Viral hepatitis and alcoholism

Alcohol Health & Research World,  Wntr, 1992  by Alan S. Rosman

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Viral hepatitis can cause as much damage to the liver as alcoholism. Research is now indicating that alcoholics are at high risk of contracting viral hepatitis, compounding their risk of liver damage and cirrhosis.

Liver disease is an important public health problem and is the ninth leading cause of death in the United States (Boring et al. 1991). The deaths from liver disease number about 26,000 per year (Boring et al. 1991), similar to the current death rate from acquired immune deficiency syndrome (AIDS) in the United States (Smith 1991). Cirrhosis, or scarring of the liver (see Figure 1), and liver cancer, known as hepatocellular carcinoma, are the two most devastating types of liver disease. The scarring process in cirrhosis results in impairment of liver function and interference with liver blood flow. Both excessive alcohol consumption and viral hepatitis have been known to cause cirrhosis, with the former regarded as the most common cause of cirrhosis in the United States (Haberman and Weinbaum 1990). Hepatocellular carcinoma is also associated with patients afflicted with alcoholism or viral hepatitis, although it is relatively rare in the United States (Dusheiko 1990).

This article will review studies that suggest that alcoholic patients have an increased risk of viral hepatitis. The reasons for the increased risk are unclear but may be related to social habits and conditions sometimes associated with alcoholism (e.g., intravenous drug use, poverty, "unsafe" sexual habits). The risk of severe liver injury in alcoholics, including cirrhosis and hepatocellular carcinoma, may be compounded by the dual effects of both alcohol and viral hepatitis (Nalpas et al. 1991). The therapy for cirrhosis is often related to its cause: when caused by excessive alcohol consumption, complete abstinence can be effective even in late stages of the disease (Powell and Klatskin 1968); when caused by viral hepatitis, cirrhosis can progress despite abstinence from alcohol. Therefore, if alcoholics are at high risk of contracting viral hepatitis, preventive measures should be instituted to avoid further liver damage.

Before any relationship between alcohol and viral hepatitis can be analyzed, a little must be known about viral hepatitis itself and how researchers measure for viral infection. This review will summarize the features of viral hepatitis and then analyze the studies investigating the association between alcoholism and viral hepatitis. Further understanding of this association could lead to improved prevention and treatment programs.

CLINICAL FEATURES OF VIRAL HEPATITIS INFECTIONS

Many human viruses are capable of infecting liver cells (hepatocytes) as part of a generalized infection. (For a general discussion of viruses, see the sidebar "Characteristics of Viral Infections.") However, there are some viruses that primarily infect liver cells and are classified as hepatitis viruses. Currently, five types of hepatitis viruses have been identified in humans: hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E.

Transmission, symptoms, treatment, and long-term effects of viral hepatitis vary somewhat from type to type. The following discussion will provide an overview of viral hepatitis infection and significant features for each type.

Transmission

Hepatitis types A and E are both transmitted through food or water that has been in contact with infected feces. This type of transmission is known as the fecal-oral route and is more common in Third World countries lacking modern sanitation systems. Types B, C, and D are primarily transmitted through "needlesticks" and blood products. Type D cannot infect liver cells by itself but results in significant infection when type B is already present. Venereal transmission is common for hepatitis B and may occur for hepatitis C, but at reduced levels (Alter 1991).

Because of the routes of transmission for hepatitis B and hepatitis C, health care workers, intravenous drug users, and people receiving blood transfusions are most susceptible to infection. People with high-risk sexual behavior (see the sidebar in the article by Cooper, p. 65) have been found most at risk for venereal transmission of hepatitis B.

Symptoms

Viral hepatitis infections are classified as either acute or chronic. Acute viral hepatitis infections generally resolve within 6 months, whereas chronic viral hepatitis infections may persist for several years.

The presentations of acute viral hepatitis infections are variable. Many of these cases are mild with symptoms of fever, muscle aches, and fatigue, and are difficult to distinguish clinically from the flu. In classic viral hepatitis, patients may develop problems with bilirubin metabolism (see the sidebar "Effects of Viral Hepatitis on Bilirubin Metabolism") causing yellowish skin (known as jaundice), yellowing of the white covering of the external eye (known as scleral icterus), darkening of the urine to a yellow-green color, and lightening of the color of the stool. Viral hepatitis may also impair the ability of liver cells to remove bile salts from the blood. The accumulation of bile salts in the blood may result in itching. Finally, classic viral hepatitis can be associated with fever, chills, and right-sided abdominal pain. In most cases of acute viral hepatitis, the immune system neutralizes the virus, and both the symptoms and the infection resolve within a few months (Ockner 1988). Once acute viral hepatitis has resolved, the patient is no longer infectious or susceptible to further liver injury from the particular virus that caused the infection.