Causes of gallstone diseases

  

Gallstones contain about 80% cholesterol. Cholesterol is a steroid molecule that is absorbed from certain digested fats, such as butter, and is also produced in the liver. It is a precursor to many of the body's important steroid hormones. Even though cholesterol is vital for proper body functioning, it is often not handled well by our bodies.

If there is an excess of cholesterol or insufficient amounts of bile salts or lecithin to keep it soluble, the cholesterol will precipitate, forming a hard solid mass called a gallstone.


If a gallstone is small, it will pass through the bile duct and out into the intestine, causing no complications. A larger stone, however, may lodge in the neck of the gall­bladder. when this happens, both bile and the pancreatic juice are blocked in their passages, resulting in severe impairment of both digestion and absorption in the intestinal tract. Since no bile reaches the intestine, there is also decreased emulsification and absorp­tion of fats. Gallstones may sometimes lodge at the point where the bile duct and pancreatic duct join before they enter the duodenum.

This is because it is almost completely insoluble in body fluids. Excess cholesterol in the blood may be deposited along the arterial walls and in the heart. This can lead to arteriosclerosis and ultimately, to heart disease. A complete blockage may lead to a condition known as jaundice, in which the skin yellows due to an accumulation of bile pigments in the body.
       

The body's major mechanism for the removal of cholesterol from the blood takes place in the liver, which releases cholesterol into the intestine as part of the bile. Bile contains bile salts and lecithin that emulsify lipids such as cholesterol. 

In the gallbladder, bile is stored and slowly concentrated by the removal of water. As this happens, the concentration of cholesterol increases to a level near the saturation point.


This leads to pain and contractile spasms of the gallbladder wall. Since the gallbladder is off to the side of the bile duct, bile can still flow from the liver to the intestine for digestion. If the spasms of the gall­bladder are powerful enough, the stone may be forced out of the gallbladder and become lodged in the bile duct, obstructing it.


Gallstones may be removed surgically if they are not dissolved by the body. If necessary, the gallbladder may be removed without any great effect on digestion.