Overview
Liver disease is any condition that causes liver inflammation or tissue damage and affects liver function. The liver is a vital organ located in the upper right-hand side of the abdomen. It is as large as a football, weighs 2-3 pounds, and performs numerous functions for the body: converting nutrients derived from food into essential blood components, storing vitamins and minerals, regulating blood clotting, producing proteins and enzymes, maintaining hormone balances, and metabolizing and detoxifying substances that would otherwise be harmful to the body. The liver makes factors that help the human immune system fight infection, removes bacteria from the blood, and makes bile, which is essential for digestion.
Bile, a greenish-yellow fluid consisting of bile acids or salts and waste products such as bile pigments, flows through small bile ducts inside the liver. The bile moves from these small ducts into larger ones, like streams into a river, eventually converging into the common bile duct and exiting the liver. Some of the bile flows directly to the duodenum; the rest is stored and concentrated in the gallbladder. After a person eats, the gallbladder, a fist-sized organ that sits next to the liver, releases some of the stored bile into the small intestine, where it helps to digest fats.
What is liver disease?
Liver disease is categorized both by the cause and the effect it has on the liver. Causes may include infection, injury, exposure to drugs or toxic compounds, an autoimmune process, or a genetic defect that leads to the deposition and build-up of damaging substances such as iron or copper. Effects may include inflammation, scarring, obstructions, clotting abnormalities, and liver failure. The following table summarizes some types of liver disease. The links lead to more information about the various types.
| Type of Liver Disease | Description | Examples of Causes/Conditions |
| Acute liver failure | Rapid decrease in liver function | Drugs, toxins, a variety of liver diseases |
| Autoimmune-associated | The body produces an inappropriate immune response against itself; sometimes develops antibodies against own liver tissue | PBC (Primary biliary cirrhosis), PSC (Primary sclerosing cholangitis), Autoimmune hepatitis |
| Budd-Chiari syndrome | Blood clots impede blood flow from the liver; symptoms such as ascites, enlarged liver, jaundice, and abdominal pain can develop | Hypercoagulable disorders, liver injury, cancer, parasitic infection |
| Cirrhosis | Scarring of liver tissue leads to decreased liver function | Can be caused by a variety of conditions but usually a result of chronic hepatitis, alcoholism, or chronic bile duct obstruction |
| Genetic | Gene mutations can lead to liver damage, disease; relatively rare conditions | Hemochromatosis, Alpha-1 antitrypsin deficiency, Wilson's disease |
| Hepatitis | Acute or chronic liver inflammation | Viruses, alcohol abuse, drugs, toxins, autoimmune, nonalcoholic fatty liver disease (NAFLD) |
| Infections | Certain infections can cause various degrees of liver damage, blockage of bile ducts | Viral hepatitis, Parasitic infection |
| Liver cancer | A cancer that originates in the liver | Increased risk with cirrhosis and chronic hepatitis; hepatocellular carcinoma (HCC) is most common primary liver tumor |
| Obstruction of bile ducts | Complete or partial blockage of bile ducts | Tumors, gallstones, inflammation, trauma |
