Viral Hepatitis A & E

Question 1

Define Hep A/ Hep E

Answer 1

DEFINITION: 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

Causes

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

Histological features:

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

Question 3

Epidemiology

Answer 3

• 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 4

Symptoms

Answer 4

Incubation period of HAV and HEV: 3-6 weeks

Prodromal period symptoms:

• Malaise
• Anorexia
• Fever
• Nausea and vomiting

Hepatitis symptoms:

• Dark urine
• Pale stools
• Jaundice lasting around 3 weeks

Occasionally, itching and jaundice may last several weeks in HAV infection

Question 5

Signs

Answer 5

Pyrexia

Jaundice

Tender hepatomegaly

Spleen may be palpable

ABSENCE of stigmata of chronic liver disease (although some spider naevi may appear transiently)

Question 6

Investigations

Answer 6

Bloods

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

Vital Serology

Hepatitis A:

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

Hepatitis E:

• Anti-HEV IgM (raised 1-4 weeks after onset)
• Anti-HEV IgG

Urinalysis

• Positive for bilirubin
• Raised urobilinogen

Question 7

Management

Answer 7

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

Prevention and Control

• Public Health - safe water, sanitation and food hygiene

These are notifiable diseases

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 8

Complications

Answer 8

• 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 9

Prognosis

Answer 9

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%