What causes cirrhosis of the liver?
Long-term alcoholism is the primary cause of cirrhosis. Men and women respond differently to alcohol. Although most men can safely consume two to five drinks a day, one or two drinks a day can cause liver damage in women. Individual tolerance to alcohol varies, but people who drink more and drink more often have a higher risk of developing cirrhosis. In some
people, one drink a day can cause liver scarring.
Alcohol is absorbed from the small intestine, and the blood carries it directly into the liver, where it becomes the preferred energy source. In the liver, alcohol converts to toxic chemicals, such as acetaldehyde (AcH), which trigger the production of powerful immune factors called cytokines. These molecules in large amounts can cause inflammation and tissue injury and are proving to be major culprits in the destructive process in the liver. AcH is particularly being researched because it plays a role in most actions of alcohol, including damaging effects on the liver that may lead to cirrhosis. The injured liver eventually is unable to breakdown fatty acids, compounds that make up fat. Over time, then, fat accumulates, further impairing the liver's ability to absorb oxygen and increasing its susceptibility to injury. During the initial phase, the fat-laden liver becomes greatly enlarged, but it eventually shrinks as cirrhosis develops.
Another common cause of cirrhosis in the US is chronic hepatitis, either hepatitis B or C. Chronic hepatitis C is the more dangerous form and accounts for one-third of all cirrhosis cases. Between 20% and 30% of people with chronic hepatitis C develop cirrhosis after 20 years, and about 5% to 10% of hepatitis B patients eventually develop cirrhosis. Viruses or other mechanisms that cause hepatitis produce inflammation in liver cells, resulting in their injury or destruction. If the condition is severe enough, the cell damage becomes progressive, building a layer of scar tissue over the liver. In advanced cases, as with alcoholic cirrhosis, the liver shrivels in size, a condition called postnecrotic or posthepatic cirrhosis.
Other causes of cirrhosis include:
Autoimmune hepatitis, which is caused by a problem with the immune system.
Alpha-1 antitrypsin deficiency, hemochromatosis, Wilson's disease, galactosemia, and glycogen storage diseases, which are inherited diseases that interfere with the way the liver produces, processes, and stores substances the body needs.
Nonalcoholic steatohepatitis or NASH, in which fat builds up in the liver and eventually causes scar tissue. This type of hepatitis appears to be associated with diabetes (Read about "Diabetes"), protein malnutrition, obesity, coronary artery disease (Read about "Obesity" "Coronary Heart Disease"), and corticosteroid treatment.
Blocked bile ducts, which causes bile to back up and damage the liver. NIDDK says that in babies, blocked bile ducts are most commonly caused by biliary atresia, a disease in which the bile ducts are absent or injured. In adults, the most common cause is primary biliary cirrhosis, a disease in which the ducts become inflamed, blocked, and scarred. Secondary biliary cirrhosis can happen after gallbladder surgery, if the ducts are inadvertently tied off or injured.
Severe reactions to prescription drugs, prolonged exposure to environmental toxins, the parasitic infection schistosomiasis, and repeated bouts of heart failure with liver congestion can also lead to cirrhosis.
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