Week 4: Viral Hepatitis A, B, and D

Question 1

Symptoms in acute hepatitis

Answer 1

-asymptomatic
Icteric hepatitis:
-malaise, anorexia, nausea/vomiting, jaundice, low grade fever, ab pain
-Hep A: diarrhea
-Extra-hepatic: joint pain/skin rash, due to immune complex deposition
-acute liver failure: mental status change
-In young infants, can be asymptomatic.

Question 2

Laboratory findings in acute hepatitis

Answer 2

• elevated ALT and AST out of proportion to alkaline phosphatase level: hepatocellular pattern
• elevated bilirubin level in symptomatic cases
• prolonged prothrombin time (INR) in severe cases

Question 3

Hepatitis A

Answer 3

• ssRNA virus, non enveloped (and resistant to SDS), only one serotype
• Incubation: 3-5 weeks
• transmitted fecal-oral route P2P or via contamination of food/water
• self-limiting disease, no chronic form. Acute liver failure 2-3% in older adults.
• dx: based on + anti-HAV IgM antibody

Question 4

Hepatitis B virus

Answer 4

• DNA virus
• transmission can be P2P via needles, sexual, blood or mother to infant transmission
• incubation: 60-90 days average, up to 180 days
• risk of chronic infection is highest when infected young and lower when infected as adult

Question 5

Serology of Hepatitis B

Answer 5

HbsAg: indicates activate infection
Anti-HBc: antibodies against core. Positive only when acutely or chronically infected.
IgM anti-HBc: positive in acute infection
Anti-Hbs: positive in vaccinated or immune. Appears ~32 weeks after exposure
HBeAg and anti-HBe: marker of replication and immune response

Question 6

Phases of Chronic hep B

Answer 6

1. Immune tolerant
   - minimal inflammation. ALT is low
2. Immune activation
   - active inflammation. ALT increases. The earlier that this phase occurs, the more likely that the individual will do well
   - more likely of relapse if this transition occurs later
3. Low replicative
   - mild inflammation. HBV viral load is low. Anti HBe+.
4. Reactivation
   - with active inflammation
5. Remission
   - inactive and HBsAg-

Question 7

Natural progression of chronic hep b

Answer 7

• diagnosis of CHB is HBsAg positive or HBV DNA for 6 months
• 30% of CHB develop cirrhosis, which can lead to liver failure or liver cancer
• chronic infection can lead to HCC or liver failure without cirrhosis as well
• risk for HCC increased with increased viral load

Question 8

Therapies for Chronic Hep B

Answer 8

• all patients with chronic HBV infection are at risk for progression to cirrhosis and HCC
• treatment can suppress HBV replication and decrease progression
  1. First line therapy
• peginterferon alfa-2a
• tenofovir
• entecavir

Question 9

Hepatitis D virus

Answer 9

-requires Hep B infection
-associated with IV drug use
-high incidence of acute liver failure in acute co-infection
or superinfection of acute HDV on chronic HBV
-can involve to chronic delta infection with more rapid progression to cirrhosis and higher incidence of HCC