Gallstones are formed from bile, a fluid composed mostly of water, bile salts, lecithin, and cholesterol. Bile is first produced by the liver and then secreted through tiny channels within the liver into a duct. From here, bile passes through a larger tube called the common duct, which leads to the small intestine. Then, except for a small amount that drains directly into the small intestine, bile flows into the gall bladder through the cystic duct. The gallbladder is a four-inch sac with a muscular wall that is located under the liver. Here, most of the fluid (about two to five cups a day) is removed, leaving a few tablespoons of concentrated bile. The gallbladder serves as a reservoir until bile is needed in the small intestine for digestion of fat. When food enters the small intestine, a hormone called cholecystokinin is released, signaling the gallbladder to contract. The force of the contraction propels the bile back through the common bile duct and then into the small intestine, where it emulsifies fatty molecules so that fat and the fat-absorbable vitamins A, D, E, and K can enter the blood stream through the intestinal lining. This “emulsification process” is much like how soap detergent can work on grease.
About three-quarters of the gallstones found in the U.S. population are formed from cholesterol. Cholesterol makes up only five percent of bile; it is not very soluble, however, in order to remain suspended in the fluid, it must be properly balanced with bile salts. If the liver secretes too much cholesterol into the bile, or if the bile becomes stagnant because of a defect in the mechanisms that cause the gallbladder to empty, or if other factors are present, supersaturation can occur. Cholesterol may then precipitate out of the bile solution to form gallstones — a condition known as cholelithiasis. The process is very slow and most often painless. Gallstones can range from a few millimeters to several centimeters in diameter.
The other 25% of gallstones are known as pigment gallstones. They are composed of calcium bilirubinate, or calcified bilirubin, the substance formed by the breakdown of hemoglobin in the blood. These black stones often form in the gallbladders of people with sickle cell anemia, hemolytic anemia, or cirrhosis.
At any point, stones may obstruct the cystic duct, which leads from the gallbladder to the common bile duct and causes pain (biliary colic) or infection and inflammation (cholecystitis). About 10% of people with stones in the gallbladder also have stones in the common bile duct (the medical term is choledocholithiasis), which can lodge in the duct and cause blockage of the bile duct, infection, or inflammation of the pancreas (pancreatitis).
About 80% of people with gallstones never experience any symptoms. If symptoms do occur, the chance of developing pain is about 2% per year for the first ten years after stone formation, after which the chance for developing symptoms decreases. Pain is usually the first symptom, but some patients develop other problems from the outset.
If you have no symptoms but you know you have gallstones, then it means that the stones probably showed up on other medical tests. Another situation may be that the test was done looking for gallstones, but the symptoms you have are not typical for pain caused by gallstones. In such cases, there may be no need to have your gallbladder removed. Some surgeons may be more likely to recommend surgery in such cases than others. The surgeons at DeKalb Surgical frequently recommend a “wait and see” approach in such situations where the gallbladder is not causing you any symptoms. However, once you have any pain or other complication from the gallstones, it’s a different story, as discussed below.
The mildest and most common symptom of gallbladder disease is intermittent pain called biliary colic, which occurs either in the middle or the upper-right portion of the upper abdomen. The pain often is also felt in the back, between the shoulder blades, as well. Large or fatty meals can precipitate the pain, but it usually occurs about one hour or more after eating, often at night. Biliary colic produces a steady pain, which can be quite severe and may be accompanied by nausea and vomiting. Changes in position, over-the-counter pain relievers and passage of gas do not relieve the symptoms. Biliary colic usually disappears after several hours.
Pain from gallstones sometimes occurs higher up in the lower chest, similar to pain like a heart attack. If a patient has pain in this area, it is important to consider the possibility of a heart problem first. If no heart abnormality is found, then one can consider whether gallstones might be the problem.
One of the most common stories we hear from our patients with gallstones is that they were awakened at about 2 am with horrible pain, either in the chest, upper abdomen or back. The pain was so bad they went to the emergency room, where an ultrasound or other test showed gallstones. In most of these cases the pain will go away after several hours, or after a dose of strong pain medicine. If your own story is like this, then you should not delay in calling us for an appointment to discuss surgery, since it is highly likely you are going to have more such episodes unless you have your gallbladder removed.
