Hepatitis B Flashcards
What type of virus is hepatitis B?
enveloped, double stranded, circular, DNA virus
What does hepatitis B attack?
It attacks the liver leading to acute (first 6 months) or chronic infection
How is hepatitis B transferred?
- blood exposure
- sexual contact
- sharing needles
What are the complications of hepatitis B?
cirrhosis and hepatocellularcarcinoma (HCC)
What is the vaccine schedule for hepatitis B?
3 shots: 0, 2, and 6 months
What is the treatment for hepatitis B?
NRTIs
What is HBsAg?
surface antigen that indicates live, active virus is present
What is HBeAg?
indicates the presence of active replication of HBV as seen in phase 2 of chronic HBV infections
What is anti-HBc?
Core antigen that is only positive if active virus is present or was present but cleared by the immune system
What are IgM anti-HBs?
early antibody production that occurs in the acute phase of infection
What are IgG anti-HBs?
Reflects immunity against HBV either from clearing infection or from immunization by vaccine
Lab findings for a susceptible patient who has never been infected or vaccinated?
(-) HBsAg
(-) anti-HBc
(-) anti-HBs
What lab findings indicate HBV immunity due to infection?
(-) HBsAg
(+) anti-HBc
(+) anti-HBs
What lab findings indicate HBV immunity due to immunization?
(-) HBsAG
(-) anti-HBc
(+) anti-HBs
What lab findings indicate acute HBV infection?
(+) HBsAg (+) anti-HBc (+) IgM anti-HBc (-) anti-HBs (+/-) HBeAg
What lab findings indicate chronic HBV infection?
(+) HBsAg
(+) anti-HBc
(-) IgM anti-HBc
(-) anti-HBs
Describe the immune tolerant phase?
- ALT is normal
- HBV DNA is > 1 million
- (+) HBeAg
- minimal inflammation/fibrosis
Describe the immune active phase?
- ALT is elevated
- HBV DNA is ≥ 20,000
- (+) HBeAg
- mod-severe inflammation/fibrosis
Describe the inactive phase?
- ALT is normal
- HBV DNA is < 2,000
- (-) HBeAg
- variable inflammation/fibrosis
Describe the reactivation phase?
- Elevated ALT
- HBV DNA ≥ 2,000
- (-) HBeAg
- mod-severe inflammation/fibrosis
What should a work-up consist of for HBV?
- immunization status
- comorbidities and family hx
- baseline labs (renal and liver)
- HIV, HCV, or HDV coinfection
- baseline imaging of liver
What is the MOA of the NRTIs?
they interfere with HBV polymerase and prevent the HBV DNA from making a copy of itself