hepatitis%20b
HEPATITIS B

Hepatitis B is transmitted through perinatal, percutaneous, sexual, and close person-to-person contact, ie by open cuts and sores.

Human hepatitis B virus belongs to the family of Hepadnaviridae of small, enveloped, primarily hepatotropic DNA viruses. The virus replicates in the host and assembles exclusively in the hepatocytes and virions are released non-cytopathically through the cellular secretory pathway.

Chronic hepatitis B is defined as a chronic necroinflammatory liver disease due to persistent hepatitis B virus infection.

Hepatitis D infection is found only in patients with hepatitis B as it requires the hepatitis B outer coat. It is transmitted through sexual and percutaneous (especially IV drug use) routes.

Hepatitis B and D both have an incubation period of 30-180 days.

Hepatitis%20b Signs and Symptoms

Introduction

  • Hepatitis B affects 240 million people worldwide
    • Intermediate to high prevalence in the Asia Pacific region that represents ¾ of chronic HBV-positive people worldwide
    • Nearly half of the people with chronic HBV infection globally is from the Western Pacific region (37 countries that include China, Japan, South Korea, Philippines and Vietnam according to WHO)
  • Chronic hepatitis B is defined as chronic necroinflammatory liver disease due to persistent hepatitis B virus infection
  • Chronic hepatitis B virus infection is when the patient is HBsAg seropositive for more than 6 months
    • Chronic infection may develop in nearly half of children infected with HBV before the age of 6 years and in <5% of individuals infected as adults
  • Human hepatitis B virus belongs to the family of Hepadnaviridae of small, enveloped, primarily hepatotropic DNA viruses
    • The virus replicates in the host and assembles exclusively in the hepatocytes and virions are released non-cytopathically through the cellular secretory pathway

Signs and Symptoms

  • The majority of acute viral hepatitis infections are asymptomatic or they can cause an anicteric illness that may not be diagnosed as hepatitis
  • Hepatitis A generally causes minor illness in childhood with >80% of infections being asymptomatic
    • Adults are more likely to produce clinical symptoms
  • Hepatitis B, C and D may also be asymptomatic
  • Symptomatic hepatitis B will depend on the mode and time of transmission
    • Vertical transmission from mother to child is almost always asymptomatic
    • Other routes of transmission are more likely to produce symptomatic disease (30% of cases transmitted by IV drug use are icteric)

Preicteric Phase

  • Nonspecific systemic symptoms (eg myalgia, nausea, vomiting, fatigue, malaise with discomfort in the right upper quadrant of the abdomen)
  • Altered sense of smell or taste, coryza, photophobia, headache, cough, diarrhea, dark urine and serum sickness-like syndrome
  • Hepatomegaly, splenomegaly and lymphadenopathy may be seen on physical exam

Icteric Phase

  • Jaundice, usually noted after onset of fever or upon lysis of fever

Fulminant Hepatitis

  • Development of symptoms of hepatic encephalopathy (eg confusion, drowsiness within 8 weeks of symptoms or within 2 weeks of onset of jaundice)
  • Hypoglycemia, prolonged prothrombin time (PT)

Pathogenesis

Routes of Transmission of Hepatitis

Hepatitis A: Oral-fecal

Hepatitis B: Perinatal, percutaneous, sexual, close person-to-person contact ie by open cuts and sores

Hepatitis C: Blood transfusions, organ transplants, percutaneous (especially IV drug use), sexual, perinatal

Hepatitis D: Sexual, percutaneous especially IV drug use

  • Found only in patients with hepatitis B since it requires the hepatitis B outer coat

Hepatitis E: Oral-fecal, blood transfusion in endemic areas

Incubation Period

Hepatitis A: 15-50 days

Hepatitis B: 30-180 days

Hepatitis C: 14-180 days

Hepatitis D: 30-180 days

Hepatitis E: 21-60 days

Other Characteristics of Hepatitis Viruses

  • Hepatitis B virus contains a DNA nucleic acid while A, C, and E viruses have an RNA nucleic acid
    • Hepatitis D has an incomplete RNA and needs the B virus to replicate
  • Hepatitis A and E viruses cause epidemics
  • Hepatitis B, C, and D viruses may predispose to chronic disease and hepatic malignancy
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