Acute gallbladder inflammation (acute cholecystitis) is a more serious problem than biliary colic. It begins abruptly and subsides gradually. Nausea, vomiting, and severe pain and tenderness in the upper right abdomen are the most common complaints; fever is common but may be absent. The discomfort is intense and steady and lasts until the condition is treated with medicine or surgery. Patients with acute cholecystitis frequently complain of pain along the right lower rib cage when taking a deep breath. Acute cholecystitis is usually caused by gallstones, but, in some cases, can occur without stones.
Chronic gallbladder disease (chronic cholecystitis) basically refers to the changes that occur in the gallbladder as a result of the presence of gallstones. Scarring causes the gallbladder to become stiff and thick. If you keep having episodes of pain (biliary colic) over and over without surgery, it can make the surgery a lot more difficult once you decide on having your gallbladder removed. So again, if you are having such symptoms you should not delay in talking to us about surgery.
Common Bile Duct Stones (Choledocholithiasis) and Gallstone Pancreatitis
Stones lodged in the common bile duct (choledocholithiasis) can block the flow of bile and cause a yellowing of the skin, called jaundice. Serious infection of the bile duct (cholangitis) may develop that causes high fever, chills, nausea and vomiting, and severe pain in the upper-right quadrant of the abdomen. This is an especially serious type of infection that requires prompt treatment.
If stones get in the bile duct they can also affect the pancreas, causing its enzymes to back up in the pancreas, essentially digesting itself. This can cause a very serious problem, called gallstone pancreatitis, or biliary pancreatitis. Although this condition often subsides over just a few days, the inflammation can in some cases progress very rapidly, and some patients may even die from this. Most patients with this problem get sick so quickly that they are admitted through the emergency room to the hospital. In almost all cases, surgery should be strongly considered to remove the gallbladder (and any stones remaining in the bile duct) before leaving the hospital.
There are three approaches to gallstone treatment: expectant management, nonsurgical removal of the gallstone, and surgical removal of the gallbladder.
Guidelines from the American College of Physicians state that when a person has no symptoms, the risks of both surgical and nonsurgical treatment for gallstones outweigh the benefits. Experts suggest a wait-and-see approach for such patients, which they have termed expectant management. Exceptions to this policy are people at risk for gallbladder cancer; subgroups at high risk for complications of gallstones (including Pima Native Americans); those with stones larger than three centimeters; and people who have polyps in the gallbladder (or at least for polyps more than 1 centimeter in size). One study reported that very small gallstones increase the risk for acute pancreatitis, a serious condition; some experts, therefore, believe that gallstones smaller than five millimeters warrant elective surgery even without symptoms.
There are some minor risks with expectant management. Gallstones almost never spontaneously disappear, except sometimes when they are formed under special circumstances, such as pregnancy or sudden weight loss. At some point, then, the stones may cause pain, complications, or both, and require treatment. For 30-year olds with asymptomatic gallstones, the probability of eventually needing an operation is about 30%; for 50-year olds, it is 20%; and for 70-year olds, it is 15%. In addition, the slight risk of developing gallbladder cancer might encourage younger people who are asymptomatic to have their gallbladders removed.
With the advent of laparoscopic cholecystectomy, surgical treatment of symptomatic gallstones is usually the preferred management. For patients who are unwilling to undergo surgery or who have serious medical problems that increase the risks of surgery, nonsurgical therapy for gallstones is available. Non-surgical treatment, however, usually cannot be used for patients who have acute gallbladder inflammation or common bile duct stones since delaying or avoiding surgery could be hazardous in these cases. The introduction of laparoscopic cholecystectomy has greatly reduced the use of non-surgical therapies.
Oral Dissolution Therapy
Oral dissolution therapy uses bile acids in pill form to dissolve The technique is generally safe but only moderately effective, since gallstones recur in the majority of patients. In addition, this therapy works only on cholesterol-based stones that are less than 1.5 cm in diameter and is less effective in obese patients.
