Cancer and other causes of liver disease
Cancers. Primary cancers of the liver arise from liver structures and cells. Two examples include hepatocellular carcinoma and cholangiocarcinoma.
Metastatic cancer (secondary cancer of the liver) begins in another organ and spreads to the liver, usually through the bloodstream. Common cancers that spread to the liver begin in the lung, breast, large intestine, stomach, and pancreas. Leukemia and Hodgkin's lymphoma may also involve the liver.
Blood flow abnormalities. Budd Chiari syndrome is a disease in which blood clots form in the hepatic vein and prevent blood from leaving the liver. This can increase pressure within the blood vessels of the liver, especially the portal vein. This pressure can cause liver cells to die and lead to cirrhosis and liver failure. Causes of Budd Chiari syndrome include polycythemia (abnormally elevated red blood cell count), inflammatory bowel disease, sickle cell disease, and pregnancy.
Congestive heart failure, where poor heart function causes fluid and blood to back up in the large veins of the body can cause liver swelling and inflammation.
Gallstones. Normally, bile flows from the liver into the gallbladder and ultimately into the intestine to help with the digestion of food. If bile flow is obstructed, it can cause inflammation within the liver. Most commonly, gallstones can cause an obstruction of the ducts that drains bile from the liver.
Abnormalities of the opening of the bile duct into the small intestine (sphincter of Oddi) can lead to abnormalities of bile flow. The sphincter of Oddi acts as a "valve" that allows bile to flow from the common bile duct into the intestine.
Primary biliary cholangitis (PBC, formerly referred to as primary biliary cirrhosis) and primary sclerosing cholangitis can lead to progressive scarring of the bile ducts, causing them to become narrow, which results in reduced bile flow through the liver. Eventually, damage and scarring of the liver architecture occur, resulting in liver failure.
Other causes of liver disease
Since the liver is responsible for the functions that affect so many other organs in the body, liver disease and failure may cause complications. Examples include:
Hepatic encephalopathy: Increased ammonia levels due to the liver's inability to process and metabolize proteins in the diet can cause confusion, lethargy, and coma.
Abnormal bleeding: The liver is responsible for manufacturing blood clotting factors. Decreased liver function can cause an increased risk of bleeding in the body.
Protein synthesis or manufacture: proteins made in the liver are the building blocks for body function. Lack of protein affects many bodily functions.
Portal hypertension: Because the liver has such a great blood supply, damage to the liver tissue can increase pressure within the blood vessels in the liver and adversely affect blood flow to other organs. This can cause spleen swelling, and the development of varices or swollen veins in the gastrointestinal tract, from the esophagus (esophageal varices) and stomach to the anus (these are different than the swollen veins of hemorrhoids).