How chronic alcoholism causes liver disease and cirrhosis?

In westernized cultures, predisposed to heavy routine drinking liver cirrhosis is one of the ten leading causes of death. Alcohol is exclusively metabolized in liver. The exact quantity and duration of drinking to cause liver injury in the grave from of liver cirrhosis is unknown but it is generally agreed that continued daily drinking of 80grams of any type of alcoholic beverages for at least ten years is likely to result in liver cirrhosis. Liver injury is limited to alcohol content only and not to the type of alcohol beverage consumed. So every kind of alcohol causes liver injury. The liver injury due to alcohol consumption culminates in morphological legions of fatty liver (alcoholic steatosis), alcoholic hepatitis and reaches its climax in alcoholic cirrhosisSteatosis is an excessive buildup of fat inside liver cells. The major heptototoxic effects of alcohol consumption are exerted by its metabolite acetaldehyde. Acetaldehyde is more toxic than ethanol and is responsible for hangover symptoms. Acetaldehyde level is elevated in chronic alcoholics. Acetaldehyde is extremely toxic and brings about Hepto- necrosis. The chemical formula for ethyl alcohol is C₂H₆O. The formula for acetaldehyde is C₂H₄O. Acetaldehyde is formed when 2 hydrogen atoms are removed from the alcohol molecule.

Chronic liver disease is characterized by variable degree of these three factors and the ultimate result may be neoplasm or cancer.

Fibrosis

Cirrhosis

Neoplasm

The following four features are very characteristic of liver cirrhosis

1. It involves entire liver structure.
2. The normal and health lobular architecture of hepatic parenchyma is disorganized.
3. There is formation of nodes separated by eahchother by irregular bands of fibrosis
4. Hepto cellular necrosis of varying etiology is always found.

There are alternate areas of necrosis and regenerative nodules. Regenerative of nodules are not essential for diagnosis for cirrhosis as biliary cirrhosis have little regeneration of nodules. Irrespective of etiology liver cirrhosis is in general is initiated by heptocellular necrosis. Continued and gradual destruction of heptocytes causes collapse of normal lobular Hepto parenchyma. This is followed by fibrosis around necrotic cell and there is compensatory regeneration of nodules. The cause of proliferation of heptocytes to form regenerative nodules is still obscure.

Fibrosis

Fibrosis is initiated by synthesis of all types of collagen and increase in the number of collagen producing cells. Development of fibrosis leads to proliferation of fat storing cells. Besides collagen, two glycoproteins, fibronectin and laminin are also deposited in excessive amounts in area of liver cell damage.

Alcoholic liver disease is the term to describe the spectrum of liver cell injury associated with acute and chronic alcoholism. There are three distinct stages in chronic liver disease.

Fatty liver and fibrosis

Alcoholic hepatitis

Alcoholic cirrhosis

An Alcoholic person, who continues to drink over years and becomes confirmed chronic alcoholic; progresses from fatty liver to alcoholic hepatitis and eventually to liver cirrhosis,. The alcoholic liver cirrhosis is gradual process spread over time. The period for production of cirrhosis depends on susceptibility of the concerned person in most cases and the nature of the acetaldehyde breaking enzyme alcohol hydrogenase. This enzyme is present in mitochondria of liver cells. .It is considered to be between five and ten years. There is experimental evidence that fatty changes by itself do not lead to the development of liver cirrhosis. Alcoholic hepatitis in some cases appears to be forerunner or precursor of alcoholic cirrhosis. In cirrhotic condition of live, thehealthy liver cells are replaced by scar tissue, and enough of this scarring can render the liver unable to perform its vital normal functions.