Hepatitis C, Acute

Key Features

Essentials of Diagnosis

• Often asymptomatic

• Prodrome of anorexia, nausea, vomiting, malaise, aversion to smoking

• Fever, enlarged and tender liver, jaundice

• Markedly elevated aminotransferases early in the course

• Liver biopsy shows hepatocellular necrosis and mononuclear infiltrate

• Source of infection is unknown in many

General Considerations

• The hepatitis C virus (HCV) is a single-stranded RNA virus (hepacivirus) with properties similar to those of flavivirus

• Seven major genotypes of HCV have been identified

• Coinfection is found in at least 30% of persons infected with HIV

• HIV leads to more rapid progression of chronic hepatitis C to cirrhosis

• Anti-HCV is not protective; in patients with acute or chronic hepatitis, its presence in serum generally signifies that HCV is the cause

Demographics

• In the past, HCV caused over 90% of cases of posttransfusion hepatitis, yet only 4% of cases of hepatitis C were attributable to blood transfusions

• Over 50% of cases are transmitted by injection drug use

• Body piercing, tattoos, and hemodialysis may be risk factors

• The risk of sexual and maternal-neonatal transmission is low and may be greatest in those with high circulating levels of HCV RNA

  • Multiple sexual partners may increase the risk of HCV infection

  • Transmission via breast-feeding has not been documented

• Hospital-acquired transmission may occur between patients on a liver unit or via

  • Multidose vials of saline

  • Reuse of disposable syringes

  • Contamination of shared saline, radiopharmaceutical, and sclerosant vials

Clinical Findings

Symptoms and Signs

• The incubation period averages 6–7 weeks

• Clinical illness

  • Often mild

  • Usually asymptomatic

  • Characterized by waxing and waning aminotransferase elevations and a high rate (> 80%) of chronic hepatitis

• In patients with the CC genotype,

  • Spontaneous clearance of HCV following acute infection is more common (64%)

  • Jaundice is more likely to develop during the course of acute hepatitis C

Differential Diagnosis

• Hepatitis A, B, D, E virus

• Hepatitis G virus (HGV) rarely, if ever, causes frank hepatitis

• TT virus (TTV)

  • Found in up to 7.5% of blood donors

  • Readily transmitted by blood transfusions

  • However, an association between this virus and liver disease has not been established

• A related virus known as SEN-V has been found in 2% of US blood donors

  • Is transmitted by transfusion

  • May account for some cases of transfusion-associated non-ABCDE hepatitis

• Cytomegalovirus, Epstein-Barr virus, and herpes simplex virus, particularly in immunocompromised hosts

Diagnosis

Laboratory Tests

• Antibodies to HCV (Figure 16-3)

  • The immunoassay has moderate sensitivity (false-negatives) for the diagnosis early in the course and in healthy blood donors and has low specificity (false-positives) in persons with elevated γ-globulin levels

  • In these situations, a diagnosis of hepatitis C may be confirmed by use of an assay for HCV RNA

• Occasional persons are found to have anti-HCV in serum without ...