Viral Hepatitis A & B Flashcards
1
Q
What are the causes of hepatitis?
A
- Alcoholic hepatitis
- NAFLD
- Virus (Hep A,B,C,D,E)
- Autoimmune
- Paracetamol overodse
2
Q
What is the transmission route for Hep A?
When does this infection mostly occur?
A
- Faecal-oral
- shellfish
- Childhood
- Travellers to e.africa and s.america
- Higher risk sexual activity
3
Q
What are the Sx for Hep A?
A
- fever
- malaise
- anorexia, arthralgia, nausea
- jaundice
- hepatosplenomegaly
- adenopathy
4
Q
What are the RF for hep A?
A
- Travel: those travelling to endemic areas
- Sexual: high risk activities (e.g analingus, digital-rectal contact, chemsex), multiple partners
- Haematological disorders: factor VIII and factor IX concentrates have been implicated in transmission
- Occupational risks: for example laboratory or sewage workers
- IVDU: known to be at increased risk.
5
Q
What are the 4 clinical phases of Hep A?
A
-
Incubation:
- Hepatitis A as a relatively long incubation period that may last from 2 - 6 weeks (mean 28-30 days).
-
Prodromal:
- Early part of the disease, characterised by fever, joint pain and rash. Flu-like symptoms may be present
-
Icteric:
- In addition to jaundice, the icteric phase is characterised by anorexia, abdominal pain and change in bowel habit.
-
Convalescent:
- Recovery phase as the body returns to normal and symptoms subside. Symptoms like malaise may last months.
6
Q
What will the test be like for Hep A?
A
Liver enzymes
- AST and ALT raise - significant
- Biilirubin raise - moderate
- Prothrombin time - normal
Serology
- +ve HAV-IgM, +ve HAV-IgG: Likely acute hepatitis A infection
- +ve HAV-IgM, -ve HAV-IgG: May indicate acute infection or false positive IgM
- -ve HAV-IgM, +ve HAV-IgG: Indicates previous infection or vaccine based immunity
- -ve HAV-IgM, -ve HAV-IgG: No evidence of infection, may be very early or still in the incubation
7
Q
How would you Mx hep A?
A
- Self resolve 1-3months
- Vaccination + booster in 6-12 months offerd to high risk
- Travel (to endemic areas)
- Chronic liver disease
- Sexual (MSM, high risk activities e.g analingus, digital-rectal contact, chemsex)
- Occupational risks
- IVDU
8
Q
What are the types of Hep B disease?
A
-
Acute
- occur in any age
- in adults and older children - self limiting
- in younger children - chronic infection
-
Chronic
- persistence of hepatitis B surface antigen (HBsAg) for >6 month
9
Q
What are the 4 major genes within the HBV genome?
A
- Surface (S) gene: encodes the small surface protein HBsAg
- Core (C) gene: encodes the hepatitis B core antigen (HBcAg), which also helps form the e antigen (HBeAg)
- Polymerase (P) gene: encodes DNA polymerase/reverse transcriptase
- X gene: encodes the hepatitis B x (HBx) protein
10
Q
What are the 5 proteins of HBV?
A
- HBsAg: needed for construction of the outer HBV envelope
- HBcAg: composed within the nucleocapsid that contains the viral DNA.
- HBeAg: acts as an immune decoy to promote viral persistence. Presence is a marker of viral replication and infectivity.
- DNA polymerase: involved in the synthesis of DNA molecules. Has reverse transcriptase activity, which means it can form DNA from RNA.
- X protein: a transcriptional regulator that promotes cell cycle progression.
11
Q
What is the transmission route of Hep B?
A
- perinatally
- parenterally (e.g. infected needles)
- percutaneously
- contact
- close household contact (sharing toothbrush etc)
12
Q
Which groups are at risk of Hep B?
A
- IVDU and their sexual partners
- Health workers
- Haemophiliacs
- homosexual men
- haemodialysis
- babies of HbSAg + mother
13
Q
What are the Sx of Hep B?
A
- Same as Hep A
- Urticaria and arthralgia more common
14
Q
What would the Ix look like for Hep B?
A
- HBSAg present 1-6months post exposure
- HBeAG present 1-3months post exposure - high infectivity
- anti-HBC: past infection
- anti-HBS alone: vaccination
*
15
Q
How would you Mx Hep B?
A
- Self resolve within 2 months. 10% will go to become chronic hep B
- Vaccination (3 doses at different intervals)
*
19
Q
What are the 5 phases of chronic Hep B?
* they dont necessarily go in sequence
A
-
Phase 1 - HBeAg +ve chronic infection
- minimal liver inflammation and high viral replication
-
Phase 2 - HBeAg +ve chronic hepatitis
- moderate to severe inflammation in the liver
- accelerated progression to fibrosis
- occurs many years after first phase
-
Phase 3 - HBeAg -ve chronic infection
- significant viral suppression and absence of significant liver disease
-
Phase 4 - HBeAg -ve negative chronic hepatitis
- moderate to severe liver inflammation
- low rate of spontaneous clearance
- genetic mutations in the HBV genome
-
Phase 5 - HBsAg negative phase (spontaneous clearance)
- recovery from hepatitis B infection
23
Q
Interpret the serology for Hep B
A
