Viral hepatitis B and D

Question 1

definition of hepatitis B

Answer 1

hep caused by HBV

may follow acute or chronic (viraemia and hepatic inflammation >6mo) course

Question 2

definition of Hep D

Answer 2

HDV a defective virus may onlu co-infect with HBV or superinfect people who are already carriers of HBV

incomplete DNA virus - needs HBV for assembly

Question 3

aetiology of Hep B

Answer 3

HBV is an enveloped, partially double-stranded DNA virus

transmission - sexual contact, direct contact, blood and vertical transmission

viral proteins produced:

• core antigen - HBcAg
• surface antigen - HBsAg
• e antigen - HBeAg - marker of increased infectivity

Question 4

structure of HDV

Answer 4

single stranded RNA virus coated with HBsAg

Question 5

patholgy of hep B and D

Answer 5

Ab and cell mediated immune responses to viral replication = liver inflammation and hepatocyte necrosis

HBV - inculbation 1-6mo

Question 6

histology of hep B and D

Answer 6

variable

mild to severe inflammation and changes of cirrhosis

Question 7

RF for HBV

Answer 7

IV drug use,

unscreened blood and blood products

infants of HBeAg +ve mums

sexual contact with HBV carriers

risk of persistent HBV varies with age - younger, esp babies more likely to develop chronic carriage

genetic factors associated with increased rates of viral clearance

haemophiliacs

MSM

haemodialysis pts and chronic renal failure

foster carers

close family members of a carrier or case

staff at institutions/prisons

adopted children from endemic area

Question 8

epidemiology of hep B and D

Answer 8

common

350million worldwide infected with HBV

1-2million deaths/yr

common in SE asia, africa and mediterranean

HDV found worldwide

HBV relatively uncommon in UK

Question 9

sx of HBV and HDV

Answer 9

incubation period 3-6mo

1-2wk prodrome

may have serum-sickness-type illness

jaundice with dark urine and pale stools

recovery 4-8wks

1% - fulminant liver failure

chronic carriage dx after routine LFT or if cirrhosis or decompensation develops

Question 10

prodrome for HDV and HBV

Answer 10

malaise

headache

anorexia

nausea

vomiting

diarrhoea

RUQ pain

Question 11

serum-sickness-type illness sx in HBV and HDV

Answer 11

fever

arthralgia

polyarthritis

urticaria

maculopapular rash

Question 12

signs of acute HBV or HDV

Answer 12

jaundice

pyrexia

tender hepatomegaly

splenomegaly

cervical lymphadenopathy in 10-20%

occaisionally urticaria/maculopapular rash

Question 13

signs of chronic HBV and HDV

Answer 13

may be none

signs of chronic liver disease or decompensation

Question 14

Ix for HDV and HBV

Answer 14

viral serology

PCR - detection of GBV DNA - most sensitive measure of ongoing viral replication

LFT - V high AST and ALT, high BR and ALP

clotting - high PT in severe

liver biopsy - percutaneous, or transjugular if clotting is deranged or ascites is present

Question 15

viral serology of HBV and HDV

Answer 15

acute HBV - HBsAg +ve 1-6mo post exposure, IgM anti-HBcAg imply past infection

anti-HBsAg alone = vaccination

HBeAg present 1.5-3mo after acute illness - implies high infectivity

chronic HBV - HBsAg +ve, IgG anti-HBcAg. HBeAg +ve/-ve (-ve in precore mutant variant)

HBV cleared or immunity - anti-HBsAg +ve, IgG anti-HBcAg

HDV infection - detected by IgM or IgG against HDV

Question 16

prevention of HBV and HDV

Answer 16

blood screening

instrument sterilisation

safe sex practices

passive immunisation

• hep B immunoglobulin (HBIG) following acute exposure and to neonates born to HBeg +ve mums - in addition to active immunisation

active immunisaton

• recombinant HBsAg vaccine for individuals at risk and neonates born to HBV +ve mums.
• immunisation against HBV protects against HDV

Question 17

Mx of acute HBV hep

Answer 17

symptomatic treatment with bed rest, anti-emetics, anti-pyretics and cholestyramine for pruritis

notification to consultant in communicable disease control

Question 18

managemnt of chronic HBV

Answer 18

indications for treatment with antivirals:

• HBeAg +ve or HBeAg -ve chronic hep (depending on ALT and HBV DNA levels - ie chronic liver inflammation)
• compensated cirrhosis and HBV DNA >2000IU/mL
• decompensated cirrhosis and detectable HBV DNA by PCR

INF-a (standard or pegylated whihc has an increased half life)

nucleoside/nucleotide analogues

avoid alcohol, immunise sexual partners

aim: clear HBsAg and prevent complications

Question 19

nucleoside/nucleotide analogues

Answer 19

adefovir

entecavir

telbivudine

tenovir

lamivudine - less used because high resistence

Question 20

INF-a for chronic HBV

Answer 20

cytokine - augments natural antiviral mechanisms

SE:

• flu like sx
• fever
• chills
• myalgia
• headaches
• bone marrow suppression
• depression

Question 21

complications of HBV and HDV

Answer 21

fulminant hepatic failure - 1%

chronic HBV infection - 10% in adults, much higher in neonates

cirrhosis and hepatocellular ca

cholangiocarcinoma

extrahepatic immune complex disorders - glomerulonephritis, polyarteritis nodosa

cryoglobulinaemia

membranous nephropathy

superinfection with HDV may -> acute liver failure or more rapidly progressive disease

Question 22

Px of HBV or HDV

Answer 22

in adults - 10% infections become chronic - of these 20-30% develop cirrhosis

factors predictive of a good response to INF:

• high serum transaminases
• low HBV DNA
• active histological changes
• abscence of complicating diseases

Question 23

mx of HDV

Answer 23

INF-a has limited success - might need liver transplant