Disease Information for Hepatitis C virus (non-A, non-B): Definition

Most patients (3/4) infected with HCV have chronic liver disease, which can progress to cirrhosis and hepatocellular carcinoma (HCC); Chronic infection with HCV is one of the most important causes of chronic liver disease, and the most common indication for orthotopic liver transplantation in the United States; HCV is a spherical, enveloped, single-stranded RNA virus belonging to the Flaviviridae family and Flavivirus genus;HCV is closely related to hepatitis G, dengue, and yellow fever viruses; HCV can produce at least 10 trillion new viral particles each day; RNA-dependent RNA polymerase, an enzyme critical in HCV replication, lacks proofreading capabilities and generates a large number of mutant viruses known as quasispecies; The envelope protein E2 also contains the binding site for CD-81, a tetraspanin receptor expressed on hepatocytes and B lymphocytes that acts as a receptor or coreceptor for HCV; The major HCV genotype worldwide is genotype 1, which accounts for 40-80% of all isolates; Genotypes 1a and 1b are prevalent in the United States, whereas in other countries, genotype 1a is less frequent; HCV genotype 1, particularly 1b, does not respond to therapy as well as genotypes 2 and 3;

This predominantly transmitted by means of percutaneous exposure to infected blood; In developed countries, most new HCV infections are related to intravenous drug abuse; HCV may also be transmitted by means of acupuncture, tattooing, and sharing razors; Nosocomial patient-to-patient transmission may occur by means of a contaminated colonoscope, via dialysis, or during surgery, including organ transplantation before 1992; most are aged 30-49 years, females have milder disease as do younger patients;

History: Most patients with chronic hepatitis C are asymptomatic or may have nonspecific symptoms such as fatigue or malaise in the absence of hepatic synthetic dysfunction; Patients with decompensated cirrhosis from HCV infection frequently have symptoms typically observed in other patients with decompensated liver disease, such as sleep inversion and pruritus;Most patients do not have abnormal physical examination findings until they develop portal hypertension or decompensated liver disease; One exception is patients with extrahepatic manifestations of HCV infection, such as porphyria cutanea tarda or necrotizing vasculitis, perhaps erythema induratum, cryoimmunoglobulinemia;[Adapted from online Emedicine 2005]

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