Viral Hepatitis (A & E)

Question 1

Definition

Answer 1

Hepatitis caused by infection with the RNA viruses, hepatitis A or hepatitis E virus, that
follow an acute course without progression to chronic carriage

Question 2

Aetiology

Answer 2

• HAV = picornavirus
• HEV = calicivirus
• Transmission = faecal-oral route
• Both viruses replicate within hepatocytes and are secreted into bile
• Liver inflammation and hepatocyte necrosis is caused by the immune response
• Infected cells are targeted by CD8+ T cells and NK cells

Question 3

Histological features

Answer 3

o Inflammatory cell infiltration of portal tracts
o Zone 3 necrosis
o Bile duct proliferation

Question 4

Epidemiology

Answer 4

• HAV is endemic in the developing world
• Infection often occurs sub-clinically
• Better sanitation in the developed world means that it is less common, age of exposure is higher and, hence, patients are more likely to be symptomatic
• HEV is endemic in Asia, Africa and Central America

Question 5

Incubation period

Answer 5

Incubation period of HAV and HEV: 3-6 weeks

Question 6

Presenting symptoms (prodromal period - period just after incubation)

Answer 6

o Malaise
o Anorexia
o Fever
o Nausea and vomiting

Question 7

Presenting symptoms (hepatic)

Answer 7

o Dark urine
o Pale stools
o Jaundice lasting around 3 weeks
o Occasionally, itching and jaundice may last several weeks in HAV infection

Question 8

Signs on physical examination

Answer 8

• Pyrexia
• Jaundice
• Tender hepatomegaly
• Spleen may be palpable
• ABSENCE of stigmata of chronic liver disease (although some spider naevi may appear
transiently)

Question 9

Investigations (bloods)

Answer 9

o LFTs - high AST, ALT, ALP and bilirubin
o High ESR
o Low albumin + high platelets (if severe)

Question 10

Investigations (serology)

Answer 10

o Hepatitis A:
• Anti-HAV IgM (during acute illness, disappears after 3-5 months)
• Anti- HAV IgG (recovery phase and lifelong persistence)

o Hepatitis E:
• Anti-HEV IgM (raised 1-4 weeks after onset)
• Anti-HEV IgG

Question 11

Investigations (urinalysis)

Answer 11

o Positive for bilirubin

o Raised urobilinogen

Question 12

Management plan (symptomatic)

Answer 12

There is no specific management other than bed rest and symptomatic treatment (e.g. antipyretics, antiemetics or cholestyramine (for severe pruritus))

Question 13

Management plan (prevention and control)

Answer 13

o Public Health - safe water, sanitation and food hygiene

o These are notifiable diseases

o Immunisation is available for HAV
• Passive immunisation with IM human immunoglobulin (effective for a short
time)
• Active immunisation with attenuated HAV vaccine offers safe and effective
immunity for those travelling to endemic areas and high-risk individuals

Question 14

Possible complications

Answer 14

• Fulminant hepatic failure (in a very small proportion of patients but is more common in pregnant women)
• Cholestatic hepatitis with prolonged jaundice and pruritus can develop after HAV infection
• Post-hepatitis syndrome: continued malaise for weeks to months

Question 15

Prognosis

Answer 15

• Recovery is usually within 3-6 weeks
• Occasionally patients may relapse during recovery
• There is no chronic sequelae
• Fulminant hepatic failure has a mortality of 80%