Hepatitis B Flashcards
Incubation period
40-160 days
Extrahepatic manifestations
Cryoglobulinaema, serum siisckness like syndrome, polyarteritis nodosa, arthritis, glomerulonephrit
First line therapy for Hep B and outcomes?
What are the:
Stopping rules?
What blood tests should be done to monitor Rx?
48 week course of weekly Interferon alpha. ~30% eAg seroconversion and 7% sAg loss at end of treatment
- Stopping rules - Dependent on GT. If E Ag pos - A or D - no decline in qHBsAg at 12 weeks or >20000 at 24 then stop. B or C >20000 at 12 or 24 weeks then stop.
- Monitoring - HBV markers, ALT, TSH (3 monthly due to risk of thyroiditis)
Indications for treatment of hep B?
- HBV DNA >2000, ALT >ULN and moderate liver fibrosis
- HBV DNA >20000 and ALT >2xULN without fibrosis
- Cirrhosis and detectable HBV DNA (regardless of ALT)
- eAg Pos with “high” HBV DNA and persistently abnormal ALT
- Family history of HCC or extrahepatic manifestations of HBV
NAs with high barrier to resistance in HBV?
Entecavir
TDF/TAF
NAs with low barrier to resistance in HBV?
Lamivudine
Adefovir
HBV mutation that confers resistance to lamivudine?
M204V/I (remember similar to M184V in HIV)
HBV mutations that conver resistance to entecavir?
Multiple substitutions required.
L180M + M204V/I ± I169T ± V173L ± M250V
L180M + M204V/I ± T184G ± S202I/G
TDF resistance detected in HBV. What would you change therapy to?
Lam naive - ETV
Lam experience - Add ETV to TDF/TAF
Fanconi syndrome in HBV
Caused by TDF
Characterised by low phosphate, normoglycaemia glycosuria, metabolic acidosis and proteinuria. Managed by removing the offending drug.
Which baby doesn’t receive HBIG + HBV vaccination after birth?
Babies born weighing >1500g to eAg neg/eAb pos mums who had a viral load <1x10^6. All other infants born to sAg pos mums get HBIG.
Babies also get 2 extra doses of HBV vacccine at birth and 4 weekks (as well as the usual 8 12 16)
Management of babies born to hep B pos mum
Vaccine +- HBIG
Vaccine at birth, 2, 8, 12, 16 and 52 weeks.
Check HBsAg at 1 year
Indications for HBIG in adults following exposure?
Significant exposure in an unvaccinated individual from a known HBsAg pos source or non responders should be given HBIG if unknown or known positive source. Second dose of HBIG at 1 month for non responders.
What is bulevirtide and how does it work?
synthetic myristoylated lipopeptide consisting of 47 amino acids of the preS1 domain of the HBV large surface protein. i.e. protein similar to HBV Large surface protein
Works by blocking HBV and HDV viral entry into cells
Who is bulevirtide indicated in?
HBV/HDV coinfection. For patients in whom interferon is contraindicated or in whom it has failed with at least moderate fibrosis.
Which hep B vaccine is indicated in renal patients?
Fendrix - more immunogenic in this group.
Mutations which confer resistance to TDF in HBV?
A181T/V
N236T
Both adefovir R and TDF I
