Hepatitis B Definition, Diagnosis, Treatment, Prevention,

Monday, March 24th 2014. | Disease

Hepatitis B Definition, Diagnosis, Treatment, Prevention, virus

Hepatitis B is a leading cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma.
Transmission of HBV in the United States occurs predominantly through contact with infected blood products or body secretions (saliva, vaginal fluids, and semen) or sharing of needles by intravenous drug abusers.
The incubation period for HBV is 1 to 6 months. This is followed by a symptomatic prodromal phase consisting of malaise, fatigue, weakness, anorexia, myalgias, and arthralgias. Jaundice occurs in about one-third of patients and may persist for several weeks.
Clinical manifestations of acute HBV infection are age dependent. Infants infected with HBV are generally asymptomatic, while about 85% to 95% of children aged 1 -to 5 years are asymptomatic.
Acute symptomatic infections vary in severity and include fever, anorexia, nausea, vomiting, jaundice, dark urine, clay-colored or pale stools, and abdominal pain.
Approximately 90% of infants but 10% of adolescents or adults develop chronic HBV. Chronic HBV predisposes patients to chronic liver disease, cirrhosis, and hepatocellular carcinoma.
Signs and symptoms of Hepatitis B :
  • Easy fatigability, anxiety, anorexia, and malaise 
  • Ascites, jaundice, variceal bleeding, and hepatic encephalopathy can manifest with liver decompensation 
  • Hepatic encephalopathy is associated with hyperexcitability, impaired mentation, confusion, obtundation, and eventually coma 
  • Vomiting and seizures
Physical examination 
  • Icteric sclera, skin, and secretions 
  • Decreased bowel sounds, increased abdominal girth, and detectable fluid wave 
  • Asterixis 
  • Spider angiomata
Laboratory tests 
  • Presence of hepatitis B surface antigen for at least 6 months 
  • Intermittent elevations of hepatic transaminase (alanine transaminase [ALT] and aspartate transaminase [AST]) and hepatitis B virus DNA greater than 105 copies/mL 
  • Liver biopsies for pathologic classification as chronic persistent hepatitis, chronic active hepatitis, or cirrhosis
Treatment of Hepatitis B :
  • The key goal of therapy is to eradicate or permanently suppress HBV. The short-term goal is to limit hepatic inflammation and to reduce the risk of fibrosis and/or decompensation. The long-term goal is to prevent transaminase flares and the development of complications, and to prolong survival.
  • No specific therapy is available for the management of acute HBV infection.
  • Interferon alpha2b (IFN-alpha2B), lamivudine, and adefovir dipivoxil are approved in the US for treatment of HBV.
  • Drug therapy is not recommended for patients with normal ALT values.
  • Patients with persistent ALT levels greater than twice the upper limit of normal should be considered for treatment.
  • Patients with ALT levels greater than 5 times the upper limit of normal are experiencing an exacerbation and should receive lamivudine.
  • Patients considered for treatment are those who are HBsAg-positive for greater than 6 months with persistent elevations in serum aminotransferases, detectable markers of viral replication (HBeAg and HBV DNA) in serum and signs of chronic hepatitis on liver biopsy. Patients should not have decompensated liver disease.
  • In patients with chronic HBV who are HBeAg-positive and have intermittent or persistent elevation of ALT, either interferon or lamivudine may be used as first-line therapy.
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