Viral Hepatitis B&D

Question 1

def of hepatitis B

Answer 1

infection with hepatitis B virus (HBV)

may follow an acute or chronic course

Question 2

what is chronic HBV defined as

Answer 2

viraemia and hepatic inflammation >6months

Question 3

def of hepatitis D

Answer 3

defective virus
may only:
1 co-infect with HBV
2 superinfect carriers of HBV

Question 4

what sort of virus is HBV

Answer 4

enveloped, partially DS DNA virus

Question 5

what sort of virus is HDV

Answer 5

SS RNA virus coated with HBsAg

Question 6

aetiology

Answer 6

HBV:

• transmission by sexual contact, blood, vertical (mother to baby)
• viral proteins are produced (HBcAg-core antigen, HBsAg-surface antigen, HBeAg)

antibody + cell-mediated immune responses to viral replication lead to liver inflammation + hepatocyte necrosis

Question 7

what is HBeAG a marker of

Answer 7

increased infectivity

Question 8

associations/risk factors

Answer 8

1 HBV

• IV drug use
• infants of HBeAg positive mothers
• sexual contact with HBV carriers

Question 9

who is at risk of chronic HBV carriage

Answer 9

babies

Question 10

epi

Answer 10

HBV common in southeast asia, africa, uncommon in UK

350m worldwide infected with HBV, 1-2million deaths annually

Question 11

history

Answer 11

1 incubation period (time between infection exposure and symptoms) of 3-6months
2 prodromal symptoms
-malaise
-nausea, vomiting, diarrhoea
-RUQ pain
3 (occasionally) serum-sickness-type illness
-arthralgia
-maculopapular rash
4 dark urine + pale stools

Question 12

examination

Answer 12

1 acute
-jaundice
-pyrexia
-tender hepatomegaly
-cervical lymphadenopathy
2 chronic
-may have no findings
-may be signs of CLD

Question 13

investigations

Answer 13

1 viral serology
2 PCR
3 bloods
-LFTs (very high AST + ALT, high bilirubin, high alkphos)
-clotting (prolonged PT in severe disease)
4 liver biopsy

Question 14

what does HBsAg positive, IgM anti-HBcAg indicate

Answer 14

acute HBV

Question 15

what does HBsAg positive, IgG anti-HBcAg indicate

Answer 15

chronic HBV

Question 16

what does anti-HBsAg positive, igG anti-HBcAg indicate

Answer 16

HBV cleared or immunity

Question 17

why is PCR used in investigating HBV?

Answer 17

detection of HBV DNA is the most sensitive measure of ongoing viral replication

Question 18

management by prevention

Answer 18

1 instrument sterilisation (IV drug users)
2 safe sex
3 passive+active immunisation (against HBV)

Question 19

why is immunisation only required against HBV

Answer 19

HBV immunisation protects against HDV too

as HDV co-infects with HBV or superinfects carriers of HBV

Question 20

management of acute HBV hepatitis

Answer 20

1 symptomatic control (antipyretics, antiemetics, cholestryamine for pruritis)
2 notify communicable disease control

Question 21

management of chronic HBV

Answer 21

1 antivirals (if indicated)

• interferon-alpha, or
• nucleos/tide analogues (adefovir, tenofovir)

Question 22

what are the indications for antivirals

Answer 22

1 HBeAg-positive or negative with chronic hepatitis

2 cirrhosis with HBV DNA by PCR

Question 23

what is inteferon alpha

Answer 23

a cytokine which enhances the bodies antiviral effects

Question 24

complications

Answer 24

1 fulminant hepatic failure (1%)
2 chronic HBV infection
3 cirrhosis

Question 25

what is fulminant hepatic failure

Answer 25

acute liver injury impairing functioning and causing hepatic encephalopathy in a patient without previous liver disease

Question 26

prognosis

Answer 26

10% become chronic, and of these, 20-30% will develop cirrhosis
high serum transaminases and low HBV DNA indicate a good response to interferon