user: What causes Cirrhosis ?

assistant: Cirrhosis has various causes. Many people with cirrhosis have more than one cause of liver damage.
                
The list below shows common causes of cirrhosis in the United States.2 While chronic hepatitis C and alcohol-related liver disease are the most common causes of cirrhosis, the incidence of cirrhosis caused by nonalcoholic fatty liver disease is rising due to increasing rates of obesity.
                
Most Common Causes of Cirrhosis
                
Chronic hepatitis C. Hepatitis C is due to a viral infection that causes inflammation, or swelling, and damage to the liver. The hepatitis C virus spreads through contact with infected blood, such as from a needlestick accident, injection drug use, or receiving a blood transfusion before 1992. Less commonly, hepatitis C can be spread by sexual contact with an infected person or at the time of childbirth from an infected mother to her newborn.
                
Hepatitis C often becomes chronic, with long-term persistence of the viral infection. Chronic hepatitis C causes damage to the liver that, over years or decades, can lead to cirrhosis. Advanced therapies for chronic hepatitis C now exist, and health care providers should treat people with chronic hepatitis C before they develop severe fibrosis or cirrhosis. Unfortunately, many people first realize they have chronic hepatitis C when they develop symptoms of cirrhosis. More information is provided in the NIDDK health topic, What I need to know about Hepatitis C.
                
Alcohol-related liver disease. Alcoholism is the second most common cause of cirrhosis in the United States. Most people who consume alcohol do not suffer damage to the liver. However, heavy alcohol use over several years makes a person more likely to develop alcohol-related liver disease. The amount of alcohol it takes to damage the liver varies from person to person. Research suggests that drinking two or fewer drinks a day for women and three or fewer drinks a day for men may not injure the liver.3 Drinking more than these amounts leads to fat and inflammation in the liver, which over 10 to 12 years can lead to alcoholic cirrhosis.4
                
Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). In NAFLD, fat builds up in the liver; however, the fat buildup is not due to alcohol use. When the fat accompanies inflammation and liver cell damage, the condition is called nonalcoholic steatohepatitis, or NASH, with steato meaning fat, and hepatitis meaning inflammation of the liver. The inflammation and damage can cause fibrosis, which eventually can lead to cirrhosis.
                
Extra fat in the liver has many causes and is more common in people who
                
- are overweight or obese.  - have diabetesa condition characterized by high blood glucose, also called high blood sugar.  - have high blood cholesterol and triglycerides, called hyperlipidemia.  - have high blood pressure.  - have metabolic syndromea group of traits and medical conditions linked to being overweight and obese that makes people more likely to develop both cardiovascular disease and type 2 diabetes. Metabolic syndrome is defined as the presence of any three of the following: large waist size, high triglycerides in the blood, abnormal levels of cholesterol in the blood, high blood pressure, and higher than normal blood glucose levels. NASH may represent the liver component of the metabolic syndrome.
                
NASH now ranks as the third most common cause of cirrhosis in the United States. More information is provided in the NIDDK health topic, Nonalcoholic Steatohepatitis.
                
Chronic hepatitis B. Hepatitis B, like hepatitis C, is due to a viral infection that causes inflammation and damage to the liver. Chronic infection can lead to damage and inflammation, fibrosis, and cirrhosis. The hepatitis B virus spreads through contact with infected blood, such as by needlestick accident, injection drug use, or receiving a blood transfusion before the mid-1980s. Hepatitis B also spreads through sexual contact with an infected person and from an infected mother to child during childbirth.
                
In the United States, hepatitis B is somewhat uncommon, affecting less than 1 percent of the population, or fewer than one in 100 people.5 In many areas of the world, however, hepatitis B is common. In some parts of Africa and in most of Asia and the Pacific Islands, about 5 to 7 percent of the population has chronic hepatitis B. In some parts of Africa, more than 8 percent of the population has chronic hepatitis B.6 For these reasons, hepatitis B is likely the major cause of cirrhosis worldwide. However, in the United States, hepatitis B ranks well behind hepatitis C, alcohol-related liver disease, and NASH.
                
Therapies for chronic hepatitis B now exist and health care providers should treat people with chronic hepatitis B before they develop severe fibrosis or cirrhosis. Unfortunately, many people first realize they have chronic hepatitis B when they develop symptoms of cirrhosis.
                
