Hepatitis C virus (HCV) was isolated in 1988. In the United States, multiple studies have confirmed that the hepatitis C virus is the viral agent causing non-A, non-B hepatitis. HCV infection is associated with both acute and chronic liver disease.
HCV, like hepatitis B virus, is a bloodborne pathogen. Most transmission occurs by direct contact with infected blood or blood products. Contact with contaminated needles or syringes is also a means of exposure. HCV may be spread by sexual contact, but the risk of infection is less than with exposure to blood. The number of infectious viral organisms is presumably greater in blood than in vaginal secretions, semen, or saliva.
The first serologic test for HCV antibody became available in 1990, allowing a better understanding of the prevalence of HCV. There are several additional tests currently available. The second generation tests currently available are sensitive and specific. These tests are reliable when used in high-prevalence populations, but in low-prevalence populations the positive predictive value is only 50 percent. Among substance abusers, however, especially injection drug users, the prevalence of HCV infection is high; therefore, the second generation tests are reliable. There are additional confirmatory tests available that may be indicated.
Persons at increased risk for acquiring HCV infection are injection drug users and persons with multiple sexual partners. Injection drug use is the risk factor for acquisition of HCV infection in approximately 35 percent of reported cases. Parenterally transmitted hepatitis attributable to HCV also exists among recipients of transfused blood products, hemodialysis patients, and health care workers. Post-transfusion hepatitis occurs in about 50 to 80 percent of persons exposed to HCV-infected blood. HCV may also be transmitted by close sexual or household contact and may be transmitted from an infected mother to her fetus or neonate. The risk to the infant may be increased when the mother is also HIV infected. In about 40 percent of cases of HCV infection, no identifiable risk factor is found.
Approximately 50 to 75 percent of acute HCV infections in adults are asymptomatic. Acute HCV infection may be subclinical or may be clinically manifested by vague abdominal discomfort, anorexia, nausea, vomiting, and jaundice with elevated liver enzymes. Fulminant hepatitis may occur, but rarely.
As many as 60 to 70 percent of persons with acute HCV infection will develop chronic hepatitis. In patients who have acquired HCV infection in the community, approximately 7 to 43 percent have developed chronic hepatitis; about 10 percent of those who developed chronic hepatitis have in turn developed cirrhosis. In persons who have had a transfusion exposure to HCV, approximately 50 percent have developed chronic hepatitis and approximately 10 to 20 percent of those who developed chronic hepatitis in turn have developed cirrhosis. The diagnosis and medical followup of HCV-infected persons will be an ongoing medical concern in the coming years, now that interferon is available to treat severe and progressive cases of chronic active HCV infection and liver transplantation is feasible for some people.
The seroprevalence rate of HCV infection in injection drug users ranges from about 50 percent to 90 percent in some areas. Since the rate of HCV infection in drug users is high, the screening for and management of this infection are important issues for methadone and other drug treatment programs. In drug treatment programs, hepatitis C testing should be requested when a patient's liver function profiles are elevated and all other possible causes of the inflammation have been ruled out. Both the treatment of symptoms and palliative support are indicated.
Methadone maintenance programs need to be aware that methadone dosing may be hazardous in persons who have severely compromised liver function resulting from viral hepatitis of any type. Any patient who is suspected of having acute or chronic viral hepatitis should be evaluated for continuation of and/or adjustments to pharmacological therapy.
Methadone and other drug treatment sites that are instituting a screening program for HCV infection should consider the following:
The laboratory doing the testing needs to be qualified to do HCV serologic testing.
Even with the improved testing now available for HCV, there are still some problems with false-positive and false-negative results. Because of this, some tests will need to be repeated or interpreted by a knowledgeable physician.
Direct-care staff who have percutaneous exposure to blood or body fluids from an HCV-infected person may benefit from receiving serum immune globulin, as described under "Medical Management Issues."
Patients with serologic evidence of HCV infection should be referred to a physician, preferably a liver specialist. Chronically infected HCV patients should be evaluated medically on a routine periodic basis to monitor the course of their liver disease.
Patients who refuse screening should be treated as if they are potentially infected with HCV, but they should not be excluded from treatment programs solely on the basis of presumed or actual infection. Admission to a treatment program should not be restricted unless the illness precludes participation in the program and limits the person's ability to perform activities of daily living.
All staff members should implement basic infection control measures, including universal precautions (blood and body fluid precautions). Good personal hygiene, especially hand washing, should be observed by both staff members and patients. Disposable units should be used, and syringes, needles, and other equipment used for parenteral injections must be properly sterilized if not disposable.
Patients should be advised to minimize intimate contact with persons who may be infected with HCV. Patients should use condoms and follow safer-sex guidelines. Patients should not share personal items such as toothbrushes or razors. Health and sex education are of major value in primary prevention and should be provided whenever possible.
Requirements for reporting of acute cases of hepatitis C to local and State health departments vary among States. Check with your State health department. Programs need to coordinate contact tracing and partner notification concerning hepatitis C with local health authorities.
Isolation is not necessary for patients with HCV infection. However, patients who are hepatitis C antibody positive should be advised not to share razors, toilet articles, toothbrushes, or drinking and eating utensils.
