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 

  • Hepatitis B affects 240 million people worldwide
    • Intermediate to high prevalence in the Asia Pacific region that represents ¾ of chronic hepatitis B virus (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 the World Health Organization (WHO)]
  • Chronic hepatitis B is defined as chronic necroinflammatory liver disease due to persistent HBV infection
  • Chronic HBV 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
    • Screening for chronic HBV infection is recommended for the following: Household members, sex partners and drug-sharing partners of a person with chronic HBV infection, men who have sex with men (MSM), human immunodeficiency virus (HIV)-positive individuals, persons born in or unvaccinated US-born individuals born to parents from regions with ≥2% prevalence of chronic HBV infection, pregnant women, blood/plasma/organ/tissue/semen donors, infants born to HBsAg-positive mothers, patients on hemodialysis/chemotherapy/immunosuppressive therapy, patients with elevated aspartate transaminase (AST)/alanine aminotransferase (ALT) of unknown etiology
  • Human HBV 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

Hepatitis D

  • Hepatitis D requires hepatitis B infection for replication
  • Disease caused by HDV can be acute or chronic, as a coinfection or as a superinfection
  • Acute HBV/hepatitis D virus (HDV) coinfection may resolve spontaneously
  • Superinfection can lead to rapid disease progression to liver cirrhosis and hepatic failure within 5-10 years in 70-80% or 1-2 years in 15% of patients with chronic HBV/HDV infection
  • Affects nearly 5% of patients with chronic HBV infection globally
  • High prevalence rates for HDV infection were reported from countries in Western and Central Africa, Eastern and Southern Europe, Middle East, and East Asia

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
    • Symptoms usually last for <2 months; some patients may have prolonged infection or may experience disease relapse
  • 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)
  • Hepatitis E is usually asymptomatic; patients with symptoms are usually older adolescents or young adults
    • Extrahepatic manifestations [eg Guillain-Barré Parsonage-Turner syndrome, neuralgic amyotrophy, bilateral brachial neuritis, peripheral neuropathy, encephalitis, membranoproliferative glomerulonephritis with or without cryoglobulinemia, membranous glomerulonephritis, acute pancreatitis, other autoimmune manifestations (eg myocarditis, arthritis, thyroiditis), thrombocytopenia] have been observed
    • Some patients may experience persistent hepatitis E virus (HEV) replication and immunocompromised patients or those with chronic liver disease are at risk for chronic HEV infection with prolonged viremia (>6 months)

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 (eg ingestion of contaminated food or water), person-to-person contact, sexual contact
  • 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, mucous membrane contact with infectious blood or body fluids
    • Found only in patients with hepatitis B since it requires the hepatitis B outer coat 
  • Hepatitis E: Oral-fecal (ingestion of contaminated food or water), 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: 15-60 day

Other Characteristics of Hepatitis Viruses

  • Hepatitis B virus (HBV) 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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