What Are Gallstones?

February 28, 2016

What Are Gallstones?
Gallstones comprise cholesterol stones, pigment stones and ‘mixed stones’, which are stones comprising different ratios of pigment and cholesterol. Photo: Wikimedia Commons

The gallbladder is a 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, i.e. 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 the liver cells through bile.

Cholesterol is dissolved in bile and is further concentrated in the gallbladder 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 the ingestion of foods.

Due to factors that are still not clear, for some people, the process of gallbladder contraction becomes inefficient over time. This leads to the stagnation of bile, which then becomes too viscid, leading to the formation of cholesterol particles.

Eventually, these particles coalesce to form stones. As such, it is the diseased gallbladder that 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 and 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, 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 colic, which are 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. Stone impaction at this site is likely to cause severe, unrelenting pain.

The end result of gallstone formation will be chronic cholecystitis – the irreversible state of a diseased gallbladder that 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 that never really cause any symptoms.

In fact, there is ample evidence to suggest that if one is diagnosed with gallstones and has no symptoms, it is much more likely than not they will remain asymptomatic 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 that 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 people however, one must be cautious, for example, those with chronic haemolytic anaemias like thalassaemia.

Medical treatment of gallstones has 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 aims 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 either laparoscopy or a more traditional “open” incision, depending on the clinical circumstances.

This procedure has been carried out since the 18th century, when it was proven that the gallbladder was 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 life-threatening complications that may arise as a result of gallstones.

Complications of gallstones
These complications are rare, but when they occur, they can be serious and frightening.

Acute cholecystitis is a condition where 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 and less pressing circumstances).

The pancreas is a gland that 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 that 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 recurrence.

Gallstones can also obstruct the bile ducts, giving rise to jaundice. Jaundice is a yellow discolouration 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 the 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 are 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.

Gallbladder cancer is a rare type of cancer, which is also associated with gallstones.

It is found incidentally in one percent of patients undergoing surgical removal of the gallbladder for gallstones.

The incidence may be even higher in persons known to be at higher risk. If removed while in the early stages, gallbladder cancer can be cured. At later stages, the disease is not treatable.

Gallstones are a frequent cause of discomfort and early treatment is very effective. The symptoms are upper abdominal discomfort and flatulence related to rich, fatty meals.

A healthy lifestyle can be preventive. When in doubt, consult a doctor. Prompt treatment can avoid needless complications.

Dr. Haritharan Thamutaram
Consultant General & Hepatobiliary Surgeon
Columbia Asia Hospital – Petaling Jaya

See our Press Clipping:
•  The Star Online, 28 February 2016
•  Vernacular National Paper Tamil Thanthi, 27 March 2016