What are Gallstones?
Gallstones are stones formed within the gallbladder out of the components of bile.
The term cholelithiasis, is a medical term that refers to the presence of gallstones within the gallbladder
Types of Gallstones
These are the most common type of gallstone accounting for 80% of gallstones. They are usually yellow-green in colour being composed principally of cholesterol. As they don’t contain calcium they are not usually visible by x-ray.
They are less common and being composed of bilirubin they are darker in colour. The are often associated with conditions relating to the break down of red blood cells.
Causes of Gallstones
In most people there is no known cause for developing gallstones.
Gallstones may develop when
- There is too much cholesterol in the bile. Cholesterol is normally disolved in bile. If the liver excretes too much cholesterol than the bile can dissolve, the excess cholesterol may form crystals that eventually from stones.
- There is too much bilirubin. Bilirubin is one of the end products of red blood cell break down. There are a number of conditions that increase the production of bilirubin including certain blood conditions, liver disease or infections in the bile ducts. The excess bilirubin can cystalise to form pigment stones.
- The gallbladder doesnt completely empty. Incomplete emptying of the gallbladder causes the bile within it to become concentrated, that allows for crystalisation and subsequent stone formation.
Symptoms of gallstones
Gallstones often cause no symptoms or signs.
If a gallstone becomes lodged within the neck of the gallbladder it may cause biliary colic which is characterised by
- Sudden onset of intense pain in the upper abdomen that may radiate to between the shoulder blades or tip of the right shoulder
- Pain is associated with restlessness, and inability to sit still
- Nausea and/or vomiting. The pain usually comes on soon after eating fatty food, and may last several minutes to a few hours. If the gallstones are displaced from the gallbladder they can cause a number of complications
Risk Factors for Gallstones
There are a number of risk factors attributed to the development of gallstones.
This includes female, pregnancy, 40 years of age or older,overweight or obese, diabetes mellitus, family history of gallstones, losing weight rapidly, eating high fat diet, eating a low-fibre diet, taking estrogen containing medications (oral contraceptive pill or hormone replacement therapy), taking medicine to lower cholesterol (may increase amount of cholersterol excreted into bile), liver disease, conditions increasing red blood cell breakdown
How are Gallstones Diagnosed
Most gallstones are picked up incidentally by either ultrasound or other cross sectional imaging.
In patients with suspected gallstones your doctor may arrange for;
- Imaging to confirm the presence of stones. This is usually performed by an ultrasound scan of the upper abdomen. Occasionally you may require an MRI and rarely a CT.
- Endoscopic evaluation of the bile ducts. This may involve either an endoscopic ultrasound (EUS) evaluation or a endoscopic procedure to canulate the bile duct and potentially remove any stones that are in the main duct system.
- Blood tests to evaulate whether stones may have been displaced into the common bile duct (main duct draining bile from the liver to the gut).
Complications that can arise if Gallstones are not treated
Complications of gallstones may include;
If a gallstone becomes lodged within the common bile duct (duct draining bile from the liver to the gut) it can prevent the flow of bile from the liver. The stagnant bile within the liver can become infected leading to a condition termed cholangitis. Symptoms include jaundice (yellow colour), rigors (involuntary shaking) and high temperature. This is a life threatening condition that requires immediate specialist care.
Gallstones expelled out out of the gallbladder, can block the bile duct, preventing pancreatic enzymes from being excreted into the duodenum (first part of the small intestine). The enzymes accumulate within the pancreas and irritate the pancreatic cells, the associated inflammation is called pancreatitis. This can be life threatening, and usually rquires a period of hospital admission.
Bile duct blockage
Gallstones can become lodged within the common bile duct (duct draining bile from the liver into the gut). The medical term for this is choledocholithiasis. Patients usually present with sympomts of biliary colic associated with jaundice. The stones need to be removed, and can either be done at the time of surgery or endoscopically by a procedure referred to as ERCP (Endoscopic Retrograde Cholangiopancreatography).
Gallstones are the most common risk factor for gallbladder cancer (also called gallbladder carcinoma). The basis for the development of cancer in the setting of gallstones likely occurs through chronic irritation and local production of carcinogens such as secondary bile acids, leading to epithelial dysplasia and carcinoma. The larger the gallstones (>2–3 cm in diameter), the greater the association with the development of gallbladder cancer.
Not all patients with gallstones require treatment. Asymptomatic gallstones may be managed expectantly.
It is estimated that in Western countries around 1/4 patients will become symtomatic over a period of 5-10 years. It is rare of the first presentation of gallstones to be life threatening, almost all patients present with at least one episode of biliary colic. Once gallstones become symtomatic, surgical intervantion is usually indicated.
There are drugs (Ursodeoxycholic acid) that may be able to dissolve cholesterol gallstones. They are not funded in New Zealand for this indication, are associated with side effects (diarrhoea), may need to be taken for a number of years and the stones usually recur once you stop taking the medication.
Removal of Gallbladder
Surgery involving the removal of the gallbladder is called cholecystectomy (koh-luh-sis-TEK-tuh-me). It can be performed either laparoscopically (key hole surgery) or open depending upon the indication