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Hepatitis C virus. HCV is similar to the animal pestivirus and is close to the human Flaviviridae group. The infection is spread by contact associated with intravenous drug use and nosocomial transmission. Seventy to 80 percent of persons infected by hepatitis C are affected by chronic hepatitis, and 20 to 30 percent of these cases lead to cirrhosis with a risk of liver cancer 10 to 20 years after the initial infection. Viral diameter approximately 50-60 nm. Viral magnification 1,800,000x at 10 cm and image colorization with HDRI treatments on a transmission electron micrograph view (TEM).
Case
A 65-year-old male with a history of a motor vehicle accident that required emergency surgery in 1982 is hospitalized for acute renal failure. He reports a distant history of IV heroin use and a brief incarceration. He does not currently use illicit drugs. He has no signs or symptoms of liver disease. Should this patient be screened for chronic hepatitis C virus (HCV) infection?
Brief Overview
HCV is a major public health concern in the United States and worldwide. It is estimated that more than 4.1 million people in the U.S. (1.6% prevalence) and more than 180 million worldwide (2.8% prevalence) are HCV antibody-positive.1,2 The acute infection is most often asymptomatic, and 80% to 100% of patients will remain HCV RNA-positive, 60% to 80% will have persistently elevated liver enzymes, and 16% will develop evidence of cirrhosis at 20 years after initial infection.3
A number of organizations in the United States have released HCV screening guidelines, including the CDC, the American Association for the Study of Liver Disease (AASLD), and the U.S. Preventive Services Task Force (USPSTF); however, despite these established recommendations, an estimated 50% of individuals with chronic HCV infection are unscreened and unaware of their infection status.4 Furthermore, in a recent study of one managed care network, even when one or more risk factors were present, only 29% of individuals underwent screening for HCV antibodies detection.5 The importance of detecting chronic HCV infection will have greater significance as newer and better-tolerated treatment options become available.6
Multiple organizations recommend screening for chronic HCV infection. This screening is recommended for patients with known risk factors and those in populations with a high prevalence of HCV infection.
Risk Factors and High-Prevalence Populations
IV or intranasal drug use. IV drug use is the main identifiable source of HCV infection in the U.S. It is estimated that 60% of new HCV infections occur in people who have injected drugs in the past six months.7 The prevalence of HCV antibodies in current IV drug users is between 72% and 96%.8 Intranasal cocaine use is also associated with a higher prevalence of HCV antibodies than the general population.8
Blood transfusion prior to July 1992. Testing of donor blood was not routinely done until 1990, and more sensitive testing was not implemented until July 1992.8 The prevalence of HCV antibodies in people who received blood transfusions prior to 1990 is 6%.8 Prior to 1990, the risk for transfusion-associated HCV infection was one in 526 units transfused.9 Since implementation of highly sensitive screening techniques, the risk of infection has dropped to less than one in 1.9 million units transfused.10
Clotting factors prior to 1987 or transplanted tissue prior to 1992. Individuals who have received clotting factors, other blood product transfusions, or transplanted tissue prior to 1987 are at an increased risk for developing HCV infection. For instance, individuals with hemophilia treated with clotting factors prior to 1987 had chronic HCV infection rates of up to 90%.8 In 1987, widespread use of protocols to inactivate HCV in clotting factors and other blood products was adopted.8 In addition, widespread screening of potential tissue donors and the use of HCV antibody-negative donors became routine.8