Robbins 9th ed - Chapter 18 - Infectious Hepatitis (1)

Question 1

What is the incubation period for Hepatitis A?

Answer 1

2-6 weeks (Robbin’s 9th ed).

2-4 weeks (Robbin’s 8th ed).

Question 2

Name some risk factors for Hepatitis A infection.

Answer 2

Overcrowded populations, children in developing countries. In developed nations, by eating contaminated shellfish: seropositivity for HAV in USA is 50% by age 50yo.

Question 3

What is the mortality rate of Hepatitis A?

Answer 3

Only 0.1-0.3% worldwide.

Question 4

Classify the Hepatitis A virus.

Answer 4

Small, unenveloped, ssRNA picornavirus.

Question 5

What is the transmission route for Hepatitis A?

Answer 5

Faecal-oral.

Question 6

What is the incubation period of Hepatitis B?

Answer 6

2-26 weeks (Robbin’s 9th ed).

Question 7

Describe the populations that suffer Hepatitis B infection.

Answer 7

Asia, Southern/Eastern Europe, IVDU, unprotected intercourse / multiple sex partners.

Question 8

Classify the Hepatitis B virus.

Answer 8

Circular dsDNA molecule, in a hexagonal core, with an outer surface envelope of protein, lipid and carbohydrate.

Question 9

What are important serum markers of active viral replication in a person infected with hepatitis B?

Answer 9

HBeAg, HBV DNA, DNA polymerase.

Question 10

What is the most well-describe mutation in Hepatitis B virus, and how does this manifest in the patient?

Answer 10

Occasionally, mutated strains of HBV emerge that do not produce HBeAg, and so the patient’s serum levels of HBeAg may be low or undetectable, despite the presence of HBV DNA.

Question 11

What are the potential outcomes after initial HBV infection, and how common is each outcome?

Answer 11

5% develop chronic infection, 25% develop acute hepatitis almost always followed by recovery, 10% become asymptomatic chronic carriers, 60% have subclinical disease with full recovery.

Question 12

Describe the risk factors for developing chronic HBV infection.

Answer 12

Young age at time of transmission (vertical transmission). 90% of infected neonates develop chronic HBV.

Question 13

What is the route of transmission of Hepatitis B virus?

Answer 13

Transmitted by blood and any other bodily fluid.

Question 14

What are the most prominent risk factors for acquiring Hepatitis C infection?

Answer 14

IVDU and multiple sex partners. NB: One third of affected individuals have no identifiable risk factors.

Question 15

Classify the Hepatitis C virus.

Answer 15

Small, enveloped ssRNA flavivirus.

Question 16

Why is there no vaccine for hepatitis C?

Answer 16

Because the virus is inherently unstable, and has a constantly varying antigen make-up (even within one individual), which means that development of IgG does not confer immunity.

Question 17

What is the incubation period for Hepatitis C?

Answer 17

4-26 weeks (Robbin’s 9th ed).

7-8 weeks (Robbin’s 8th ed).

Question 18

What are the clinical features of acute Hepatitis C infection?

Answer 18

The acute illness is generally asymptomatic.

Question 19

What is the rate of progression to chronic infection in individuals acquiring Hepatitis C infection?

Answer 19

80-90% will develop chronic infection.

Question 20

What happens to the serum transaminases in chronic Hepatitis C infection?

Answer 20

They are episodically elevated, with normal intervals, as the infection waxes and wanes.

Question 21

Describe the difference in patterns of cell death between acute hepatitis and chronic hepatitis.

Answer 21

Acute: Apoptosis, centrilobular necrosis (around the central vein) – looks like “spotty necrosis” because it is scattered throughout the parenchyma across multiple lobules.
Chronic: Scarring, fibrosis, bridging necrosis, mononuclear portal infiltration.

Question 22

What is important to know about Hepatitis E in pregnancy?

Answer 22

It has a 20% mortality rate in pregnancy.

Question 23

How is Hepatitis E transmitted?

Answer 23

Faecal-oral route.

Question 24

What is the incubation period for Hepatitis E?

Answer 24

4-5 weeks.

Question 25

What is the envelope that allows Hepatitis D to replicate and cause infection?

Answer 25

HDV is only infectious when encapsulated by HBsAg. This means the HDV infection can only occur in individuals co-infected with HBV.