Gallstones are medically known as cholelithiasis. The gall bladder is a structure that stores bile and its location is under the right part of the liver. The gall bladder has a capacity of 30 to 50mls. Bile is formed in the liver and moves through a pipe connection (hepatic duct) either into the intestine to help in the absorption of fatty meals and some vitamins while the excess goes into the gall bladder for storage. Another connecting pipe from the gall bladder (bile duct) is joined by a connecting pipe from the pancreas (pancreatic duct) and then opens into the intestine where the gall bladder empties some of its contents into when required.

Bile in the gall bladder is more concentrated than bile in the liver because the inner walls of the gall bladder absorbs water and other substances from bile that is stored in it. Bile consist mainly of bile acids (which are produced from cholesterol in the liver), cholesterol and other substances and chemicals.

Bile acids are like detergents which help to dissolve cholesterol, thereby converting it to a form that can be easily excreted. Other functions of bile acids include facilitating absorption of fat soluble vitamins (vitamins A, D, E, and K) and fatty and high protein meals. When a meal containing fat is ingested for instance, fried foods, the duodenum (the 1^st part of the small intestine) releases a hormone called cholecystokinin which causes the gall bladder to squeeze and release some of its contents into the intestine.

What causes gallstones?

When there is an imbalance in the constituents of bile- either cholesterol content is higher than it should be or the bile acid content is less than it should be then bile stones begin to form. If the gall bladder is not squeezing to release its content as much as or as often as it should, bile stones could form as well because the longer the contents remain in the gall bladder, the more the walls absorb the content and make it become thicker. The thicker bile is, the higher the likelihood that gall stones would form.

Gallstones could be either cholesterol stones or pigment stones. Cholesterol stones are the most common type, constituting about 80 percent of gallstones. The cholesterol stones contain mostly cholesterol whereas pigment stones contain mainly calcium and other substances. Gall stones are more common in females than in males.

Risk factors of gallstones (Cholelithiasis)

The predisposing factors for gall stones include

Obesity
Diet-High calorie, cholesterol rich diet and very low calorie diet
High blood cholesterol levels
Increased uptake of cholesterol from blood
Genetic causes due to increased activity of certain enzymes which cause imbalance in bile constituents
Rapid weight loss particularly through very low calorie diets. With rapid weight loss, cholesterol in the tissues get into the systemic circulation resulting in increased cholesterol secretion in bile. In addition, there is reduced contraction of gall bladder to release its content into intestine for absorption of fat since the individual is also on very low calorie, low fat diet.
Pregnancy. During pregnancy, there is sluggish contraction of the gall bladder and in the third trimester there is increased cholesterol saturation in bile. High levels of oestrogen (female sex hormone) contributes to sluggish contraction of the gall bladder in pregnancy. Women on contraceptives with high oestrogen content may also be at risk of developing gall stones.
Drugs such as octreotide and clofibrate
Fasting state
Prolonged feeding through the veins – total parenteral nutrition
Increasing age is associated with increased bile secretion of cholesterol and reduced secretion of bile salts
Chronic (prolonged) infection of the biliary tract
Prolonged breakdown of red blood cells (haemolysis) as seen in individuals with abnormal haemoglobin such as sickle cell disease.
Liver cirrhosis
Removal of the 3^rd part of the small intestine (ileum)

Symptoms of gallstones

Gallstones may not produce symptoms, these ‘silent gallstones’ are only incidental findings during investigation for other ailments. Symptoms occur when there is swelling (inflammation) of the bile ducts or lodging of a gallstone in the bile duct thereby causing obstruction. Symptoms include

Pain in the right upper quadrant of the abdomen
Right shoulder pain
Nausea and vomiting
Flatulence especially after eating fatty foods
Fever
Yellowness of eyes
Pale stools
Dark coloured urine
Itchiness of skin

Diagnosis of gallstone

Diagnosis of gallstones is by

Blood tests
Abdominal ultrasound
Endoscopic ultrasound (EUS)
Other imaging tests such as endoscopic retrograde cholangiopancreatography (ERCP), oral cholecystography, computerized tomography (CT), hepatobiliary iminodiacetic acid (HIDA) scan and magnetic resonance cholangiopancreatography (MRCP)

Treatment of gallstone

Gallstones are treated by:

Using medication to dissolve the stone
Having surgery to remove the gallbladder (cholecystectomy).