Screening for hepatitis C virus on a routine basis is controversial because of the lack of documented effective prevention measures, such as a vaccine. In general, drug treatment programs should consider screening patients to identify those infected with HCV.
Certain patients and staff members should be screened. Any person in a treatment program who has an elevated serum alanine aminotransferase (ALT) should be screened for antibody to HCV. Patients should be tested for hepatitis C if their liver enzymes are elevated and all other possible causes of the inflammation have been ruled out. Such causes could include other infectious agents and adverse reactions to medications and treatment regimens. In addition, any health care worker who sustains a needlestick or other exposure to blood or blood-contaminated body fluids should be screened. See table 1 for behavioral risk indicators.
Approximately 50 to 75 percent of acute HCV infections in adults are asymptomatic. When the acute HCV infection is symptomatic, the illness is no different from any other form of viral hepatitis. See table 2 for symptoms.
Symptoms of chronic hepatitis are present in up to 60 to 70 percent of persons with chronic, ongoing HCV infection; these symptoms may include fatigue and malaise. With chronic hepatitis from HCV infection, clinical jaundice may or may not be present.
The preliminary evaluation for acute or chronic HCV infection should include the following elements:
Check for presence of symptoms associated with liver disease
Take a history and conduct a physical examination
Compile a complete review of patient drug use, including illicit, prescription, and nonprescription drugs; toxin exposure; and alcohol consumption. Many different drugs are hepatotoxic either alone or in combination.
Perform liver function tests, including the following:
In 1989, a portion of the genome of a non-A, non-B viral agent was cloned and designated the hepatitis C virus. The entire HCV genome has now been sequenced. Specific assays for HCV have been developed to determine the presence of hepatitis C antibodies. The presence of these antibodies is diagnostic of HCV infection.
In the majority of cases, these assays detect HCV antibodies within 20 weeks of exposure. There are several assays currently available to detect the presence of antibodies to HCV. They include the first generation enzyme immunoassay, which has now been replaced by the more sensitive and specific assays, including the Abbott HCV EIA 2.0, Abbott Laboratories, an enzyme immunoassay; the Ortho HCV ELISA test, Ortho Diagnostics, Inc., an enzyme-linked immunoassay; the supplemental anti-HCV immunoblot system (Matrix HCV, Abbott); and the recombinant immunoblot assay system (RIBA-1, Ortho Diagnostics). In addition, some laboratories are analyzing serum samples for the presence of HCV ribonucleic acid (RNA) after amplification with PCR (polymerase chain reaction).
Each center testing for HCV needs to arrange to send the serum samples to a qualified reference laboratory. If interpretation of the results is not clear, the center should discuss the results with a liver specialist.
If the clinical and serologic evaluation for HCV infection reveals evidence of acute or chronic hepatitis, the client should be referred out for further medical evaluation and followup. Any patient with serologic evidence of hepatitis C infection should also be counseled about the risk of transmission to others. An infected person may transmit infection through continued injection drug use that involves sharing of needles or paraphernalia. HCV infection may also be acquired by sexual exposure to an infected person. However, this route of transmission is less efficient than the bloodborne route of transmission.
If acute infection is symptomatic, recovery occurs in 4 to 6 weeks. Fulminant HCV infection with acute HCV is rare, but it is associated with 90 percent mortality when it occurs.
Chronic HCV infection is associated with chronic active hepatitis, with or without cirrhosis, in about two thirds of chronically infected persons. Over a period of many years, cirrhosis with hepatic failure or hepatocellular carcinoma may develop.
Patients with serologic evidence of HCV infection should be referred to a physician, preferably a liver specialist, who can make appropriate recommendations for followup. Some infected patients may require a liver biopsy, treatment with a -interferon, or possibly even a liver transplant.
Chronically infected HCV patients should be medically evaluated on a routine basis to monitor the course of their liver disease. Treatment with a -interferon is recommended only for those persons with advanced, symptomatic, chronic hepatitis C infection. Treatment with <F128M>a<F255D>-interferon is available only from tertiary-care facilities.
Post-exposure treatment with immune globulin (Ig) should be considered for any staff member or patient with a percutaneous or mucous membrane exposure to anti-HCV-positive blood or body fluids. There are, however, no good data to suggest that Ig in this setting is effective, and consultation with a physician knowledgeable about this issue should be obtained. If a decision is made to administer Ig, it should be given as soon as possible following the exposure. Ig is given intramuscularly at a dose of 0.06 ml/kg of body weight.
As with other patients, hepatitis C testing should be requested when a patient with HIV has elevated liver enzymes and all other possible causes of the inflammation have been ruled out.
Hepatitis C testing should be requested when liver enzymes are elevated and all other possible causes of the inflammation have been ruled out. At present, there is no specific intervention recommended for infants born to mothers who are positive for anti-HCV.
Protection against viral hepatitis: Recommendations of the Immunization Practices Advisory Committee. Morbidity and Mortality Weekly Report 39(RR-2):1-26, 1990.
Antibody to hepatitis C virus among cardiac surgery patients, homosexual men, and intravenous drug users in Baltimore, MD. American Journal of Epidemiology 134:1206-1211, 1991.
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