Hepatitis A Virus

Question 1

List the basic virological information of HAV

Answer 1

1) nonenveloped
2) icosahedral
3) +ve starnded RNA virus
4) 1 seroptye
5) Heparnavirus genus
6) Picornaviridae family

Question 2

Outline the route of HAV transmission

Answer 2

Fecal oral

Question 3

State the incubation period of HAV

Answer 3

2-6w

Question 4

How long are HAV infected individuals contagious

Answer 4

1) During incubation period of 2-6w

2) 1w after the appearance of jaundice

Question 5

Outline pre-exposure prophylaxis for HAV

Answer 5

1) Passive immunizatinon by IM polyclonal serum immunoglobulin
2) Requires 2w to take effect
3) Lasts up to 6m depending on dose of immunoglobulin
4) Not commonly done as
1. Expensive
2. Injection site reaction
3. Readministration required every 3-6m
4. Risk of blood borne infection

Question 6

Explain the pathogenesis of hepatic injury in HAV infection

Answer 6

1) Hepatic injury actually occurs due to an excessive host immune response
2) HAV replicates in cytoplasm of hepatocytes
3) Infected hepatocytes are damaged/destroeyd by HAV specific CD8+ T lymphocytes and natural killer cells

Question 7

Outline the history of HAV infection

Answer 7

1) Anorexia
2) Malaise
3) Nausea and vomiting
4) Diarrhea
5) Fever
6) Myalgia and arthralgia
7) Rash
8) RUQ pain
9) Jaundice

Children may be asymptomatic especially those less than 6y/o; increasing HAV mortality w/age

Question 8

Outline the complications of HAV infection

Answer 8

1) 0.1% fulminant hepatitis
- usually in patients w/underlying chronic liver disease
- seen most in chronic HCV hepatitis patients

2) Relapsing HAV hepatitis
3) Cholestatic HAV hepatitis

Question 9

Outline investigations to confirm HAV infection

Answer 9

1) Anti-HAV IgM (remains for 4-6m)
2) LFT –> elevated AST/ALT >1000 (>25x norm) [ALT>AST]
- also elevated conjugated bilirubin and ALP
- peak in bilirubin occurs after peak in ALT/AST
3) Elevated acute phase reactants e.g. CRP, ESR

Question 10

List differential diagnoses for HAV infection

Answer 10

1) HEV
2) HCV/HBV/HAD
3) EBV/CMV
4) Yellow fever virus
5) HSV (rare and as fulminant hepatitis)
6) Adenovirus (only in immunocompromised)
7) Malaria (Dx by peripheral smear)
8) Leptospirosis
9) Syphilis
10) Q fever by Coxiella burnetii

Question 11

Outline the management for HAV hepatitis

Answer 11

1) Disease is self-limiting –> supportive treatment only

2) Full biochemical recovery within 3-6m