Ursodiol or ursodeoxycholic acid (Actigall) is the oral bile acid drug which is approved for dissolution. Patients with small stones of high cholesterol content are most likely to benefit from this treatment, although a recurrence rate of 10% per year for the first five years has been reported in patients on this therapy. The drug is considered to be one of the safest common drugs and does not seem to have significant side effects. Gallstones that are calcified or composed of bile pigments are not amenable to oral dissolution therapy. Only a small percentage of patients are candidates for oral dissolution therapy. Ursodiol is very expensive; the treatment can take up to two years can cost thousands of dollars per year, and may ultimately be unsuccessful. For these reasons, this option is rarely considered to be appropriate for symptomatic gallstones.
Surgical Removal of the Gallbladder (Cholecystectomy)
Every year, about 500,000 people have their gallbladders removed. The gallbladder is not an essential organ, and even today, only surgical removal of the gallbladder (cholecystectomy) assures that the patient will not suffer a recurrence of gallstones and their symptoms. This is one of the most common surgical procedures performed and can even be performed during pregnancy with low risk to the baby and mother. The primary advantage of the surgical removal of the gallbladder over nonsurgical treatment is that the potential risk of complications from gallstones is basically eliminated.
Until the early 1990s, open cholecystectomy (the removal of the gallbladder through an abdominal incision) was the standard treatment. Now, laparoscopic cholecystectomy (commonly called lap chole, pronounced “lap KOHL-lee”), which uses small incisions, is the most commonly used surgical approach. First performed in 1987, laparoscopy is now used in nearly all cholecystectomies in the United States
Candidates for surgery include patients who have experienced one or more typical gallstone attacks, or who have other complications due to their gallstones, such as jaundice, cholangitis, or gallstone (biliary) pancreatitis.
With laparoscopy, removal of the gallbladder is guided by a laparoscope, which is a bit like a periscope. The surgeon first creates space in the abdomen by filling it with carbon dioxide, which flows out of a tube inserted through the navel. Four small incisions in the abdomen enable the surgeon to insert instruments and a laparoscope — a thin lighted optical telescope that can relay an image of the area to a video monitor. The surgeon separates the gallbladder from the liver and removes it through one of the incisions. Laparoscopic cholecystectomy requires general anesthesia, but patients can still leave the hospital earlier than with open surgery, and there is less post-operative pain and disability than with the open procedure. Patients usually go home on the same day as the surgery and return to work within ten days.
As experience with laparoscopy has grown, patients are tending to have the operation earlier, by choice and are therefore less likely to develop acute cholecystitis or common bile duct stones. If cholecystitis or common bile duct stones are present, a laparoscopic procedure may be more challenging to perform, and the procedure may have to be “converted” to the traditional open technique. Others at higher risk for conversion to open surgery are those with thick-walled and contracted gall bladders, those whose gallbladder can be felt as a palpable lump before the operation, and patients who have undergone multiple abdominal operations. In about 5% of laparoscopies, conversion to standard, or open, cholecystectomy is required.
The most serious potential complication of laparoscopy is an injury to the bile duct, which can cause serious liver damage and other complications. Fortunately, this complication is rare, occurring on average in only 1 out of every 1000 cases. Other potential complications include bile leakage into the abdominal cavity from where the gallbladder was removed or injury to the bowels.
Single Incision (Bellybutton) Gallbladder Removal
In December 2008, Dr. Michael Champney performed the first single-incision laparoscopic cholecystectomy at DeKalb Medical. Laparoscopic techniques for gallbladder removal developed rapidly in the late 1980’s, with a quick evolution of improved instruments and equipment, including high-resolution cameras and monitors, refined graspers and trocars, and clips. For the past 20 years, most surgeons have utilized fairly standard methods for the actual procedure, which typically includes the use of four separate small incisions for trocars and instruments. Although this was a marked improvement over the previous traditional 6-inch long incision, options for further minimizing the invasiveness of the procedure are now being exploited.
The new technique utilizes a single incision virtually hidden within the umbilicus (bellybutton), through which all the necessary instruments are passed. Improved trocars, instruments and optics allow for a safe and efficient operation, with further cosmetic improvement over the now standard four incision technique. Patients benefit from a further decrease in postoperative pain, potentially more rapid return to normal activities and improved cosmetic result.
