A gallstone is an abnormal stone that is formed in the gallbladder.

Gallstones are usually made up of either bile pigments or cholesterol. When they form in the gallbladder, they can cause complications.

It used to be taught that gallstones are most commonly found in females in their 40s or 50s, who were fertile and who had fair hair. However it seems to be more often now found in women who have had their first baby and who had previously been on the oral contraceptive pill.

The commonest complication of gallstones is inflammation of the gallbladder. This is called cholecystitis.

Other complications of gallstones include:

Pancreatitis:

Pancreatitis is a very severe condition, caused by inflammation of the pancreas gland. Gallstones can pass down the common bile duct and can get stuck at the point where the common bile duct enters the duodenum. This junction is called the Ampulla of Vater. At this point, not only does the common bile duct enter the duodenum, but the main duct of the pancreatic gland, the pancreatic duct, also joins the duodenum.

If a gallstone gets caught at the Ampulla of Vater, it can hold this tube open allowing juices from the duodenum to reflux back up into the pancreatic duct. When this happens, very strong enzymes are activated inside the pancreatic duct causing the pancreas to start digesting itself. This can be very severe and sometimes fatal.

Obstructive jaundice:

If a gallstone passes down the common bile duct, and gets stuck in the duct itself, there is no route for the bile to pass into the bowel. Therefore, bile produced by the liver starts backing up, causing distension of the bile ducts and often the gallbladder, causing the bile pigments to back up back into the bloodstream.

As the bile pigments stay in the blood, the patient turns yellow - jaundice. As the bile pigments cannot get into the bowel, the faeces lose their colour and instead of being a normal brown become very pale. The combination of jaundice and pale stools means obstructive jaundice.

Empyema of the gallbladder:

The gallbladder only has one entrance and exit called the cystic duct. If a gallbladder stone gets caught at the cystic duct, no bile can get into the gallbladder. However, the wall of the gallbladder continues to produce mucus and so the gallbladder gets large and distended with mucus, causing increasing tension of the wall and pain. Eventually, if this is not relieved, this can get infected causing a severe abscess.

Gallstone ileus:

If a large gallstone moves from the gallbladder into the bowel, it can get caught lower down in the small intestine. This is quite a rare, but very interesting condition. The gallstone gets impacted in the small intestine causing obstruction. This manifests itself by pain in the abdomen, followed later by swelling of the stomach, vomiting and then constipation.

Occasionally, the stone can move, relieving the obstruction and symptoms - and then get impacted again causing them to come back once again.

Investigations for gallstones.

Unlike kidney stones, gallstones are invisible on x-rays in about 90% of cases. As such, other tests are needed such as ultrasound or special contrast studies.