Hepatitis Infection And Testing

Question 1

Tests for HAV infection

Answer 1

Anti HAV IgM indicates recent infection

Anti HAV IgG indicates previous infection

Look at LFTs for ALT/AST, signs of liver damage

Question 2

Tests for HBV infection

Answer 2

Test for HBsAg, positive confirms current infection

Test for anti HBcAg IgM, positive confirms recent infection.

Negative indicates that the infection is chronic HBcAg can be tested HBeAg indicates lots of replication (very infectious)

☆ There is an infection window during which viral proteins and host immunoglobulins cannot be detected

PASSIVE immunisation using HBIg is available

Question 3

Tests for HCV infection

Answer 3

Test for Anti-HCV Ig, positive indicates infection has occurred but not if the virus is still present

Test for HCV RNA using PCR.

If present then this indicates that the virus is still present. If negative test again in 6 months

Question 4

Key features of Hepatitis infection

Answer 4

Malaise, muscle pain, jaundice, mild fever, loss of appetite, RUQ pain

Question 5

Outcomes of HAV infection

Answer 5

Asymptomatic infection

Icterus infection

Fulminant infection

☆ Vaccination is available

Question 6

Outcomes of HBV infection

Answer 6

• Subclinical infection
• Icteric infection
• Fulminant infection
• Chronic infection (10% )
  
  • NEONATES: 90 % chronic infection

Question 7

Outcomes of HCV infection

Answer 7

Acute infection Chronic infection (75%)

Question 8

Transmission routes of hepatitis viruses

Answer 8

A and E: Orofaecal route

B: Parenteral, placental, sexual

C: Parenteral

Question 9

Describe the clinical presentation of acute hepatitis

Answer 9

• Pre-icteric
  
  • Malaise
  • Anorexia
  • Pyrexia
  • Nausea
  • Abdominal discomfort
• Icteric
  
  • Jaundice
  • Pale stools and dark urine

Question 10

Describe the significance of HBeAg and anti-HBe testing in chronic HBV infection

Answer 10

Chronic infection is defined as HBsAg persistence for > 6 months

HBeAg positive: High infectivity, increased risk of inflammatory liver disease

Anti-HBe positive: Lower infectivity, decreased risk of inflammatory liver disease

Question 11

HCV: Genetic diversity and consequences of this

Answer 11

Flavivirus - same group as Dengue virus

Genetic diversity:

• 1-6 genotypes with > 30 difference in genome sequence
• Quasispecies

Consequences:

• May result in false negative tests
• May have different levels of virulence
• May respond differently to treatment
• Creates a problem for vaccine development