The gallbladder is pear shaped organ intimately related to the liver and the digestive tract in form and function. It serves as a reservoir of bile which is a vital body fluid produced in the liver and flows through the bile ducts to the intestines. As bile is continuously secreted, excess bile flows passively into the gallbladder. At variable intervals, usually when food is ingested, the gallbladder actively contracts to squirt its contents into the intestines through the bile ducts.
Gallstones are tricky customers. Certainly not all gallstones are the same. Scientifically, they comprise cholesterol stones, pigment stones and ‘mixed stones’ – which are really what they sound like, stones comprising different ratios of pigment and cholesterol. Pure pigment stones are rare. Cholesterol stones however are very common. They make up the vast majority of gallstones and are responsible for the largest share of the problem. As such let me limit this discussion to these stones.
Cholesterol is essential to life. In the human body it is produced in cells. Ingested cholesterol, from eating meat or animal products such as butter, cheese and lard is also absorbed into the body. Excess cholesterol is excreted in a complex manner but mostly by liver cells through bile. Cholesterol is dissolved in bile and is further concentrated in the gallbladder (see Figure 1) by the absorption of water. The longer bile is retained in the gallbladder, the more concentrated it becomes.
The gallbladder empties itself under the influence of hormones such as cholecystokinin and secretin which are released on ingestion of foods. Due to factors which are still not clear, for some, the process of gallbladder contraction becomes inefficient with time. This leads to stagnation of bile which becomes too viscid, leading to formation of cholesterol particles. Eventually these particles coalesce to form stones. As such, it is the diseased gallbladder which gives rise to gallstones.
While this is true, there is no doubt that many underlying factors predispose to gallstone formation and conspire to provide the ideal environment for this phenomenon. Obesity, a diet rich in animal products (which include not just meat and poultry but dairy products and lard as well), hormonal changes in women as they approach menopause, crash diets, excessive vitamin supplementation , among others, have been implicated in the formation of gallstones.
Natural history of Gallstones
Precipitation of cholesterol in bile will, in time, coalesce to form stones. Stone size and number vary greatly, for the most part they are between 0.5 – 2cm in size. In some patients, these stones come to partially obstruct the outlet channel of the gallbladder, called the cystic duct. Attempts by the gallbladder to empty its content against this resistance triggers biliary colics, which are the episodes of upper abdominal discomfort that often follow a meal. Repeated episodes cause the gallbladder wall structure to thicken pushing the stones up against the cystic duct forming what is called a Hartmann’s pouch. Stone impaction at this site is likely to cause to severe, unrelenting pain.
The end result of gallstone formation will be chronic cholecystitis – the irreversible state of a diseased gallbladder which has lost the ability to perform its functions and becomes the source of chronic pain. This process takes a variable amount of time. For many, this process is so slow they remain pain free throughout their natural lives. As such, it is entirely possible that one may have gallstones which may never really cause any symptoms. In fact, there is ample evidence to say that if one is diagnosed to have gallstones and has no symptoms, it is much more likely than not, they will remain asymptomatic of these stones for the rest of their lives.
For others, the disease process continues more quickly. In a small number, about 2%, serious life threatening complications arise. Among these include acute cholecystitis, acute cholangitis and acute pancreatitis. The association between gallstones and cancer of the gallbladder is controversial in that while only a tiny number of patients with gallstones develop cancer, the vast majority of patients with gallbladder cancer have gallstones.
Treatment of gallstones
Gallstones which are found incidentally, and cause no trouble, are best left alone. Large studies have shown that fewer than 20% of these will ever give rise to symptoms. Serious complications are even less likely. In certain groups of persons, however, one must be cautious. In those with chronic hemolytic anemias like thalassemia, which are not uncommon in Malaysia, for example.
Medical treatment of gallstones have not proven to be very useful in the long term. There is evidence that ursodeoxycholic acid, a bile component found in both humans and bears, can promote dissolution of gallstones. The treatment may well work although it is costly and has been associated with long term side effects. Unfortunately, the gallstones often recur with cessation of treatment. Anecdotal and online reports of treatments to expel gallstones, the gallbladder ‘flush’ or ‘cleanse’, which aim to cause a strong contraction of the gallbladder to force out the stones through the bile ducts by oral ingestion of a large amount of fatty acids such as olive oil or apple sauce, are not supported by clinical evidence.
The treatment for troublesome gallstones is surgery. Surgical removal of the gallbladder (called a cholecystectomy) is curative. This can be performed with laparoscopy or a more traditional ‘open’ incision depending on the clinical circumstances. The procedure has been carried out since the eighteenth century when it was proven that the gallbladder is not essential for life. However, the procedure should not be taken lightly. Potential side effects exist for cholecystectomy and these are more likely when the operation is carried out hastily. Nevertheless, for the person who suffers recurrent episodes of pain due to gallstones, surgery remains the most effective option for relief. It also protects the patient from some life threatening complications that may arise as a result of gallstones.
Complications of gallstones
Pain from a gallstone colic is felt in the upper abdomen
These complications are rare but when they occur, they can be serious and frightening. Acute cholecystitis is a condition when the gallstones relentlessly obstruct the gallbladder triggering an infection. The pain is continuous and made worse by fever. Prompt surgery provides the best results in this situation although it is technically challenging (as opposed to surgery in elective, less pressing circumstances).
The pancreas is a gland which is involved in the production of digestive enzymes. It is also closely related to the gallbladder and bile ducts. Gallstones can migrate down the bile duct and obstruct the pancreas leading to pancreatitis. Pancreatitis is a painful condition which has an unpredictable course – although the majority of patients recover completely, serious complications have led to fatal outcomes in a few. Early cholecystectomy is advised to prevent a recurrent attack.
Gallstones can also obstruct the bile ducts giving rise to jaundice. Jaundice is a yellow discolorations of the skin and the whites of the eyes. It is a frightening symptom especially if it occurs over a short time. Jaundice is frequently accompanied by intense itching and a deep darkening of urine which is often described as tea-coloured. Treatment for this complication is less straightforward as it can be coupled with a dangerous infection. Laparoscopic bile duct clearance and cholecystectomy is an effective treatment where the expertise exists. Clearing the bile duct using an endoscope followed by surgical removal of the gallbladder later to prevent recurrence is another option.
Written by Dr T. Haritharan, Consultant Hepatobiliary Surgeon, SJMC