Chronic Viral Hepatitis

Overview
  • Chronic Viral Hepatitis refers to a clinico-pathological pattern of disease caused by infection with certain Hepatitis Viruses that results in greater than 6 months of hepatic inflammation and injury.
Etiology
  • Overview
    • All cases of Chronic Viral Hepatitis are ultimately due to long-term infection with hepatitis viruses. However, these viruses each have different propensities to induce chronic infection as discussed below.
  • Hepatitis A Virus
    • Almost never results in chronic infection.
  • Hepatitis B Virus
    • If transmission occurs in neonates via mother-to-child transmission: Nearly 99% of individuals display chronic infection
    • If transmission occurs in immunocompetent adults: Only 1% of individuals display chronic infection
    • If transmission occurs in immunocompromised adults: Rate of chronic infection is significantly higher than 1%
  • Hepatitis C Virus
    • Nearly 80% of infected adults will display chronic infection.
  • Hepatitis D Virus
    • If acquired through co-infection with HBV, follows same pattern as HBV. If acquired on top of chronic HBV infection, will result in chronic HDV infection.
Pathogenesis
  • Long-term infection with hepatitis viruses results in variable degrees of low-grade inflammation. In many cases, inflammation is so minute and pathological changes so nuanced that clinical consequences are not observed. In other cases, inflammation smolders sufficiently that over time extensive fibrosis is observed that ends in a picture of cirrhosis. Finally, in some individuals the immune system may suddenly and spontaneously mount a stronger response to the virus leading to a syndrome of acute viral hepatitis.
Morphology
  • The morphology of chronic hepatitis is extremely variable. When mild, a predominantly lymphocytic infiltrate may occur just within the portal tracts. Frequently, steatosis is observed along with lymph node-like aggregations within the hepatic parenchyma
  • When severe, hepatocyte necrosis may be apparent. Progression to cirrhosis is manifested by increasing fibrosis.
Clinical Consequences
  • Overview
    • Analagous to the wide range of hepatic pathology displayed by individuals with chronic infections, clinical consequences are equally variable.
  • Symptomology
    • Fatigue is the most common symptom and in some cases malaise and anorexia. Intermittent bouts of jaundice may occur associated with hyperbilirubinemia.
  • Laboratory Results
    • Mild to moderate elevations in serum aminotransferases are common.
  • Complications
    • The most feared complication of chronic viral hepatitis is irreversible progression to cirrhosis and ultimately hepatic failure. In those infected with HBV and HCV, especially HBV, development of immune complexes and their deposition in various locations may cause arthralgias, certain types of glomerulonephritis, and polyarteritis nodosa. In those infected with HCV a mixed cryoglobulinemia may develop.