Gallstones and Gallbladder Disease
What are gallstones?
Stones which form in the gallbladder and are known as gallstones, are responsible for a whole spectrum of disease entities ranging from simple biliary colic to fulminant cholangitis or necrotizing pancreatitis. In order to understand this disease spectrum it is first necessary to understand the normal anatomy of the biliary tree and the function of the gallbladder and bile. The gallbladder serves as a reservoir for bile. When we eat a fatty meal (in the US, this means every meal) a hormone called cholecystokinin is secreted by the intestinal lining and causes the gallbladder to contract, thus releasing the bile into the intestines which helps to digest fat. Bile is made in the liver secreted into the bile ducts ( or tubes) within the liver that ultimately join to form the right and left hepatic ducts. These ducts unite to form the common hepatic duct. The gallbladder is a pouch that is attached to the under surface of the liver and is connected to the common hepatic duct via the cystic duct. After its union with the cystic duct, the common hepatic duct becomes the common bile duct that then enters the duodenum after passing a short course through the head of the pancreas. The pancreatic duct usually enters the duodenum either through a common channel with the common bile duct or through an immediately adjacent point of entry. Thus, stones which form within the gallbladder can cause symptoms by interfering with normal gallbladder function, by obstruction of the cystic duct, or by their passage out of the gallbladder and obstruction of the common bile duct or pancreatic duct. Bile consists of varying quantities of cholesterol, lecithin, bile salts and bile pigments. Stones form when either cholesterol or bile pigments exist in very high concentrations in the bile and end up precipitating out of the bile in the form of gallstones.
Who gets gallstones?
The incidence of gallstones in the American population is high and increases with age. Approximately 20% of the population has gallstones. Twenty percent of these patients will go on to develop symptoms or complications from these gallstones that require surgical attention. Women are more commonly affected than men and the incidence increases with pregnancy. There is most definitely a familial predisposition but it is difficult to say whether there is truly a genetic factor since most members in a family usually have similar dietary habits. In addition, certain disease states have a higher incidence of gallstone formation. Diabetics have a higher incidence of stone formation and tend to suffer the more severe complications of gallstones, notably acute cholecystitis ( an infected gallbladder). Additionally, diabetics may have an altered perception of their symptoms ( i.e. less or no pain, lack of fever, etc) and thus be more difficult to diagnose. Hereditary diseases which result in the increased destruction of red blood cells, such as sickle cell disease, hereditary spherocytosis, and others have an associated high incidence of gallstone formation. This results from the increased circulation of breakdown products of hemoglobin which are secreted in the bile as bile pigments and pay precipitate out to form pigment stones. Patients with Crohn’s disease, a form of chronic inflammatory bowel disease, have an associated high incidence of gallstones. The reason for this is unknown.
What are the symptoms of gallstones?
The classic symptom of biliary colic (gallbladder pain) is pain after eating in the right upper quadrant (under the ribcage) of the abdomen. This pain may radiate around to the back and there may be associated nausea and vomiting. Patients with gallstones in the absence of acute inflammation or colic may experience only fatty food intolerance with mild pain, acid reflux symptoms or diarrhea after a fatty meal. The above symptoms, with the addition of fever, chills, and severe tenderness of the abdomen on physical exam, implies the presence of acute cholecystitis. There may be bacteria present in the bile causing the patient to become very ill. As stated earlier, diabetic patients are particularly prone to the more extreme forms of this disease and their symptoms may not be as evident as in non-diabetic patients. Though any patient who develops acute cholecystitis may go on to develop gangrene ( severe infection) of the gallbladder, diabetic patients are particularly prone to this. Another complication of gall stones is the passage of a stone out of the gallbladder into the bile ducts connecting the liver to the intestines. If a small stone passes out of the gallbladder it can lodge in the common bile duct causing partial or complete obstruction of that structure. Clinically, this presents as jaundice, a yellow discoloration of the skin or eyes. There may be pain as well which is indistinguishable from that of biliary colic. The presence of fever in this clinical setting implies cholangitis (infection of the bile ducts) which can be extremely serious. If emergency treatment is not undertaken death can result within hours. In some cases, a stone may pass through the common duct and obstruct the pancreas. This may result in pancreatitis. The pain is typically located in the upper mid-abdomen and radiates straight through to the back. It is usually constant rather than colicky (pain that comes and goes). There may be associated nausea, vomiting and fever as well. Fortunately, pancreatitis caused by gallstones is not usually very severe and is usually self limited, but occasionally a full blown course of necrotizing pancreatitis (severe infection of the pancreas) may develop. Any of the above clinical pictures may be seen alone or in combination thus sometimes making diagnosis more difficult. Nevertheless, correct and complete diagnosis is essential in all patients.
