Viral Hepatitis Flashcards
Which Viral Hepatitis is not an RNA virus?
Hep B: DNA virus
Which Viral Hepatitis is a member of the Picorna Virus family?
Hep A (PERCH)
Non-enveloped, (+)ssRNA, linear, icosahedral
Synthesizes a large polypeptide that is cleaved to smaller viral proteins
Hep A incubation period
30 days
Acute disease
Anti-HAV IgM antibodies plus symptoms
Prior disease
Anti-HAV IgG antibodies
Hep E virus
Hepevirus
Non-enveloped, (+)ssRNA, linear, icosahedral
25% mortality rate in pregnancy
Hep B virus
Hepadnavirus (DNA virus) Enveloped, circular, icosahedral capsid Partially double stranded DNA virus Envelope from ER Incubation period: 1-4 months
Immune Reconstitution
If HIV is treated w/o treating Hep B it can cause severe liver damage
Hep B is usually done prior to HIV therapy
Hep B Extrahepatic Manifestations
Polyarteritis nodosa
Glomerular disease
Hep B Surface Antigen
HBsAg
Hallmark of infection
Glycoprotein that forms spheres and tubules (EM)
From surface of envelope
Detectable weeks after exposure, prior to symptoms
Hep B Vaccine
Contains recombinant HBsAg
Contains (+) anti-HBsAg
All other antibodies (HBc, HBe) should be negative
Hep B Core Antigen
HBcAg IC ag (comes from w/n hepatocytes) Capsid core protein Expressed by infected hepatocytes NOT detectable is serum
Window Period
Brief period where:
HbsAg undetectable
Anti-HBsAg not yet detectable
Can give false appearance of no infection
SOLE marker of infection is anti-HBc (IgM)
Hep B e Antigen
HBeAg Viral protein secreted by infected cells Part of capsid core Indicates significant viral rep -Correlates well with levels of HBV DNA -HBsAg indicates presence of virus, not necessarily replication Highly infectious
Hep B DNA
Detectable with PCR
Major role is determining “viral load” for treatment
Acute Hep B
HBsAg (except window)
IgM Anti-HBc (even during window)
HBeAg (indicates infectivity)
HBV DNA
Recovery after acute Hep B
Anti-HBs Anti-HBe Anti-HBc (IgG) Undetectable HBsAg Absence of HBV DNA
Prior Vaccination
Anti-HbsAg only
Not anti-HBc or anti-HBe
Chronic Infection
HBsAg positive
If HBeAg = High infectivity
Anti-HBc positive
Viral DNA may be high, low depending on viral load
(+) HBsAg
Pt infected
(-) HBsAg
Pt not infected
Acute Hep B
Supportive care
Chronic Hep B
Interferon
Lamivudine (NRTI): also HIV drug, Hep B also uses reverse transcriptase
Other antiviral drugs
Which Hep Virus is a Flavivirus?
Hep C (+) ssRNA, linear, icosahedral High degree of antigenic variation Envelope glycoproteins: -Contains hypervariable region -high mutation rate in genome -Lack of proofreading by viral RNA polymerase -Prone to frequent mutations so difficult for immune system to eradicate; becomes chronic
Chronic Hep C
Often asymptomatic
Incidental finding on liver function test
Hep C Dx
HCV RNA by PCR -elevated soon after exposure Anti-HCV -elevated by 12 weeks after exposure Both elevated in chronic disease (common)
Chronic Hep C Tx
Interferon (cytokine)
Ribiviron (anti-viral)
Others
Hep D
Delta Agent
Small, enveloped, (-) RNA virus, circular genome
Defective virus
Lacks gene for envelope proteins so uses HBsAg for envelope protein
Genome encodes one protein: delta antigen (HDAg)
Virus particles carry HDAg
Hep D Pathogenesis
Invades hepatocytes Travels to nucleus to replicate Uses HBV to provide envelope Virus particle coated with HBsAg Uses host cell RNA polymerase to replicate genome
Hep D Coinfection
Get Hep B and Hep D at same time
Hep D Superinfection
Hep D infection on top of chronic Hep B infection. Often leads to hepatitis flare.
Hep D dx
HDAg in serum
HDV RNA
Anti-HDV antibodies
