Viral Hepatitis Flashcards
Acute hepatitis definition
Inflammation of the liver
Raised ALT/AST/jaundice/clotting derrnagments
Chronic hepatitis definition
hepatitis virus present for more than 6 months
Hepatitis A (HAV) type of organsims
picornavirus (ssRNA)
Transmission of hepatitis A virus
Faeco-oral transmisson
Contaminated water and food with infected faeces or urine
Humans only reservoir
Virus can survive for months in contaiminated water
Virus shed via bilary tree into gut
no chronic carriage
good immunity after infection
Hepatitis A- Clinical features
Incubation period 30 days
Many infections are asymptomatic.
Nausea, fever, malaise, and anorexia may last for 2-7 days before jaundice develops
usually self limiting illness
Mostly asymptomatic in children. Jaundice is more common in adults and is associated with dark urine, pale stools and tender hepatomegaly
Treatment of hepatitis A
Symptomatic treatment-
maintain hydration, avoid alcohol
no role for vaccine or igG in the treatment.
Vaccine should be considered for close contacts
Vaccine in hepatitis A
Inactivate virus
95% efficacy
Protection 4 weeks after 1st dose
2nd dose gives long term cover
Pre-exposure
-travelers/homosexual men/IVDU/Chronic liver lisease pts
Post-exposure
- outbreak control
- effective up to 7 days after exposure
Alternative vaccine in hepatitis A
pooled immunoglobulin
Pre-exposure
-if vaccine allergic
Hepatitis E type of virus
calcivirus (RNA)
Transmission of hepatitis E
faeco-oral
faecal contamination of water supply
-minimal person-to-person transmission
Incubation period for hepatitis E
40 days
Clinical features of hep E
Anorexia, jaundice, nausea, joint pains, fever
In pregnant women (fetal and materanal mortality of 25%
Self-limiting illness
Treatment of hep E
supportive
Chronicity in hepatitis E
No
Vaccine for hep E
No
Hepatitis B type of virus
hepadnavirus (DNA)
Transmission of hep B
Blood, sexual, Vertical (mother to baby)
Concentration of HBV in body fluids
High
- blood
- wound exudates
Moderate
- semen
- vaginal fluid
- saliva
Low/not detectable
- urine
- faeces
- sweat
- tears
- breast milk
Incubation period in hep B
2-6months
Clinical features of hep B
fever, fatigue, jaundice, myalgia, joint pains
Age at the time of illness determines:
- severity of illness
- risk of chronic HBV infection
Infection at birth/young child is asymptomatic but leads to chronic
infection an an adult is symptomatic but cleared
Complications of chronic HBV
chronic liver disease in 25%
cirrhosis
hepatocelular carcinoma
death
Hepatitis B serology
HBsAg (Hep B surface antigen)
HbsAB (hep B surface antibody)
cAb - core antibody
eAB- e anti-body
HBV DNA
HbsAG Hep B surface antigen
Carrier of infection
>6 months then chronic carrier
HbsAB (hep B surgace antibody)
Infection in the past and cleared through vaccination
cAB core antibody
previous infection through natural immunity
How to tell how infectious a patient is?
eAg - high infectivity
eAb - low infectivity
Chronic hepatitis markers
carrier >6 months
eAg +ve
- high viral load
- high risk of CLD and HCC
- highly infectious
eAg-ve
- low viral load
- lower risk of CLD and HCC
- less infectious
Treatment for hepatitis B
Acute
-no treatments
Chronic
- treat those with liver inflammation
- small number, 5% will clear sAg spontaneously
- aim of treatment is NOT to cure, but to suppress viral replication a/- to convert from eAg to eAb+
Two types of HepB therapy
Immunological
- pergylated interforn alpha
a. increases cellular immune responses
b. lots of side-effects
Antiviral drugs (nucleoside/tides) to suppress viral replication
a. tenofovir
b. entecavir
Prevention of HbV
Education (safe sex, injecting etc)
screening (pregnancy etc)
Protect blood supply & hospital supples
Immunisation
a. active (HBVsAG vaccine)
(high risk grouups in UK and all in USA, most african/asian)
b. passive (HBIG)
-babies born to some HBV+ mothers, post exposure in non-immune
Pregnany - prevention of HBV transmission
Three interventions
- HBC vaccination to all newborns
- HBV immunoglobulins if eAG or high VL
- tenofovir during the lst trimester if high VL
Hepatitis D type of virus
ssRNA
Transmission of hepatitis D
requires HBV to replicate
Vertical tm rare
acuired by:
- co-infection with HBV
- super-infection of chronic HBV carriers
Increases risk of chronic liver disease
Hepatitis C type of virus
ssRNA flavivirus
Transmission of hepatitis C
injecting drugs
transfusion + transplant
-sexual/ verticlal rare
Prevention of hepatitis C
No vaccine, no post exposure prophylaxis
No reliabble immunity after infection
multiple genotypes of HCV
Incubation period of hepatitis C
6-7 weeks
Complications of hepatitis C
70% develop crhonic hepatitis
25% develop chronic liver disease (cirrhosis, liver transplantation, and hepatoceullar carcinoma
multitude of extra-hepatic manifestations
-cryglobuminaemia, vasculitis, glomerulopnephritis
HCV diagnosis
mostly asymptomatic
Most diagnsed by screenign of high risk groups
-drug users
-immigrants to UK from high prevalance countries
Anti-HCV IgG positive = chronic infection or cleared infection
PCR positivity = current infection
Treatment
Aim
- cure= PCR negative
- Prevent and reverse fibrosis
Who to treat
- acute infections failing to clear virus by 3/12
-chronic infections
(especially those with significant liver fibrosis and inflammation)
-assess liver using LFT, liver biopsy and fibroscan
Treatment
- Pegalated interferon alpha
- Ribavirin (anti-viral)
- Protease inhibitor - Bocepravir and telapravir
Sustained virological response = PCR -ve 6/12 after treatment