What is the treatment?
Proper treatment depends on and begins with proper diagnosis. All patients presenting with symptoms attributable to gallstones should have an ultrasound performed. The ultrasound will assess the presence of gallstones as well as evidence of acute inflammation of the gallbladder or evidence of stones within the common bile duct. Blood tests are also done and usually include a blood cell count, chemistries, liver function tests, and tests of pancreatic enzyme levels in the blood which may be suggestive of pancreatitis if elevated. A nuclear medicine exam such as a HIDA scan may be useful in determining the presence of acute cholecystitis. This test is very safe and involves injection of a radioactive substance intravenously. This substance is picked up by the liver and excreted into the biliary system. Under normal circumstances this substance is detected in the gallbladder, bile duct, and small bowel in a typical time related manner. In the presence of acute cholecystitis there is non-visualization of the gallbladder and in the case of bile duct obstruction, as with a stone, there may be a delay in excretion into the small intestine. If there is evidence of common bile duct stones as demonstrated by the ultrasound or suggested by liver function abnormalities in the blood work, or if the patient has pancreatitis, ERCP is then indicated. Endoscopic Retrograde Cholangio-Pancreatography (ERCP) is performed by a Gastroenterologist (a medical doctor that specializes in treatment of the intestines) with the aid of X-ray. To accomplish this a endoscope is passed through the stomach and into the small intestine where contrast is then injected into the bile ducts and X-rays are taken. If stones are found in the bile duct they may be removed with instruments passed through the endoscope. Additionally, a small incision may be made in the papilla to enlarge the entrance of the common duct into the duodenum permitting easier drainage of bile and stone fragments. This procedure may obviate the need for open bile duct surgery and its associated complications. The definitive treatment for symptoms of gallstones or for the prevention of recurrent passage of stones into the bile duct is surgical removal of the gallbladder. Today, Laparoscopic Cholecystectomy is the preferred method. This is typically an outpatient procedure but if hospitalization following this procedure is required it is usually for only one day. Recovery at home is only one to two weeks. Cholecystectomy requiring an incision usually results in four to five days in the hospital and a month recuperating at home. In some patients who have severe symptoms, acute cholecystitis or with gangrene of the gallbladder, Laparoscopic Cholecystectomy may not be able to safely be completed and an open procedure will be required. It is difficult to predict in whom this will be necessary but for patients in whom there is found to be severe inflammation or scarring or other problems making completion of Laparoscopic Cholecystectomy hazardous, the procedure will be converted to an open procedure. Well over 90% of patients will be able to have the procedure completed Laparoscopically and enjoy the benefits of this. Patients are occasionally encountered who have typical symptoms attributable to gallstones yet do not have any stones visible on ultrasound and have a HIDA scan that shows no evidence of acute cholecystitis or cystic duct obstruction. Many of these patients will be found to have a dysfunctional gallbladder. In this situation, although there are no stones present, the gallbladder does not contract normally in response to ingestion of fats, and symptoms are produced with eating. This entity is diagnosed by performing a HIDA scan with injection of cholecystokinin or CCK. The volume of the gallbladder before and after injection of CCK is measured and the ejection fraction is calculated. An ejection fraction of less than 40% is considered abnormal. Approximately 70% of these patients will usually obtain relief of their symptoms following cholecystectomy if they have undergone a previous workup for their abdominal pain that is negative for any other cause of the pain