11. Viral Hepatitis Flashcards
What are hepatitis viruses?
Replication specifically in hepatocytes
Destruction of hepatocytes
What is the incubation period for hep B?
6 weeks to 6 months
What is the incubation period for hep C?
6-12 weeks
What is the viral structure of hep B?
DNA, double stranded, enveloped
What is the viral structure of hep C?
RNA, single trained, positive strand, enveloped, icosahedral
What are the types of jaundice?
Prehepatic - haemolysis (excess RBC breakdown)
Cholestatic intrahepatic - viral hepatitis, drugs, cirrhosis, pregnancy
Cholestatic extrahepatic - common duct stones, carcinoma of bile duct, head of pancrease or ampulla
What are the liver function tests?
Bilirubin Liver transaminases - alanine transaminase, aspartate aminotransferase Alkaline phosphatase Albumin Tests of coagulation
What does it mean is ALT and AST are raised?
Hepatocyte damage/cellular integrity
What does it mean iff ALP is raised?
Biliary tract cell damage/cholestasis
Who is at risk of transmission of hep B?
Vertical transmission is main transmission
Sexual contact
People who inject drugs
Close household contacts (significant blood exposure)
HCW via needlestick injuries
What are the symptoms of acute hep B?
Jaundice Fatigue Abdominal pain Anorexia/nausea/vomiting Arthralgia
Describe the acute hep B on body
AST/ALT in 1000s
Up to 50% no/vague symptoms
Clear infection within 6 months
Becomes chronic in <10% if infected as adult, 90% if infected in infancy
Describe hep B serology
- Surface antigen first (HBsAg) - within 6/52, rise in ALT/DNA
- Followed by e-antigen (HBeAg) - highly infectious
- Core antibody (HBcAb: IgM) - first antibody to appear
- Followed by e-antibody (HBeAb) - Heralds disappearance of e-antigen and infectivity
- Surface antibody - last antibody to appear, clear ace of virus/recovery
- Core antibody (IgG) - persist for life
What is chronic hep B infection?
Persistence of HBsAg after 6 months
25% chronic infection leas to cirrhosis and 5% will develop hepatocellular carcinoma
What is the treatment for hep B?
No cure
Life-long anti-virals to suppress viral replication
Not required for everyone
What is the hep B vaccination?
Genetically engineered surface antigen
3 doses and boosters if required
Effective in most people
Produces surface antibody response
Who is at risk of transmission of hep C?
People who inject drugs Sexual contact Infants born to HCV positive mothers Blood transfusion prior to 1991 Needlestick injuries to HCW
What is the disease progression of hep C?
80% become chronically infected
Of these some will develop chronic liver disease/cirrhosis resulting in: decompensated liver disease, hepatocellular carcinoma, transplant, death
What are the symptoms of hep C?
80% have no symptoms
20% have vague symptoms (fatigue, anorexia, nausea, abdominal pain)
What blood tests are done for hep C?
Serology - anti-hep C antibody only
Remains positive life-long, even after clearance/cure
Viral PCR - if positive confirms on-going/chronic infection
What is the treatment for hep C>?
Can be cured
Directly acting antiviral drug combo - 8-12 weeks, >90% chance of cure, can get re-infected
No vaccine
What is the rationale for HIV PEP?
Early initiation of ARVs reduces dissemination and replication of HIV in tissue and bodily fluid
