L17 - Viral hepatitis Flashcards
Briefly describe the hepatitis viruses?
Hep A, B, C, D & E
Hepatotrophic viruses
Can cause:
- fever
- jaundice
- joint pain
Give examples of viruses which may cause acute hepatitis as part of their clinical spectrum?
- Epstein-Barr virus
- Cytomegalo virus
- Herpes simplex
Hepatitis E
- structure
- transmission
- treatment
Structure
- small RNA virus
Transmission
- Faecal-oral route
Treatment
- supportive
- no proven effective drugs
What happens to the Hep E virus when it enters body?
- Crosses across wall of alimentary canal
- Transported to liver
- Liver damage occurs via T-Cell mediated immune responses
- Viral replication in liver cells
- Virus released into bile in vesciles
Incubation period of Hepatitis E
10-50 days
average: 28 days
Patients infected with Hepatitis E will usually present with…
Some patients will also have the following symptoms:
Jaundice
Fever, malaise, nausea, vomiting, upper abdominal pain
Hepatitis B
- transmission
- incubation period
- at risk?
Hep B Parenteral, sexual, perinatal (40-160 days), avg. 90 days Risk: - injecting drug users - infants of carrier - multiple sexual partners
Hepatitis C
- transmission
- incubation period
- at risk?
Hep C Parenteral, sexual, perinatal (15 - 160 days) avg. 60 days Risk: - recepient of unscreened blood products - injecting drug users
Hep D
- transmission
- incubation period
- at risk?
Hep D - parenteral - (20 - 50 days) Risk: - injecting drug users
Hep E
- transmission
- incubation period
- at risk?
Hep E - feacal oral - 40 days Risk: - travellers to endemic areas
Describe investigations of IgA in diagnosing hep A
- anti HAV antibodies usually present at onset of symptoms (decline over 3-6 months)
Presence of anti HAV IgG antibodies will reflect:
- immunity from previous exposure (or immunisation)
Liver function test results in presence of Hep A
- raised alanine
- raised asparate aminotransferase
- rise in bilirubin
Management of hep A
- supportive
Prevention
- good sanitation
- personal hygiene
- active immunisation with dead virus
Is the acute infection of hepatitis B, symptomatic or asymptomatic?
usually asymptomatic
How might you determine presence of chronic hepatits B?
- presence of HBV surface antigen (HBVsAg) in blood for more than 6 months
Hepatitis B
- structure
- forms
DNA virus
Can occur in three forms
1. Dane particle
2. & 3. Variants of HBVsAg
Describe structure of Dane particle
Complete virus
HBV DNA polymerase in outer coat.
Describe the structure of HBV core antigen?
HBVcAg
- formed of core protein containing incompletely double stranded circular DNA and DNA polymerase
Clinical features of hepatitis B
- acute infection present as mild illness then followed by jaundice.
Some patients:
- fever, malaise, anorexia, nausea, vomiting, upper abdominal pain.
Characteristics of acute infection of hepatitis A
- Liver function tests
- raised serum AST
- raised serum ALT
- rise in bilirubin - HBVsAg: +
- HBVeAg: +
- indicates high degree of infectivity
- HBVsAg cleaves to form HBVeAg
Hep B infection will be assessed by its serology for what
- surface antigen
- early antigen
Why must Hep B also be present if Hep D is present?
- Hep D virus borrows its outer coat from hep B.
- requires coat of HBVsAg for its replication and survival
If acute infection of hep b resolves what will occur?
- HBVeAg disappears within few months
- disappearance HBVsAg
- normalisatoin of aminotransferases
