Gallstones
What is the Gallbladder?
The gallbladder is a small organ underneath the liver on the right hand side of the abdomen. The gallbladder stores bile (produced in the liver) that is released into the duodenum to aid in digestion and absorption of fat.
What are Gallstones?
Gallstones are stones formed in the gallbladder from the constituents of bile. The term “cholecystolithiasis” refers to the presence of gallstones in the gallbladder. They can be variable in size (sand/sludge up to a few centimetres) and number. The important factor in guiding management is whether the gallstones are causing any symptoms.
Types of Gallstones
There are two types of gallstone: cholesterol and pigment.
Cholesterol
This is the most common type of gallstone in the Western world and accounts for >80% of gallstones in New Zealand. Cholesterol stones are made of predominantly of cholesterol and do not contain calcium. As such, they are unlikely to be radio-opague (show up) on an X-Ray. Cholesterol stones are usually green-yellow in colour.
Pigment
These are less common and are darker in colour as they are made of bilirubin. In patients with high turnover or break down of red blood cells (haemolysis) such as liver disease or blood disorder (e.g. sickle cell anaemia), they are more likely to get pigment gallstones.
Causes of Gallstones
There are a few reasons why gallstones may form:
Excess cholesterol in bile
Cholesterol normally dissolves in bile but if there is excess cholesterol beyond the capacity of what bile can dissolve, the excess cholesterol may crystalise. Over time, these crystals will merge to form gallstones.
Excess bilirubin
Excess bilirubin may lead to formation of pigment stones. There are a few conditions that may lead to increased bilirubin such as liver disease, infections in the bile ducts and certain blood conditions. If there were increased breakdown of red blood cells (haemolysis), this would lead to increased bilirubin as bilirubin is one of the end by-product of haemolysis.
Decreased gallbladder emptying
If there is decreased gallbladder emptying (exact reasons are unknown), the bile within the gallbladder concentrates and leads to formation of crystals and gallstones.
Risk Factors for Gallstone Formation
There are some risk factors in the formation of gallstones. These include:
Female gender, pregnancy, 40 years of age or older, overweight/obesity, family history of gallstones, rapid weight loss, liver disease and blood conditions leading to haemolysis (red blood cell breakdown).
Symptoms from Gallstones
Gallstones can be asymptomatic (20-30% chance) but if a gallstone causes symptoms, it is termed “biliary colic” and features include:
- Onset of intense ache/pain in the upper abdomen (typically on right hand side) that can radiate to the back or to the right shoulder. The pain usually comes on after eating (particularly fatty food) and can last up to a few hours. The pain is like a cramp with waves of pain on and off throughout the duration (“colic”).
- The pain can be associated with nausea and/or vomiting, and loss of appetite
- Biliary colic can be associated with the inability to sit still or restlessness (“unable to get comfortable”)
Potential Complications from Gallstones
Gallstones can cause different complications depending on the location of the stone.
Biliary colic
If the stone is impacted at the opening of the gallbladder, patients will suffer from biliary colic (as described above) and this usually resolves after 4-6 hours when the stone dislodges back into the gallbladder.
Gallbladder inflammation
If the stone remains impacted at the opening of the gallbladder, the on-going secretion produced by the gallbladder and reduced drainage from the gallbladder leads to gradual distension of the gallbladder. As the gallbladder continues to distend, this may lead to inflammation of the gallbladder (“cholecystitis”). There is persistent pain in the right upper abdomen lasting greater than 4-6 hours and can be associated with fever, nausea/vomiting and loss of appetite.
Cholangitis
If the gallstone exits the gallbladder and become stuck within the common bile duct (main duct draining the liver to the duodenum), the bile is unable to flow from the liver and can become infected (“cholangitis”). This is a life threatening issue that requires immediate specialist input and can present with jaundice (yellow skin/eyes), fevers and abdominal pain.
Pancreatitis
Gallstones can block the end of the bile duct and not only cause cholangitis (as above), it can also block the pancreatic duct leading to reduced secretion of pancreatic enzymes. These enzymes can cause inflammation of the pancreatic cells (“pancreatitis”). This is also a life threatening condition and requires hospital admission.
Choledocholithiasis
The presence of gallstones within the common bile duct is termed “choledocholithiasis”. Some patients can be asymptomatic but the majority of patients usually have symptoms of biliary colic (see above) and/or jaundice depending on whether the stone has obstructed the bile duct. The stones will need to be removed and can be done endoscopically (ERCP, Endoscopic Retrograde Cholangiopancreatography) or surgically (common bile duct exploration).
Gallbladder Cancer
Gallbladder cancer is also called gallbladder carcinoma. It is a rare type of cancer and develop from the mucosa (lining) of the gallbladder. The most common risk factor for gallbladder cancer are gallstones. Theoretically, gallstones may cause irritation/inflammation of the lining of the gallbladder and over time, chronic inflammation may lead to dysplasia (abnormal cells), and subsequently develop into cancer. This is more likely with larger gallstones of >2-3 cm in diameter.
Diagnosis
The majority of gallstones are incidental findings detected on imaging for another reason (ultrasound or cross-sectional imaging such as CT). If there are suspicions of gallstones, the tests may include:
Blood tests
The important blood test to check for is bilirubin and liver enzymes, to assess whether there is blockage of the common bile duct.
Imaging
To evaluate/confirm the presence of gallstones within the gallbladder. An ultrasound scan is the initial test of choice and if there is concerns about gallstones within the common bile duct, you will require an MRI scan. Rarely, a CT scan is requested for evaluation of gallstones.
Endoscopy
If gallstones were not detected on ultrasound or MRI scan, and there are still suspicion of small gallstones (microlithiasis), you may be referred for an endoscopic ultrasound (EUS). This involves an ultrasound probe at the end of a thin telescope which allows internal assessment of your gallbladder and bile ducts.
Choledocholithiasis (common bile duct stones) can be treated with an endoscopic procedure (ERCP) where the bile duct is cannulated to remove any stones that are in the common bile duct.
Treatment
Asymptomatic gallstones may be managed non-operatively and observed. It is thought that around 20-25% of patients will become symptomatic over the next 15-20 years. The majority of patients will present with a history of recurrent biliary colic and surgical intervention is recommended for symptomatic gallstones.
Cholecystectomy (Removal of Gallbladder)
Surgery to remove the gallbladder can be performed either laparoscopically (key-hole surgery) or open depending on indication and patient’s surgical history. The majority of cholecystectomy in New Zealand are performed laparoscopically.