Liver disease is a broad term describing any number of diseases affecting the liver. Many are accompanied by jaundice caused by increased levels of bilirubin in the system. The bilirubin results from the breakup of the hemoglobin of dead red blood cells; normally, the liver removes bilirubin from the blood and excretes it through bile.

• Hepatitis, inflammation of the liver, caused mainly by various viruses but also by some poisons, autoimmunity or hereditary conditions.
• Cirrhosis is the formation of fibrous tissue in the liver, replacing dead liver cells. The death of the liver cells can for example be caused by viral hepatitis, alcoholism or contact with other liver-toxic chemicals.
• Haemochromatosis, a hereditary disease causing the accumulation of iron in the body, eventually leading to liver damage.
• Cancer of the liver (primary hepatocellular carcinoma or cholangiocarcinoma and metastatic cancers, usually from other parts of the gastrointestinal tract).
• Wilson's disease, a hereditary disease which causes the body to retain copper.
• Primary sclerosing cholangitis, an inflammatory disease of the bile duct, likely autoimmune in nature.
• Primary biliary cirrhosis, autoimmune disease of small bile ducts.
• Budd-Chiari syndrome, obstruction of the hepatic vein.
• Gilbert's syndrome, a genetic disorder of bilirubin metabolism, found in about 5% of the population.
• Glycogen storage disease type II, the build-up of glycogen causes progressive muscle weakness (myopathy) throughout the body and affects various body tissues, particularly in the heart, skeletal muscles, liver and nervous system.

There are also many pediatric liver disease, including biliary atresia, alpha-1 antitrypsin deficiency, alagille syndrome, and progressive familial intrahepatic cholestasis, to name but a few.

A number of liver function tests are available to test the proper function of the liver. These test for the presence of enzymes in blood that are normally most abundant in liver tissue, metabolites or products.

Symptoms of a diseased liver

The external signs include a coated tongue, bad breath, skin rashes, itchy skin, excessive sweating, offensive body odour, dark circles under the eyes, red swollen and itchy eyes, acne rosacea, brownish spots and blemishes on the skin, flushed facial appearance or excessive facial blood vessels.

Other symptoms include jaundice, dark urine, pale stool, bone loss, easy bleeding, itching, small, spider-like blood vessels visible in the skin, enlarged spleen, fluid in the abdominal cavity, chills, pain from the biliary tract or pancrea, and an enlarged gallbladder.

The symptoms related to liver dysfunction include both physical signs and a variety of symptoms related to digestive problems, blood sugar problems, immune disorders, abnormal absorption of fats, and metabolism problems.