Viral Hepatitides Flashcards
How is Hep A spread
Faeco-oral route
Where are there high rates of Hep A
In communities with low standards of sanitation
Where are there outbreaks of Hep A
Daycare centres
association with sewage contaminated shellfish
Homosexual men
IV drug abusers
What is the incubation period for Hep A
15-50 days
What are the clinical features in symptomatic individuals
Acute febrile illness with jaundice anorexia nausea abdominal discomfort malaise dark urine
What happens to the severity of Hep A as age increases
The severity increases
How is Hep A diagnosed
It relies on the detection of serum antibodies to HAV
What does high IgM indicate
Recent infection
What is the management of Hep A
Largely symptomatic
Vaccination is effective in preventing infection and disease
What is the vaccine for Hep A
Inactivated hepatitis A vaccines
Who is the Hep A vaccine recommended for
Those at high risk of infection Those infected with Hep B and C Travellers to countries with high rates of Hep A Employees of early childhood services Healthcare workers exposed to faeces Men who have sex with men Injecting drug users
How many people are estimated to be carriers of the Hep B virus
400 million worldwide
What are the risk factors for HBV infection
Transfusion Needle sharing sexual transmission perinatal transmission men who have sex with men promiscuous heterosexuals immunosuppressed patients patients on haemodialysis transplantation health care transmission
How many genotypes are recognised for Hep B
8
What immune response is initiated in Hep B
Adaptive
What are the clinical manifestations of HBV in the acute phase
Most are asymptomatic or demonstrate mild fatigue
What are the clinical manifestations of HBV in the chronic phase
Some are asymptomatic,
Abnormal LFTs
Cirrhosis
HCC
What does the severity of the acute disease determine
The progression to chronicity
What are the 3 phases of Hep B
- Replicative, during which aminotransferases are largely normal and there is little liver damage
- Inflammatory - where the aminotransferases become elevated, liver biopsy shows chronic hepatitis and viral replication declines
- Patients may enter the inactive phase where viral replication has stopped, the amino transferases normalise and there is no ongoing liver inflammation
How is a diagnosis of Hep B made
The hepatitis B surface antigen (HBsAg) must be positive for 6 months
What does the level of HBV-DNA correlate with
The amount of virus in the circulation and has prognostic implications
What is the management for Hep B
Prevention is the cornerstone!
Safe sex
Avoidance of sharing of IV drug use
Use of gloves
Careful cleaning of blood or body fluid spills
Disposal or adequate sterilisation of surgical instruments (tattoo and piercing)
Careful disposal of sharps
Use of goggle where there is a risk of infected material splashing into the eye
Immunisation
Who is the Hep B vaccination recommended for in the UK
Those exposed to blood or blood born products
Travellers who plan to spend long periods in high prevalence areas or with pre-existing medical conditions that place them at a higher risk of requiring medical procedures abroad
Haemophiliacs
Prisoners and prison officers
What is the treatment for Hep B
Oral nucleoside and nucleotide analogues (lamivudine)
IFN-alpha: used for a finite period with durable response in a subset of patients
What is Hep D
A subviral agent, dependent for its life cycle on HBV
What is it called when an individual receives both viruses
Co infection
What is superinfection
When a person chronically infected with HBV then contracts HDV
What is a requirement for the replication of HDV
The presence of HBV
What is the association with liver damage and HDV infection
Chronic HDV results in much more rapid progressing liver damage
What are the investigations for HDV
Should be considered in patients diagnosed with HBV.
HDAg-S is produced early and is required for viral replication
HDA-L is produced later and is an inhibitor of viral replication but is required for viral particle assembly
What is the management fo HDV
Antivirals such as lamivudine do not reduce HDV titres
Extensive IFN alpha therapy or
Liver transplantation
What is Hep C
The most common of the chronic blood-borne infections
How many genotypes does Hep C have
6
What are the risk factors for Hep C
Blood transfusions IV drug use, tattos , ear or body piercing Secual promiscuity An HCV positive partner Incarceration
What is HCV often coinfected with
HIV
What is enhanced in HCV infection
Hepatocyte apoptosis (programmed cell death_
What are the clinical features of Hep C
Often asymptomatic
mild complaints - fatigue, abdominal pain, anorexia, itching and flu-like symptoms
What is an acute infection
The first 6 months following initial infection
What percentage of patients with acute infection go on to become chronically infected
75%
What are the investigations for Hep C
Anti HCV antibodies - positive in 80% within 3 months of infection
RNA testing is necessary when antibody tests are negative but the clinical suspicion is high
What is the management for Hep C
Prevention - avoid sharing IV needles
What is the treatment for Hep C
Pegylated IFN-alpha which gives increased and sustained duration of activity due to longer serum half-life than conventional IFN -alpha
Ribavirin, the nuceloside antimetabolite
What are some of the adverse affects of IFN-alpha and PEG-IFNs
Fatigue Flu-like symptoms GI disturbances haematological abnormalities neuropsychiatric effects throid dysfunction dermatological effects
Why should dose reductions or discontinuing ribavirin not be an option
Treatment success is directly related to adherence to treatment
What is Hep E
A distinct agent, unrelated to HAV which causes epidemics of largely waterborne enterically transmitted, acute hepatitis
Where are the most common outbreaks of Hep E
South-East Asia and Northern Africa
How is Hep E transmitted
Primarily faecal oral route
food borne
vertical transmission in pregnant women
Parenteral transmission seems to be low
What are the clinical features of HEV
Asymptomatic
Acute viral febrile illness without any characteristic features
What are the two divisions of symptomatic disease
Pre-icteric phase (1-10days) with GI symptoms
Icteric phase - beginning abrupty with jaundice, dark urine and clay coloured stools
arthralgia
rise in serum bilirubin
marked elevation in aminotransferases
What are the investigations for Hep E
HEV RNA in stool
Anti-HEV IgM in serum
Anti-HEV IgG increases promptly after IgM
What is the management for HEV
Improving hygiene conditions in endemic areas and detecting contaminated sources
improving sanitation and providing clean drinking water and proper sewage disposal
What are some other viral hepatitides
EPstein-Barr virus
Cytomegalobirus
Varicella zoster virus
Herpes Simplex virus
What are the clinical features of EBV
Fever
sore throat
adenopathy
What are some of the investigations for EBV
Liver enzyme elevations
Transmainases are elevated to two or three times the upper normal limit
Alkaline phosphatase is elevated in 60%
Bilirubin is elevated in 45% and is self-limited
How is the diagnosis of EBV infection made
Revolves around the typical symptoms in association with postiive EBV IgM antibody
What is the management of EBV infection
Supportive
steroids and antiviral medications
