Cirrhosis
Cirrhosis
Cirrhosis is a degenerative liver disease in which the lobes of the liver become infiltrated with fat and fibrous tissue. (Fibrous tissue is a type of connective tissue composed of protein fibers called collagen.) The word cirrhosis is derived from the Greek words kirrhos, meaning yellowish orange and osis, meaning condition, and aptly describes the appearance of the liver of a patient with cirrhosis.
The infiltration of these substances within the liver disrupts liver functions, including the conversion of the storage carbohydrate glycogen into glucose; detoxification of drugs and other substances; vitamin absorption; gastrointestinal functions; and hormone metabolism. Because the blood vessels of the liver are affected by fibrous tissue formation, blood flow through the liver is impaired, leading to increased blood pressure within the liver. Impaired blood flow in the liver also causes a condition called esophageal varices, in which blood vessels in the esophagus bleed due to their increased internal pressure. In addition, patients with cirrhosis are often weakened by hypoglycemia, or low blood sugar.
Complications of cirrhosis include coma, gastrointestinal hemorrhage, and kidney failure. No definitive treatment for cirrhosis is available besides management of symptoms and complications. The mortality rate of cirrhosis ranges from 40–63%, and it is the ninth leading cause of death in the United States.
Causes of cirrhosis
Cirrhosis is most often caused by excessive ingestion of alcohol. In the United States, 90% of all cases of cirrhosis are related to alcohol overconsumption. Although researchers still do not have a clear understanding of how alcohol damages the liver, evidence suggests that consuming more than 1 pint of alcohol (86 proof) daily for 10 years increases the risk of cirrhosis by 10%. The risk of cirrhosis increases to 50% if this consumption lasts 25 years. Women may be more susceptible to alcoholic cirrhosis than men. Women have lower levels of the enzyme alcohol dehydrogenase, which breaks down alcohol in the stomach. Lower levels of this enzyme lead to higher blood alcohol levels.
Researchers believe that the main cause of alcohol-induced cirrhosis is acetaldehyde, the first product created when alcohol is broken down in the stomach. Acetaldehyde combines with proteins in the body and damages the liver cells, leading to fat accumulation and fibrous tissue formation. Further damage to liver cells may be caused by a secondary effect of alcohol on the liver: the acetaldehyde may make the liver cells vulnerable to the potentially damaging effects of substances such as acetaminophen (a common over-the-counter pain reliever), industrial solvents, and certain anesthetics on the liver cells.
Although excessive alcohol intake is considered the leading cause of cirrhosis, there are numerous other causes of the disease. These include several types of viral hepatitis, nutritional factors, genetic conditions, and others. In addition, these are often contributing factors in alcoholic cirrhosis. Chronic infection with hepatitis B virus (HBV) can lead to cirrhosis and is also related to liver cancer.
Progression of cirrhosis
Cirrhosis is a progressive disease; in other words, the symptoms become more severe and more numerous over time. In cases of alcoholic cirrhosis, it begins with a condition called alcoholic fatty liver. In this condition, fat accumulates in the liver. The liver enlarges, sometimes to as much as 10 lb (5000 g), and appears yellow and greasy. Patients with this condition often have no symptoms beyond low blood sugar or some digestive upset. Some patients have more severe symptoms, such as jaundice (a condition caused by the accumulation of a yellowish bile pigment in the blood; patients with jaundice have yellow-tinged skin) and weight loss. Complete recovery is possible at this stage of liver disease if the patient abstains from alcohol.
The next stage in the progression of cirrhosis is often a condition called hepatitis. Hepatitis is a general term meaning inflammation of the liver. Hepatitis may be caused by alcohol, several different types of virus, or other factors. In acute alcoholic hepatitis, the inflammation is caused by alcohol. Fibrous tissue is deposited in the liver, the liver cells degenerate, and a type of connective tissue called hyaline infiltrates the liver cells. Regardless of the cause, patients with hepatitis have serious symptoms, which include general debilitation, loss of muscle mass, jaundice, fever, and abdominal pain. The liver is firm, tender, and enlarged. Vascular “spiders,” or varicose veins of the liver, are present. Again, no definitive treatment is available, although some patients respond well to corticosteroids. General treatment for this condition includes treatment of symptoms and complications.
Acute alcoholic hepatitis often progresses to cirrhosis. In cirrhosis, the fibrous tissue and fat
Key Terms
Acute alcoholic hepatitis —Inflammation of the liver caused by excessive alcohol consumption.
Collagen— A type of protein that comprises connective tissue; infiltrates the liver in cirrhosis.
Fatty liver— A condition in which the liver accumulates fat due to excessive alcohol consumption.
Fibrous tissue— Connective tissue composed primarily of collagen.
Hepatitis— General inflammation of the liver; may be caused by viral infection or by excessive alcohol consumption.
Jaundice— condition in which a yellowish bile pigment increases in the blood; patients with jaundice have a characteristic yellow tinge to their skin.
accumulation is prominent. Collagen is deposited around the veins of the liver, leading to impairment of blood flow. The liver cells degenerate further and die, leading to formation of nodules in the liver, and the liver shrinks (atrophy). Symptoms of cirrhosis include nausea, weight loss, jaundice, and esophageal varices. Gastrointestinal symptoms, such as diarrhea and gastric distention, are also features of cirrhosis. The mortality rate of cirrhosis is high. Studies have established that the five-year survival of patients with cirrhosis is only about 65% for patients who stop drinking, and around 40% for patients who continue to drink. Death results from kidney failure, coma, malnutrition, and cardiac arrest.
Treatment of cirrhosis depends on the type and cause. For patients with alcoholic cirrhosis, it includes general support, treatment of complications, a nutritious diet, and abstention from alcohol consumption. In selected patients, liver transplant may be indicated. Although the liver has a remarkable ability to regenerate, the damage that cirrhosis inflicts on the liver may be so severe that recovery is not possible. In cirrhosis caused by viral hepatitis, the use of experimental drugs has had some success. Research continues into blocking the effects of the various hepatitis viruses, or preventing their replication in the liver cells.
Resources
BOOKS
Chen, T.M. New Developments in Liver Cirrhosis Research. Hauppage NY: Nova Biomedical Books, 2006.
Dickerson, James L. and Fredric Regenstein. The First Year: Cirrhosis: An Essential Guide for the Newly Diagnosed. Washington: Marlowe & Company, 2006.
Parker, James N. and Philip M. Parker. The Official Patient’s Sourcebook on Primary Biliary Cirrhosis. San Diego: Icon Health Publications, 2002.
Kathleen Scogna