Viral Hepatitis A & B

Question 1

What are the causes of hepatitis?

Answer 1

• Alcoholic hepatitis
• NAFLD
• Virus (Hep A,B,C,D,E)
• Autoimmune
• Paracetamol overodse

Question 2

What is the transmission route for Hep A?

When does this infection mostly occur?

Answer 2

• Faecal-oral
• shellfish
• Childhood
• Travellers to e.africa and s.america
• Higher risk sexual activity

Question 3

What are the Sx for Hep A?

Answer 3

• fever
• malaise
• anorexia, arthralgia, nausea
• jaundice
• hepatosplenomegaly
• adenopathy

Question 4

What are the RF for hep A?

Answer 4

• Travel: those travelling to endemic areas
• Sexual: high risk activities (e.g analingus, digital-rectal contact, chemsex), multiple partners
• Haematological disorders: factor VIII and factor IX concentrates have been implicated in transmission
• Occupational risks: for example laboratory or sewage workers
• IVDU: known to be at increased risk.

Question 5

What are the 4 clinical phases of Hep A?

Answer 5

• Incubation:
  
  • ​Hepatitis A as a relatively long incubation period that may last from 2 - 6 weeks (mean 28-30 days).
• Prodromal:
  
  • ​Early part of the disease, characterised by fever, joint pain and rash. Flu-like symptoms may be present
• Icteric:
  
  • In addition to jaundice, the icteric phase is characterised by anorexia, abdominal pain and change in bowel habit.
• Convalescent:
  
  • Recovery phase as the body returns to normal and symptoms subside. Symptoms like malaise may last months.

Question 6

What will the test be like for Hep A?

Answer 6

Liver enzymes

• AST and ALT raise - significant
• Biilirubin raise - moderate
• Prothrombin time - normal

Serology

• +ve HAV-IgM, +ve HAV-IgG: Likely acute hepatitis A infection
• +ve HAV-IgM, -ve HAV-IgG: May indicate acute infection or false positive IgM
• -ve HAV-IgM, +ve HAV-IgG: Indicates previous infection or vaccine based immunity
• -ve HAV-IgM, -ve HAV-IgG: No evidence of infection, may be very early or still in the incubation

Question 7

How would you Mx hep A?

Answer 7

• Self resolve 1-3months
• Vaccination + booster in 6-12 months offerd to high risk
  
  • Travel (to endemic areas)
  • Chronic liver disease
  • Sexual (MSM, high risk activities e.g analingus, digital-rectal contact, chemsex)
  • Occupational risks
  • IVDU

Question 8

What are the types of Hep B disease?

Answer 8

• Acute
  
  • occur in any age
  • in adults and older children - self limiting
  • in younger children - chronic infection
• Chronic
  
  • persistence of hepatitis B surface antigen (HBsAg) for >6 month

Question 9

What are the 4 major genes within the HBV genome?

Answer 9

• Surface (S) gene: encodes the small surface protein HBsAg
• Core (C) gene: encodes the hepatitis B core antigen (HBcAg), which also helps form the e antigen (HBeAg)
• Polymerase (P) gene: encodes DNA polymerase/reverse transcriptase
• X gene: encodes the hepatitis B x (HBx) protein

Question 10

What are the 5 proteins of HBV?

Answer 10

• HBsAg: needed for construction of the outer HBV envelope
• HBcAg: composed within the nucleocapsid that contains the viral DNA.
• HBeAg: acts as an immune decoy to promote viral persistence. Presence is a marker of viral replication and infectivity.
• DNA polymerase: involved in the synthesis of DNA molecules. Has reverse transcriptase activity, which means it can form DNA from RNA.
• X protein: a transcriptional regulator that promotes cell cycle progression.

Question 11

What is the transmission route of Hep B?

Answer 11

• perinatally
• parenterally (e.g. infected needles)
• percutaneously
• contact
• close household contact (sharing toothbrush etc)

Question 12

Which groups are at risk of Hep B?

