There are four stages of liver damage known as fatty liver, hepatitis, fibrosis and cirrhosis. Although liver damage is reversible in the early stages, the changes of cirrhosis are not. Sometimes fibrosis and cirrhosis are considered as one stage, making three main stages altogether. Most often, liver damage is caused by excessive consumption of alcohol, although what is called nonalcoholic fatty liver disease (NAFLD) progresses through similar stages. NAFLD is associated with obesity and is becoming more common.
Symptoms may not be noticeable in the early stages of liver damage. In the first stage, fatty liver, abnormally large amounts of fat accumulate inside liver cells. When this is caused by alcohol, fat can build up after only a few days of heavy drinking. Other causes of liver damage, such as drugs, a condition called fatty liver of pregnancy and NAFLD, lead to very similar changes. Where alcohol is the cause, stopping drinking reverses the problem within a couple of weeks.
If the fat deposits of fatty liver become severe, people may experience symptoms of abdominal pain, nausea and weakness. The liver damage might progress to the next stage, hepatitis, where the liver is inflamed. In alcoholic hepatitis, there may be no symptoms, but problems such as jaundice, pain, nausea and tiredness may occur. Occasionally, a sudden, heavy bout of drinking can cause severe hepatitis and liver failure, followed by coma and death. This can occur even though a person has not yet developed the later stages of liver damage.
Fibrosis, the third stage, is the process of scar formation. Scarring may gradually build up in the liver, causing cells to die and reducing the liver's blood supply. As long as sufficient numbers of liver cells remain, the liver continues to function. Eventually, cirrhosis develops, where the normal liver tissue is replaced by lumps known as nodules. The liver no longer functions properly and the person may have numerous symptoms including jaundice, a painful, swollen abdomen, weight loss and personality changes.
Treatment methods vary according to the different stages of liver damage and the underlying cause. Giving up alcohol, or losing weight, can reverse some cases of fatty liver and hepatitis. Severe hepatitis may require intensive care in the hospital, while cirrhosis has no cure and a liver transplant may become necessary. Usually, it takes several years for people to progress from asymptomatic to end-stage liver disease, so there may be many opportunities for reversal.