Although this new technique might not be appropriate for all patients, it is a welcome addition to our armamentarium. If you or a patient are interested in more information or would like to schedule a consultation, please call our office at 404-508-4320, or contact Dr. Champney at firstname.lastname@example.org.
Before laparoscopy, the standard surgical treatment for gallstones was open cholecystectomy (surgical removal of the gallbladder). As in laparoscopic cholecystectomy, bile duct injury is a possible complication. Injury to the common bile duct requires additional operations that may be difficult to perform. This occurs, however, in only 0.1% to 0.2% of procedures. Because the procedure requires an abdominal incision, the patient usually needs to stay in the hospital for two to six days and might not return to work as quickly.
Common Bile Duct Stones (Choledocholithiasis)
Laparoscopic Common Bile Duct Exploration
If stones are detected in the common bile duct during the course of a laparoscopic procedure, they can sometimes be removed at the same time. Exploration of the common bile duct by laparoscopy is technically more difficult than removal of the gallbladder. But if the stones can be removed safely at the time of surgery, there is no need for any further procedures. If the surgeon chooses to leave detected stones in the bile duct, they would be removed at a later date using the ERCP technique described below.
Endoscopic Retrograde Cholangiopancreatography (ERCP) with Endoscopic Sphincterotomy
In cases where stones are left in the common bile duct after surgery, endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy, also called papillotomy, is used to remove the stones. Also, in cases where stones are detected in the common bile duct before surgery, ERCP with sphincterotomy may be considered. It also has a role for cholangitis caused by common bile duct stones and in cases of acute pancreatitis caused by gallstones, although its use in this latter condition is controversial.
In this procedure, the endoscope is passed through the mouth and stomach and into the duodenum (top part of the small intestine) to the common bile duct. After injection of contrast material into the duct orifice, ERCP allows visualization by x-ray of the biliary tree and any contained stones. In endoscopic sphincterotomy, tiny incisions are made through the scope to widen the ampulla of Vater (the junction between the common bile duct, pancreas, and intestine). The catheter passes into the common bile duct and the stones are captured, usually in a micro basket, and pulled back into the intestine. Endoscopic sphincterotomy is the procedure of choice when stones remain after gallbladder surgery.
Complications of ERCP and endoscopy sphincterotomy occur in up to 9.8% of cases and can be serious. Of major concern is inflammation of the pancreas (pancreatitis); younger adults are at higher risk for pancreatitis than the elderly. Pancreatitis is caused by certain enzymes that are produced in increased levels if the pancreas is irritated during the procedure. In such cases, some obstruction can occur and the condition can become life-threatening. The use of a drug called gabexate may lower the risk for this problem, though studies on this drug have had mixed results. The next most common complications are bleeding and infection. Antibiotics may be given before the operation to prevent infection, although one study reported that they had little benefit. All of these complications are the same whether the procedure is used for diagnosis or treatment. This procedure is difficult and patients must be certain their physician is experienced with it; ideally, he or she should have performed at least 180 ERCPs.
Choledocholithotomy, or traditional common bile duct exploration, is an open surgical procedure that is still used in difficult cases. In this procedure, the physician removes the stones through an incision in the common bile duct. A special T-tube is routinely left in the common bile duct after surgery. This tube is brought out through the skin and is left in place for about two weeks.
Many gallstones provoke no symptoms at all. In the absence of symptoms, gallstones seldom lead to problems. Death from gallstones is very rare, accounting for only 0.2% of annual deaths in the United States. Serious effects from gallstones are usually from infection or stones in the bile duct.
Gallbladder cancer is very rare. Gallstones are present in about 80% of people with gallbladder cancer. Less than one percent of people with gallstones develop this cancer. People who have symptomatic gallstones have four times the risk as those without symptoms. Whether gallstones themselves cause cancer, or whether some factor in bile is responsible for both conditions, is unknown. One study demonstrated that gallbladder removal reduced the likelihood of bile duct cancer, suggesting that gallstones themselves were responsible for this cancer.
