S8) Blood Borne Viruses – Hepatitis Flashcards
What is hepatitis?
Hepatitis is the inflammation of the liver due to cell injury or viruses (hepatotropic) which can cause collateral liver damage e.g. EBV, CMV, VZV
Outline Hepatitis B and C in terms of transmission, incubation and affirmation of chronic illness
Outine the viral structure of different types of hepatitis
- Hepatitis B: dsDNA, enveloped
- Hepatitis C: ssRNA, positive, enveloped, icosahedral
Outline the production and excretion of bilirubin
Identify the different types of jaundice and their causes
- Prehepatic – caused by haemolysis
- Intrahepatic – caused by viral hepatitis, drugs, alcohol hepatitis, cirrhosis
- Extrahepatic – caused by common duct stones and carcinoma
Identify some liver function tests (LFTs)
- Bilirubin
- Albumin
- ALT & AST
- Alkaline phosphatase (ALP)
- Coagulation tests – INR & PT
How can Hepatitis B be transmitted?
- Vertical transmission
- Sexual contact
- Contaminated needles (IVDU, HCW)
What are the symptoms of acute Hep B?
- Jaundice
- Fatigue
- Abdominal pain
- Anorexia / nausea / vomiting
- Arthralgia
What are the microbiological findings of Acute Hep B?
AST/ALT in 1000s
Describe the complications of Acute Hep B
- Up to 50% – no/vague symptoms & clear infection within 6 months
- <1% – fulminant hepatic failure
- <10% – becomes chronic (if adult)
- Up to 90% – becomes chronic (if infant)
Outline the 6 steps in Hepatitis B serology
⇒ Surface antigen, within 6 weeks (HBsAg)
⇒ Highly infectious e-antigen (HBeAg)
⇒ Core antibody appears first (IgM)
⇒ e-antibody appears, less infectious now (HBeAb)
⇒ Surface antibody appears last, clears virus (HBsAb)
⇒ Core antibody persists for life (IgG)
What is a chronic Hep B infection and what are its consequences?
A chronic Hep B infection is the persistence of HBsAg after 6 months:
- 25% chronic infection leads to cirrhosis
- ~5% will develop hepatocellular carcinoma
What is the treatment for chronic Hepatitis B?
- NO CURE – integrates into host genome
- Life-long anti-virals required to suppress viral replication
- Not required for everyone e.g. “inactive” carrier (Low VL / normal LFTs / no liver damage)
Describe the composition and effective response of the Hepatitis B vaccination
- The vaccination consists of a genetically engineered surface antigen (3 doses + boosters if required)
- Produces surface antibody response:
I. >10 adequate
II. >100 long-term protection
What’s the status (HBsAg, HBsAb, HBcAb) for Hepatitis B in terms of:
- Acute infection
- Cleared infection
- Chronic infection
- Vaccinated
Who is at risk of Hep C transmission?
- IVDU
- Sexual contact
- Infants born to HCV positive mothers
- Blood transfusion prior to 1991
- HCW via needlestick injuries
Outline the disease progression of Hepatitis C
- ~80% become chronically infected
- Of these some will develop chronic liver disease/cirrhosis
What are the complications of chronic liver disease/cirrhosis due to a chronic Hepatitis C infection?
- Decompensated liver disease
- Hepatocellular carcinoma (primary liver cancer)
- Transplant
- Death
What are the symptoms of Hepatitis C?
- 80% have no symptoms (acute or chronic)
- 20% have vague symptoms:
I. Fatigue
II. Anorexia
III. Nausea
IV. Abdominal pain
Identify and describe the blood tests involved in Hepatitis C
- Serology – anti-Hep C antibody as it remains positive throughout life, even after clearance/cure (not protective, can get reinfected)
- Viral PCR – if positive, confirms on-going / chronic infection
Discuss the treatment for Hepatitis C
- Cure/but no vaccine
- Directly acting antiviral drug combo:
I. 8-12 weeks
II. >90% chance of cure
III. £20,000 - £60,000 per course
IV. Can get re-infected
Discuss the risk of transmission of HIV, Hep B and C from needlestick injury
- Hep B – 1/3 (much lower if recipient has been vaccinated)
- Hep C – 1/30
- HIV – 1/300 (much lower if patient is on ARVs / VL undetectable)
Distinguish between HIV, Hep B and Hep C in terms of:
- Acute infection
- Prevention
- Outcome of untreated infection
- Treatment
