Viral Hepatitis Flashcards
Define hepatitis
Inflammation of the liver
Many systemic viruses cause “collateral” liver damage.
- eg EBV, CMZ, VZV.
Hepatitis viruses
- Replication specifically in hepatocyes (hepatotropic)
- Destruction off hepatocytes.
What liver function tests can be conducted?
- Bilirubin
- Liver transaminases
- ALT - alanine transaminase
- AST - aspartate aminotransferase
- Test for hepatocyte damage / cellular integrity
- Alkaline phosphatase (ALP)
- Bilary tract cell damage / cholestasis
- Albumin
- A protein synthesised in liver
- Tests of coagulation
- Clotting factors are synthesised in liver
- INR
- PT (prothrombin time)
Who is at risk of contracting Hep B?
- Vertical transmission (75% cases globally)
- Perinatal transmission in pts from highly endemic areas
- Sexual contact
- IV drug users
- Close household contacts
- Significant blood exposure
- HCW via needlestick injuries
What are symptoms of acute Hep B?
- Jaundice
- Fatigue
- Abdominal pain
- Anorexia / Nausea / Vomiting
- Arthralgia (pain in a joint)
Acute Hep B
- Incubabtion 6wks-6months
- AST / ALT in 1000s
- Up to 50% - no/vague symptoms
- Clear infection within 6 months
- < 1% - fulminant hepatic failire
- Becomes chronic in under 10% if infected as an adult whereas, 90% if infected in infancy (China / Asia)
Hep B serology
HBsAg - HBsAb (Surface antigen / Surface antibody)
HBeAg - HBeAb (e-antigen / e-antibody)
HBcAg - HBcAb: IgM and IgG (Core antibody / core antigen)
Ag = antigen
Ab = antibody
What is the response to Hep B?
- Surface antigen first - confirms Hep B
- Within 6/52; rise in ALT / DNA
- Followed by a-antigen
- Highly infectious
- Core antibody (IgM)
- First antibody to appear
- Followed by e-antibody
- Herelds dissappearance of e-antigen, less infectious
- Surface antibody
- Last antibody to appear
- Clearance of virus / recovery
- Core antibody (IgG)
- Persists for life.
Define Chronic Hep B
Persistance HBsAg (surface antigen) after 6 months
25% chronic infection leads to cirrhosis and about 5% will develop hepatocellular carcinoma
What is the treatment of chronic Hep B?
- NO CURE integrates into host genome
- Life-long anti-virals to suppress viral replication
- Not required for everyone (e.g. inactive carrier)
- Low viral load / Normal liber function tests / No liver damage
- If immunocompormised ect.. then it can reactivate so, need to monitor life long.
Hep B Vaccination?
- Genetically engineered surface antigen
- 3 doses + boosters if required
- Effective in most people
- Produced surface antibody respose
- >10adequate
- >100 long-term protection
Who is at risk of Hep C?
- People who inject drugs (IV) over 90% of those with Hep C in the UK.
- IV heroin / crack / metamphetamines
- Crack or heroin smokers
- Sexual contact (less than 1% bit higher if HIV co-infected)
- Infants born to HCV positive mothers (less than 5%)
- Blood transfusions prior to 1991
- Needlestick injuries to healthcare workers ect.
How does Hep C progress?
80% become chronically infected.
Of these some will develop chronic liver disease / cirrhosis
Resulting in:
- Decompensated liver disease
- Hepatocellular carcinoma (primary liver cancer)
- Transplant
- Death
Symptoms of Hep C?
80% have no symptoms (acute or chronic)
20% have vague symptoms
- Fatigue
- Anorexia
- Nausea
- Abdominal pain (RUQ)
Hep C serology
- Anti-Hep C antibody only.
- Remain positive life longe, even after clearance / cure
- Antibody is NOT protective, can get re-infected.
- Viral PCR - if positive, confirms on-going / chronic infection.
Treatment of Hep C
Can be cured!
- Directly acting antiviral drug combo
- 8-12 weeks
- >90% chance of cure
- £10,000 per course! (Can be more… Used to be MUCH higher!)
- Can get re-infected
BUT, no vaccine