Hepatitis B And C Flashcards
Hepatitis B epidemiology
33% have been infected at some point
- > 8% is seen in Asia Africa and western pacific regions
There is a 400 million population that has chronic HBV
- 10% of HIV patients have chronic HBV
Children have significantly higher carrier rates than adults
HBV facts
Also called “serum hepatitis”
Is a hepaDNAviridae virus
- partially circular DsDNA virus
- 3200 nucleotide genome (smallest DNA virus known to made)
Is 42nm with “Dane particles”
- Also has 22nm subviral particles attached to it
Is enveloped and complexed capsid
Encodes for a RT transcriptase even though its a DNA virus
How does HBV replicate
Replicates only in hepatocytes
Goes DNA -> RNA -> DNA again (unique)
- uses reverse transcriptase to revert to an RNA intermediate and then uses host cell machinery to go back to DNA
- also releases “decoy particles” to prevent finding
- makes multiple mRNAs and the 3.5kb RNA template is the one that is converted back to DNA
targets sodium taurocholate co-transporter polypeptide receptor (NTCP) on hepatocytes
Pathogenesis of HBV
Symptoms are caused by cytotoxic cell-mediated responses to infections
90-95% of acute infections spontaneously resolve
- if infant of immunocompromised is actually asymptomatic.
- **symptoms are actually good in this case and it means your immune system is working!!
Transmission:
- cutaneous or mucosal exposure to blood/body fluids (not found in urine/sweat/stool)
- perinatal transmission (high chances)
*can go through horizontal (infected household contact -> child) or vertical (infected mother directly to infant)
Symptoms: (if any)
- rashes
- right quad pain
- serum sickness symptoms
- jaundice
- renal damage (chronic only)
- cirrhosis (chronic only)
- hepatic cell carcinomas (chronic only)
antiboides to the surface capsid proteins (HBsAg) = immunity of disease
HBV serology
HBsAg = surface antigen
- signals an active infection of HBV is present
- presence alone DOESNT mean the patient is infectious
- is the vaccination target**
HBcAg = core/capsid antigen
HBeAg = excreted antigen
- signals active infection
- alone can signal the patient is infectious**
HBV DNA
- found in PCR and can signal active or chronic infection of HBV
Antibodies for HBV
Anti-HBs
- presence = acclimation of clearance or acute HBV infection has occurred
- is NON-DETECTABLE while antigen is being produced
- usually presents around 5 months in
- **seroconversion and is protective
Anti-Hbe
- presence = had an infection at one point
- is NON-DETECTABLE while antigen is being produced
- starts after a month into infection
- **is non protective (can get infected again)
Anti-HBc
- earliest detectable antibody and indicates an acute active HBV infection (IgM)
- is non protective (can get infected again)
When during an HBV infection do you see elevated ALT/AST?
2-5 months after exposure
- correlates directly with increases of anti-HBC
What is the “eclipse period” in an HBV infection?
Time frame during a typical HBV infection where you cant detect antigen or antibodies to the virus
Usually shows around 4-5 months and 5-6 months
How to tell if a patient is in an acute or chronic HBV infection?
Acute = IgM and anti-HBc and HBsAg are present
Chronic = IgG and anti-HBc and Anti-HBs are present
Acute HBV infection symptoms
Long incubation period (1-6 months)
Symptoms:
- ALT/AST >1
- anorexia
- malaise
- nausea
- right upper quadrant
- fever/rash
- jaundice/dark urine/pale stools (if liver failure)
- arthritis
children have high risks of asymptomatic periods
What levels of HBV particles are required for Chronic HBV to be present?
> 10^5 IU/mL
Results in:
- greater transmission
- greater hepatocellular carcinoma
can degrade into extrahepatic vasculitis/arthritis/glomerulonephritis/ fulminant hepatitis
Can the HBV vaccine prevent hepatocellular carcinoma?
YESS
- 80% of these cancers are caused by HBV chronic infections and can be halted if a vaccine is given, even if already infected
HBV treatment options
HBV immunoglobulin and vaccine = acute/prophylaxis
Chronic HBV:
1) RT polymerase antivirals
- Lamivudine/entecavir/Tenofovir
2) nucleoside analogs
- adefovir/dipivoxil/famciclovir
3) high dose Pegylated interferon (IFN-a)
HBV vaccine
Is a recombination s. Cerevisidae antigen with attenuated HBsAG
- the HBsAg self assembles into “pseudovirons” that replicate like normal HBV but cant induce infection properly
- *Vaccine is recommended for everyone pretty much (except pregnant women if given alone!!)
***new Heplosav-B vaccine (experimental) can be given in adults)
pregnancy = HB immunoglobulin +HBV vaccine
HCV epidemiology
150 million worldwide with highest incidence in the Middle East
3.6 million in US
Is seen in 90% of HIV-infected IV drug users (strong correlation to both factors separately)
- as well tattoos