Complications from Gallstones
Acute cholecystitis can cause severe inflammation and even necrosis (tissue death) in the gallbladder. Perforation and abscess formation may occur when severe symptoms persist for days. The risk for perforation increases with a condition called emphysematous cholecystitis, in which gas forms in the gallbladder. This condition is most common in people with diabetes.
Empyema of the gallbladder, or pus in the gallbladder, occurs in 2% to 3% of patients with acute cholecystitis. Abdominal pain is usually severe and is typically present for more than seven days. Mortality approaches 25% for those with empyema; death often occurs as a result of septicemia (the spread of infection through the bloodstream). Both perforation and empyema require prompt surgery. The complications can be avoided, however, by seeing a physician as soon as gallbladder symptoms occur.
Complications of Common Bile Duct Stones
Gallstones occasionally lodge in the common bile duct instead of the gallbladder, a condition called choledocholithiasis. When this occurs, stones can block the flow of bile out of the liver, causing a type of jaundice. Cholangitis (infection of the bile ducts) is a serious complication of choledocholithiasis. If antibiotics are administered immediately, the infection clears up in 75% of patients. When cholangitis does not improve the condition can be life-threatening, and either surgery or a procedure is known as endoscopic sphincterotomy is required to open and drain the ducts.
Elderly patients who develop acute cholangitis may require special care. If they develop symptoms of widespread infection (fever, rapid heartbeat, fast breathing, mental confusion) or do not respond to standard treatment, immediate drainage of the common bile duct is necessary.
Gallstones are responsible for about 45% of all cases of acute pancreatitis (acute inflammation of the pancreas), a condition that can be life-threatening. Alcohol accounts for most other cases of pancreatitis. Pancreatitis can result from stones in the bile duct, because the pancreatic duct, which carries digestive enzymes, joins the common bile duct right after it enters the intestine and so may be blocked by common duct stones. If a gallstone passes through or lodges in the lower common bile duct, pancreatitis can result. It is sometimes difficult to differentiate between pancreatitis and acute cholecystitis, but a correct diagnosis is critical since treatment is very different. Blood tests showing high levels of pancreatic enzymes (amylase and lipase) can usually indicate the diagnosis of pancreatitis. Imaging techniques are useful in confirming a diagnosis. Ultrasound is frequently used. A computed tomography (CT) scan along with a number of laboratory tests can help to measure the severity of the condition. The initial treatment is intravenous fluids and painkillers; also, the patient is not allowed to eat or drink anything. Mild cases usually subside within a week, and if gallstones are present, cholecystectomy (removal of the gallbladder) is often then performed. About 25% of pancreatitis cases are severe, and this rate is much higher — about 66% — in people who are obese. Urgent endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy and drainage of the ducts to remove any stones may be very beneficial in these cases (see How Is Gallstone Disease Diagnosed? below).
Age and Gender
Gallstones affect about 10% of all adults over 40. They occur in nearly 25% of women in the U.S. by age 60 and in up to 50% by age 75. About 20% of men have gallstones by the time they reach 75 years of age. About 80% of men and women over age 90 show evidence of gallstones. Gallstone disease is relatively rare in children, although those with a spinal injury or a history of abdominal surgery are at risk. Children who have damaged immune systems or who receive nutrition intravenously also have a higher incidence of cholelithiasis. Girls do not seem to be more at risk than boys.
Women are probably at increased risk because the female hormone estrogen stimulates the liver to remove more cholesterol from blood and divert it into the bile. Increased risk of gallstone formation has been observed in women who take oral contraceptives, and taking estrogen replacement therapy after menopause doubles the risk of gallbladder disease. Women of childbearing age may want to select an oral contraceptive with a low estrogen level to reduce their risk. Postmenopausal women may benefit from estrogen administered through skin patches, which does not appear to affect the liver but still provides other health benefits
Obesity and Rapid Weight Loss
Obesity in both men and women increases the risk for gallstones. Experiments using rats showed that obesity resulted in lower levels of bile salts relative to cholesterol in the bile causing a higher risk for cholesterol supersaturation and the formation of stones. The risk for gallstones is also increased, however, with rapid weight loss. One study reported new gallstones in 28% of obese subjects consuming ultra-low calorie liquid diets.
