence, gallstones are rare. As a person ages, the risk of developing gallstones increases. Approximately 10% to 15% of men and 25% to 30% of women will develop gallstones by age 70.

    Body weight and diet are risk factors for developing gallstones. Obesity greatly increases a person's risk of developing gallstones, primarily by increasing the amount of cholesterol excreted in the bile. A diet high in fat and sugar also increases the risk for gallstones. Fasting or other rapid weight loss diets may reduce the frequency with which the gallbladder is emptied, increasing the risk for developing gallstones.

    Gallstones are more common in certain ethnic groups. For reasons that are not well-understood, certain ethnic groups have a higher risk for developing gallstones. Native Americans and Mexican-Americans are two groups with higher-than-normal risk.

    During the initial visit, your doctor will start by taking a medical history. When gallstones are suspected, your physician will ask you to describe your symptoms as well their timing and onset. Specifically, he or she will focus on whether you have experienced pain, jaundice, fever, or chills.

    Your doctor will then perform a physical examination, feeling your abdomen to identify any tenderness, and observing your eyes and skin color to identify any jaundice.

    Your doctor will order blood tests to identify signs of infection or changes in liver or pancreatic enzymes that may indicate the presence of gallstones.

    A definitive diagnosis of gallstones is usually obtained through ultrasound or other x-ray or imaging tests. Ultrasound is a safe, effective method for identifying gallstones in the gallbladder. Another test, called cholecystography, is also used. In cholecystography, the patient swallows a contrast agent that is observed with x-rays as it flows through the body. If the gallbladder is not functioning, the contrast agent will not enter the gallbladder. If the gallbladder is functioning but gallstones are present, they will show up on the x-ray.

    If the gallstones have moved into one of the bile ducts, diagnosis may require ultrasound, computed tomography (CT scan), or other x-ray techniques using contrast agents.

    For many years, a technique called endoscopic retrograde cholangiopancreatography (ERCP) was the method of choice for diagnosing obstructions of the common bile duct. In this technique, a small flexible viewing tube is inserted down the patient's food pipe, through the stomach, and into the small intestine to observe the openings of the bile and pancreatic ducts. If obstructing stones are observed, they can be removed with a small basket attached to the end of a catheter, or the opening of the duct can be widened to allow the stone to pass through. More recently, magnetic resonance imaging (MRI) has become more common in diagnosing gallstones. The primary advantage to MRI is that it is non-invasive, and has fewer risks of complications. A disadvantage is that if gallstones are observed in the common bile duct during imaging, a separate procedure is required to remove them.

    Diet and exercise can reduce a person's risk of developing gallstones Figure 02. Maintaining a healthy body weight, avoiding foods high in fat or sugar, eating a diet rich in fruits, vegetables, and fiber, exercising regularly, and avoiding crash diets will help reduce the risk of developing gallstones.

    Click to enlarge: BMI calculator

    Figure 02. BMI calculator

  • Prevention and Screening

    Diet and exercise can reduce a person's risk of developing gallstones Figure 02. Maintaining a healthy body weight, avoiding foods high in fat or sugar, eating a diet rich in fruits, vegetables, and fiber, exercising regularly, and avoiding crash diets will help reduce the risk of developing gallstones.

    Click to enlarge: BMI calculator

    Figure 02. BMI calculator

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