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Hepatitis
Med school micro - all about Hep
37
Microbiology
Graduate
03/29/2011

Additional Microbiology Flashcards

 


 

Cards

Term
Common features of Viral Hepatitis
Definition
  • Upper right quadrant ab. pain, nausea, anorexia, fatigue, fever
  • Jaundice, hepatomegaly
  • Elevated: liver enzymes, bilirubin in blood and urin, Alkaline phosphatase, LDH
Term
Hepatitis A Virus (HAV): General
Definition
  • Picornaviridae, Enterovirus group
  • (+)ssRNA virus
  • very stable in environment
  • causes acute or asymptomatic infection
  • "infectious hepatitis"
Term
HAV: Transmission
Definition
  • Fecal/oral due to crowding and poor hygiene
  • community outbreaks
  • assymptomatic = source of new infections
Term
HAV: clinical features
Definition

Incubation period: avg = 30 days

 

Jaundice:

  • >14 yrs 70-80%
  • 6 - 14 yrs 40%-50%

Complications: Fulminant hepatitis, cholestatic hepatitis

 

Typical disease: acute for weeks


Term
HAV pathogenesis:
Definition
enters intestinal tract -> blood -> liver -> replicates in hepatocytes -> liver damge from virus and immune response -> leaves liver via bile duct -> shed in feces
Term
Diagnosis of HAV infection:
Definition

Definitive diagnosis of acute infection:

α-HAV IgM in serum

 

Definitive diagnosis of past infection:

α-HAV IgG

Term
Hepatitis B Virus (HBV): General
Definition
  • Hepadnaviridae family
  • enveloped, dsDNA
  • replicates via RNA intermediate
  • heat and pH resistant
  • humans are only reservoir
  • acute and chronic infections

 

Term
HBV: outcomes of infections
Definition
  • 90% acute infections
  • Chronic persistent (asymptomatic)
  • Chronic active (symptomatic)
Term
Clinical features of HBV
Definition

Incubation period: avg = 100 days

 

Jaundice: >5 yrs 30-50%

 

Chonic infection: more likely in children <5 yrs

Acute infection more likely in adults

 

15-25% die of chronic liver disease

Term
HBV: pathogenesis
Definition
entry via blood or semen -> travel to liver -> replication in liver (100days) -> liver damage due to immune response (not virus)
Term
HBsAg=
Definition
general marker of HBV infection
Term
α-HBsAb =
Definition
recovery and/or immunity to HBV infection
Term
α-HBc IgM =
Definition
marker of acute infection
Term
α-HBc IgG =
Definition
past or chronic infection
Term
HBeAg =
Definition
active replication of virus and infectiveness
Term
α-HBe =
Definition
virus no longer replicating
Term
HBV-DNA =
Definition

active replication of virus

-more accurate than HBeAg

Term
List the expected serological findings in an acute HBV infection
Definition

HBsAg +

HBeAg +/-

α-HBcAg IgM +

α-HBcag IgG + right after infection; - rest of the time

Term
List the expected serological findings following recovery of and acute HBV infection
Definition

HBsAg -

HBeAg -

α-HBsAg +

α-HBcAg IgM -

α-HBcAg IgG (total) +

Term
List the expected serological findings in a chronic persistent HBV infection
Definition

HBsAg +

HBeAg -

α-HBcAg IgM -

α-HBcAg IgG (total) +

α-HBeAg +

DNA polymerase -

Term
List the expected serological findings in a chronic active HBV infection
Definition

HBsAg +

HBeAg +

α-HBcAg IgM -

α-HBcAg IgG (total) +

DNA polymerase +

Term
Hepatitis D (delta) Virus (HDV): general
Definition
  • ssRNA, unclassified virus
  • contains HDV Ag derived from HDV
  • contains HBsAg derived from HBV
  • needs HBV as helper to code its surface protein
  • aquired as coinfection or superinfection of HBV

 

Term
HDV: transmission and risk group
Definition
  • percutaneous exposures
  • permucosal exposures
  • Intravenous drug users and their partners
Term
HDV: clinical features of coinfection
Definition

severe acute disease - mostly adults


low risk for chronic infection


serology will show α-HBs in later weeks

Term
HDV: clinical features of superinfection
Definition

usually from contracting HDV while person already has a chronic HBV infection

 

-high risk of severe chronic liver disease (chronic active or fulminant hepatitis)

 

serology: will continually have HDV-RNA, HBsAg, α-HDV IgM; will not have α-HBs

Term
α-HDV IgM =
Definition

acute

 

high titers in chronic during times of reactivation

Term
HDV Ag =
Definition
acute or chronic HDV infection
Term
α-HDV IgG =
Definition
declines late in acute, high titers in chronic
Term
Hepatitis E Virus (HEV): general
Definition
  • a NANB hepatitis virus
  • non enveloped, (+)RNA
  • related to calicivirus
Term
HEV: transmission
Definition
  • fecal/oral
  • acute sporadic outbreaks
Term
HEV clinical features:
Definition

Incubation: avg 40 days

 

Case-fatality rate: pregnant 15 - 25%

 

severity increases with age

Term
Hepatitis G Virus
Definition

Flavivirus; (+)ssRNA

mild acute hepatitis that usually becomes chronic persistent

 

can be found in coinfections with HC, HBV and HIV

Term
Hepatitis C Virus (HCV): General
Definition
  • Flavivirus; (+)ssRNA
  • accounts for 90% of NANBH infections
  • reservoirs = humans and chimpanzees
  • causes chronic infections
  • undergoes rapid antigenic variation in infected individuals
Term
HCV: transmission
Definition

percutaneous route

  • injecting drugs
  • needle stick injuries
  • formerly blood transfusion (pre 1990)

permucosal

Term
Clinical features of HCV infection
Definition

Incubation: avg 8 - 9 weeks

 

Jaundice: <25%

chronic infection: 70 - 85%

chronic hepatitis: 60 - 70 %

cirrhosis 5 - 20% (takes 10 - 20 yrs of infection)

Term
Factors that promote progression of chronic HCV infection
Definition
  • increased alcohol intake
  • age >40 yrs at time of infection
  • HIV co-infection
Term
Diagnosing HCV:
Definition
  1. test for presence of anti-HCV
  2. if positive, confirm with RIBA test
  3. Qualitative (yes/no) and Quantitative (viral load) PCR tests
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