Hepatitis Flashcards
What are complications of Hep A
Fulminant liver failure (0.1% but increases with age and co-morbidites)
Viral relapse - common, occurs around 8 -9months after recovery
Mortality rate 1% over age of 40
Cholestasis following infection - higher chance if on OCP or HRT
Treatment of hep a
Supportive only Admission to hospital for severe disease - elderly - coagulopathic - severe jaundice - inability to keep down oral intake
Prevention with vaccine
How does the hepatitis b virus differ from the other hepatitis viruses?
DNA virus
- all other viruses are RNA viruses
What is the significance of genotypes of hep B
Not routinely tested
8 different genotypes
Only role is that genotype A patients who are HBeAg positive have a better response to interferon treatment
What are the main routes of transmission of hep B
High prevalence areas (SE Asia, subsaharan africa, china)
- perinatal transmission (vertical)
- horizontal transmission during childhood
Low prevalence areas
- IVDU
- sexual contact
- transfusion of blood pre-screening era
Clinical presentation of acute hepatitis B
70% sub clinical hepatitis
30% icteric hepatitis
Prodrome - rash, fatigue, fever, arthritis, arthralgia usually precedes jaundice, RUQ pain
0.5% present with fulminant liver failure
What is the serology of hepatitis A
IgM HAV develops 4-12 weeks after aquiring virus and persists for around 20 weeks
IgG HAV develops around 4-12 weeks and persists for life and confers life long immunity
Blood tests in acute hepatitis B
Raised transaminases (usually around 1000-2000, ALT higher then AST) Raised PT/INR (indicates severity) Elevated bilirubin HBsAg positive IgM anti-Hbc positive HBV DNA positive HBeAg positive
What is meant by the window period in acute hep b
When the HBsAg disappears but the anti-Hbs is yet to be at the level of detection
The only positive marker at this time of infection will be IgM-antiHbc
This period is more common in fulminant hepatitis as the virus is cleared rapidly by the immune system
What blood tests indicate recovery in acute hep b
Normalisation of transaminases in 1-4 months
HBsAg seroconverts to anti-HBs
HBeAg seroconverts to anti-HBe
Disappearance of HBV DNA
What is the rate of progression to chronic hep b and what does it depend on
Depends on age of acquisition of the virus
- perinatal 90% progression to chronic
- 1-5 years 20-50%
- adult less than 5%
What is the treatment for acute hep b
Mainstay of treatment in adults is supportive - as risk of chronic infection less then 5%’and risk of fulminant hepatitis 1%
Treatment can be offered in immunosuppressed, fulminant liver failure (need to clear virus pre-transplant), older age, underlying liver disease, hep c or d co-infection or severe disease
If drug treatment is required for acute hep b what agents are used
In general tenofovir, abacavir, entecavir etc
Interferon avoided in acute hepatitis as can worsen liver necro-inflammation
What is the goal and usual duration of treatment in acute hep b
Goal is seroconversion of HBsAg to anti-HBs
Short duration of treatment usual required
Need to check for resolution 2 tests for HBsAg 4 weeks apart before stopping
What are the 2 most common extra-hepatic manifestations of chronic hep b
Polyarteritis nodosa
Glomerular disease - nephrotic most common, membranoproliferative next
What are the 5 phases of chronic hep b infection
Immune tolerance Immune clearance Immune control Immune escape Resolution
What is the immune tolerance phase
Almost exclusively in those with perinatal acquisition
Virus is free to replicate without any recognition from immune system due to underdeveloped immune system
HBeAg positive, high levels of HBV DNA
Normal transaminases as no killing off of infected hepatocytes
Low rate of spontaneous clearance of HBsAg
Generally lasts 10-20 years
Treatment not effective in this phase due to low immune response
What are the 2 markers of HBV infectivity and replication
HBV DNA
HBeAg
What is the immune clearence phase
The initial phase in those affected as adults (don’t have an immune tolerance phase as immune system is mature)
When immune system recognises virus and starts to kill infected hepatocytes
Spontaneous HBeAg seroconversion increase to 10-20% per year
Fluctuating transaminases and liver fibrosis is seen
Treatment is effective in this phase as it enhances HBeAg seroconversion and prevents longer time in this phase (without treatment 5-6 years) therefore reducing liver damage
What is the immune control phase
Aka chronic carrier state
After HBeAg seroconversion ALT returns to normal HBV DNA levels drop and there is minimal fibrosis
Treatment is not effective in this phase as immune response is minimal
Confirmation of this phase is by 3x ALT levels and 3x HBV DNA levels (both negative) over 12 months
What is immune escape phase
Caused by selection out of mutated viruses that do not express HBeAg (ie pre-core)
See fluctuating HBV DNA and ALT levels despite HBeAg negative
Progression of fibrosis
Treatment is indicated to control viral replication
What is meant by resolution of chronic hep b
Spontaneous seroconversion of HBsAg to anti-HBs
Annual rate of clearance in western populations 0.5%-2%, asian 0.1-0.8%
Seroconversion does not preclude the development of cirrhosis or HCC especially when it occurs over the age of 50
What are some poor prognostic factors for chronic hep b
Etoh use Co-infection with hep c or d HBV variants (core-promoter or pre-core mutant) Longer time HBeAg positive Higher HBV DNA levels
What is meant by pre-core mutant HBV
Mutated hep b virus which has a mutation at gene 1896 which creates a stop codon which prevents development of HBeAg
What is a core- promoter mutant HBV
Paired mutation which leads to reduced HBsAg, not complete absence as in pre-core
What is the clinical significance of pre-core mutant HBV
More aggressive disease
Lower rates of spontaneous HBeAg seroconversion
Treatment aim instead of being for HBeAg seroconversion is to suppress viral load, often needed life-long (don’t use drugs with high rates of resistance)
Mutations are selected out throughout illness, they don’t occur in de novo disease
Who are at risk for re activation of hep b with immunosuppression
Highest risk - those who are HBsAg positive
Lower but risk with Rituximab and HSCT are those positive for anti-HBc but negative for HBsAg (theoretically have “cleared” the virus but still have very low levels of virus)
Treatment and duration of treatment to prevent re-activation
Duration is to continue 6 months after immunosuppression is stopped (12 months with Rituximab as longer to re-constitute immunity)
Options are lamivudine, tenofovir, entacavir
Interferon is avoided in acute hepatitis due to increased liver inflammation
What needs to be considered when treating lamivudine resistant patients with hep b
Entacavir shouldn’t be used as there are also high rates of resistance among lamivudine resistant patients