Hepatitis Flashcards
what types of hepatitis are there
- bacteria
- viral
- noninfectious etiologic agents
how is hepatitis transmitted
via blood and sex while others via fecal-oral route
what is the pathogenesis of viral hepatitis
- liver damage due mostly to host cell-mediated immune response
- mainly CTL (immunopathology)
- hepatitis viruses are not cytolytic
what are the three viral pathogens of hepatitis
- hepatitis A virus (HAV)
- hepatitis B virus (HBV)
- hepatitis C virus (HCV)
describe the pathogenesis of acute viral hepatitis
- robust immune response
- lots of CTLs activated
- CTL-mediated apoptosis of hepatocytes
- signs/symptoms; jaundice
- virus cleared
describe the pathogenesis of chronic viral hepatitis
- insufficient immune response
- few CTLs activated
- little damage to hepatocytes
- no or mild symptoms
- virus persists
- scar tissue accumulates
- sequelae
describe hepatitis disease
- inflammation of the liver
- hepatocytes are destroyed
- acute symptoms:
- bilirubinemia -> jaundice -> yellow skin and
yellow skin and eyes; dark urine
- bilirubinemia -> jaundice -> yellow skin and
- abdominal pain
- vomiting, nausea, anorexia
- fatigue
describe hep A
- HAV is a naked virus
- acute disease, usually mild and self-limiting
- fecal-oral route
describe hep C
- HCV is enveloped
- usually chronic asymptomatic disease but causes serious problems many years later
- no vaccine
how is HCV transmitted
blood, sexual contact, and vertical transmission; “blood-borne pathogen”
what are some complications of chronic hepatitis
- can lead to: cirrhosis, liver failure, liver cancer
- increases risk for liver cancer by 10-fold
describe hep B
- HBV is enveloped
- acute and chronic infections possible
how is HBV transmitted
blood, sexual contact, and vertical transmission; “blood-borne pathogen”
studies show that age of infection is the single most important factor associated with chronicity of HBV infection. hosts that mount a robust CTL response tend to have acute hepatitis infections whereas hosts who mount an insufficient CTL response, have chronic infections. which age group would you predict to be more likely to develop chronic HBV infections?
- newborns
- children > 5 years
- young adults (18-35 years)
- adults (36-64 years)
newborns
how is HBV in adults, infants, and young children
- HBV in adults -> usually acute disease, occasionally severe
- HBV in infants and young children -> chronic disease
- infants born to HBV+ mothers are given HB immune globulin
- all pregnant women are routinely screened for HBV
HBV vaccine is routinely offered to all newborns within how many hours of birth
48
describe HDV
- aka “delta agent”
- uncommon in the U.S.
- causes severe fulminant hepatitis in hosts already infected with HBV
what does HDV require for replication
HBV
vaccination against HBV is also protective against
HDV infection
what is the prevention for HAV, HBV, and HCV
- HAV = inactivated virus vaccine
- HBV = subunit vaccine
- HCV = no HCV vaccine; avoid high risk behavior; screen high risk individuals
- treatment: interferon and antiviral drugs
for people born between 1945-1965
- treatment: interferon and antiviral drugs
what is the diagnosis of viral hepatitis
- initial diagnosis made by observation of jaundice, enlarged liver, or fluid in the abdomen
- serological testing can identify viral antigens or antibodies
- molecules tests (ie PCR) to detect viral genomes
