Viral Hepatitis Flashcards
What family is hepatitis A virus from? Describe its structure.
The family Picornaviridae, genus hepatovirus
Single-stranded, positive sense RNA genome
Quasi-enveloped virions
How is it transmitted and what is the incubation period?
Faeco-oral versus blood-borne transmission
Incubation period of 15-50 days
Describe the epidemiology of HAV?
- o More common in countries in which access to clean water is poor - Sub Saharan Africa and India
- Approx. 1.5 millions of cases worldwide annually
- Developing countries with poor socio-economic conditions
- 300-500 cases annually in the UK
- Mostly among age 15-34 and non-travellers
- Outbreaks among MSM (2016/17) & IVDU (2001 & 2017)
What is the Clinical manifestation of HAV?
- Wide disease spectrum from asymptomatic to fulminant hepatitis
- Strong correlation with age: <10% symptomatic among children <6 years old versus 70% in adults
- Typical symptoms: fever, malaise, anorexia/nausea, abdominal discomfort, diarrhoea, jaundice
- Extra-hepatic diseases
- Acute presentation; 99% resolution
•NOT an aetiology for chronic hepatitis
Describe the natural history of HAV infection/vaccine.
- 2-6 weeks after the infection you get hepatitis
What is the diagnostic test for HAV?
•Diagnostics based on HAV serology
Acute infection: IgM reactive; unlikely if bilirubin level < 30umol/L
Past infection: IgM non-reactive, IgG reactive
What is the tx for HAV?
Supportive
What are the public health implications of HAV infection?
- Notifiable disease in the UK – must alert HPT immediately upon diagnosis•
- Infectious period of index case: two weeks before onset of first symptoms and until one week after the onset of jaundice
What is pre and post exposure prophylaxis forHAV?
- Pre-exposure immunisation among population at risk
- Post-exposure prophylaxis
- Within 14 days of exposure to index case: HAV vaccine +/- HNIG (for 60 years and above, chronic liver diseases incCHB/CHC, immunocompromised contact)
- Over 14 days: HAV vaccine +/- HNIG (for chronic liverdiseases inc CHB/CHC, immunocompromised contact)
Acute HAV infection
What family his hepatitis B from? Describe the structure.
- The family Hepadnaviridae
- Double-strained DNA with reverse transcriptase
- Enveloped virions
- 10 genotypes (A-J) with distinctive geographic distribution
Hw is HBV transmitted? What is the incubation period?
- Blood-borne transmission: horizontal & vertical
- Incubation period of 40-160 days
What is the clinical manifestation of acute HBV infection?
•Age related presentation & prognosis in acute hepatitis B
- Neonates & children: mostly asymptomatic or anicteric; 90% HBV-infected neonates develop CHB, and 30% among children age <5 years
- Adult: 30-50% icteric hepatitis; 10% become CHB•
- 0.1-0.05% risk of fulminant hepatitis; related to co-infection with HCV/HDV
- Maternal HBeAg/Ab status & HBV viral load
- HBeAg as the most important risk predictor for vertical transmission
Describe the natural history of acute hepatitis B infection.
- Incubation period: 2-6 months
- Presence of IgM anti-HBc = recent infection
- The symptoms and rise in ALT will probably subside after around 6 months
- They will eventually clear HBsAg and HBeAg
- Prolonged presence of HBsAg is suggestive of chronic infection
What is chronic HBV infection? What are the complications?
- Definition: persistence of HBsAg for 6 months or more after acute HBV infection•
- Complications
- Cirrhosis: 8-20% untreated CHB in 5 years;
- Hepatocellular carcinoma: the annual risk of 2-5% among CHB cirrhotic patients; affected by host (e.g. alcohol abuse) and viral factors (e.g. high HBV viral load & qHBsAg)
Describe the epidemiology go chronic hepatitis B.
•Approximately 296 million people are living with CHB worldwide;
CHB-related mortality at roughly 820,000 people per year
Describe the natural history of chronic hep B infection.
e antigen - marker for replication
How do we interpret HBV serology?
- HBsAg: infection
- HBsAb: immunity through either immunisation or past infection
- HBcAb: exposure
IgM: acute infection
- HbeAg: replication activity
- HBeAB - not replicating as frequently
IgM might be negative in acute hep B infection - very early in infection
What are the treatment options for CHB?
- Chronic HBV Treatment
- Interferon Alpha (used in a subset of patients who look like they are clearing the virus by themselves)
- Do not use in patients who may require a liver transplant
- Lamivudine
- Tenofovir
- Entecavir
- Interferon Alpha (used in a subset of patients who look like they are clearing the virus by themselves)
Emtricitabine
What is the pre and post exposure prophylaxis for HBV?
Previous Vaccination
Acute infection
10%
Hepatocellular carcinoma
How does HBV/HDV infection present? How likely is it to become chronic infection? What is HDV super infection?
Describe the epidemiology of HCV infection.
How common is HCV chronic infection? What is the clinical manifestation? What are the complications?
What is the natural history of HCV infection? How is it diagnosed?
How do we treat HCV infection?
CURABLE DISEASE NOW
3 types:
- protease inhibitors
- NS5A inhibitors
- NS5B inhibitors
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Describe the epidemiology of HEV?
What are the clinical manifestations of HEV? Who is the at risk population?
What are the extrahepatic manifestations of HEV?
Describe the natural history of HEV infection? How do we diagnose it?
How do we treat and prevent HEV infection?