Answer 12

• IVDU and their sexual partners
• Health workers
• Haemophiliacs
• homosexual men
• haemodialysis
• babies of HbSAg + mother

Question 13

What are the Sx of Hep B?

Answer 13

• Same as Hep A
• Urticaria and arthralgia more common

Question 14

What would the Ix look like for Hep B?

Answer 14

• HBSAg present 1-6months post exposure
• HBeAG present 1-3months post exposure - high infectivity
• anti-HBC: past infection
• anti-HBS alone: vaccination
  *

Question 15

How would you Mx Hep B?

Answer 15

• Self resolve within 2 months. 10% will go to become chronic hep B
• Vaccination (3 doses at different intervals)
  *

Question 16

What are the Cx of Hep B?

Answer 16

• fulminant hepatic failure
• cirrhosis
• Hepatocellular carcinoma (HCC)
• Cholangiocarcinoma
• cryoglobinamea
• membranous nephorpathy
• polyarteritis nodosa

Question 17

What is the risk of chronic infection in Hep B?

Answer 17

Inverse relationship with age

• Perinatal transmission: 90% risk of chronic infection
• Early childhood transmission: 25-50% risk of chronic infection
• Adult transmission: < 5% risk of chronic infection

Question 18

How would acute Hep B present?

Answer 18

• Subclinical hepatitis(70%)
• Anicteric hepatitis 30%
  
  • jaundice
  • malaise
  • anorexia
  • N&V
  • RUQ pain
• Icteric hepatitis
  
  • same as anicteric + jaundice
• Fulminant hepatitis failure
  
  • jaundice
  • confusion
  • coagulopathy

Question 19

What are the 5 phases of chronic Hep B?

* they dont necessarily go in sequence

Answer 19

• Phase 1 - HBeAg +ve chronic infection
  
  • minimal liver inflammation and high viral replication
• Phase 2 - HBeAg +ve chronic hepatitis
  
  • moderate to severe inflammation in the liver
  • accelerated progression to fibrosis
  • occurs many years after first phase
• Phase 3 - HBeAg -ve chronic infection
  
  • significant viral suppression and absence of significant liver disease
• Phase 4 - HBeAg -ve negative chronic hepatitis
  
  • moderate to severe liver inflammation
  • low rate of spontaneous clearance
  • genetic mutations in the HBV genome
• Phase 5 - HBsAg negative phase (spontaneous clearance)
  
  • recovery from hepatitis B infection

Question 20

What are the features of chronic Hep B?

Answer 20

• Asymptomatic carrier state (majority)
• Chronic hepatitis
  
  • jaundice, vomiting, RUQ pain, malaise, anorexia
• Cirrhosis
  
  • hepatosplenomegaly, portal hypertension
• Decompensated cirrhosis
  
  • ascites, encephalopathy, jaundice, coagulopathy and GI bleeding

Question 22

What are the extrahepatic manifestations of Chronic Hep B?

Answer 22

• Polyarteritis Nodosa
• Glomerulopnephritis
• Mixed cryoglobulinaemia
• Papular acrodermatitis

Question 23

Interpret the serology for Hep B

Answer 23

Question 24

How would you mx acute Hep B?

Answer 24

• Self limiting (majority)
• nucleoside analogues (severe or fulminant hepatitis)
  
  • Entecavir
  • Tenofovir
  • Lamivudine

Question 25

How would you mx chronic Hep B?

Answer 25

• Nucleoside analogues
  
  • entecavir
  • lamivudine
  • tenofovir
• Pegylated Interferon
  
  • Given weekly as subcutaneous injection for 48 weeks
• Mx liver cirrhosis
• Transplant

Question 26

What is the Hep B prevention programme like in the UK?

Answer 26

• All newborns
• All children and adolescents not vaccinated at bith
• High risk adults (e.g. healthcare workers, intravenous drug users, haemodialysis patients, etc)