hepatitis B Flashcards
type of virus
enveloped
hepatotrophic
DNA virus
blood borne virus
sexually transmitted
acute & chronic
what can acute hep B develop into
chronic infection
- liver cancer
- cirrhosis
- liver failure (decompensation)
- liver transplant
RF
- perinatal exposure
- multiple sexual partners
- MSM
- injection drug use
- Asian, estern European, African ancestry
- FHx HCC, HBC
- household contact with HBV
- male
- Hx STDs
- infected with HIV
- infeted with HCV
- health care worker
- Hx improsonment
- haemodialysis
prevention
immunisation
vaccine to high risk
- hyperendemic areas
- IVDU
- dialysis patient
- HIV patient
- pregnant
- MSM
- sexual & household contacts of HBV carriers who are -ve for HBV serology
-> vaccine at 0, 1, 6mth intervals
How infectious is hepatitis B?
x100 more times infectious than HIV
incubation period of Hep B
40 - 160 days
symptoms
anorexia
abdominal pain
N&V
fever, chill
malaise
rash
dark urine
pale stools
jauncide (in acute)
differential diagnosis
chronic Hep C virus
CMV - cytomegalovirus
EBV - Ebstein barr virus
HSV - herpes simplex virus
autoimmune hepatitis
tests
LFTs
FBC
U&Es
coaguloathy - liver clotting cascade
serum antigens
treatment for hep B
nucleoside analogue +- liver transplant
1st line = Lamivudine 100mg OD oral
When is Hep b chronic?
> 6 months
How many develop chronic HB?
10 - 30%
aim of Tx for Hep B
slow progression of liver disease and reduce infections
secondary prevention
hep A vaccine
avoid heavy alcochol intake
complications of Hep B
cirrhosis
HCC (hepatocellular carcinoma)
What is cirrhosis?
immune reaction
inflammmation, cell death (necrosis), scarring (fibrosis) in the liver
more likely in older patients, alcohol abuse, infectd with HBeAg (-ve strain)
HCC - hepatocellular carcinoma
usually 25-30yrs after acute infection
poor survival (5-6% survive >5yrs)
When is Tx indicated?
in patients with high ALT, HBV DNa serum levels and inflammation of liver on biopsy
indicated if high risk of liver related morbidity or mortalityin ST (5-10yrs) or future (10-20yrs) and viral suppression likely during and after Tx
Tx goal
HBV DNA levels that are not detectable
1st line therapy (single agent)
entecavir
peginterferon alpha 2a
tenofovir
How do the treatments work?
used to boost the immunesystem to raise a defence against the virus
How often is the pegylated interferon given?
once a week injection
Tx length for hepatitis B
up to 48 weeks Tx
nucleoside/nucleotide analogues
lamivudine
telbivudine
entecavir
emtricitabine
adefovir & tenofovir
How do nucleoside/nucleotide analogues work?
suppress/destroy HBV by preventing replication
advantages of interferon therapy
– Short course therapy (48 weeks)
– Durable response
– Lack of resistance (just boosting immune system)
disadvantages of interferon therapy
– Side effects (not tolerated by all pts)
– Parenteral administration
– Monitoring requirements (FBC etc)
– Moderate antiviral effect (main fxn is just boosting immune system)
advantages of Nucleos(t)ide Analogues (NAs)
– Potent antiviral effect
– Good tolerance
– Oral Administration (tablet > injection)
disadvantages of Nucleos(t)ide Analogues (NAs)
– Indefinite duration (LT)
– Potential for resistance
– Long term safety? (trials not long enough to ID safety info)
What does Tx depens on?
patient factors:
- age
- severity of liver disease
- likely response
- potential for ADRs
- co-infection or co-morbidity?
– compensated cirrhosis?
– decompensated cirrhosis?
– HIV? (on Tx?)
– Hep D co-infection?
– chemotherapy? (immunosuppressant)
– pregnant?
– adult or child?
