MI: Viral Hepatitis Flashcards
Name some primary and secondary hepatotropic viruses?
Primary - hepatitis A, B, C, D, E
Secondary - EBV, CMV, HIV, parovirus B19
What type of virus is hepatitis A?How is hepatitis A spread?
Single-stranded RNA virus
Faecal-oral
- Person-to-person (sex)
- Contaminated food/drink
What is the incubation period for hepatitis A?
2-6 weeks (usually 4 weeks)
What are symptoms of hepatitis A infection?
Symptoms of acute hepatitis
- Non-specific - fever, fatigue, abdominal pain, malaise, loss of appetite
- Elevated bilirubin - jaundice, pale stools + dark urine, pruritius
Describe the natural history of hepatitis A infection.
- 2-6 weeks after the infection you will develop hepatitis (transaminitis)
- This will be accompanied by a rise in IgM
- A more gradual rise in IgG will follow
NOTE: hepatitis A infection is often subclinical
What is the diagnostic test for acute hepatitis A?
Anti-hepatitis A IgM
- Only request if symptomatic patient has if ALT >500u/L)
- If <500 may get false negative because antibody titres have not risen enough
may be negative in 1st week
Which antibodies will be present if someone has received a hepatitis A vaccine?
Anti-HAV IgG
(if infected, they will have high IgM and IgM, but no transaminitis)
When are those with hepatitis A infectious?
2 weeks before until 1 week after onset of jaundice
How is HAV treated?
Supportive, no chronicity
What type of virus is hepatitis B?How is hepatitis B transmitted?
DNA virus
* Sexually transmitted
* Blood products
* Mother-to-baby (eAg is the biggest predictor)
What is the incubation period of hepatitis B?
2-6 months
What are 3 possible courses of hepatitis B infection in adults?
- Clearance (90%)
- Chronic infection (10%)
- Fulminant liver failure (0.5-1%)
40% are symptomatic
What is the course of HBV infection in children under 5 ?
Asymptomatic, 90% develop chronic infection
What the biochemical definition of chronic HBV infection?
HBsAg positive > 6 months
What do the presence of the following antigen/antibodies indicate:
- HBsAg
- HBeAg
- Anti-HBc IgM
- Anti-HBc IgG
- Anti-HBe IgG
- Anti-HBs IgG
What are some possible consequences of chronic HBV infection?
- Hepatocellular carcinoma
- Cirrhosis
What is a strong predictor of risk of cirrhosis in people with hepatitis B infection?
HBV DNA level (copies/mL)
Scored with Child-Pugh score, diagnosed fibroscan
List some treatment options for chronic HBV.
Pegylated IFN-a - aim is to induce long term immune control
* 48 weeks
* Low tolerability, lots of contraindications
Nucleoside analogues - aim is to inhibit viral replication
* Tenofovir
* Entecavir
* Lamivudine
* Adefovir
What is the mechanism of action of nucleoside analogues?
Inhibit viral reverse transcriptase
Which of these treatments should not be used in liver transplant patients?
Interferon alpha
What is the management of babies born to mothers with chronic HBV?
Depends on HBeAg status
- HBsAg positive, HBeAg negative - give vaccine at birth
- HBsAg positive, HBeAg positive - give vaccine at birth PLUS HBIG
Give HBIG also if HBV DNA >1 x 10^6 IU/ml
What type of virus is HCV and how many genotypes are there? How is it transmitted?
Single-stranded RNA virus (6 genotypes)
- Sexually transmitted (MSM)
- Blood products (IVDU)
What is the incubation period of HCV?
2 weeks - 6 months
Describe the course of acute HCV infection
Most asymptomatic
- 30% will clear vrius
- 70% progress to chronic infection
What is the presentation of chronic HCV?
- Incidental finding
- CLD/cirrhosis
- Hepatocellular carcinoma
Diagnosis of HCV infection?
HCV RNA should be requested if acute infection is suspected
Anti-HCV antibodies - develop 4 weeks post infection
How is HCV treated?
Direct acting antivirals for 12 weeks
- 12 week treatment course with daily pill
- Very effective against all genotypes
- Development of DAA means that HCV is now curable
What do HCV DAAs target and give an example of a drug regimen
DAAs target HCV-encoded proteins responsible for viral replication
Ledipasvir PLUS sofosbuvir
How can HCV infection be prevented?
No vaccine
- Screen blood, organ, and tissue products
- Needle exchange programs
What type of virus is hepatitis D? What is a key feature about HDV?
Incomplete RNA virus
Requires the presence of HBV to replicate within the host
How is HDV transmitted?
Same way as hepatitis B (sexual, parenteral, vertical)
What is the difference between hepatitis D co-infection and superinfection?
Co-infection:
- This happens when you are inoculated with HBV and HDV at the same time (e.g. sharing a needle with someone infected by both viruses)
- Anti-HDV IgM will rise after inoculation causing hepatitis
- Causes more severe acute disease, but low-risk chronic infection
Superinfection:
- This happens when someone with chronic HBV is inoculated by HDV
- Leads to accelarated chronic infection and patients can develop cirrhosis within 2-3 years
- This is more serious than co-infection
How can HDV be prevented?
- Prevent HBV infection - vaccination, post-exposure prophylaxis
- Educate HBV patients about risky behaviours (sexual, parenteral)
What type of virus is hepatitis E and how many genotypes?
How is it transmitted?
- Single-stranded RNA virus (4 genotypes)
- Faecal-oral and eating undercooked pig/boar
In which group of people is HEV infection very dangerous and which genotype is responsible?
HEV genotype 1 infection in pregnant women can have a mortality of 30%
What are the natural courses of HEV infection?
Most asymptomatic
- Acute infection - brief and self-limiting
- Chronic infection (ONLY IN IMMUNOCOMPROMISED) - also mild disease and can be cleared by reducing immunosuppression
What is the incubation period of hepatitis E?
2 - 8 weeks
How is HEV diagnosed? How is chronic infection classified?
- Immunocompetent - HEV IgM and IgG
- Immunocompromised - HEV RNA (Ab often undetectable)
Chronic infection classified as HEV RNA positive >3 months
Outline the treatment of hepatitis E.
Supportive
- Severe acute hepatitis - consdier ribavirin
- Chronic hepatitis - reduce immunosuppression
What are some extrahepatic manifestations of HEV infection?
What viruses can cause chronic hepatitis?
B, C, D, E (only in IMMUNOCOMPROMISED)
