Cirrhosis occurs after the liver has suffered extensive damage for prolonged periods. Nodules in the liver, consisting of scar tissue surrounding areas of organ regeneration, are the defining feature of cirrhosis. The ratio of scar tissue to regenerating cells determines the size of the nodules, with more scar tissue resulting in smaller nodules. Cirrhosis has traditionally been classified as macronodular or micronodular, based upon the size of these nodules. According to "Pathologic Basis of Disease," the cause of the cirrhosis does not reliably predict nodule size, and nodules can change in either direction as the disease progresses. So anything that can cause cirrhosis can cause macronodular cirrhosis.
Alcohol Abuse
According to "Pathologic Basis of Disease," alcohol abuse is by far the most common cause of liver damage and cirrhosis in the developed world. Only the liver can metabolize alcohol, and the process generates toxic intermediaries. The liver can process small amounts of alcohol without problems, but a large dose results in liver damage from a build-up of the toxic intermediaries. The only way to prevent and potentially reverse this damage is to stop drinking.
Viral Hepatitis
Viral hepatitis refers to inflammation of the liver due to a virus. It is the second most common cause of cirrhosis. Three viruses cause most cases of hepatitis: hepatitis A, hepatitis B and hepatitis C. Hepatitis A spreads through fecal-oral contamination. Most hepatitis A outbreaks occur through poor sanitation or contaminated food. Hepatitis B spreads through exposure to infected blood and sexual contact. A hepatitis B vaccine was introduced in 1982, and is now recommended for all children. Hepatitis C spreads mainly through blood contact, although rare cases of sexual transmission have been reported. Now that blood donors are routinely screen for the hepatitis C virus, needle sharing by IV drug users and occupational exposure of health care workers are the principal routes of hepatitis C transmission in developed countries.
Biliary Tract Disease
The liver produces a substance called bile to aid in the digestion of fat. The gall bladder stores the bile and releases it through the common bile duct into the intestines in response to a high-fat meal. Biliary tract disease occurs when something happens to block the normal flow of bile. Bile then backs up into the liver and causes tissue damage, making biliary tract disease the third most common cause of cirrhosis. Primary biliary cirrhosis is a disease of unknown origin in which the bile channels in the liver become scarred and block the flow of bile. Bile obstruction can also occur when gallstones or tumors block the common bile duct for extended periods.
References
- "Robbins and Cotran"; Pathologic Basis of Disease; Vinay Kumar; 2005
- "Harrison's Principles of Internal Medicine"; Dennis L. Kasper; 2005
