Gallstones or cholelithiasis are responsible for one of the most prevalent digestive disorders in the United States. They are considered a disease of developed populations but are found around the world. It is both the result of a chronic disease process and the cause of subsequent acute disorders of the pancreatic, biliary, hepatic and gastrointestinal tract. Over 6.3 million females and 14.2 million males in the United States between the ages of 20 and 74 have gallstones. Most patients with gallstones are asymptomatic but 10% of patients will develop symptoms with in five years, and 20% of patients will develop symptoms with in 20 years of diagnosing gallstones. Gallstone prevalence also increases with age. Over one-quarter of females older than the age of 60 will have gallstones. Gallstones have various compositions and etiologies.
Gallstones are usually formed from bile that is in stasis. When bile is not fully emptied from the gallbladder, it can precipitate as sludge and subsequently turn into stones. Biliary obstruction may also lead to gallstones including bile duct strictures and cancers, such as pancreatic cancer. The most common cause of cholelithiasis is from the precipitation of cholesterol that subsequently forms into cholesterol stones. The second form of gallstones is pigmented gallstones which are the result of increased red blood cell destruction in the intravascular system causing increased concentrations of bilirubin which subsequently get stored in the bile. These stones are typically black. The third type of gallstones is mixed pigmented stones which are a combination of calcium substrates such as calcium carbonate or calcium phosphate, cholesterol and bile. The fourth type is made up primarily of calcium and usually found in patients with hypercalcemia. Concurrent findings include kidney stones.
Most gallstones are asymptomatic. In the United States, approximately 14 million men and 6 million women with age range of 20 to 74 have gallstones. The prevalence increases as a person ages. Obesity increases the likelihood of gallstones, especially in women due to increases in biliary secretion of cholesterol. On the other hand, patients with drastic weight loss or fasting have a higher chance of gallstones secondary to biliary stasis. Furthermore, there is also a hormonal association with gallstones. Estrogen has been shown to result in an increase in bile cholesterol as well as a decrease in gallbladder contractility. Women of reproductive age or on birth control medication that have estrogen have a two fold increase in gallstone formation compared to males. People with chronic illness such as diabetes also have an increase in gallstone formation as well as reduced gallbladder wall contractility due to neuropathy.
Gallstones occur when substances in the bile reach their limits of solubility. As bile becomes concentrated in the gallbladder, it becomes supersaturated with these substances, which in time precipitate into small crystals. These crystals, in turn, become stuck in the gallbladder mucus, resulting in gallbladder sludge. Over time, these crystals grow and form large stones. Complications caused by gallstones are a direct consequence of occlusion of the hepatic and biliary tree by sludge and stones.
Pathology can analyze the composition of gallstones and bile. This may be helpful in determining the cause of the stones, especially in cases of primary common bile duct stones, after the gallbladder has already been removed and the exact cause of the stones is unknown.
Usually, patients who are symptomatic from gallstones present with right upper abdominal pain after eating greasy or spicy foods, nausea, and vomiting. Pain can also be present in the epigastric area that radiates to the right scapula or mid back. The classic physical exam finding is a positive Murphy's sign. This is when pain is elicited on deep palpation to the right upper quadrant underneath the rib cage upon deep inspiration. Patients may be asymptomatic for months to years until gallstones are discovered. Acute cholecystitis presents similarly, however, more severe. Jaundice can be a sign of a common bile duct obstruction from an entrapped gallstone. In the presence of jaundice and abdominal pain, often a procedure is an indication to go and retrieve the stone to prevent further sequelae. One such sequela is ascending cholangitis, with symptoms of right upper abdominal pain, fever, and jaundice (Charcot's triad). Progression of this condition is indicated by neurologic changes and hypotension (Reynold's pentad). Another sequela is acute pancreatitis with symptoms of midepigastric pain and intractable vomiting.
The best diagnostic test for diagnosing gallstones and subsequent acute cholecystitis is a right upper quadrant abdominal ultrasound. It is associated with a 90% specificity rate and depending on ultrasound operator, can detect stones as small as 2 mm as well as sludge and gallbladder polyps. Ultrasound findings that point towards acute cholecystitis versus cholelithiasis include gallbladder wall thickening (greater than 3 mm), pericholecystic fluid and a positive sonographic Murphy's sign. Gallstones can also often be found on CT scans, and MRIs, however, are not as sensitive for acute cholecystitis. Approximately 10% of gallstones may be found on routine plain films due to their high calcium content. If there is a suspected stone in the common bile duct based on ultrasound results, magnetic resonance cholangiopancreatography (MRCP) is the next step. If a common duct stone is identified on the MRCP, then the gold-standard test of an endoscopic retrograde cholangiopancreatogram (ERCP) should be performed by a gastroenterologist. A percutaneous transhepatic cholangiogram (PTHC) is also useful in diagnosing common bile duct stones if an ERCP is not possible.
Cholecystectomy treats symptomatic gallstones. The laparoscopic approach is the standard of care today. Open cholecystectomies are also done when it is not practical or advised to do a laparoscopic procedure. It is not wise to simply remove the gallstones as studies have shown that they recur after about one year. In cases of acute cholecystitis in critically ill patients or patients who are poor surgical candidates, a decompression cholecystostomy tube can be done to temporize the patient until stable enough for definitive surgery. Common bile duct stones can be removed with a preoperative or postoperative ERCP, PTHC or operatively with a common bile duct exploration. Ascending cholangitis needs to be addressed urgently by removing the blockage either with ERCP, PTHC, or surgery, as well as early antibiotic administration. In cases of nonacute cholecystitis and very poor surgical candidates, gallstones can be treated medically. Actigall (ursodiol) is administered daily with the hope of dissolving the gallstones. This has shown mixed success with some studies at best showing less than a 50% response rate.