hepatitis B
definition
Hepatitis B is an enveloped DNA virus of the family
hepadnavirus. It consists of a core antigen surrounded by a
surface antigen.
The hepatitis B virus has eight distinct genotypes (A to H)
which vary in geographical distribution. The different
genotypes cause diseases that differ in severity and respond
differently to treatment.
Acute hepatitis B is a notifiable disease
Chronic hepatitis B is NOT a notifiable disease
transmission
majority of chronic hepatitis B infections occur in migrant
populations, having been acquired perinatally in the country
of birth.
new infections are acquired in adulthood, the source of
infection is most commmonly via sexual contact or sharing of
drug injecting equipment
Transmission by blood-to-blood contact- sharing of drug
equipment, occupational hazard, blood transfusion and blood
punctures, tattoos, acupuncture and piercings, household
contact and sharing of toiletries, sexual transmission and
mother to baby transmission
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high risk
injecting drug users and close contact
change in sexual partners
sex workers
men who have sex with men
travelling to high risk areas
blood transfusion
solid organ transplant
chronic renal failure on HD
people living in support accommodation
prison inmates and staff
infant born to infected women
complication
Fulminant hepatitis is a rare complication of acute hepatitis B
infection (affects less than 1% of people). If present,
however, it can progress rapidly to life-threatening liver failure
with coagulopathy, encephalopathy, and cerebral oedema.
jaundice
low mortality
Hepatitis B surface antigen (HBsAg) is cleared in 95% of
immunocompetent adults. In more than 90% of people,
lifelong immunity is achieved after clearing the infection.
differential diagnosis
viral hepatitis
HIV
non alcoholic fatty liver disease
alcohol induced hepatitis
drug induced liver disease
autoimmune hepatitis
granulomatous disorder
metabolic and genetic disorder
malignant infiltration of the liver
prevention
offer hep B immunisation to infants as part of the routine childhood immunisation programme to protect against future risk
all other people potentially exposed to hep B infected blood or body fluids immediate protection against hep B is required
immunisation schedule for hep B vaccine varies depending on vaccine product used how quickly protection is needed and whether it is given pre or post exposure
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confirmed
admit any person with hep B infection to the hospital if they are severely unwell,, refer all people found to be hep B positive to infectious diseases specialist
while awaiting referral advise person to seek medical attention, avoid drinking alcohol, take steps to minimise risk of transmission, avoid unprotected sex, avoid sharing needles,
provide supportive symptomatic care as required
provide information from resources available
ensure pregnant women with acute or chronic hep B are aware that infant should be immunised from birth, increase risk of preterm delivery, breastfeeding is safe providing infant has been immunised