Hepatitis B is also a preventable disease. Since the 1980s, a hepatitis B vaccine has been available and should be given to newborns and children in the United States. Adults at higher risk of getting hepatitis B should also get the vaccine. More information is provided in the NIDDK health topics, What I need to know about Hepatitis B and Hepatitis B: What Asian and Pacific Islander Americans Need to Know.
                
Less Common Causes of Cirrhosis
                
Less common causes of cirrhosis include the following:
                
Autoimmune hepatitis. In this form of hepatitis, the bodys immune system attacks liver cells and causes inflammation, damage, and eventually cirrhosis. Normally, the immune system protects people from infection by identifying and destroying bacteria, viruses, and other potentially harmful foreign substances. In autoimmune diseases, the bodys immune system attacks the bodys own cells and organs. Researchers believe genetics, or inherited genes, may make some people more likely to develop autoimmune diseases. At least 70 percent of those with autoimmune hepatitis are female.7 More information is provided in the NIDDK health topic, Autoimmune Hepatitis.
                
Diseases that damage, destroy, or block the bile ducts. Several diseases can damage, destroy, or block the ducts that carry bile from the liver to the small intestine, causing bile to back up in the liver and leading to cirrhosis. In adults, the most common of these diseases is primary biliary cirrhosis, a chronic disease that causes the small bile ducts in the liver to become inflamed and damaged and ultimately disappear. Primary sclerosing cholangitis is a disease that causes irritation, scarring, and narrowing of the larger bile ducts of the liver.
                
In infants and children, causes of damage to or disappearance of bile ducts that can lead to cirrhosis include
                
- Alagille syndrome, a collection of symptoms that indicates a genetic digestive disorder and leads to a loss of bile ducts in infancy.  - biliary atresia, a life-threatening condition that affects newborns in which bile ducts are missing. The cause is unknown. Biliary atresia is the most common reason for liver transplantation in children.8  - cystic fibrosis, an inherited disease of the lungs, intestines, pancreas, and bile ducts in which the body does not produce enough fluid and mucus becomes thick and blocks off small bile ducts. This blockage of the bile ducts can lead to cirrhosis.
                
Long-term blockage of the bile ducts by gallstones can cause cirrhosis. Cirrhosis may also develop if the bile ducts are mistakenly tied off or injured during surgery on the gallbladder or liver.
                
More information is provided in the NIDDK health topics:
                
- Primary Biliary Cirrhosis  - Primary Sclerosing Cholangitis  - Alagille Syndrome  - Biliary Atresia  - Gallstones
                
Inherited diseases that affect the liver. Inherited diseases that interfere with how the liver produces, processes, and stores enzymes, proteins, metals, and other substances can cause cirrhosis. These diseases include alpha-1 antitrypsin deficiency, hemochromatosis, Wilson disease, galactosemia, and glycogen storage diseases. More information is provided in the NIDDK health topics:
                
- Hemochromatosis  - Wilson Disease
                
Rare viral infections of the liver. Hepatitis D, or hepatitis delta, and hepatitis E are two rare viral infections of the liver. Hepatitis D infection occurs only in people who have hepatitis B. People infected with chronic hepatitis B and chronic hepatitis D are more likely to develop cirrhosis than people infected with chronic hepatitis B alone.9
                
Hepatitis E is a virus found in domestic and wild animals, particularly pigs, and can cause hepatitis in humans. People with weakened immune systems, including people who are liver or kidney transplant recipients or who have acquired immune deficiency syndrome (AIDS), can develop chronic hepatitis E. Chronic hepatitis E can cause scarring of the liver and cirrhosis. Current treatments for chronic hepatitis D and E are experimental and only partially effective.
                
Other causes. Other causes of cirrhosis may include
                
- reactions to medications taken over a period of time.  - prolonged exposure to toxic chemicals.  - parasitic infections.  - chronic heart failure with liver congestion, a condition in which blood flow out of the liver is slowed. Liver congestion can also occur after surgery to correct a congenital heart problema heart problem that is present at birth.
                
Trauma to the liver or other acute, or short term, causes of damage do not cause cirrhosis. Usually, years of chronic injury are required to cause cirrhosis.