Cholesterol and Cholesterol-Lowering Drugs
Gallstone formation does not correlate with blood cholesterol levels, but persons with low HDL cholesterol (the so-called good cholesterol) levels or high triglyceride levels are at increased risk. The cholesterol-lowering drugs gemfibrozil (Lopid) and clofibrate (Atromid-S) reduce blood cholesterol levels by increasing the amount secreted into the bile, thus increasing the risk for gallstones. These drugs, in any case, have potentially serious side effects and are not used for lowering cholesterol if other drugs can be tolerated, including niacin and the statins, which do not contribute to the formation of gallstones.
Conditions that decrease the flow of bile and therefore increase the risk of gallstone formation include fasting, pregnancy, and intravenous feeding. The disease may progress more rapidly in patients with diabetes, who tend to suffer worse infections. Native Americans are especially prone to developing gallstones; women in this population have an 80% chance of developing gallstones during their lives. People of Asian and African descent are at lower risk. In addition to the cholesterol-lowering drugs mentioned above, the diuretic thiazide may increase the risk for gallstones slightly.
Pigment gallstones are more likely to affect the elderly, people with cirrhosis, and those with chronic hemolytic anemia, including sickle cell anemia. People of Asian descent who develop gallstones are most likely to have the pigment type.
Maintaining a normal weight and avoiding fasts are the keys to reducing the risk of gallstones. For people who are overweight who attempt ultra-low-calorie diets, one study has shown that gallstones may be prevented by taking ursodiol or ursodeoxycholic acid (Actigall), which is ordinarily used to dissolve existing gallstones (see Non-Surgical Therapy for Gallstones under What Are the Treatments for Gallstones? below). It should be noted that this medication is very expensive. A less costly and easier solution was reported in another study, which found that incorporating a modest amount of fat (preferable monounsaturated fat) in a very low calorie diet may reduce the risk of gallstone formation.
Alcohol in small amounts (one ounce per day) has been found to reduce the risk in women by 20%, although it should be stressed that alcohol is easily abused, and higher amounts may increase the risk of many diseases, including breast cancer in women. Some studies indicate that vitamin C may be protective.
Exercising regularly and vigorously may reduce the risk of gallstones and gall bladder disease. One study indicated that men who performed endurance-type exercise (such as jogging and running, racquet sports, and brisk walking) for thirty minutes five times per week reduced their risk for gallbladder disease by up to 34%. The benefit depended more on the intensity of activity than the type of exercise. Some researchers guess that in addition to controlling weight, exercise helps normalize blood sugar levels and insulin levels, which, if abnormal, may contribute to gallstones.
Gallstones and Gallbladder Disease
The diagnostic challenge posed by gallstones is to be sure that abdominal pain is caused by stones and not by some other condition. Ultrasound or other imaging techniques easily find gallstones. Nevertheless, because gallstones are common and may cause no symptoms, simply finding stones does not necessarily explain a patient’s pain.
Irritable bowel syndrome (IBS) has some of the same symptoms as gallbladder disease, including difficulty in digesting fatty foods. In IBS, however, pain usually occurs in the lower abdomen. Acute appendicitis, pneumonia, stomach ulcers, hiatal hernia, pancreatitis, hepatitis, kidney infections, and even a heart attack may mimic a gallbladder attack, so it is important to see a physician immediately if symptoms occur.
In patients with abdominal pain, causes other than gallstones are often responsible if the pain lasts less than 15 minutes, is present most of the time, frequently comes and goes, or is not severe enough to limit activities.
History and Physical Examination
The diagnosis of any disease begins with asking questions of the patient about their symptoms. A physical exam often reveals tenderness in the right upper area of the abdomen in acute cholecystitis and sometimes in biliary colic. There is usually no tenderness in chronic cholecystitis.
