Cirrhosis Health Article

CIRRHOSIS

The term "cirrhosis" was first used by René Laënnec (1781–1826) to describe the abnormal liver color of individuals with alcohol-induced liver disease. The word cirrhosis comes from the Greek word kirrhos, the name for a yellowish-brown color.

The human liver is the largest single organ in the body and consists of parenchymal cells, which metabolize, detoxify, synthesize, and store nutrients. Normal functioning of these cells depends on their proper organization. Cirrhosis, the final common pathway for a variety of liver diseases, occurs when excessive fibrosis results in the conversion of normal liver architecture into structurally abnormal nodules. Cirrhosis is irreversible and can be life threatening—it is a public health concern because of its associated mortality and morbidity. The only available and definitive treatment is liver transplantation. Cirrhosis is, however, preventable in most cases.

PREVALENCE

The exact prevalence of cirrhosis is unknown, but it has been estimated, through autopsies, to be between 5 and 10 percent. Incidence of cirrhosis varies by country and region, and reflects relative contributions from different risk factors. In countries where alcohol consumption is common, alcoholic cirrhosis is the major contributor to the overall prevalence of cirrhosis. In countries with low alcohol consumption, hepatotropic viruses (hepatitis B and C) are the major contributors.

An estimated 25,000 individuals in the United States died from liver disease in 1998, making liver disease the tenth leading cause of death. For individuals between 45 and 64 years of age, chronic liver disease had an associated mortality rate of 19.6 per 100,000 persons and was the seventh leading cause of death. The mortality rate for

Table 1

white men between 45 and 64 years of age was 28.2 per 100,000 persons, and cirrhosis was the fourth leading cause of death (in 1998).

CAUSES OF LIVER DISEASES

Ethanol. Ethanol (alcohol) is the most common cause of cirrhosis in the United States (see Table1). Over three-quarters of Americans drink ethanol. The amount necessary to cause cirrhosis differs based on gender and nutritional status, and the relative risk of alcoholic cirrhosis increases with greater amounts of alcohol consumption. It has been estimated that alcoholic cirrhosis develops in women drinking at least 20 grams of alcohol a day for 5 to 10 years, and in men drinking at least 40 grams per day for the same period. A 12-ounce can of beer, 5-ounce a glass of wine, and a 1.5 ounce shot of hard liquor all contain between 10 and 20 grams of ethanol. Malnutrition and infection with hepatotropic viruses may also increase the risk of cirrhosis.

Compelling epidemiological data indicate a strong association between alcohol consumption and cirrhosis mortality. Between 1906 and 1934, per capita alcohol consumption in the United States dropped from 9.8 liters of absolute alcohol to 3.7 liters. Liver cirrhosis mortality fell from approximately 16 deaths per 100,000 prior to the Prohibition era, to 8 deaths per 100,000 during the Prohibition era and for several decades after Prohibition laws were repealed (see Figure 1). Between 1950 and 1973, however, mortality due to cirrhosis rose from 8.5 deaths per 100,000 to 14.9 deaths per 100,000. This increase followed and paralleled an increase in total alcohol consumption. Between 1970 and 1990, although total alcohol consumption remained stable, the mortality rate from cirrhosis decreased. Plausible reasons

Figure 1

for this discrepancy include lowering the greater than previously recognized nonalcohol contribution to the overall mortality rate due to cirrhosis and improved behavior regarding alcohol.

Hepatotropic Viruses. Hepatotropic viruses represent the second major category of the causes of cirrhosis. Hepatotropic viruses account for most orthotopic liver transplantations in the United States.

Approximately 4 million people in the United States are believed to be infected by hepatitis C. Prevalence varies considerably by country, e.g., from 0.1 to 2 percent in Europe and North America to 5 to 20 percent in Egypt (see Table 2). Hepatitis C infection results in chronic hepatitis in 85 percent of infected individuals, and in cirrhosis in 20 percent. The mean time progression to hepatic cirrhosis following viral infection is twenty years. Factors associated with progression of hepatitis C-related liver disease include chronic alcoholism and viral coinfection with hepatitis B.

Blood transfusion was the single major risk factor for hepatitis C infection until the early 1990s; today it accounts for a minority of hepatitis C cases because of blood screening for hepatitis C. Illegal drug use now accounts for more than half of the cases of hepatitis C infection, and this proportion is likely to increase in the near future when many individuals infected with hepatitis C in the 1960s and 1970s, largely as a result of sharing needles, seek medical attention.

Public health efforts are best directed at preventing viral hepatitis infection. Once patients are

Table 2

infected, antiviral therapy may eliminate the virus from the blood and prevent the progression to hepatic cirrhosis.

Approximately 1 to 1.25 million Americans are infected with the hepatitis B virus. Worldwide, an estimated 1 to 2 million people die of hepatitis B-associated liver disease annually (see Table 3). The worldwide prevalence varies greatly among countries, from 0.1 to 2 percent in Europe and North America, and from 5 to 20 percent in Southeast Asia and Eastern Europe. It is estimated that 12 to 20 percent of patients with chronic hepatitis B progress to cirrhosis within five years. The risk of hepatitis B infection from a blood transfusion was once up to 50 percent, but it is now exceedingly uncommon, largely as a result of blood screening. The implementation of hepatitis B immunization programs in infants has also contributed to the decreasing number of new cases of hepatitis B infection.

Although the major risk factor for hepatitis B transmission is sexual, the rate has also fallen significantly in recent years because of changes in high-risk sexual behavior. Like hepatitis C, progression to cirrhosis can be halted with antiviral therapy.

Cirrhosis is a major public health concern. The major causes of cirrhosis are mostly related to

Table 3

lifestyle behaviors such as alcohol consumption, injectable drug use, and unprotected sex. Public health efforts should focus on programs that address these activities.

SAMMY SAAB

SERGIO E. ROJTER

(SEE ALSO: Alcohol Use and Abuse; Hepatitis A Vaccine; Hepatitis B Vaccine)