Causes
There are several processes that can lead to cirrhosis.
Alcoholism
The liver is particularly endangered by alcoholism. Alcoholic cirrhosis (also sometimes referred to as portal, Laennec's, nutritional, or micronodular cirrhosis) is the primary cause of cirrhosis in the US. It is estimated to be responsible for 44% of deaths from cirrhosis in North America. Some experts believe this estimate is low; one Canadian study found alcohol to be the major contributor to 80% of all cirrhosis deaths.
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The relationship between alcohol and cirrhosis is generally as follows:
- 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.
Chronic Hepatitis
The second leading cause of cirrhosis in the US is chronic hepatitis, either hepatitis B or hepatitis C. Chronic hepatitis C is the more dangerous form and accounts for one-third of all cirrhosis cases. Overall, between 10% and 15% of patients with chronic hepatitis C develop cirrhosis. The risk varies widely, however. 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.
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| Hepatitis C is a virus-caused liver inflammation which may cause jaundice, fever and cirrhosis. Persons who are most at risk for contracting and spreading hepatitis C are those who share needles for injecting drugs and health care workers or emergency workers who may be exposed to contaminated blood. |
Autoimmune Liver Disease
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