Laboratory tests are usually normal in people with simple biliary pain or chronic cholecystitis. In acute cholecystitis, and especially choledocholithiasis (stones in the bile duct), however, blood tests of the liver show elevations of the enzyme alkaline phosphatase and bilirubin. Bilirubin is the orange-yellow pigment found in bile; high levels cause jaundice, which gives the skin a yellowish tone. A high white blood cell count (leukocytosis) is another common finding but should not be relied on to establish a diagnosis of acute cholecystitis.
Ultrasound, the diagnostic method most frequently used to detect gallstones, is a simple, rapid, and noninvasive imaging technique. Ultrasound detects gallstones as small as two millimeters in diameter with an accuracy of 95% to 98%. The patient must not eat for six or more hours before the test, which takes only about 15 minutes. During the same procedure, information can be obtained about the liver and common bile duct, as well as the pancreas, kidneys, spleen and blood vessels.
Cholescintigraphy (HIDA Scan, or Hepatobiliary Scan)
Cholescintigraphy, another imaging technique, is non-invasive and is occasionally useful. In this procedure, a chemical containing a radioisotope is injected intravenously. This material is excreted into bile and, in normal patients, can be seen filling the gallbladder. In acute cholecystitis, however, the dye does not enter the gallbladder, indicating that the cystic duct is blocked. Cholescintigraphy takes 60 to 90 minutes. Though the scan can detect obstruction of the cystic duct to the gallbladder it cannot identify individual gallstones. Occasionally, the scan gives false positive results, particularly in alcoholic patients with liver disease or patients who are fasting or receiving all nutrients intravenously. Other terms used for this test include hepatobiliary scan, nuclear gallbladder scan, or HIDA or DISIDA scan.
Oral Cholecystography (OCG)
Cholecystography relies on an abdominal x-ray. It was once the standard method for evaluating the gallbladder but has been essentially replaced by ultrasound and cholescintigraphy, so this test is almost never used anymore. In this procedure, tablets containing an iodine compound that appears on an x-ray is taken one day before the test. The tablets are absorbed by the intestine, excreted by the liver, and concentrated in the gallbladder, where it will be seen on an x-ray taken the following day. Stones may be outlined by the dye. A diseased gallbladder, however, will not be seen, because its outlet is blocked and so will not absorb the dye.
Gallstones may or may not be seen on a CAT scan when present in the gallbladder. As it turns out, the ultrasound is really better than CAT scan to know for sure. But it is not uncommon for gallstones to be seen on a CAT scan ordered for other reasons.
Common Bile Duct Stones (Choledocholithiasis)
If there is evidence for common bile duct stones, such as dark urine, jaundice, clay-colored stools, pancreatitis, or elevation of certain liver function tests, then more extensive tests may be appropriate.
Invasive Diagnostic Procedures
Detection of common bile duct stones must often rely on endoscopic retrograde cholangiopancreatography (ERCP) This procedure involves the use of an endoscope — a flexible telescope containing a miniature camera and other instruments — which is passed through the mouth, the stomach, and into the upper small intestine, where the bile duct empties. This is a difficult procedure and patients should be sure their physician is experienced in performing it.
Another x-ray technique, percutaneous transhepatic cholangiography, uses a long, thin needle inserted through the skin into the liver to inject a contrast dye into the bile duct.
Both of these techniques are expensive, invasive, and have rare but serious risks; they should be used only when a disease is considered likely. These invasive procedures are not necessary if preoperative ultrasound and blood tests are normal and there is no history of jaundice or pancreatitis.
Cholangiography is also sometimes used during surgery to determine if there are any stones in the common bile duct and to confirm the position of the bile duct.
Less invasive imaging techniques are being investigated for diagnosing common bile duct stones. Ultrasound, which is accurate in diagnosing stones in the gallbladder, is not as sensitive for showing if there are stones in the common bile duct.
A relatively new test which provides pictures similar to those obtained by ERCP is called magnetic resonance cholangiopancreatography, or MRCP. This study is similar to a CT scan or MRI, with the addition of a contrast agent injected into the veins, which is concentrated within the bile duct system. This test has the advantage of being less invasive than ERCP. On the other hand, when ERCP is done, treatment can be done at the same time to remove the common duct stones.