8. Viral Hepatitis Flashcards
Which types of hepatitis can form chronic viral infections?
Hep B and C
Why are Hep B and C referred to as hepatotropic infections?
They replicate specifically in hepatocyte, causing hepatocyte destruction.
How do the incubation periods of Hep B and C differ?
B: 6 weeks - 6 months
C: 6-12 weeks
What is the structure of Hep B?
dsDNA
enveloped
What is the structure of Hep C?
ssRNA
Enveloped - icosahedral
What would you expect to see in the blood test results of a patient with hepatitis?
Abnormal LFT’s - AST, ALT, bilirubin raised
Which enzyme is an indicator of extra-hepatic jaundice?
Alkaline phosphatase (ALP) is raised if there is extra hepatic jaundice.
Concentration of protein is an indicator of liver function?
Albumin
What do ALT and AST levels provide an indicator of?
Hepatocyte damage/integrity (not function!)
What other tests can be used to assess liver function?
Tests of coagulation - clotting factors synthesised in liver
PT
What type of jaundice occurs in hepatitis?
Intrahepatic
What is pre-hepatic jaundice and when is it likely to occur?
When a condition/infection increases RBC breakdown, increasing bilirubin levels.
E.g malaria, sickle cell anaemia, thalassaemia, spherocytosis
What is intra-hepatic jaundice and when is it likely to occur?
Liver not functioning properly, so cannot process bilirubin properly.
E.g cirrhosis, hepatitis (viral and alcoholic)
What extra-hepatic jaundice and when is it likely to occur?
Bile duct damaged, inflamed or obstructed so gallbladder unable to release bile into duodenum.
Gallstones, biliary stricture, carcinoma
How can Hep B be transmitted?
Vertically
Sexual contact
Drug injecting
HCW needlestick
What is the most common mode of Hep B transmission globally?
Vertical (75% cases globally)
What symptoms are associated with acute Hep B?
Up to 50% have no/vague symptoms Jaundice Fatigue Abdominal pain Anorexia/nausea/vomiting Arthralgia
What is the outcome of Hep B infections in adults?
Most clear the infection in 6 months
Becomes chronic in <10% of adults.
How do the outcomes of Hep B differ in children?
90% become chronic if infected in infancy
What 3 surface antigens are used in HepB serology?
HBsAg (surface antigen)
HBeAg
HBcAg (core antigen)
How does core antigen detection differ to e-antigen and surface antigen?
Core antigen can only be detected in liver tissue itself, it is not present in the blood.
Which 3 antibodies are detected in HepB serology?
HBsAb
HBeAb
HBcAb (antibody is detectable in the blood)
How can the viral load of Hep B be measured?
PCR of HBV DNA - detect how much viral DNA is present in the blood.
Which sequence are the antigens and antibodies detected in Hep B?
- Surface antigen
- E-antigen
- Core antibody IgM
- E-antibody
- Suface antibody
- Core antibody IgG
Which serology marker indicated the most infectious stage of Hep B?
E-antigen
Which antibody is the first to appear?
Core antibody igM
How soon after infection does surface antigen appear?
6 weeks
What stage indicates the disappearance of e-antigen and infectivity?
E-antibody
Which antibody signified clearance of the virus/recover?
Surface antibody - last antibody to appear
Which antibody is present for life?
Core antibody IgG
How is chronic Hep B diagnosed?
Persistence of HBsAg (surface antigen) after 6 months
What are the complications of chronic Hep B infection?
25% develop liver cirrhosis
5% develop hepatocellular carcinoma
What is the treatment for chronic Hep B?
No cure - DNA is integrated into host genome.
Life-long antivirals to suppress viral replication
Is there a vaccination against Hep B?
Yes
Which response does the Hep B vaccination generate?
Surface antibody response
3 doses + boosters required
Which population are most at risk of Hep C?
IV drug users represent > 90% of those with Hep C
Other than IV drug use, how can Hep C be transmitted?
Sexual contact
Vertically
Blood transfusion
HCW needlestick injury
What percentage of people with Hep C develop chronic infection?
80%
What symptoms are associated with Hep C?
80% have no symptoms
20% vague symptoms - fatigue, anorexia, nausea, abdo pain
How can Hep C be diagnosed?
Serology - anti-Hep C antibody (positive life-long)
Viral PCR to confirm if on-going infection and not previous
Is there a Hep C vaccine?
No
Can Hep C be cured?
Yes
8-12 week course of anti-virals
Can get re-infected
Which antibodies/antigens will be present in someone suffering from acute Hep B infection?
Surface antigen
Core antibody - IgM
Surface antibody may or may not be present
Which antibodies/antigens will be present in someone who has had Hep C in the past?
Core antibody - IgG
Surface antibody
Which antibodies/antigens will be present in someone who has chronic hep B?
Surface antigen
Core antibody IgG
Which antibodies/antigens will be present in someone who has been vaccinated for Hep B but never infected?
Surface antibody
