An overview of liver diseases

Diseases affecting the liver may be caused by inflammatory disorders, vascular disorders, metabolic disorders, and neoplastic disorders.

Inflammatory disorders: Hepatitis, inflammation and damage to the liver's hepatocytes, is the most common cause of liver inflammation. Hepatitis may occur from infectious agents, toxins, or immunologic attack. The most common cause of hepatitis is viral infection. Acute hepatitis may resolve without permanent liver damage; however hepatitis that lasts longer than six months becomes chronic hepatitis. The viruses that cause hepatitis A, B, and C infect approximately 500,000 people in the United States each year. Toxins, including alcohol, drugs, and various chemicals can also cause hepatitis. Chronic inflammation of the liver often leads to cirrhosis of the liver, a condition characterized by irreversible liver scarring and fibrosis. Cirrhosis may produce hepatic failure and is a significant risk factor for primary liver cancer.

Vascular disorders: Portal hypertension occurs when blood flow from the intestines, stomach, and spleen is obstructed due to liver damage. Portal hypertension leads to ascites, a collection of fluid in the abdominal cavity.

Metabolic disorders: Wilson's disease is an inherited condition that produces excess copper storage in the liver. Hemochromatosis occurs when the liver is damaged by iron overload. Alpha-1 antitrypsin deficiency is an inherited disease that predisposes the affected person to lung disease, especially if the individual smokes. Alpha-1 antitrypsin inactivates other important enzymes, causing organ damage. Although the lung is the organ most affected, in some patients the liver is also a target for damage.

Neoplastic disorders: The liver is a frequent site for blood-borne cancer metastases. Malignant tumors originating in the colon, breast, lung, stomach, pancreas, ovary, and malignant melanoma often metastasize to the liver. Primary hepatocellular carcinoma most often occurs in patients who have cirrhosis as a result of viral infection or alcoholism, hemochromatosis, or Alpha-1 antitrypsin deficiency.